Mitral regurgitation protects from left atrial thrombogenesis in patients with mitral valve disease and atrial fibrillation.

The aim of this study was to test the hypothesis that mitral regurgitation (MR) has a protective effect on the development of left atrial thrombus (LAT) in patients with rheumatic heart disease and atrial fibrillation (AF). The study population consisted of 48 anticoagulated patients (mean age = 57.1 +/- 10 years). Predominant mitral stenosis (MS) was present in 14 patients, predominant MR in 14, and a mechanical valve in 20. All patients underwent detailed transesophageal echocardiography. Severity of MR was based on measurements of the MR jet by color flow mapping. Patients were divided into two groups: (a) those with MR > or = 3+ (n = 12, 25%), and (b) those without significant MR (n = 36, 75%). A LAT was found in six patients (12.5%), who also had spontaneous echo contrast (SEC), while another group of 30 patients (62.5%) had SEC only. LAT and/or SEC were present in 2/12 patients (16.6%) with significant MR versus 34/36 patients (94.4%) without significant MR (P < 0.001). In addition to the absence of significant MR, left atrial diameter (LAD) > 60 mm, and severity of MS were also related to the presence of thrombus and/or SEC. Significant MR had a protective effect against thromboembolism, although this effect was abolished if LAD > 60 mm was present. In conclusion, in patients with mitral valve disease and AF, significant MR protects against LAT formation and systemic embolization. This protective effect was lost when LAD was > 60 mm.

Non-invasive evaluation of coronary reserve. Assessment of coronary reserve in patients with coronary artery disease by transesophageal-Doppler echocardiography.

We assessed coronary flow reserve using transesophageal Doppler echocardiography in patients with coronary artery disease. The study included 33 coronary artery disease patients who were undergoing coronary arteriography. The blood flow velocities of the left anterior descending artery before and after intravenous infusion (0.56 mg/min for 4 min) of dipyridamole were recorded using transesophageal Doppler echocardiography. Fourteen normal healthy individuals, matched for age, served as a control group. The index of coronary flow reserve, i.e. the ratio of dipyridamole to baseline maximum diastolic velocity, was calculated. Maximal coronary flow reserve in coronary artery disease patients was significantly lower than in the control group (1.4+/-0.2 vs. 2.8+/-0.3, P<0.001). The coronary artery disease patients were classified into three groups: Group A included 10 patients with <50% left anterior descending artery stenosis; Group B included seven patients with 50-69% left anterior descending artery stenosis; 16 patients with >70% left anterior descending artery stenosis constituted Group C. The maximum coronary flow reserve was significantly different for A vs. B and A vs. C. (A, 1.77+/-0.18; B, 1.51+/-0.1; C, 1.28+/-0.24). A strong and significant correlation was found between the maximum coronary flow reserve and the degree of proximal left anterior descending artery stenosis (r=0.78, P<0.001). Coronary artery disease patients without left anterior descending artery stenosis on the arteriogram exhibited lower maximum coronary flow reserve compared to the control subjects (1.78+/-0.19 vs. 2.8+/-0.3, P=0.000).

Transesophageal echocardiographic Doppler study of coronary flow in a patient with myocardial bridging--a case report.

A case report of myocardial bridging of the left anterior descending artery is described. Coronary flow proximal to the myocardial bridge was studied with transesophageal echo Doppler. The patient, a 62-year-old farmer who sustained an anterior myocardial infarction, underwent thrombolysis and was admitted. He subsequently underwent coronary angiography and left ventriculography, which showed a severe myocardial bridge of the midshaft of the left anterior descending artery. The ejection fraction improved from 25 to 48% after thrombolysis, as measured by using echocardiography. Transesophageal Doppler study proximal to the myocardial bridge revealed a relative increase of the diastolic coronary flow velocity (increased acceleration), which reached its peak value in early diastole. Despite the presence of severe myocardial bridging, coronary flow reserve increased substantially two minutes after the infusion of dipyridamole (0.56 mg/kg iv for 4 minutes). Transesophageal Doppler study of coronary blood flow proximal to the myocardial bridge in the left anterior descending artery showed a characteristic waveform that may prove to be indicative of this condition.

