RESUMEN
BACKGROUND: Cardiac parasympathetic nerves run alongside the superior vena cava (SVC) and accumulate particularly epicardially adjacent to the orifice of the coronary sinus (CS). In animals, these nerves can be electrically stimulated inside the SVC or CS, which results in negative chronotropic/dromotropic effects and negative inotropic effects in the atria but not the ventricles. Parasympathetic nerve stimulation (PS) with 20 Hz in the CS, however, also excites the atria, thereby inducing atrial fibrillation. The present study overcomes this limitation by applying high-frequency nerve stimuli within the atrial refractory period. Using this technique, we investigated for the first time whether neurophysiological effects similar to those in animals can be obtained in humans. METHODS AND RESULTS: In 25 patients, parasympathetic nerves were stimulated via a multipolar electrode catheter placed in the SVC (stimulation with 20 Hz; n=14) or CS (pulsed 200-Hz stimuli; n=11). A significant sinus rate decrease and prolongation of the antegrade Wenckebach period was achieved during PS in the SVC. During PS in the CS, a graded-response prolongation of the antegrade Wenckebach interval was observed with increasing PS voltage until third-degree AV block occurred in 8 of 11 patients. The negative chronotropic/dromotropic effects started and terminated immediately after the onset and termination of PS, respectively. Atropine abolished these effects (n=11). CONCLUSIONS: Human parasympathetic efferent nerve stimulation induces reversible negative chronotropic and dromotropic effects. PS may serve as an adjunctive tool for the diagnosis/treatment of supraventricular tachycardias and may be beneficial for ventricular rate slowing during tachycardic atrial fibrillation in patients with congestive heart failure.
Asunto(s)
Cateterismo Cardíaco/métodos , Corazón/inervación , Sistema Nervioso Parasimpático/fisiología , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/terapia , Nodo Atrioventricular/inervación , Estimulación Eléctrica , Electrocardiografía , Femenino , Corazón/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Dolor/diagnóstico , Radiografía , Vena Cava Superior/diagnóstico por imagen , Vena Cava Superior/inervaciónRESUMEN
BACKGROUND: After cardioversion of atrial fibrillation (AF), the contractile function of the atria is temporarily impaired. Although this has significant clinical implications, the underlying cellular mechanisms are poorly understood. METHODS AND RESULTS: Forty-nine consecutive patients submitted for mitral valve surgery were investigated. Twenty-three were in persistent AF (>/=3 months); the others were in sinus rhythm. Before extracorporal circulation, the right atrial appendage was excised. ss-Adrenoceptors were quantified by radioligand binding, and G proteins were quantified by Western blot analysis. The isometric contractile response to Ca(2+), isoproterenol, Bay K8644, and the postrest potentiation of contractile force were investigated in thin atrial trabeculae, which were also examined histologically. The contractile force of the atrial preparations obtained from AF patients was 75% less than that in preparations from patients in sinus rhythm. Also, the positive inotropic effect of isoproterenol was impaired, and Bay K8644 failed to increase atrial contractile force. In contrast, the response to extracellular Ca(2+) was maintained, and the postrest potentiation was preserved. Beta-adrenoceptor density and G-protein expression were unchanged. Histological examination revealed 14% more myolysis in the atria of AF patients. CONCLUSIONS: After prolonged AF, atrial contractility was reduced by 75%. The impairment of beta-adrenergic modulation of contractile force cannot be explained by downregulation of ss-adrenoceptors or changes in G proteins. Dysfunction of the sarcoplasmic reticulum does not occur after prolonged AF. Failure of Bay K8644 to restore contractility suggests that the L-type Ca(2+) channel is responsible for the contractile dysfunction. The restoration of contractile force by high extracellular Ca(2+) shows that the contractile apparatus itself is nearly completely preserved after prolonged AF.
Asunto(s)
Fibrilación Atrial/fisiopatología , Contracción Miocárdica , Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico/farmacología , Fibrilación Atrial/metabolismo , Western Blotting , Agonistas de los Canales de Calcio/farmacología , Enfermedad Crónica , Femenino , Humanos , Masculino , Microscopía , Persona de Mediana Edad , Contracción Miocárdica/efectos de los fármacos , Receptores Adrenérgicos beta/metabolismo , Transducción de SeñalRESUMEN
BACKGROUND: This study investigated whether the extent of perfusion defect determined by intravenous myocardial contrast echocardiography (MCE) in patients with acute myocardial infarction (AMI) treated by primary percutaneous transluminal coronary angioplasty (PTCA) relates to coronary flow reserve (CRF) for assessment of myocardial reperfusion and is predictive for left ventricular recovery. METHODS AND RESULTS: Twenty-five patients with first AMI underwent intravenous MCE with NC100100 with intermittent harmonic imaging before PTCA and after 24 hours. MCE before PTCA defined the risk region and MCE at 24 hours the "no-reflow" region. The no-reflow region divided by the risk region determined the ratio to the risk region. CFR was assessed immediately after PTCA and 24 hours later. Left ventricular wall motion score indexes were calculated before PTCA and after 4 weeks. CFR at 24 hours defined a recovery (CFR >/=1.6; n=17) and a nonrecovery group (CFR <1.6; n=8). Baseline CFR did not differ between groups. MCE ratio to the risk region was smaller in the recovery group compared with the nonrecovery group (34+/-49% vs 81+/-46%, P=0.009). A ratio to the risk region of =50% defined an MCE reperfusion group. It was associated with improvement of CFR from 1.67+/-0.47 at baseline to 2. 15+/-0.53 at 24 hours (P<0.001) and of regional wall motion score index from 2.6+/-0.5 to 1.9+/-0.5 at 4 weeks (P<0.001). CONCLUSIONS: Intravenous MCE can be used to define perfusion defects after AMI. Assessment of microcirculation by MCE corresponds to evaluation by CFR. Serial intravenous MCE has the potential to identify patients likely to have improved left ventricular function after AMI.
