Effect of cardiac resynchronization therapy on septal perfusion and septal thickening: Association with left ventricular function, reverse remodelling and dyssynchrony.

BACKGROUND: We evaluated the effect of cardiac resynchronization therapy (CRT) on septal perfusion and thickening at 6 months post implantation assessed on Tc99m-MIBI Gated myocardial perfusion SPECT (GMPS).We also studied the association of change in septal perfusion and thickening with primary outcome defined as at least one [improvement in ≥1NYHA class, left ventricular ejection fraction (LVEF) by ≥ 5%, reduction of end-systolic volume (ESV) by ≥ 15%, and improvement ≥ 5 points in Minnesota living with heart failure questionnaire (MLHFQ)]. METHOD: One hundred and five patients underwent clinical and GMPS evaluation before and at 6 months post CRT. RESULT: Post CRT there was significant improvement in mean normalized septal perfusion uptake and in septal thickening (P value = 0.001, both). There was no significant relation between improvement in septal perfusion and primary outcome. However, improvement in septal thickening was statistically significant with favorable primary outcome (P = 0.001).There was no significant correlation between improvement of septal perfusion and improvement in LVEF, reduction in End diastolic volume (EDV), ESV, and Left ventricular Dyssynchrony (LVD). But, there was significant correlation between improvement of septal thickening and these parameters. CONCLUSION: Improvement in septal thickening was associated with reverse remodeling, improvement in LVEF, and reduction of LVD.

Myocardial ischaemia in patients with primary APS: a 13N-ammonia PET assessment.

OBJECTIVE: Evaluate the presence and severity of myocardial ischaemia in a population of asymptomatic patients with primary APS (PAPS) using (13)N-ammonia PET. METHODS: We studied 36 patients, 18 with a diagnosis of PAPS and 18 healthy volunteers. All patients underwent a two-phase (rest-stress) (13)N-ammonia PET. Myocardial perfusion images were acquired and then analysed by two experts in the field. RESULTS: We found ischaemia in 7/18 asymptomatic PAPS patients (38.8%). The anterolateral wall was the most commonly affected cardiac territory [5/7 PAPS patients (71.4%)]. In a severity analysis, we found that five patients (71.4%) had mild ischaemia, one patient (14.2%) had moderate ischaemia and another one (14.2%) had severe defects. All the healthy volunteers studied showed normal myocardial perfusion images. CONCLUSION: An important proportion of PAPS patients, even when asymptomatic, showed myocardial perfusion defects assessed with PET. Most of the ischaemic patients had mild defects and the anterolateral wall was the territory mainly affected.

[Discordant pattern, visual identification of myocardial viability with PET]. / El patrón discordante, representación visual de viabilidad miocárdica con PET.

PET (positron emission tomography) as a non-invasive imaging method for studying cardiac perfusion and metabolism has turned into the gold standard for detecting myocardial viability. The utilization of 18 FDG as a tracer for its identification permits to spot the use of exogenous glucose by the myocardium segments. By studying and comparing viability and perfusion results, for which the latter uses tracers such as 13N-ammonia, three different patterns for myocardial viability evaluation arise:. transmural concordant pattern, non-transmural concordant pattern, and the discordant pattern; the last one exemplifies the hibernating myocardium and proves the presence of myocardial viability. The importance of its detection is fundamental for the study of an ischemic patient, since it permits the establishment of and exact diagnosis, prognosis, and the best treatment option. It also allows foreseeing functional recovery of the affected region as well as the ejection fraction rate after revascularization treatment if this is determined as necessary. All these elements regarding viability are determinant in order to reduce adverse events and help improving patients' prognosis.

Identification of severe and extensive coronary artery disease by automatic measurement of transient ischemic dilation of the left ventricle in dual-isotope myocardial perfusion SPECT.

