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Biomedical subjects

M V Herman

Publications and source records attributed to M V Herman.

At least 37 records · Page 2Linked to original sources
PubMed1989

Left ventricular response to exercise and autonomic control mechanisms in end-stage renal disease.

Left ventricular (LV) function during rest and during exercise was evaluated in patients with end-stage renal disease (ESRD) in whom other causes of LV dysfunction were eliminated through rigid selection criteria. Autonomic function was also assessed in these patients with Valsalva's maneuver and plasma catecholamine determinations. Echocardiography and radionuclide ventriculography in the group with ESRD revealed no abnormalities of LV wall motion or ejection fraction. During graded exercise, patients with ESRD achieved 85% of age-predicted heart rate, and no differences in exercise tolerance or LV function were observed. Valsalva's response was abnormal in patients with ESRD, and post exercise the norepinephrine level was markedly increased (12.5 +/- 1.43 vs 8.28 +/- 0.82 nmol/L). Our results fail to indicate an independent adverse effect of ESRD on LV function.

Adult↗
PubMed1988

Cardiopulmonary exercise testing. The clinical value of gas exchange data.

Cardiopulmonary exercise testing is a noninvasive tool whose clinical value is not yet widely recognized. The technique involves breath-by-breath measurement of respiratory gas exchange during a symptom-limited exercise test, with determination of maximal oxygen uptake and anaerobic threshold. These measurements serve as objective, reproducible indices of exercise capacity that can be applied to the management of various clinical problems. In addition, by permitting simultaneous assessment of circulatory and ventilatory reserves, the test can be especially helpful in the differential diagnosis of exertional dyspnea and fatigue. This paper reviews the physiology of gas exchange, the limitations of standard exercise tests, and the methodology and clinical applications of cardiopulmonary exercise testing.

Carbon Dioxide↗
PubMed1988

Selective hypervagotonia isolated to the atrioventricular node.

Thirteen patients with recurrent unexplained syncope or presyncope underwent electrophysiological evaluation. A prolonged effective refractory period and functional refractory period of the atrioventricular node as well as slow paced rate to atrioventricular block were the only abnormalities found. Ventricular tachycardia could not be induced. All electrophysiological abnormalities reverted to normal following atropine administration. These patients have selective hypervagotonia isolated to the atrioventricular node. Three of thirteen patients required permanent pacing, and one required propantheline to control recurrent symptoms. Selective hypervagotonia may be a distinct clinical entity that can cause symptoms and require therapy.

Adult↗
PubMed1987

Predictors, prevention, and long-term prognosis of atrial fibrillation after coronary artery bypass graft operations.

Multiple trials have suggested the use of digoxin, digoxin and propranolol, or timolol to prevent atrial fibrillation after coronary artery bypass grafting. No trial has evaluated the efficacy of digoxin verus propranolol. Furthermore, the predictors of postoperative atrial fibrillation and the long-term consequence of atrial fibrillation that reverts to sinus rhythm have not been established. One hundred fifty patients were randomized to receive no drug, propranolol (20 mg every 6 hours), or digoxin (0.5 mg followed by 0.25 mg daily). Twenty-seven patients were excluded from data analysis. In the remaining 123 patients, no preoperative parameter (age, sex, diabetes, hypertension, smoking, electrocardiographic p wave morphology, or preoperative digoxin or propranolol therapy), intraoperative parameter (bypass time, aortic cross-clamp time, or number of vessels bypassed), or postoperative parameter (peak creatinine kinase, congestive heart failure, or pericarditis) by univariate or multivariate analysis predicted patients at risk for atrial fibrillation. Sustained atrial fibrillation developed in 37.5% of control and 32.6% of digoxin-treated patients. Only 16.2% of propranolol-treated patients had sustained atrial fibrillation (p less than 0.03). There were no in-hospital complications in those patients with atrial fibrillation. After 26 +/- 7 months follow-up, those patients with postoperative atrial fibrillation had no increased incidence of angina, cerebral vascular accident, myocardial infarction, or sudden death. Therefore, in this select population, propranolol prophylaxis is effective but discretionary.

Atrial Fibrillation↗
PubMed1986

Echocardiographic and hemodynamic features of severe aortic regurgitation with diastolic opening of the aortic valve.

Severe aortic regurgitation may be associated with premature aortic valve opening. Several possible etiologies for this diastolic opening have been suggested. We present a patient with hemodynamic data, M-mode and 2-D echocardiography in the setting of severe aortic regurgitation and diastolic aortic valve opening. Our data lead us to conclude that aortic valve opening in this situation is neither from passive flotation nor dependent on atrial systole. We believe that active ventricular recoil mechanisms can facilitate increases in diastolic ventricular pressure which then can transiently exceed aortic pressure in the setting of severe aortic regurgitation. This hemodynamic observation suggests that the valve opening is an active process.