Asunto(s)
Angioplastia Coronaria con Balón , Circulación Coronaria , Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/terapia , Daño por Reperfusión Miocárdica/diagnóstico por imagen , Ultrasonografía Intervencional , Anciano , Ensayos Clínicos Fase II como Asunto , Estudios de Cohortes , Medios de Contraste/administración & dosificación , Angiografía Coronaria , Vasos Coronarios/diagnóstico por imagen , Femenino , Humanos , Inyecciones Intravenosas , Masculino , Persona de Mediana Edad , Estudios Multicéntricos como Asunto , Periodo Posoperatorio , Pronóstico , VasodilataciónRESUMEN
OBJECTIVES: The purpose of this study was to investigate whether the orifice area in aortic stenosis can be determined accurately and reliably by multiplane transesophageal echocardiography. BACKGROUND: Monoplane transesophageal echocardiography has been used for planimetry of aortic valve orifice areas; however, obtaining a precise short-axis view is sometimes impossible. METHODS: In 41 consecutive patients with known valvular calcific aortic stenosis (20 men, mean age 64 +/- 9 years), aortic valve orifice area was measured by planimetry using a multiplane transesophageal echocardiographic probe that allows full rotation of the cross-sectional plane. Results were compared with invasive measurements obtained by the Gorlin formula and areas determined noninvasively by transthoracic echocardiography using the continuity equation. RESULTS: Multiplane transducer technology enabled the rotation of the cross-sectional plane from an exactly aligned long-axis view of the stenosed valve to a precise short-axis view without moving the tip of the echocardiographic probe, thus achieving an orifice cross section at a level predetermined in the long-axis view. Planimetry was feasible in 38 patients (93%). In three patients with pinhole stenosis (area determined by the Gorlin formula < 0.4 cm2), the valve area could not be exactly delineated. Correlation between areas derived by transesophageal echocardiographic planimetry (0.56 +/- 0.31 cm2) and by the Gorlin formula (0.58 +/- 0.31 cm2) was excellent (r = 0.95; standard deviation of regression [SDR] = 0.054; Y = 0.92X + 0.085, where Y = Gorlin area and X = planimetry area). Correlation between Gorlin- and continuity equation-derived areas (0.65 +/- 0.46 cm2) was r = 0.79; for continuity equation- and transesophageal planimetry-derived areas it was r = 0.83. Severe aortic stenosis (valve area < or = 0.75 cm2) was predicted with high sensitivity (96%) and specificity (88%). CONCLUSIONS: Multiplane transesophageal echocardiography is a practical and accurate clinical tool for the assessment of the severity of aortic stenosis.
Asunto(s)
Estenosis de la Válvula Aórtica/diagnóstico por imagen , Ecocardiografía/métodos , Anciano , Anciano de 80 o más Años , Válvula Aórtica/diagnóstico por imagen , Esófago , Estudios de Evaluación como Asunto , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The diagnostic use of exercise echocardiography has been widely reported. However, transthoracic exercise echocardiography is inadequate in up to 20% of patients because of poor image quality related to exercise. In an attempt to overcome these limitations, a system was developed in which transesophageal echocardiography is combined with simultaneous transesophageal atrial pacing by means of the same probe. In a prospective study, transesophageal echocardiography was performed before, during and immediately after maximal atrial pacing in 50 patients with suspected coronary artery disease. Results of transesophageal stress echocardiography were considered abnormal when new pacing-induced regional wall motion abnormalities were observed. Correlative routine bicycle exercise testing was carried out in 44 patients. Cardiac catheterization was performed in all patients. The success rate in obtaining high quality diagnostic images was 100% by transesophageal echocardiography. All nine patients without angiographic evidence of coronary artery disease had a normal result on the transesophageal stress echocardiogram (100% specificity). Thirty-eight of 41 patients with coronary artery disease (defined as greater than or equal to 50% luminal diameter narrowing of at least one major vessel) had an abnormal result on the transesophageal stress echocardiogram (93% sensitivity). The sensitivity of the technique for one, two or three vessel disease was 85%, 100% and 100%, respectively, compared with 44%, 50% and 83%, respectively, for bicycle exercise testing; the 12 lead electrocardiogram (ECG) during rapid atrial pacing showed a sensitivity of 25%, 64% and 86%, respectively. Thus, rapid atrial pacing combined with simultaneous transesophageal echocardiography is a highly specific and sensitive technique for the detection of coronary artery disease. Ischemia-induced wall motion abnormalities were detected earlier than observed ECG changes. The technique appears to be particularly suited to patients who are unable to perform an active stress test or those with poor quality transthoracic echocardiograms.