OBJECTIVES: This study sought to assess whether a transient ischemic dilation ratio, determined from automatically derived stress and rest left ventricular volumes during stress technetium-99m (Tc-99m) sestamibi/rest thallium-201 dual-isotope myocardial perfusion single-photon emission computed tomography (SPECT), is useful for the identification of patients with severe and extensive coronary artery disease. BACKGROUND: Transient ischemic dilation of the left ventricle on stress/redistribution thallium-201 scintigraphy has been shown to be a clinically useful marker of severe and extensive coronary artery disease. However, in practice, its assessment is highly subjective. This study automatically assessed the transient ischemic dilation ratio on the basis of a previously described algorithm to estimate three-dimensional ventricular boundaries. METHODS: Normal limits for the transient ischemic dilation ratio were developed using data from 54 patients with a low likelihood (< 5%) of coronary artery disease, and criteria for abnormality were developed based on data from 97 who under-went catheterization, of whom 34 had severe and extensive coronary artery disease, defined as > or = 90% stenosis in the proximal left anterior descending coronary artery or in two or more coronary arteries, and 63 had no coronary artery disease (15 patients) or mild to moderate coronary artery disease (48 patients). The criteria were then tested in a validation cohort of 77 additional patients who underwent catheterization, of whom 36 had severe and extensive coronary artery disease. The quantitative results of the dilation ratio were compared with the visual results of the dilation ratio and perfusion defect analysis. RESULTS: For normal limits, receiver operating characteristic curve analysis showed that abnormal transient ischemic dilation ratio values corresponded to left ventricular endocardial volume ratios > 1.22 (mean +/- 2 SD). Transient ischemic dilation assessment using these criteria for abnormality showed high sensitivity (24 [71%] of 34) and very high specificity (60 [95%] of 63) for severe and extensive coronary artery disease. When the analysis was applied to the prospective catheterization group, similar sensitivity and specificity for severe and extensive coronary artery disease were observed (77% and 92%, respectively). Significant agreement (p = 0.0001) was found between the degree of transient ischemic dilation and the Tc-99m sestamibi defect extent, the latter assessed by semiquantitative visual analysis (summed stress score). CONCLUSIONS: The automatic measurement of transient ischemic dilation in dual-isotope myocardial perfusion SPECT is a clinically useful marker that is sensitive and highly specific for detection of severe and extensive coronary artery disease.

[Evaluation of coronary flow by means of PET in the Mexican population without coronary artery disease]. / Valoración del flujo coronario mediante PET en lapoblación mexicana sin enfermedad arterial coronaria.

UNLABELLED: Coronary artery disease (CAD) represents the principal cause of morbidity and mortality in our environment. Positron emission tomography (PET) is a new technique in our country that allows the assessment of myocardial perfusion and the absolute quantification of the coronary blood flow (CBF) through the utilization of radiotracers using the same criteria employed in conventional nuclear cardiology. CBF normal values have been determined in other populations around the world. No studies in our country assessing in a non-invasive way the CBF have been published before. The quantification of CBF in healthy population is important to establish a standard measure and determine through it, the effects of the many diseases that change the coronary blood flow. The quantification of the CBF, the calculation of coronary blood flow reserve (CFR) and the endothelium dependent vasodilatation index (EDVI) through PET is possible performing three different acquisition stages: rest, cold pressor test (CPT) and pharmacologic stress using Ammonia as radiotracer. The aim of this study was to evaluate the CBF, the CFR and the EDVI in healthy Mexican volunteers. RESULTS: Global basal CBF was 0.34 (+/- 0.09) mL/g/min, during CPT increased to 0.55 (+/- 0.17) mL/g/min and during the stress increased to 1.18 (+/- 0.25). CFR was 3.5 (+/- 0.65) and EDVI was 1.55 (+/- 0.33). CONCLUSIONS: CFR and EDVI values obtained in Mexican healthy population correlates very well with those reported in the literature. This values represents a reference to further research that use this technology.

[Weil's disease: report on 5 cases in the valley of Mexico]. / Enfermedad de Weil: informe de 5 casos en el valle de México.

Leptospirosis, an acute generalized infection transmitted to humans from wild or domestic mammals, is rarely found in urban areas. We report here our experience with five cases of confirmed leptospirosis in the urban area of Mexico City. All five patients had epidemiologic risk factors, fever and a multisystemic illness, and two underwent laparotomy for acute abdominal syndrome. One patient died and four recovered completely. Problems in clinical and laboratory diagnosis are discussed. Leptospirosis should be suspected in patients with fever, jaundice and multiorgan involvement, and a proper epidemiologic setting.

[Diastolic dysfunction and heart failure]. / Disfunción diastólica e insuficiencia cardiaca.

Systolic and diastolic dysfunctions might present same symptomatology, but these are totally different entities. Diastolic dysfunction is a common disease. The most important causes are coronary artery disease and/or left ventricular hypertrophy. This disease has to be diagnosed and treated according to the physiopathology mechanism. Several mechanisms exist that influence and determine diastolic function, if one or a combination of them is altered; this would result in a wide clinical spectrum ranging from a patient without symptoms to an incapacitating state.

[Rupture of the interventricular septum in acute myocardial infarct]. / Ruptura del septum interventricular en el infarto agudo del miocardio.