Stress echocardiography using adenosine combined with nitroglycerin-dobutamine in the detection of viable myocardium in patients with previous myocardial infarction.

The aim of this study was to assess the value of adenosine (A) and the combination of nitroglycerin (N) with dobutamine (D) stress echocardiography (SE) in the identification of viable myocardium. The clinical and electrocardiographic (ECG) effects of both tests were also evaluated. Fifty-two coronary artery disease patients, aged 56.4 +/- 8 years, with left ventricular dysfunction due to a previous myocardial infarction (mean ejection fraction: 49 +/- 8%) were included in the study. Cardiac catheterization was performed in all patients before A (140 micrograms/kg/minute for five minutes) and the combination of N with D (5-10 micrograms/kg/minute) stress echocardiography. On the echocardiogram, the left ventricle was divided into 16 segments and wall motion was graded semiquantitatively from 1 (normal) to 4 (dyskinesia). The echocardiographic index was also estimated. A segment was considered viable during A infusion when resting asynergy showed deterioration of one grade or more. In contrast, segmental viability was considered to be present during the combination of N with D infusion when resting asynergy showed improvement of one grade or more. A thallium 201 single photon emission computed tomography (SPECT) with reinjection was performed as reference standard for the identification of viable myocardium. Stress echocardiography during infusion of A was associated with short-duration angina attacks in 3 (5.8%) patients and transient complete atrioventricular (AV) block in 1 (1.9%), whereas during the combination of N with D infusion, 6 (11.5%) patients experienced ventricular bigeminy lasting for a short period. ST segment elevation greater than 1 mm was recorded in those leads having a Q wave, in 19 (36.5%) patients. In 10 of these 19 (52.6%), viable myocardium was present in SPECT, as it was in 33 patients (63.5%) having no ST segment elevation (P = NS). Of a total of 832 segments that were graded during A-SE, 276 exhibited resting asynergy and the remaining 556 had normal motion and thickening at rest. The echocardiographic index during A infusion increased from 1.52 +/- 0.22 to 1.71 +/- 0.24 (P < 0.001), whereas during D and N infusion it decreased from 1.53 +/- 0.31 to 1.30 +/- 0.42 (P < 0.001). With SPECT considered as the gold standard for the identification of viable myocardium, sensitivity, specificity, and positive and negative predictive values of A-SE in detecting viable myocardium were 54%, 86%, 65% and 80%, respectively. The respective values for the combination of nitroglycerin with D-SE were 91%, 89%, 78%, and 96%, respectively. Stress echocardiography during A, and the combination of N with D, constitute safe methods in the identification of viable myocardium. The detection of ST segment elevation in the ECG leads with a Q wave during the combined infusion of nitroglycerin and dobutamine is not related to the presence of viable myocardial tissue. The A-SE provide moderate diagnostic accuracy, while the combination of N with D during SE is much superior in detecting viable myocardium.

Torsades de pointes following radiofrequency catheter His ablation.

A case of polymorphic ventricular tachycardia torsade de pointes type, appearing in a 70-year-old female following radiofrequency catheter His ablation, is presented. The substrate was slow rate with ventricular bigeminy and QT prolongation which appeared after ablation. The same phenomenon reappeared after permanent VVIR pacemaker implantation with a basal rate of 55 beats/min. One episode of polymorphic ventricular tachycardia deteriorated into ventricular fibrillation, requiring a 360-J DC shock. Raising the pacemaker rate to 80 beats/min abolished the arrhythmias.

Detection of myocardial viability in the prediction of improvement in left ventricular function after successful coronary revascularization by using the dobutamine stress echocardiography and quantitative SPECT rest-redistribution-reinjection 201TI imaging after dipyridamole infusion.