Asunto(s)
Estimulación Cardíaca Artificial/métodos , Enfermedad Coronaria/diagnóstico por imagen , Ecocardiografía/métodos , Cateterismo Cardíaco , Enfermedad Coronaria/diagnóstico , Electrocardiografía , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Contracción Miocárdica/fisiología , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
Transthoracic and transesophageal echocardiography was performed in 23 consecutive adult patients with an atrial septal aneurysm. In three patients with a cerebrovascular event the diagnosis was established by the transesophageal approach only. Interatrial shunting on transthoracic imaging with use of echocardiographic contrast imaging or Doppler color mapping, or both, was detected in 7 (41%) of 17 patients. On performing contrast imaging in combination with color flow mapping during transesophageal echocardiography, positive shunting was demonstrated in 15 (83%) of 18 patients. Echocardiographic identification of multiple fenestrations (n = 4) and thrombus within the aneurysm (n = 2) could be achieved for the first time by transesophageal ultrasound application. Cerebrovascular events occurred in 12 (52%) of 23 patients and were regarded as being definitely thromboembolic in 10 (43%); 8 (67%) of the 12 patients had repeated cerebral events. Except for mitral valve prolapse in one patient, no other potential cardiac source of embolism could be identified despite the use of transesophageal echocardiography. A thickening of the aneurysmal membrane greater than or equal to 5 mm was found in 9 (75%) of 12 patients with versus 3 (27%) of 11 patients without a cerebrovascular event (p less than 0.05); this proved to be the only significant difference between the two patient groups. The mechanism of embolization may be both primary thrombus formation within the aneurysm and paradoxic embolization through an interatrial communication as demonstrated by the findings in two patients. It is concluded that atrial septal aneurysm is a cardiac abnormality with thromboembolic potential. In patients with this lesion and a history of an embolic event, long-term anticoagulant therapy is indicated.
Asunto(s)
Ecocardiografía/métodos , Aneurisma Cardíaco/diagnóstico por imagen , Embolia y Trombosis Intracraneal/etiología , Femenino , Aneurisma Cardíaco/complicaciones , Aneurisma Cardíaco/epidemiología , Cardiopatías/diagnóstico por imagen , Tabiques Cardíacos , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Trombosis/diagnóstico por imagenRESUMEN
OBJECTIVES: We sought to define the effects of short-term beta-adrenergic blocking medication on intracoronary flow characteristics, clinical symptoms and angiographic diameter changes in patients with severe myocardial bridging of the left anterior descending coronary artery. BACKGROUND: Controversy exists regarding the pathophysiology, clinical relevance and optimal therapy in symptomatic patients with myocardial bridges because antianginal drugs have not been systematically tested. METHODS: In 15 symptomatic patients with myocardial bridging of the left anterior descending coronary artery, maximal lumen diameter reductions were evaluated by quantitative coronary angiography. There were no angiographic signs of coronary artery disease. Coronary blood flow velocities (using a 0.014-in. [0.035 cm] Doppler guide wire) were measured at rest, during atrial pacing and during intravenous administration of a short-acting beta-blocker (esmolol, 50 to 500 micrograms/kg body weight per min) with continuous atrial pacing. RESULTS: The maximal angiographic systolic lumen diameter reduction within the myocardial bridges was 83 +/- 9% at rest, with a persistent diastolic diameter reduction of 41 +/- 11% (mean +/- SD). Short-term intravenous beta-blocker therapy decreased the diameter reduction during both systole (from 83 +/- 9% to 62 +/- 11%) and diastole (from 41 +/- 11% to 30 +/- 9%, both p < 0.001). The average diastolic peak flow velocity was higher within the myocardial bridges (33 +/- 13 cm/s) than the proximal (26 +/- 13 cm/s) and distal bridges (17 +/- 4 cm/s, both p < 0.001). During tachypacing, average diastolic peak flow velocity increased within the bridged segments to 63 +/- 21 cm/s versus 29 +/- 12 cm/s in the proximal and 20 +/- 4 cm/s in the distal bridges (both p < 0.001). Beta-receptor blockade produced a return to baseline values (average diastolic peak flow velocity within bridge 35 +/- 16 cm/s, p < 0.001). ST segment changes and symptoms were abolished with beta-blocker administration. CONCLUSIONS: In patients with myocardial bridges, administration of short-acting beta-blockers during atrial pacing alleviates anginal symptoms and signs of ischemia. This effect was mediated by a reduction of vascular compression and maximal flow velocities within the bridged coronary artery segment.
Asunto(s)
Antagonistas Adrenérgicos beta/farmacología , Angiografía Coronaria , Circulación Coronaria/efectos de los fármacos , Anomalías de los Vasos Coronarios/fisiopatología , Propanolaminas/farmacología , Antagonistas Adrenérgicos beta/uso terapéutico , Adulto , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Anomalías de los Vasos Coronarios/complicaciones , Anomalías de los Vasos Coronarios/patología , Vasos Coronarios/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , Contracción Miocárdica , Isquemia Miocárdica/tratamiento farmacológico , Isquemia Miocárdica/etiología , Miocardio/patología , Propanolaminas/uso terapéutico , Ultrasonografía IntervencionalRESUMEN
Two adult patients with left ventricular inflow obstruction are presented. Conventional two-dimensional echocardiography had failed to yield a definite diagnosis, whereas transesophageal two-dimensional echocardiography clearly documented a membraneous echo structure within the left atrium, diagnostic of cor triatriatum. On the basis of the transesophageal echocardiographic findings, left heart catheterization and angiocardiography were not performed and both patients successfully underwent cardiac surgery.