Ventricular septal rupture in patients with acute myocardial infarction is not a common complication. It was found in 20 patients of 4298 admitted to the coronary care unit of the Instituto Nacional de Cardiología Ignacio Chávez from January 1980 to March 1991. The diagnosis was made by right heart catheterization if 85%, by echocardiography in 35% and by postmortem study in 15% of the patients. Mortality was 70%. In all patients the functional class worsened after the rupture, from class I to III or IV. There were not significant differences in mortality in relation to risk factors, or hemodynamic findings. Mortality was higher in older patients, females and patients with anterior myocardial infarction. Angiographic studies did not increase mortality and are necessary to establish an early surgical treatment.

[Simultaneous analysis of myocardial perfusion and ventricular function. Normal values in the Mexican population]. / Análisis simultáneo de la perfusión miocárdica y la función ventricular. Valores de normalidad en la población Mexicana.

UNLABELLED: Myocardial perfusion imaging is an useful procedure in the evaluation of patients with coronary artery disease, Gated SPECT technique evaluates simultaneously perfusion and ventricular function, left ventricular ejection fraction (LVEF), ventricular volumes and the transient ischemic dilatation of the left ventricle. OBJECTIVE: To evaluate the normal ventricle volumes and the ejection fraction of the LV obtained automatically with the Gated SPECT in Mexican population. METHODS: 100 patients were studied with low likelihood for CAD. All of them were studied with Tc-99m Sestamibi Gated SPECT. We obtained automatically the LVEF, and the end diastolic and systolic left ventricular volumes. RESULTS: Myocardial perfusion, regional motion and systolic thickening were normal in all patients. We obtained the mean values of EF and end diastolic and systolic volumes. These values were lower in female. CONCLUSION: Tc-99m Sestamibi myocardial perfusion SPECT is an useful procedure, with high accuracy for the simultaneous evaluation of myocardial perfusion and ventricular function.

[Simultaneous assessment of myocardial perfusion and ventricular function using thallium-201 at rest/Tc-99m tetrofosmin at effort with single-photon emission computerized tomography, synchronized with electrocardiogram (synchronized SPECT). Initial experience in Latin America]. / Evaluación simultánea de la perfusión miocárdica y función ventricular utilizando talio-201 en reposo/Tc-99m Tetrofosmin en esfuerzo mediante tomografía computada por emisión de fotón único, sincronizada con el electrocardiograma (Spect sincronizado). Experiencia inicial en Latinoamérica.

UNLABELLED: Gated SPECT is a useful technique to evaluate myocardial perfusion, wall motion abnormalities and wall thickening. There is not published experience in Latin-America using dual isotope rest Thallium-201/stress Tc-99m Tetrofosmin Gated SPECT. METHOD: We studied 27 patients with coronary artery disease. Coronary angiography was performed in all the patients. We used an injection at rest of 3 mCi of Thallium-201 followed by stress and the administration of 15 mCi of Tetrofosmin and Gated SPECT acquisition. Five days after, the patients were injected with 20 mCi of Sestamibi at stress, with a second Gated SPECT acquisition. Perfusion data were analyzed using 20 SPECT segment analysis. To study the wall motion, we divided the heart in 29 segments and every segment was scored using a 4 points scale (3 = normal, 2 = mild hipokinesia, 1 = severe hipokinesia, 0 = akinesia). RESULTS: The perfusion and wall motion segmental score agreement between stress Tc-99m tetrofosmin and stress Tc-99m sestamibi were 97% and 84% respectively. CONCLUSIONS: Rest Thailium-201/stress Tc-99m Tetrofosmin Dual isotope Gated SPECT technique is a good protocol to assess simultaneous myocardial perfusion and wall motion. There is a good agreement of the results with the use of rest Thallium-201/stress Tc-99m Sestamibi Dual isotope Gated SPECT study.

[Usefulness of SPECT (single-photon emission-computed tomography) in the detection of coronary disease]. / Utilidad del SPECT (tomografía computada por emisión de fotón único) en la detección de enfermedad aterosclerosa coronaria.