The aim of this study was to assess the feasibility, safety, and respective diagnostic accuracy of low-dose dobutamine infusion and rest-redistribution-reinjection thallium 201 single photon emission computed tomography (SPECT) after dipyridamole infusion (Th-DIP), in the prediction of functional improvement of asynergic infarcted zones, after successful revascularization in patients with chronic ischemic heart disease. Thirty-one patients with a previous myocardial infarction and left ventricular dysfunction (mean ejection fraction: 41 +/- 5.8%) were studied. The regional wall motion of the left ventricle was evaluated by basic echocardiography before and 14 +/- 1.7 weeks after successful revascularization (19 by percutaneous transluminal coronary angioplasty and 12 by coronary artery bypass grafting). Dobutamine stress echocardiography (DSE) was performed in all patients with dobutamine infusion of 5 and 10 micrograms/kg/minute over five minutes. Within three days after DSE and prior to revascularization, all patients underwent Th-DIP for myocardial viability assessment. A 16-ventricular-segment model was used for basic, DSE, and Th-DIP images. Viability was assessed by applying the standard criteria for each technique. In the 31 patients, 496 segments were analyzed. By basic echocardiography, 164 (33%) of them were classified as asynergic. The DSE detected viable tissue in 69/496 (14%) segments, whereas Th-DIP identified viability in 95/496 (19%) segments. When the postrevascularization basic echocardiographic study was used as the gold standard in identifying myocardial viability, the sensitivity and specificity for the DSE and Th-DIP were 86.5%, 94.4% and 90.5%, 69%, respectively. No major side effects were observed with both techniques. In conclusion, DSE seems to be an accurate method for identifying viable but asynergic myocardium in patients with chronic ischemic heart disease, whereas Th-DIP overestimates the postrevascularization recovery. Detection of hibernating myocardium can be obtained by these two noninvasive methods. However, DSE seems to be more useful in determining the prospective selection of patients who are going to benefit from revascularization.

Modification of ventricular tachycardia by carotid sinus massage.

A case of ventricular tachycardia (VT) was aggravated by carotid sinus massage in a woman with an old myocardial infarction. The patient presented with a wide QRS complex tachycardia with a rate of 143 beats/min, which fulfilled the classic and newer electrocardiographic criteria for the diagnosis of VT. Carotid sinus massage performed during the tachycardia resulted in its conversion to another, wide QRS complex tachycardia, with different morphology and a faster rate resembling ventricular flutter. This latter tachycardia was converted to sinus rhythm by a thump on the patient's chest. The initial tachycardia was proved to be of ventricular origin by electrophysiologic study at a later stage during a recurrence. Vagal stimulation probably resulted in inhomogeneous increase of the ventricular refractory period, creating conditions for a reentrant circuit other than the preexisting one and for the emergence of VT with a different QRS morphology and rate. Although termination and/or initiation of VT by carotid sinus massage has been reported in the past, modification of VT by carotid sinus massage has not been described previously.

Effects of magnesium and potassium on Wolff-Parkinson-White syndrome.

To investigate the effects of electrolytes on anterograde conduction via accessory pathways, 12 patients with Wolff-Parkinson-White syndrome received, while in sinus rhythm, intravenous KCl (7 mEq in 200 mL of 0.9% NaCl), MgSO4 (10 mL 20% in 200 mL of 0.9% NaCl), NaCl (0.9%, 200 mL), and procainamide (maximal dose, 10 mg/kg of body weight over a 5-minute period) in a randomized fashion. NaCl had no effect on preexcitation. Procainamide abolished preexcitation in seven patients, of whom five had a similar response with MgSO4 and four with KCl. The finding that potassium and magnesium transiently abolish preexcitation in some Wolff-Parkinson-White patients deserves further study, especially during tachyarrhythmias in patients with accessory pathways.

Significance of echocardiographic atrioventricular plane displacement for the evaluation of left ventricular filling and end-diastolic pressure in patients with coronary artery disease.