Asunto(s)
Ecocardiografía/métodos , Cardiopatías Congénitas/diagnóstico , Adulto , Esófago , Femenino , Cardiopatías Congénitas/patología , Cardiopatías Congénitas/cirugía , Humanos , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVES: This study sought to evaluate an imaging approach using technetium-99m sestamibi scintigraphy and positron emission tomography with fluorine-18 fluorodeoxyglucose for assessment of myocardial viability proved by serial quantitative left ventricular angiography. Furthermore, the influence of successful long-term revascularization on functional recovery was studied. BACKGROUND: Previous studies using positron emission tomography of myocardial perfusion and metabolism have demonstrated accurate identification of myocardial viability. However, most of these studies used a qualitative or semiquantitative wall motion analysis approach. METHODS: Nuclear imaging with semiquantitative analysis of tracer uptake was performed in 193 patients with regional wall motion abnormalities. Regions were categorized as normal, viable with perfusion/metabolism mismatch, viable without mismatch (intermediate) and scar. Seventy-two of 103 patients with subsequent revascularization underwent follow-up angiography. In 52 of 72 patients, changes in regional wall motion were measured by the centerline method from serial angiography. RESULTS: Wall motion improved in mismatch regions from -2.2 +/- 1.0 to -1.1 +/- 1.4 SD (p < 0.001). In contrast, regions with an intermediate pattern and those with scar did not improve. Restenosis or graft occlusion influenced functional outcome because regions with preoperative mismatch and successful long-term revascularization improved at follow-up (from -2.3 +/- 1.0 to -0.8 +/- 1.4 SD, p < 0.001), whereas wall motion did not change with recurrent hypoperfusion. Metabolic imaging added diagnostic information, particularly in regions with mild and moderate perfusion defects. CONCLUSIONS: This imaging approach allows detection of viability in regions with myocardial dysfunction. Wall motion benefits most in myocardium with perfusion/metabolism mismatch and successful long-term revascularization.
Asunto(s)
Puente de Arteria Coronaria , Diagnóstico por Imagen , Corazón/diagnóstico por imagen , Disfunción Ventricular Izquierda/diagnóstico por imagen , Anciano , Supervivencia Celular , Angiografía Coronaria , Desoxiglucosa/análogos & derivados , Femenino , Radioisótopos de Flúor , Fluorodesoxiglucosa F18 , Humanos , Masculino , Persona de Mediana Edad , Contracción Miocárdica , Miocardio/patología , Periodo Posoperatorio , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión de Fotón Único , Disfunción Ventricular Izquierda/patologíaRESUMEN
OBJECTIVES: This study sought to determine the degree of interinstitutional agreement in the interpretation of dobutamine stress echocardiograms. BACKGROUND: Dobutamine stress echocardiography involves subjective interpretation. Consistent methods for acquisition and interpretation are of critical importance for obtaining high interobserver agreement and for facilitating communication of test results. METHODS: Five experienced centers were each asked to submit 30 dobutamine stress echocardiograms (dobutamine up to 40 micrograms/kg body weight per min and atropine up to 1 mg) obtained in patients undergoing coronary angiography. Thus, a total of 150 dobutamine stress echocardiograms were interpreted by each center without knowledge of any other patient data. Left ventricular wall motion was assessed using a 16-segment model but was otherwise not standardized. No patient was excluded because of poor image quality or inadequate stress level. Echocardiographic image quality was assessed using a five-point scale. RESULTS: Angiographically significant coronary artery disease (> or = 50% diameter stenosis) was present in 95 patients (63%). By a majority decision (three or more centers), the sensitivity, specificity and accuracy of dobutamine echocardiography were 76%, 87% and 80%, respectively. Abnormal or normal results of stress echocardiography were agreed on by four or all five of the centers in 73% of patients (mean kappa value 0.37, fair agreement only). Agreement on the left anterior descending artery territory (78%) was similar to that for the combined right coronary artery/left circumflex artery territory (74%), and for specific segments the agreement ranged from 84% to 97% and was highest for the basal anterior segment and lowest for the basal inferior segment. Agreement was higher in patients with no (82%) or three-vessel coronary artery disease (100%) and lower in patients with one- or two-vessel disease (61% and 68%, respectively). Agreement on positivity or negativity of stress test results was 100% for patients with the highest image quality but only 43% for those with the lowest image quality (p = 0.003). CONCLUSIONS: The current heterogeneity in data acquisition and assessment criteria among different centers results in low interinstitutional agreement in interpretation of stress echocardiograms. Agreement is higher in patients with no or advanced coronary artery disease and substantially lower in those with limited echocardiographic image quality. To increase interinstitutional agreement, better standardization of image acquisition and reading criteria of stress echocardiography is recommended.
Asunto(s)
Cardiotónicos , Enfermedad Coronaria/diagnóstico por imagen , Dobutamina , Ecocardiografía/métodos , Angiografía Coronaria , Enfermedad Coronaria/epidemiología , Ecocardiografía/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Función Ventricular IzquierdaRESUMEN
OBJECTIVES: We sought to define the effects of time on contractile function, morphology and functional recovery after coronary revascularization in patients with dysfunctional but viable (hibernating) myocardium. BACKGROUND: Functional recovery after coronary artery bypass graft surgery in patients with chronic myocardial hibernation is incomplete or delayed. The proposed cause is a progressive temporal degeneration of cardiomyocytes. METHODS: In 32 patients with multivessel coronary disease, regional wall motion analysis was performed in hypoperfused but metabolically active areas before and 6 months after bypass surgery. During bypass surgery, transmural biopsy samples were obtained from the center of the hypokinetic zone for light and electron microscopic analyses. The proposed duration of myocardial hibernation was retrospectively assessed. RESULTS: Patients with a subacute hibernating condition (<50 days) demonstrated a higher preoperative ejection fraction (EF, 50+/-8%), and a better preserved wall motion (WM) in the supraapical wall (-1.4+/-0.4) than did patients with intermediate-term (>50 days, EF 37+/-9%, p < 0.05; WM -2.4+/-1.5, p = 0.08) or chronic (>6 months, EF 40+/-14%, WM -2.7+/-0.9, p < 0.005) ischemia. Structural degeneration correlated with the duration of ischemia (r = 0.56, p < 0.05). Postoperative recovery of function was enhanced in patients with a short history of hibernation compared with patients with an intermediate-term or chronic condition (EF 60+/-10% vs. 40+/-10%, p < 0.001, and vs. 47+/-14%, p < 0.05). CONCLUSIONS: Hibernating myocardium exhibits time-dependent deterioration due to progressive structural degeneration with enhanced fibrosis. Early revascularization should be attempted to salvage the jeopardized tissue and improve postoperative outcome.