OBJECTIVE: To evaluate the clinical usefulness of cardiac SPECT in the detection of coronary artery disease, and the relation with the site, number and severity of the angiographic lesions. METHOD: We studied 216 patients; with myocardial perfusion imaging with SPECT (T1-201 and/or Tc-99 Sestamibi) and coronary angiogram. We defined the localization of myocardial perfusion defects (anterior, inferior, septal, lateral or apex), and their correlation with coronary angiogram, based on the location, number and severity of coronary angiographic lesions. We considered significative coronary stenosis obstructions of 60% or more. RESULTS: Of the 216 patients studied, 181 (83.8%) were male and 35 (16.2%) female. Age ranged between 30 and 82 years; 143 males and 23 females had a previous myocardial infarction. The SPECT sensitivity for diagnosing ischemia of one, two and three vessel disease was 94%, 96% and 100%. The sensitivity for diagnosing disease in specific vascular territories was 91.6% for LAD 100% for RCA, 92.8% for CX and 100% for left main. CONCLUSIONS: Myocardial perfusion imaging with SPECT has high sensitivity for diagnosing coronary artery disease. The sensitivity and specificity were more accurate in proximal anterior descending artery disease, left main and three-vessel coronary artery disease. We found correlation in the site, number and severity of the angiographic lesions and in myocardial perfusion defects.

[Simultaneous assessment of perfusion and myocardial viability with 2 isotope studies (thallium at rest and sestamibi in exercise). Initial experience in Mexico and Latin America]. / Valoración simultánea de la perfusión y la viabilidad miocárdica a través del estudio de dos isótopos (Talio reposo/MIBI esfuerzo). Experiencia inicial en México y América Latina.

UNLABELLED: Rest-stress sestamibi single photon emission computed tomography (SPECT) has sensitivity and specificity similar to those of thallium 201 SPECT for detection of coronary artery disease. However, sestamibi is not ideal agent to study myocardial viability. There is not published experience in Latin American using dual isotope SPECT protocol to evaluate myocardial perfusion and viability. We studied 44 consecutive patients with coronary artery disease, 37 of them with previous myocardial infarction. Coronary angiography was performed in all patients. We used a 3 mCi rest T 201 SPECT followed by stress and 25 mCi sestamibi injection. Sestamibi SPECT was performed 30 minutes after exercise or 1 hour after pharmacologic stress with dipyridamole. To validate perfusion findings patients returning next day for rest sestamibi injection and SPECT. Scintigraphic data were read by two blinded expert using 20 SPECT segment analysis and each segment was scored using 5 points scoring system (0 = normal, 4 = absent uptake). The segmental score agreement between rest thallium 201 and rest sestamibi and the comparison of defect reversibility percentage and non reversibility between both protocols was 90.7%. CONCLUSION: Separate acquisition dual isotope myocardial perfusion SPECT is accurate for coronary artery disease evaluation. It showed a good agreement with rest-stress sestamibi SPECT for assessment of rest perfusion defects and reversibility and it was a better method to evaluate myocardial viability.

[An assessment of myocardial ischemia in women with the exercise test validated by coronary angiography]. / Evaluación de la isquemia miocárdica en mujeres con la prueba de esfuerzo validada mediante coronariografía.

Ischemic heart disease has been studied in men and women only as a group. We studied the sensitivity and specificity of the exercise stress testing in women. The exercise stress testing (EST) was validated with the coronary arteriography. We studied 72 women and 129 men, the mean age was 55 years for women and 51 years for men. We found in women 83.2% of estimated maximal heart rate; the rate pressure product was 2.4, no different from the values recorded in men (p greater than 0.06). The blood pressure response to exercise was higher in women, and the maximal work capacity was more elevated in men (p less than 0.006). We found normal coronary arteries in 41 women, 70.7% with a positive (EST) compared with a 87.07% in men. The sensitivity and specificity of the exercise stress testing for the diagnosis of ischemic heart disease is smaller in women.

[The thickness/radius ratio (h/r) of the left ventricle in pure mitral insufficiency]. / La relación grosor/radio (h/r) del ventrículo izquierdo en la insuficiencia mitral pura.

We studied 11 patients with severe mitral regurgitation (MR). With 2-D echocardiogram we could obtain the septal and posterior wall thickness, left ventricular internal dimensions and ventricular function. With parasternal short axis view we calculate the h/r ratio (left ventricular thickness/radius). The results were compared with normal values: we found important left atrial and ventricle dilatation with significative difference from the normal values (P < 0.001), the diastolic and systolic h/r ratio was significative lower than the normal values (P < 0.005): the systolic wall stress was significative higher in relation to normal values (P < 0.001). We conclude that patients with severe (MR) initially have an important ventricular dilatation but no hypertrophy despite volume overload. The possible explanation is that in early stages of the disease, the afterload of the left ventricle is low and does not trigger the development of hypertrophy. The hypertrophy appears only when the systolic stress is high secondary to myocardial failure. The excessive dilatation of the left ventricle probably damages the myocardial fibers by excessive stretch. This mechanism probably explains the poor late surgical evolution of patients with mitral prosthesis. This we propose that the optimal surgical timing for such patients is when the systolic wall stress elevates over the normal limits, because this is an early sign of myocardial failure.