Adult↗
PubMed1986

The cardiointegram: detection of coronary artery disease in males with chest pain and a normal resting electrocardiogram.

The cardiointegram is a non-invasive technique for the analysis of the electrical signals of the heart obtained by a transformation of the voltage vs. time format by a series of integrations. This multicenter study compares the results of the cardiointegram with coronary arteriography in 140 male patients with chest pain and a normal resting electrocardiogram. The cardiointegram was determined on two resting complexes of Leads I, II, V4, V5 and V6 and called abnormal if greater than or equal to four of ten complexes were abnormal, i.e., fell outside of a previously determined template of normality. The sensitivity was 73% and specificity was 78% for the diagnosis of occlusive coronary artery disease. When greater than or equal to five of ten abnormal complexes were used as the cut-off for an abnormal test and "equivocal" results (four of ten abnormal, n = 18) were excluded from analysis there was a sensitivity of 69% and specificity of 88%. Thirty-seven of 38 patients (97%) with an abnormal cardiointegram and a positive exercise stress test had coronary artery disease. Thus, the cardiointegram appears to be a useful non-invasive test for the detection of coronary artery disease in males with chest pain and a normal resting electrocardiogram in whom the diagnosis of coronary artery disease is being considered.

Angiocardiography↗
PubMed1985

Ventricular arrhythmias after coronary artery bypass graft surgery: incidence, risk factors and long-term prognosis.

The incidence, risk factors and long-term prognosis of complex ventricular arrhythmias after coronary artery bypass graft surgery are not known. Complex ventricular arrhythmias are defined as Lown grades 4a (couplets), 4b (ventricular tachycardia) and 5 (R on T phenomenon). Ninety-two patients with normal left ventricular function who underwent elective coronary artery bypass graft surgery were prospectively evaluated. Ventricular arrhythmias were documented by predischarge 24 hour ambulatory electrocardiographic monitoring; 43% of patients had no or simple ventricular arrhythmias (Lown grades 1 to 3) and 57% had complex ventricular arrhythmias. Risk factors analyzed included age, sex, diabetes, hypertension, smoking, preoperative digoxin or propranolol therapy, cardiopulmonary bypass time, aortic cross-clamp time, number of vessels bypassed, peak creatine kinase (CK) elevation and pericarditis. No risk factor identified patients at higher risk for complex ventricular arrhythmias. Patients were followed up for 6 to 24 months (mean 16). Patients with complex ventricular arrhythmias did not have a higher incidence of sudden death, cardiac death, syncope, angina, myocardial infarction or cerebrovascular accident. It was concluded that: Complex ventricular arrhythmias are common after coronary artery bypass graft surgery. None of the risk factors considered identify high risk patients. Complex ventricular arrhythmias after coronary artery bypass graft surgery do not indicate a poor prognosis in patients with normal left ventricular function.

Ambulatory Care↗
PubMed1984

Percutaneous transluminal coronary angioplasty of a coronary artery with a total occlusion.

Percutaneous transluminal coronary angioplasty has become an accepted therapeutic modality for patients with coronary artery disease. Until the present, its use has been restricted to vessels that are subtotally obstructed. We recently successfully utilized coronary angioplasty in a patient with a totally occluded coronary artery. The experience is described and criteria proposed for the selection of patients with totally obstructed coronary arteries for coronary angioplasty.

Adult↗
PubMed1983

Can noninvasive exercise test criteria identify patients with left main or 3-vessel coronary disease after a first myocardial infarction?

This study attempts to determine whether exercise treadmill testing with clinical, electrocardiographic, and thallium-201 myocardial perfusion imaging data can identify which patients have left main or 3-vessel (anatomically high-risk) coronary artery disease (CAD) after their first transmural myocardial infarct (MI). Twelve exercise test criteria for high-risk disease were compared in 40 patients referred for cardiac catheterization; 34 had a history of chest pain and 17 had angiographically defined high-risk CAD. A thallium image defect outside the vascular distribution of the MI was the most reliable criterion to distinguish patients with high-risk CAD (p = 0.00052 for Fisher's exact test of discrimination). Thallium imaging was somewhat more sensitive (92 versus 65%, p = 0.108) when patients with negative thallium imaging criteria who failed to achieve 85% of the age-predicted maximal heart rate were excluded. Failure to achieve 85% of predicted heart rate was by itself a useful criterion for detecting high-risk CAD (p = 0.017), especially in patients not taking propranolol (p = 0.004). Development of positive S-T segment depression at less than 70% predicted heart rate also discriminated left main or 3-vessel disease from less extensive CAD (p = 0.016). Other criteria failed to discriminate significantly between high-risk and less extensive CAD in patients after their first MI (p greater than 0.05). S-T segment depression (p = 0.199) or chest pain (p = 0.577) during exercise testing were particularly unreliable. Further, none of the criteria for high-risk CAD were influenced by irreversible left ventricular dysfunction. It is concluded that patients with thallium imaging defects outside the region of the infarct, decreasing blood pressure during exercise, failure to achieve 85% of predicted heart rate, or S-T depression at less than 70% of predicted heart rate have a high probability of having left main or 3-vessel disease. Patients without these criteria have a very low probability of having high-risk CAD and probably do not need coronary angiography for the purpose of excluding these high-risk coronary lesions after a first MI.