Asunto(s)
Puente de Arteria Coronaria , Aturdimiento Miocárdico/patología , Aturdimiento Miocárdico/fisiopatología , Miocardio/patología , Anciano , Enfermedad Coronaria/cirugía , Progresión de la Enfermedad , Femenino , Fibrosis , Humanos , Masculino , Persona de Mediana Edad , Contracción Miocárdica , Daño por Reperfusión Miocárdica/patología , Daño por Reperfusión Miocárdica/fisiopatología , Miocardio/citología , Periodo Posoperatorio , Factores de TiempoRESUMEN
OBJECTIVES: The aim of this study was to examine the value of dynamic three-dimensional (3D) transesophageal echocardiography (TEE) for the postoperative evaluation after extended myectomy and surgical reconstruction of the subvalvular mitral valve apparatus in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Two-dimensional imaging techniques such as echocardiography, computed tomography and magnetic resonance imaging have not been able to precisely quantify the effects of surgical therapy on the morphology of the left ventricular outflow tract (LVOT). METHODS: Multiplane TEE with 3D reconstruction was performed in 11 patients before and after the operation and in 16 normal control subjects for comparison. The preoperative maximal systolic pressure gradient in the LVOT was 69 +/- 59 mm Hg. The following variables were measured within the dynamic 3D data set: depth, width, length and cross-sectional area (CSA) gain caused by the myectomy trough, minimal CSA of the LVOT at each time point and its cyclic changes and maximal mitral leaflet deviation during systole. RESULTS: Functional class improved from 3.0 +/- 0.2 before the operation to 1.5 +/- 0.6 after it. The maximal systolic pressure gradient in the outflow tract decreased to 26 +/- 21 mm Hg postoperatively (p < 0.001). Minimal CSA of the outflow tract increased from 1.1 +/- 1.2 to 3.8 +/- 1.9 cm2 postoperatively (p < 0.001), similar to the value of the control group (4.2 +/- 1.5 cm2, p = NS). The area gain due to the myectomy trough was 1.3 +/- 1.0 cm2, corresponding to 48 +/- 12% of the total operative area difference. Maximal systolic depth of the myectomy was 7 +/- 2 mm, maximal width was 20 +/- 8 mm and length was 28 +/- 7 mm. Maximal deviation of the mitral leaflets fell from 15 +/- 7 to 6 +/- 7 mm postoperatively (p < 0.01). In five patients mass measurements of the intracavitary portion of the papillary muscle (PM) revealed an increase from 7.3 +/- 1.0 to 12.1 +/- 2.5 g due to surgical mobilization of PMs (p < 0.01). CONCLUSIONS: 3D TEE quantifies the differences in outflow tract morphology before and after surgery for HOCM. This technique may have an impact on the planning of operative interventions and allow for the evaluation of its results.
Asunto(s)
Cardiomiopatía Hipertrófica/diagnóstico por imagen , Cardiomiopatía Hipertrófica/cirugía , Ecocardiografía Transesofágica , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/cirugía , Adulto , Anciano , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
OBJECTIVES: The objective of this study was to compare electroanatomic mapping for the assessment of myocardial viability with nuclear metabolic imaging using positron emission computed tomography (PET) and with data on functional recovery after successful myocardial revascularization. BACKGROUND: Animal experiments and first clinical studies suggested that electroanatomic endocardial mapping identifies the presence and absence of myocardial viability. METHODS: Forty-six patients with prior (> or =2 weeks) myocardial infarction underwent fluorine-18 fluorodeoxyglucose (FDG) PET and Tc-99m sestamibi single-photon emission computed tomography (SPECT) before mapping and percutaneous coronary revascularization. The left ventricular endocardium was mapped and divided into 12 regions, which were assigned to corresponding nuclear regions. Functional recovery using the centerline method was assessed in 25 patients with a follow-up angiography. RESULTS: Regional unipolar electrogram amplitude was 11.0 mV +/- 3.6 mV in regions with normal perfusion, 9.0 mV +/- 2.8 mV in regions with reduced perfusion and preserved FDG-uptake and 6.5 mV +/- 2.6 mV in scar regions (p < 0.001 for all comparisons). At a threshold amplitude of 7.5 mV, the sensitivity and specificity for detecting viable (by PET/SPECT) myocardium were 77% and 75%, respectively. In infarct areas with electrogram amplitudes >7.5 mV, improvement of regional wall motion (RWM) from -2.4 SD/chord +/- 1.0 SD/chord to -1.5 SD/chord +/- 1.1 SD/chord (p < 0.01) was observed, whereas, in infarct areas with amplitudes <7.5 mV, RWM remained unchanged at follow-up (-2.3 SD/chord +/- 0.7 SD/chord to -2.4 SD/chord +/- 0.7 SD/chord). CONCLUSIONS: These data suggest that the regional unipolar electrogram amplitude is a marker for myocardial viability and that electroanatomic mapping can be used for viability assessment in the catheterization laboratory.