The aim of this study is to assess the left ventricular filling and estimate the end-diastolic pressure of the left ventricle in patients with coronary artery disease (CAD) by echocardiographic measurement of the atrioventricular plane displacement (AVPD). In 101 patients (mean age 59 +/- 12 years) with CAD, a complete transthoracic echocardiographic study was performed, just prior to cardiac catheterization. The AVPD was recorded by M-mode echocardiography, from apical four and two chamber views. The recordings were obtained at four sites, corresponding to the septal, lateral, anterior and inferior walls of the left ventricle. The mean AVPD resulting from atrial systole (At), the mean total (T) diastolic AVPD, the ratio At/T(%) and the ratio of mitral annulus excursion during early and late diastole [(T-At)/At] were calculated. Firty-two age-matched healthy subjects served as control group. Both At and At/T were significantly greater in patients with CAD than in the controls (6.06 +/- 0.94 vs 5.53 +/- 0.55 mm, p < 0.01 and 43.4 +/- 5.9% vs 33.49 +/- 4.45%, p < 0.001 respectively). The ratio [(T-At)/At] correlated with the E/A ratio of transmitral flow, both in healthy subjects (r = 0.850, p < 0.001) and in patients with CAD (r = 0.722, p < 0.001). Correlation also existed both in patients with segmental wall motion abnormality (SWMA) (r = 0.691, p < 0.001) and in patients with SWMA (r = 0.818, p < 0.001). In patients with CAD, At/T further correlated with the left ventricular end-diastolic pressure (r = 0.517, p < 0.001). In patients with SWMA and in patients without, a correlation was also found (r = 0.516, p < 0.001 and r = 0.566, p < 0.001 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of left atrioventricular plane movement during diastole in ischemic heart disease.

The aim of the present study was to investigate the properties of diastolic left atrioventricular plane displacement (AVPD) in coronary artery disease (CAD) patients. In 125 patients (mean age 58.7 +/- 13.7) with CAD and in 51 age-matched healthy subjects, a complete transthoracic echocardiographic study was performed. The AVPD was recorded by M-mode echocardiography, from apical four and two chamber views at four sites corresponding to the septal, lateral, anterior and inferior walls of the left ventricle. Mean AVPD in early diastole (E-AVPD), mean AVPD from atrial systole (A-AVPD) and the ratio A-AVPD/E-AVPD were determined. In normal subjects, such as in 35 patients without left ventricular segmental wall motion abnormalities (SWMA), stepwise multiple regression analysis showed none of these factors to be significantly related to E-AVPD or A-AVPD. Aging was correlated negatively to the E-AVPD/A-AVPD ratio (p < 0.05). In 90 patients with left ventricular SWMA, stepwise multiple regression analysis showed that indices of left ventricular systolic function correlated positively to E-AVPD (p < 0.001) and A-AVPD (p < 0.001). The E-AVPD/A-AVPD ratio was correlated to left ventricular ejection fraction and heart rate (p < 0.005). Mean E-AVPD was significantly lower in CAD patients than in normal subjects (p 0.001), while A-AVPD was higher in patients without left ventricular SWMA in comparison to normal subjects (p = 0.02). Also, mean A-AVPD/E-AVPD was higher in CAD patients than in the control group (p < 0.001). Mean E-AVPD/A-AVPD was correlated to the E/A ratio of transmitral flow in CAD patients with (r = 0.669) and without (r = 0.771) SWMA. The E-AVPD and A-AVPD in CAD patients with SWMA is reduced according to the deterioration of left ventricular systolic function. The atrial contribution to the longitudinal distension of the left ventricle is increased in CAD patients. In CAD patients, especially those without left ventricular SWMA, the E-AVPD/A-AVPD ratio has a good correlation to left ventricular filling behavior.

Doppler echocardiographic study of pulmonary venous flow in mitral stenosis and early after mitral valve replacement.