[Acute myocardial infarction related to cocaine use. Report of a case]. / Infarto agudo del miocardio relacionado con el consumo de cocaína. Informe de un caso.

Cocaine use has been associated with ischemic syndromes, especially angor pectoris, myocardial infarction, cardiac arrhythmias and sudden death. A significant number of persons suffering from myocardial infarction associated with cocaine abuse do not have significant coronary atherosclerosis, and the mechanism for infarction in these patients have remained obscure. This report describes a young man with angiographically normal coronary arteries in whom cocaine abuse probably produced coronary artery spasm leading to coronary thrombosis and infarction.

[The clinical and electrophysiological characteristics of patients with idiopathic ventricular tachycardia]. / Características clínicas y electrofisiológicas en pacientes con taquicardia ventricular idiopática.

Clinical and electrophysiological characteristics in 20 patients with clinical ventricular tachycardia and normal hearts documented by physical examination, echocardiography, and angiocardiography were analysed. There were 11 males and 9 females. All patients had sustained ventricular tachycardia without hemodynamic instability during tachycardia. A right bundle branch block morphology of ventricular tachycardia was present in 14 patients and left bundle branch block morphology in six patients. During electrophysiologic studies, ventricular tachycardia was induced in 10/15 (66%) patients. Intravenous verapamil terminated the ventricular tachycardia in 9/10 (90%) of cases. However oral verapamil not prevented recurrences. Among 14 patients on whom exercise tests were performed, only two had exercise-induced ventricular/tachycardia. Late potentials were positive in 3/14 (21%) cases and one patient died suddenly during exercise without antiarrhythmic drugs.

[Myocardial ischemia detection with adenosine administration and SPECT. Initial experience in Mexico]. / Detección de isquemia miocárdica mediante la administración de adenosina y técnica SPECT. Experiencia inicial en México.

UNLABELLED: Myocardial perfusion SPECT has a high sensitivity for the diagnosis of myocardial ischemia. Adenosine has been recently used to induce myocardial ischemia in the United States and Europe. At the present time there is not published experience using adenosine in Mexico. METHOD: We studied 22 patients with suspected myocardial ischemia. Coronary angiography was performed in 17 patients. We used a 8 mCi rest Tc-99m sestamibi followed by a 6 minute infusion of adenosine at a dose of 140 ug/kg/min; 24 mCi of Tc-99m were injected after the third minute of adenosine infusion. Patients returned 2 or 3 days later for a new stress study using physical stress or dipiridamole and the images were read using a 20 segments analysis and each segment was scored using a 5 points scale (0 = normal to 4 = absent uptake). The results were then compared with the adenosine images. RESULTS: The segmental score agreement between adenosine and physical or dipyridamole stress were good with 90% exact correlation. The side effects experienced by patients who received dipyridamole and adenosine were similar. CONCLUSION: Adenosine is a good alternative to induce myocardial ischemia. It showed a good correlation with physical or dipyridamole stress test.

[Myocardial perfusion evaluated with a 2-isotope technique. Experience with the first 1600 cases in Mexico]. / Perfusión miocárdica valorada con técnica de dos isótopos. Experiencia de los primeros 1600 casos en México.

SPECT has a high sensitivity for the diagnosis of coronary artery disease. Dual isotope protocol using rest thallium and stress MIBI was introduced in Mexico 4 years ago. This protocol reunite the advantages of both radiotracers for the study of myocardial perfusion. We present our experience of the first three years. One thousand six hundred patients were studied with suspected myocardial ischemia; 288 were excluded because of an absence of a proper follow up. In 895 of the 1312 patients a coronariography was performed. Images were evaluated by dividing the heart in 20 segments using a 5 points scale (0 = normal to 4 = absence of perfusion). It was considered a perfusion defect when a segment had a score greater or equal to 2 and the SPECT study was considered abnormal if two or more segments had a MIBI stress score equal or greater than 2. The global sensitivity for diagnosis of ischemia was 96.28%. Dual isotope method is appropriate for the diagnosis of ischemic heart disease. It has a high sensitivity and specificity for the recognition of global coronary disease and for specific coronary territories. This work constitutes the greatest series in Latin America that uses this diagnosis method.