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Biomedical subjects

M A Alpert

Publications and source records attributed to M A Alpert.

At least 109 records · Page 6Linked to original sources
PubMed1986

Comparative survival after permanent ventricular and dual chamber pacing for patients with chronic high degree atrioventricular block with and without preexistent congestive heart failure.

To determine whether survival after permanent ventricular demand (VVI) pacing differs from survival after permanent dual chamber (DVI or DDD) pacing in patients with chronic high degree atrioventricular (AV) block (Mobitz type II or trifascicular block), 132 patients who received a VVI pacemaker (Group 1) and 48 patients who received a DVI or DDD pacemaker (Group 2) were followed up for 1 to 5 years. There was no significant difference in sex distribution, mean age or incidence of coronary heart disease, hypertension, valvular heart disease, diabetes mellitus, stroke or renal failure between Groups 1 and 2. Overall, the predicted cumulative survival rate at 1, 3 and 5 years was 89, 76 and 73%, respectively, for Group 1 and 95, 82 and 70%, respectively, for Group 2. In patients with preexistent congestive heart failure, the predicted cumulative survival rate at 1, 3 and 5 years was 85, 66 and 47%, respectively, for Group 1 (n = 53) and 94, 81 and 69%, respectively, for Group 2 (n = 20). The 5 year predicted cumulative survival rate was significantly lower in Group 1 patients with preexistent congestive heart failure than in Group 2 patients with the same condition (p less than 0.02). There was no significant difference in 5 year cumulative survival rate between Groups 1 and 2 for patients without preexistent congestive heart failure. The results suggest that permanent dual chamber pacing enhances survival to a greater extent than does permanent ventricular demand pacing in patients with high degree AV block and preexistent congestive heart failure.

Age Factors↗
PubMed1986

Limitations of echocardiography in the diagnosis of left atrial myxoma: a case report.

The classical echocardiographic features of left atrial myxoma are quite distinctive but do not comprise the full spectrum of abnormalities encountered. This case demonstrates atypical echocardiographic features of left atrial myxoma that initially obscured the correct diagnosis. Our findings underscore the potential limitations of echocardiography in the diagnosis of left atrial myxoma.

Diagnostic Errors↗
PubMed1986

Effect of beta-blockade on right ventricular performance in patients with and without right ventricular dysfunction due to coronary artery disease.

To assess the effects of beta-blockade on right ventricular performance in patients with and without right ventricular dysfunction due to coronary artery disease, we performed radionuclide ventriculography on eight patients with normal right ventricular ejection fraction (RVEF greater than or equal to 35%) and 14 patients with mild to moderate right ventricular dysfunction (RVEF less than 35%) at rest. All patients had chronic stable angina pectoris, and nine patients had prior myocardial infarction. Radionuclide ventriculography was performed on placebo and during clinical beta-blockade (heart rate, 50 to 60 beats per minute and less than or equal to 20% increase in heart rate over baseline during stage I treadmill exercise, Bruce protocol) with the oral, cardioselective beta-blocking agent, betaxolol. The resting RVEF (mean +/- 1 SD) was 33% +/- 7% on placebo and 34% +/- 7% during clinical beta-blockade. Mean exercise RVEF was 40% +/- 8% on placebo and 39% +/- 8% during clinical beta-blockade. These differences were not statistically significant. Resting left ventricular ejection fraction ranged from 22% to 60% (mean, 42% +/- 8%). On placebo, one of eight patients with a resting RVEF greater than or equal to 35% had a normal exercise RVEF response (greater than or equal to 5% increment) whereas nine of 14 patients with resting RVEF less than 35% had normal exercise response. The discordant relationship between baseline RVEF and exercise response on placebo became less marked during clinical beta-blockade. We conclude that beta-blockade does not produce significant deterioration of right ventricular systolic function or right ventricular reserve either in patients with normal or in those with mild to moderately impaired resting right ventricular systolic function.

Adrenergic beta-Antagonists↗
PubMed1985

Effect of weight loss on cardiac chamber size, wall thickness and left ventricular function in morbid obesity.

To determine cardiac chamber size, wall thickness and left ventricular (LV) systolic function in morbidly obese patients, M-mode and cross-sectional echocardiography was performed in 62 patients whose body weight was greater than or equal to twice their ideal weight but who were free from underlying organic heart disease and systemic hypertension. The initial clinical protocol consisted of a medical history, physical examination, electrocardiogram at rest, chest x-ray and echocardiogram. Thereafter, each patient underwent gastric restriction. Thirty-four patients returned for follow-up echocardiography 4.3 +/- 0.3 months after substantial weight loss was achieved. For the whole group (n = 62) and LV internal dimension in diastole was enlarged in 24 (39%), the right ventricular internal dimension was enlarged in 20 (32%), the left atrial dimension was enlarged in 25 (40%) and the ventricular septal and LV posterior wall thickness was increased in 35 (56%). In the 34 patients who returned for follow-up, mean body weight decreased significantly, from 135 +/- 8 to 79 +/- 6 kg (73 +/- 4% of the amount over ideal body weight). In the subgroup with low preoperative LV fractional shortening (n = 13), mean LV fractional shortening increased from 22 +/- 2% to 31 +/- 2% (p less than 0.01). This was accompanied by a significant decrease in the mean LV internal dimension in diastole and mean blood pressure. The results indicate that cardiac chamber enlargement, LV hypertrophy and LV systolic dysfunction occur frequently in morbidly obese patients and that LV systolic dysfunction in such persons may improve following substantial weight loss.