Asunto(s)
Técnicas Electrofisiológicas Cardíacas , Endocardio/fisiología , Corazón/diagnóstico por imagen , Infarto del Miocardio/patología , Anciano , Angioplastia Coronaria con Balón , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/terapia , Miocardio/metabolismo , Radiofármacos , Sensibilidad y Especificidad , Procesamiento de Señales Asistido por Computador , Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión , Tomografía Computarizada de Emisión de Fotón Único , Función VentricularRESUMEN
OBJECTIVES: This study evaluated the effect of the glycoprotein IIb/IIIa (GPIIb/IIIa) antagonist abciximab on myocardial hypoperfusion during percutaneous transluminal rotational atherectomy (PTRA). BACKGROUND: PTRA may cause transient ischemia and periprocedural myocardial injury. A platelet-dependent risk of non-Q-wave infarctions after directional atherectomy has been described. The role of platelets for the incidence and severity of myocardial hypoperfusion during PTRA is unknown. METHODS: Seventy-five consecutive patients with complex lesions were studied using resting Tc-99m sestamibi single-photon emission computed tomography prior to PTRA, during, and 2 days after the procedure. The last 30 patients received periprocedural abciximab (group A) and their results were compared to the remaining 45 patients (group B). For semiquantitative analysis, myocardial perfusion in 24 left ventricular regions was expressed as percentage of maximal sestamibi uptake. RESULTS: Baseline characteristics did not differ between the groups. Transient perfusion defects were observed in 39/45 (87%) patients of group B, but only in 10/30 (33%) patients of group A (p < 0.001). Perfusion was significantly reduced during PTRA in 3.3 +/- 2.5 regions in group B compared to 1.4 +/- 2.5 regions in group A (p < 0.01). Perfusion in the region with maximal reduction during PTRA in groups B and A was 76 +/- 15% and 76 +/- 15% at baseline, decreased to 56 +/- 16% (p < 0.001) and 67 +/- 14%, respectively, during PTRA (p < 0.01 A vs. B), and returned to 76 +/- 15% and 80 +/- 13%, respectively, after PTRA. Nine patients in group B (20%) and two patients in group A (7%) had mild creatine kinase and/or troponin t elevations (p = 0.18). Patients with elevated enzymes had larger perfusion defects than did patients without myocardial injury (4.2 +/- 2.7 vs. 2.3 +/- 2.5 regions, p < 0.05). CONCLUSIONS: These data indicate that GPIIb/IIIa blockade reduces incidence, extent and severity of transient hypoperfusion during PTRA. Thus, platelet aggregation may play an important role for PTRA-induced hypoperfusion.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Aterectomía Coronaria , Enfermedad Coronaria/cirugía , Fragmentos Fab de Inmunoglobulinas/uso terapéutico , Complicaciones Intraoperatorias/tratamiento farmacológico , Isquemia Miocárdica/tratamiento farmacológico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/antagonistas & inhibidores , Tomografía Computarizada de Emisión de Fotón Único , Abciximab , Anciano , Circulación Coronaria/efectos de los fármacos , Enfermedad Coronaria/diagnóstico por imagen , Femenino , Humanos , Complicaciones Intraoperatorias/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Isquemia Miocárdica/diagnóstico por imagen , Estudios Prospectivos , Tecnecio Tc 99m SestamibiRESUMEN
OBJECTIVES: This quantitative angiographic and intravascular ultrasound study determined the mechanisms of acute lumen enlargement and recurrent restenosis after rotational atherectomy (RA) with adjunct percutaneous transluminal coronary angioplasty in the treatment of diffuse in-stent restenosis (ISR). BACKGROUND: In-stent restenosis remains a significant clinical problem for which optimal treatment is under debate. Rotational atherectomy has become an alternative therapeutic approach for the treatment of diffuse ISR based on the concept of "tissue-debulking." METHODS: Rotational atherectomy with adjunct angioplasty of ISR was used in 45 patients with diffuse lesions. Quantitative coronary angiographic (QCA) analysis and sequential intravascular ultrasound (IVUS) measurements were performed in all patients. Forty patients (89%) underwent angiographic six-month follow-up. RESULTS: Rotational atherectomy lead to a decrease in maximal area of stenosis from 80+/-32% before intervention to 54+/-21% after RA (p < 0.0001) as a result of a significant decrease in intimal hyperplasia cross-sectional area (CSA). The minimal lumen diameter after RA remained 15+/-4% smaller than the burr diameter used, indicating acute neointimal recoil. Additional angioplasty led to a further decrease in area of stenosis to 38+/-12% due to a significant increase in stent CSA. At six-month angiographic follow-up, recurrent restenosis rate was 45%. Lesion and stent length, preinterventional diameter stenosis and amount of acute neointimal recoil were associated with a higher rate of recurrent restenosis. CONCLUSIONS: Rotational atherectomy of ISR leads to acute lumen gain by effective plaque removal. Adjunct angioplasty results in additional lumen gain by further stent expansion and tissue extrusion. Stent and lesion length, severity of ISR and acute neointimal recoil are predictors of recurrent restenosis.