The aim of the study was Doppler echocardiographic assessment of the effect of mitral stenosis (MS) on pulmonary venous flow (PVF), and of any changes occurring after mitral valve replacement. Fifty patients with MS (22 in atrial fibrillation (AF)) and 28 healthy subjects (control group) underwent transthoracic echocardiographic evaluation of PVF. Fourteen of the 22 patients in AF were submitted in addition to transesophageal echo study before and after mitral valve replacement. Pulmonary wedge pressure was measured in 18 patients. Patients in sinus rhythm (SR) and more than mild MS showed significantly decreased peak velocity and flow velocity time integral of the systolic forward PVF. This finding was more exaggerated in MS with AF. Concerning diastolic forward PVF, patients in SR showed significantly decreased peak velocity and velocity time integral, irrelevant of the degree of MS, while patients with AF exhibited adequate signs of flow. In all patients duration, deceleration time (D-DT) and pressure half-time (D-PHT) of the diastolic forward PVF were significantly increased. The last two parameters correlated with the corresponding variables of mitral flow and with echocardiographically determined mitral valve area and the D-DT of the pulmonary wedge pressure. Concerning reversed PVF, patients with more than mild MS exhibited significantly increased peak velocity and velocity time integral. After mitral valve replacement, a significant increase of diastolic forward peak velocity and velocity time of the PVF were detected. The duration of diastolic forward peak velocity of PVF, D-DT and D-PHT decreased. The systolic forward phase did not change significntly after the valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Apical hypertrophic cardiomyopathy with unusual features in a Greek woman.

We present a Mediterranean female patient with abnormal electrocardiographic findings and a history of shortness of breath during excessive effort (NYHA I) in whom apical hypertrophic cardiomyopathy with unusual features was detected by echocardiography and magnetic resonance imaging. There was a single fused apical hypertrophic papillary muscle and akinesia of the left ventricular apical segment. Abnormal left ventricular filling was also detected by Doppler echocardiography.

Clinical characteristics and electrophysiologic properties of atrioventricular accessory pathways: importance of the accessory pathway location.

OBJECTIVES: This study was designed to assess the influence of accessory atrioventricular (AV) pathway location on the clinical and electrophysiologic characteristics of 384 consecutive symptomatic patients having a single accessory pathway. METHODS: Four locations were studied: left free wall (n = 270), posteroseptal (n = 52), anteroseptal (n = 29) and right free wall (n = 33). Ten clinical variables and 12 electrophysiologic variables were analyzed, including the effective refractory period of the accessory pathway and the different clinically occurring and inducible arrhythmias. RESULTS: Only two clinical findings were associated with accessory pathway location: 1) later age at onset of symptoms in the left free wall versus other accessory pathway locations (24 +/- 12 vs. 20 +/- 11 years, p = 0.02), and 2) later age at the time of electrophysiologic study in the left free wall accessory pathway location (36 +/- 13 vs. 32 +/- 11 years, p = 0.01). Six electrophysiologic variables showed a correlation with the accessory pathway location: 1) retrograde conduction only was found less frequently in right free wall (9%) and anteroseptal (10%) than in left free wall (26%) and posteroseptal (29%) accessory pathway locations (p = 0.05); 2) the retrograde effective refractory period of the accessory pathway was shorter in anteroseptal (253 +/- 52 ms) and left free wall (270 +/- 72 ms) as compared with right free wall (296 +/- 101 ms) and posteroseptal (301 +/- 76 ms) locations (p = 0.05); 3) retrograde decremental conduction over the accessory pathway was present in the posteroseptal (17%) and left free wall (3%) but absent in the other locations (p less than 0.001); 4) anterograde decremental conduction was only seen in the right free wall location (12%) (p less than 0.001); 5) orthodromic reentrant tachycardia was induced less frequently in the right free wall than in other locations (70% vs. 93%, p less than 0.001); and 6) inducibility of atrial fibrillation was greater in anteroseptal (62%) than in right free wall (21%), left free wall (44%) and posteroseptal (36%) locations (p = 0.01). CONCLUSIONS: The location of the accessory AV pathway is associated with specific electrophysiologic characteristics.

Parasystolic ventricular tachycardia with exit block.

A rare case of parasystolic ventricular tachycardia with variable exit block concurring with runs of reentrant ventricular tachycardia is described. The reentrant ventricular tachycardia or isolated ventricular extrabeats modified the exit block patterns of the parasystolic tachycardia.