Adult↗
PubMed1983

Pacemaker-induced pseudotricuspid regurgitation.

A patient with aortic stenosis and ventricular pacemaker had clinical findings suggesting tricuspid regurgitation. Her presentation was actually caused by regular and constant cannon waves resulting from ventriculoatrial conduction of paced beats. The correct diagnosis was confirmed by abolition of hepatic pulsations during atrial pacing at the time of cardiac catheterization. Therapy consisted of restoring antegrade atrioventricular conduction.

Aged↗
PubMed1983

Coronary thrombosis in the absence of angiographically-evident obstructive coronary disease.

A 31-year-old man with an acute myocardial infarction underwent intracoronary thrombolysis with streptokinase. Post-thrombolytic angiography revealed no underlying obstructive coronary disease. This particular syndrome of a documented thrombus in a normal vessel causing infarction has not previously been described. Such a sequence may explain the occurrence of myocardial infarction in some patients with normal coronary arteries. The mechanism by which thrombus occurs in an angiographically-normal coronary artery is at present undefined.

Adult↗
PubMed1982

Coronary collateral function during exercise.

A totally occluded coronary vessel subtending a noninfarcted, entirely collateral-dependent myocardial region (NIECDMR) provides an opportunity to assess collateral perfusion during exercise stress. Collateral function was determined by analysis of exercise thallium-201 myocardial perfusion images from 31 patients who had at least one NIECDMR (total 41 NIECDMRs) documented during catheterization. Twenty-two of 41 NIECDMRs manifested exercise-induced perfusion defects and 19 were normally perfused. The exercise-negative NIECDMRs were further categorized: Group 1 NIECDMRs (n = 13) were associated with defects in other myocardial regions supplied by diseased vessels and were considered negative relative to other jeopardized regions; group 2 NIECDMRs (n = 6) were not associated with exercise-induced defects in other myocardial regions, which suggests that collateral perfusion was adequate during maximal exercise. Regions supplied by a diseased left anterior descending coronary artery manifested exercise defects regardless of collaterals, possibly because these regions were larger and required more perfusion. Angiographic indexes of collateral function did not clearly predict exercise results.

Adult↗
PubMed1982

Angina pectoris before and after myocardial infarction. Angiographic correlations.

Clinical, hemodynamic, and angiographic data were examined in 97 consecutive patients who underwent catheterization within two years of documented acute transmural myocardial infarction. The patients were divided according to the absence or presence of angina pectoris prior to myocardial infarction (groups 1 and 2). Group 1 had more females, was younger, and had a greater prevalence of one-vessel coronary artery disease. Of the patients surviving the myocardial infarction until hospital discharge, group 1 had fewer cases of postinfarction angina pectoris. The following were not statistically different for the two groups: mean time from infarction to catheterization, location of infarction, heart failure, coronary risk factors, mean left ventricular end-diastolic pressure, and mean ejection fraction. The angiographic significance of angina following infarction was analyzed in the 94 survivors. Patients with angina after infarction had a greater prevalence of two- and three-vessel coronary artery disease compared with patients without angina following infarction. Group 1 patients who had developed angina after infarction also had a greater prevalence of two- and three-vessel disease than patients who had no postinfarction angina. One-vessel disease was found in 82 percent of patients who had no angina before and after infarction. Infarction as the first manifestation of coronary artery disease (group 1) is often associated with one-vessel disease, especially if angina does not appear after infraction. Angina before or after infarction suggests two- and three-vessel disease.

Adult↗
PubMed1982

Unsuspected giant cell arteritis diagnosed at open heart surgery.

A 62-year-old patient undergoing aortocoronary bypass grafting had giant cell arteritis diagnosed by routine aortic biopsy done at the graft insertion site. This finding led to the tissue diagnosis of temporal arteritis and the institution of steroid therapy. In retrospect, vague symptoms of headache and fatigue, which had been attributed to side effects of antianginal therapy, were probably caused by giant cell arteritis. The population undergoing aortocoronary bypass grafting is in an age group at risk for giant cell arteritis. Routine aortic biopsy specimens should be carefully examined with this in mind.

Aortic Diseases↗