Asunto(s)
Aterectomía Coronaria , Angiografía Coronaria , Enfermedad Coronaria/terapia , Oclusión de Injerto Vascular/terapia , Stents , Ultrasonografía Intervencional , Anciano , Angioplastia Coronaria con Balón , Vasos Coronarios/patología , Femenino , Oclusión de Injerto Vascular/patología , Oclusión de Injerto Vascular/fisiopatología , Humanos , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVES: We sought to evaluate whether transthoracic contrast echocardiography using second harmonic imaging (SHI) is a diagnostic alternative to transesophageal contrast echocardiography (TEE) for the detection of atrial right to left shunt. BACKGROUND: Paradoxic embolism is considered to be the major cause of cerebral ischemic events in young patients. Contrast echocardiography using TEE has proven to be superior to transthoracic echocardiography (TTE) for the detection of atrial shunting, SHI is a new imaging modality that enhances the visualization of echocardiographic contrast agents. METHODS: We evaluated 111 patients with an ischemic cerebral embolic event for the presence of atrial right to left shunt using an intravenous (IV) contrast agent in combination with three different echocardiographic imaging modalities: 1) TTE using fundamental imaging (FI); 2) TTE using SHI; and 3) TEE. The severity of atrial shunting and the duration of contrast visibility within the left heart chambers were evaluated for each imaging modality. Image quality was assessed separately for each modality by semiquantitative scoring (0 = poor to 3 = excellent). Presence of atrial right to left shunt was defined as detection of contrast bubbles in the left atrium within the first three cardiac cycles after contrast appearance in the right atrium either spontaneously or after the Valsalva maneuver. RESULTS: A total of 57 patients showed evidence of atrial right to left shunt with either imaging modality. Fifty-one studies were positive with TEE, 52 studies were positive with SHI, and 32 were positive with FI (p<0.001 for FI vs. SHI and TEE). The severity of contrast passage was significantly larger using SHI (61.6+/-80.2 bubbles) compared to FI (53.7+/-69.6 bubbles; p<0.005 vs. SHI) but was not different compared to TEE (43.9+/-54.3 bubbles; p = NS vs. SHI). The duration of contrast visibility was significantly longer for SHI (17.4+/-12.4 s) compared to FI (13.1+/-9.7 s; p<0.001) and TEE (11.9+/-9.6 s; p<0.02). Mean image quality improved significantly from FI (1.5+/-0.8) to SHI (2.0+/-0.8; p<0.001 vs. FI) and TEE (2.5+/-0.7; p<0.001 vs. SHI). CONCLUSIONS: In combination with IV contrast injections, TEE and SHI have a comparable yield for the detection of atrial right to left shunt. Both modalities may miss patients with atrial shunting. In young patients with an unexplained cerebrovascular event and no clinical evidence of cardiac disease, a positive SHI study may obviate the need to perform a TEE study to search for cardiac sources of emboli.
Asunto(s)
Trombosis Coronaria/diagnóstico por imagen , Ecocardiografía Transesofágica , Ecocardiografía/métodos , Embolia Paradójica/diagnóstico por imagen , Defectos del Tabique Interatrial/diagnóstico por imagen , Aumento de la Imagen , Embolia Intracraneal/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Aneurisma Coronario/complicaciones , Trombosis Coronaria/complicaciones , Embolia Paradójica/complicaciones , Femenino , Defectos del Tabique Interatrial/complicaciones , Humanos , Embolia Intracraneal/fisiopatología , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVES: The aim of this study was to analyze the morphologic characteristics of myocyte degeneration leading to replacement fibrosis in hibernating myocardium by use of electron microscopy and immunohistochemical techniques. BACKGROUND: Data on the ultrastructure and the cytoskeleton of cardiomyocytes in myocardial hibernation are scarce. Incomplete or delayed functional recovery might be due to variable degree of cardiomyocyte degeneration in hibernating myocardium. METHODS: In 24 patients, regional wall motion abnormalities were analyzed by use of the centerline method before and 6 +/- 1 months after coronary artery bypass surgery. Preoperative technetium-99m sestamibi uptake was measured by single-photon emission computed tomography for assessing regional perfusion. Fluorine-18 fluorodeoxyglucose uptake was measured by positron emission tomography to assess glucose metabolism. Transmural biopsy specimens were taken during coronary artery bypass surgery from the center of the hypocontractile area of the anterior wall. RESULTS: The myocytes showed varying signs of mild-to-severe degenerative changes and an increased degree of fibrosis. Immunohistochemical analysis demonstrated disruption of the cytoskeletal proteins titin and alpha-actinin. Electron microscopy of the cell organelles and immunohistochemical analysis of the cytoskeleton showed a similarity in the degree of degenerative alterations. Group 1 (n = 11) represented patients with only minor structural alterations, whereas group 2 (n = 13) showed severe morphologic degenerative changes. Wall motion abnormalities showed postoperative improvements, and nuclear imaging revealed a perfusion-metabolism mismatch without significant differences between the groups. CONCLUSIONS: Long-term hypoperfusion causes different degrees of morphologic alterations leading to degeneration. Preoperative analysis of regional contractility and perfusion-metabolism imaging does not distinguish the severity of morphologic alterations nor the functional outcome after revascularization. The insufficient act of self-preservation in hibernating myocardium may lead to a progressive structural degeneration with an incomplete and delayed recovery of function after restoration of blood flow.