Adult↗
PubMed1985

Amiodarone and sustained ventricular arrhythmias: statistical evidence of drug effectiveness.

Previous studies have shown that amiodarone prevents sustained ventricular arrhythmias in 77% to 93% of patients. To date, a study using statistical analysis to verify the drug's effectiveness has not been reported. Amiodarone was given to 17 patients with drug refractory sustained ventricular arrhythmias. All patients had serious underlying heart disease including coronary artery disease (15 patients) or cardiomyopathy (two patients). Ten patients had angiographic evidence of a left ventricular aneurysm. All patients had left ventricular dysfunction. The mean left ventricular ejection fraction was 33%. In the 5.5 +/- 8.3 months prior to amiodarone, these 17 patients had documented sustained ventricular arrhythmias requiring countershock (41 episodes), overdrive pacing (four episodes), or intravenous drugs (three episodes). Amiodarone was given as a loading dose (1 gm/day for 10 days) and a maintenance dose (200 to 600 mg/day). During a follow-up period of 8.9 +/- 5.7 months, only eight episodes occurred requiring countershock (5) or overdrive pacing (2); one patient died suddenly. A statistical test constructed for this problem showed a significant (p greater than 0.001) reduced risk of experiencing a sustained ventricular arrhythmia after amiodarone. This statistical model confirms previous studies showing that amiodarone prevents sustained ventricular arrhythmias and prevents sudden cardiac death.

Aged↗
PubMed1985

Comparative effects of acetate and bicarbonate hemodialysis on left ventricular function.

To assess the comparative effects of hemodialysis with acetate versus bicarbonate base on left ventricular systolic function, we performed M-mode echocardiography on 36 patients prior to and immediately following 4-hr maintenance hemodialysis. Patients were initially dialyzed against either sodium acetate or sodium bicarbonate and 1 week later were dialyzed against the alternate base. The mean velocity of circumferential fiber shortening (mean Vcf, circumferences/s) was used to assess left ventricular systolic function. In patients with normal pre-dialysis mean Vcf hemodialysis with acetate produced no significant change in mean Vcf, whereas hemodialysis with bicarbonate produced a significant increase in mean Vcf. In patients with low pre-dialysis mean Vcf hemodialysis with either base produced a significant increase in mean Vcf. Mean Vcf values obtained after hemodialysis with bicarbonate were significantly higher than those obtained after hemodialysis with acetate, both in patients with normal and low pre-hemodialysis mean Vcf. We conclude that hemodialysis with bicarbonate produces a comparatively greater improvement in left ventricular systolic function than hemodialysis with acetate.

Acetates↗
PubMed1985

Pulmonary hemodynamics in systemic hypertension.

We reviewed cardiac catheterization data and the medical records of 30 patients with systemic hypertension to establish their pulmonary hemodynamic profiles and the relationship between certain clinical and demographic variables and increased pulmonary vascular resistance. Mean systemic arterial pressure ranged from 110 to 210 mm Hg, and systemic vascular resistance ranged from 17.6 to 47.0 units. Seven patients had normal pulmonary wedge pressure and normal pulmonary vascular resistance, one had elevated pulmonary wedge pressure and normal pulmonary vascular resistance, five had elevated pulmonary wedge pressure and increased pulmonary vascular resistance, and 17 had normal pulmonary wedge pressure and increased pulmonary vascular resistance. There were significant positive correlations between systemic vascular resistance and pulmonary vascular resistance and between mean systemic arterial pressure and mean pulmonary artery pressure, but there was no correlation between mean pulmonary wedge pressure and pulmonary vascular resistance. Of the 17 patients with normal pulmonary wedge pressure and increased pulmonary vascular resistance, seven had clinical or radiologic evidence of prior left ventricular failure. We conclude that increased pulmonary vascular resistance occurs commonly in patients with systemic hypertension. Although some cases of increased pulmonary vascular resistance relate to active or preexistent left ventricular failure, the majority remain unexplained, suggesting that neurohumoral or other factors may produce a hypertensive response in both the systemic and pulmonary arterial circuit.

Adult↗
PubMed1984

Sensitivity and specificity of two-dimensional echocardiographic signs of mitral valve prolapse.