Asunto(s)
Isquemia Miocárdica/patología , Miocardio/citología , Adulto , Anciano , Muerte Celular , Citoesqueleto/ultraestructura , Femenino , Fibrosis , Humanos , Inmunohistoquímica , Masculino , Microscopía Electrónica , Persona de Mediana Edad , Contracción Miocárdica , Isquemia Miocárdica/fisiopatología , Revascularización Miocárdica , Miocardio/patología , Miocardio/ultraestructura , Volumen SistólicoRESUMEN
Smoking and interleukin-6 are important factors in driving inflammation. This study assessed the relationship between smoking, interleukin-6 genotype, physical fitness, and peripheral blood count in healthy young men. For this interleukin-6 promoter polymorphism -174 genotype-phenotype association study 1,929 healthy German male aviators recruited at the central German Air Force Institute of Aviation Medicine were stratified by smoking habits. Cardiovascular fitness was expressed as maximal physical working capacity (PWCmax) in watts per kilogram body weight as assessed by maximal exercise testing by cycle ergometry up to physical exhaustion. Smokers had higher leukocyte and lymphocyte counts than nonsmokers and lower PWCmax. In the overall study population the C allele of the interleukin-6 polymorphism was weakly associated with elevated leukocytes and lymphocytes; in nonsmokers the interleukin-6 polymorphism was not associated with altered phenotypes, but in smokers the interleukin-6 C allele was associated with higher leukocytes, lymphocytes, and monocytes and with lower PWCmax. Smoking is thus associated with elevated leukocytes and lymphocytes and with reduced physical fitness. Gene carriers with the interleukin-6 C allele may suffer particularly from cigarette smoking.
Asunto(s)
Enfermedades Cardiovasculares/sangre , Interleucina-6/genética , Recuento de Leucocitos , Recuento de Linfocitos , Aptitud Física/fisiología , Polimorfismo Genético , Fumar/sangre , Adulto , Frecuencia de los Genes , Genotipo , Humanos , Estilo de Vida , Masculino , Monocitos , Análisis de Regresión , MuestreoRESUMEN
To test the feasibility of a small and simple system for telephonic transmission of 12-lead electrocardiograms (ECGs), 70 patients with acute coronary syndrome admitted to the cardiac care unit (CCU) were included in a feasibility study. The transmission system consisted of a belt with multiple electrodes, which was positioned around the chest. The ECG signal was sent to a call centre via a standard telephone line. In parallel, a standard 12-lead ECG was recorded on site. In a retrospective analysis, each lead of the transmitted ECG was compared with the on-site 12-lead ECG with regard to ST-segment changes and final diagnosis. In all 37 patients with acute ST-elevation myocardial infarction, the diagnosis was correctly established on the basis of telephone-transmitted ECGs. In 96% of limb and 88% of chest leads, ST elevations which were visible in standard ECGs were correctly displayed on telephonically transmitted ECGs. In the remaining 33 patients no false-positive diagnosis was made using transtelephonic ECG analysis. A control group of 31 patients without apparent heart disease showed high concordance between standard ECGs and telephonically transmitted ECGs. Telephonically transmitted 12-lead ECGs interpreted by a hospital-based internist/cardiologist might allow a rapid and accurate diagnosis of ST-elevation myocardial infarction and may increase diagnostic safety for the emergency staff during prehospital decision making and treatment of acute myocardial infarction.
Asunto(s)
Electrocardiografía/normas , Bloqueo Cardíaco/diagnóstico , Infarto del Miocardio/diagnóstico , Telemetría/normas , Teléfono/normas , Enfermedad Aguda , Electrocardiografía Ambulatoria , Servicios Médicos de Urgencia , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Procesamiento de Señales Asistido por ComputadorRESUMEN
DESIGN AND METHODS: Local elastic properties of the descending aorta at different levels were evaluated by means of intravascular ultrasound images and pressure measurements. For this purpose, 30 normotensive patients and 30 age-matched medically treated patients with essential hypertension, all undergoing diagnostic cardiac catheterization, were studied. RESULTS: Hypertension was well controlled in the essential hypertensives (137.1 +/- 6.79/74.5 +/- 2.65 mmHg). Systolic but not diastolic blood pressure in the hypertensive patients was significantly different from that of the normotensives (118.8 +/- 4.38/69.7 +/- 1.65 mmHg). The continuous loss of volume compliance with increasing distance from the heart was significantly higher in the hypertensives than in the normotensive patients [normotensives (1.45 +/- 0.19) x 10(-10) m5/N at the thoracic aorta, (0.08 +/- 0.05) x 10(-10) m5/N at the external iliac artery; hypertensives (0.81 +/- 0.09) x 10(-10) and (0.05 +/- 0.01) x 10(-10) m5/N at the corresponding sites]. Similarly, the hypertensives had an elevated elastic modulus proximal to the aortic bifurcation compared with the normotensives (244.47 +/- 44.06 versus 108.10 +/- 17.76 m/s, respectively). The decrease in buffering function of the vessel at this site is presumably caused by a turbulent flow pattern. Compared with the normotensives, the treated hypertensives had a significantly higher elastic modulus at each site where this was measured, whereas volume compliance and sectional compliance were lower. CONCLUSION: The differences in elastic modulus and compliance between hypertensive and normotensive patients seem disproportionate to the difference in systolic blood pressure (within the normal range in both the treated hypertensives and the normotensives). Therefore, normalization of high blood pressure by long-term antihypertensive treatment may not fully reverse changes, caused by arterial hypertension, in the viscoelastic properties of the arterial wall.