The sensitivity and specificity of previously described 2-dimensional echocardiographic signs of mitral valve prolapse (MVP) were assessed in 70 patients with MVP and in 100 normal control subjects. Specificity of individual signs was uniformly high, ranging from 88% for excessive motion of the posterior mitral ring to 100% for several signs including systolic arching in the parasternal long-axis view, excessive posterior coaptation and diastolic doming of the anterior mitral leaflet. Sensitivity of individual signs was low to moderate, ranging from 1% for whip-like motion of both mitral leaflets to 70% for excessive posterior coaptation of the mitral leaflets in the apical 4-chamber view. The highest sensitivity value (87%) was associated with the presence of systolic arching of 1 or both mitral leaflets in the parasternal long-axis view or systolic bowing of 1 or both mitral leaflets in the apical 4-chamber view or excessive posterior coaptation of the mitral leaflets or a combination. This increase in sensitivity was achieved without sacrificing specificity (97%). Thus, the individual 2-dimensional echocardiographic signs tested possess uniformly high specificity, but only low to moderate sensitivity; however, sensitivity can be markedly enhanced without sacrificing specificity by using selected combinations of echocardiographic signs.

Adult↗
PubMed1984

Sensitivity and specificity of commonly used electrocardiographic criteria for left atrial enlargement determined by M-mode echocardiography.

To assess the sensitivity and specificity of 6 commonly used electrocardiographic criteria for left atrial (LA) enlargement, the rest ECGs of 99 patients in normal sinus rhythm were analyzed. Fifty-seven of the patients had LA enlargement and 42 had a normal LA dimension as determined by M-mode echocardiography. The 6 criteria studied and their respective sensitivities and specificities were as follows: (1) duration of the negative phase of the P wave in lead V1 greater than 40 ms: sensitivity, 83%; specificity, 80%; (2) notched P wave in any standard lead with an interpeak duration greater than 40 ms: sensitivity, 15%; specificity, 100%; (3) P terminal force (depth X duration of the terminal portion of the P wave) in lead V1 more negative than -0.04 mm X s: sensitivity, 69%; specificity 93%; (4) depth of the negative phase of the P wave in lead V1 greater than or equal to 1 mm: sensitivity, 60%; specificity, 93%; (5) total P-wave duration greater than 110 ms in any standard lead: sensitivity, 33%; specificity, 88%; (6) total P wave duration/P-R interval duration greater than 1.6: sensitivity, 31%; specificity, 64%. Combining 2 or more of these criteria did not substantially improve sensitivity and specificity.

Cardiomegaly↗
PubMed1984

Mexiletine for recurring ventricular arrhythmias: assessment by long-term electrocardiographic recordings and sequential electrophysiologic studies.

Mexiletine, an oral lidocaine-like drug, was initially thought to be effective treatment for recurring ventricular arrhythmias. Recent work has cast doubt on its efficacy. We administered mexiletine to 32 patients with chronically recurring ventricular arrhythmias. In 22 patients with no history of syncope or documented sustained ventricular arrhythmia (group 1), mexiletine was effective in only 27% (six patients) as assessed by 24-hour ambulatory ECG recordings before and during mexiletine treatment. Ten other patients had a history of syncope or documented sustained ventricular tachycardia or ventricular fibrillation. Only 10% (one patient) responded to mexiletine based on sequential electrophysiologic studies with programmed ventricular stimulation. Four of the seven patients responding to mexiletine had not received prior antiarrhythmic therapy. We conclude that mexiletine has limited efficacy in the treatment of recurring drug-refractory ventricular arrhythmias.

Adult↗
PubMed1984

Symptomatic cardiac amyloidosis in an American family.

This report describes an American family with a high incidence of symptomatic cardiac amyloidosis among four siblings, and explores the role of echocardiography and technetium pyrophosphate myocardial scintigraphy in the detection of this infiltrative cardiomyopathy within the involved family.

Amyloidosis↗
PubMed1984

Effect of hemodialysis on left ventricular performance. Analysis of echocardiographic subsets.

To assess the effect of hemodialysis on left ventricular performance, we performed M-mode echocardiography on 31 patients with end-stage renal disease prior to and immediately following 4-hour chronic maintenance hemodialysis. Overall, hemodialysis produced a significant increase in mean heart rate and the mean velocity of circumferential fiber shortening (mean Vcf), a significant decrease in mean stroke index and no significant change in mean cardiac index. Hemodialysis resulted in a significant increase in mean Vcf in the subset of patients with reduced mean Vcf prior to dialysis, but produced no significant change in mean Vcf in the group with normal predialysis mean Vcf. Hemodialysis resulted in a significant increase in mean Vcf in the subset of patients with normal left ventricular end-diastolic volume prior to dialysis, but produced no significant change in mean Vcf in the group with increased predialysis left ventricular end-diastolic volume. The presence of left ventricular hypertrophy appeared to blunt the expected increase in mean Vcf in the group with reduced mean Vcf prior to hemodialysis. These results suggest that predialysis left ventricular volume, wall thickness and contractility are important determinants of the effect of hemodialysis on left ventricular performance.

Cardiac Output↗