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Biomedical subjects

R Gorlin

Publications and source records attributed to R Gorlin.

At least 91 records · Page 5Linked to original sources
PubMed1982

Role of coronary vasospasm in the pathogenesis of myocardial ischemia and angina pectoris.

Spasm, either of heart muscle or of coronary arteries, has long been postulated as a possible cause of anginal pain. Yet early necropsy observations of obstructed coronary arteries in cases of cardiac death so focused attention on the fixed obstruction as the source of myocardial ischemia that the role of vasospasm is only now becoming evident. Further, the fact that spasm most commonly occurs together with a fixed obstruction has obscured its presence and its role in producing myocardial ischemia. In classic angina, ischemia results when increased oxygen demand is placed on the heart; the variant form of angina results from a restriction in myocardial oxygen supply, frequently even at rest. The mechanisms of coronary vasospasm are unclear, although such factors as excessive alpha-adrenergic activity, imbalances in prostaglandin synthesis, and increased Ca++ entry into myocytes through alterations in pH and blood gas tensions have been implicated.

Angina Pectoris↗
PubMed1982

Central hemodynamic effects of dipyridamole in severe heart failure: comparison with hydralazine.

The effects of dipyridamole, a coronary and peripheral vasodilator drug, on cardiac performance were investigated in nine patients with severe chronic heart failure. Dipyridamole (30 to 80 mg IV) increased cardiac index (1.63 to 2.65 l/min/m2) and decreased systemic vascular resistance (2097 to 1124 dyn/sec/cm-5). Left ventricular filling pressure decreased (23.7 to 20.7 mm Hg) without significant changes in mean right atrial pressure or heart rate. These effects were similar to the hemodynamic responses after 100 mg hydralazine in the same patients, but they were of shorter duration (less than 90 min). In contrast, oral dipyridamole induced only modest responses in three of eight patients despite large single doses of the drug (150 to 300 mg). Dipyridamole is a rapid-acting short-lived vasodilator, which exerts predominantly arterial vasodilator actions similar to those of hydralazine. Due to inconsistent response after oral doses, however, the therapeutic application of dipyridamole in long-term management of chronic heart failure appears to be limited.

Administration, Oral↗
PubMed1982

Hemodynamic consequences of combined beta-adrenergic and slow calcium channel blockade in man.

The administration of verapamil to patients receiving beta-adrenergic blocking drugs is reported to produce adverse circulatory reactions, but a systematic investigation of this potential drug interaction has not been performed in man. We administered 40-, 80- and 120-mg doses of verapamil orally to 15 patients with angina pectoris who were receiving high doses of propranolol or metoprolol. Verapamil produced dose-dependent decreases in cardiac performance: with 120 mg, cardiac index decreased by 0.38 l/min/m2, stroke volume index decreased by 2.8 ml/beat/m2 and heart rate decreased by 6 beats/min, associated with increases in pulmonary capillary wedge (2.2 mm Hg) and mean right atrial pressures (1.7 mm Hg) (all p less than 0.01); two patients had marked, but asymptomatic, hypotensive reactions. In contrast, repeat administration of 120-mg doses of verapamil 24--30 hours after withdrawal of beta blockade produced no significant cardiodepressant effects despite significantly higher plasma levels of verapamil than during propranolol therapy (383.1 vs 205.1 ng/ml, p less than 0.01). In conclusion, verapamil produces significant negative inotropic and chronotropic effects in patients treated with beta-adrenergic antagonists; combination therapy should therefore be used with caution in patients with angina pectoris.

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↗
PubMed1981

Preliminary experience with reversal of venoatrial flow in the diagnosis of tricuspid regurgitation.

Present methods of assessing tricuspid regurgitation are often unreliable. We present preliminary data concerning a new angiographic method for identification of tricuspid regurgitation which evaluates direction of flow of contrast media during right ventricular (RV) systole in the inferior vena cava (IVC) and hepatic veins following right atrial or IVC angiography. Group I consisted of 15 patients who had tricuspid regurgitation by conventional criteria. All 15 patients exhibited reversal of venoatrial flow by right atrial or inferior vena cava angiography. In a control group (group III) of 20 patients who do not have clinical tricuspid regurgitation, one patient demonstrated retrograde flow. Group II consisted of 11 patients with mitral valve disease and mild to moderate pulmonary hypertension. All 11 had no conventional evidence of tricuspid regurgitation; however, all 11 had the pathophysiologic potential for tricuspid regurgitation. Five of 11 had reversal of venoatrial flow during RV systole, suggesting the presence of clinically inapparent tricuspid. In conclusion, preliminary data suggest that angiographic reversal of venoatrial flow may be both sensitive and specific for the presence of tricuspid regurgitation. Further investigation with comparison to RV angiography and real-time echocardiography should be performed.

Adult↗
PubMed1981

The idiopathic hyperkinetic heart syndrome: clinical course and long-term prognosis.

Nineteen of the originally reported 24 patients having the idiopathic hyperkinetic heart syndrome were followed for periods of 11 to 25 years. One patient died of complicating severe mitral stenosis. Of the remaining 18 patients, nine had complete physical examinations and ECG records. Only one of these patients was symptomatic at the time of reexamination. Murmurs originally present in eight of nine patients were present in only five of nine at reexamination; hyperkinetic circulation and heart, originally present in eight, were found in only two at follow-up; and systolic hypertension, present in seven at beginning of the study, was only present in four at follow-up. ECG abnormalities (usually left ventricular hypertrophy) regressed in the majority. Persistent elevation of cardial index and systolic ejection rate were found at repeat catheterization in the single symptomatic patient who had congestive cardiomyopathy. Uncomplicated idiopathic hyperkinetic heart syndrome appears to have an excellent long-term prognosis.

Adult↗
PubMed1981

Septal myocardial perfusion imaging with thallium-201 in the diagnosis of proximal left anterior descending coronary artery disease.

The use of myocardial perfusion imaging (MPI) to identify obstructive coronary disease of the left anterior descending coronary artery proximal to the first septal perforator (prox LAD) was studied in 60 patients. Perfusion of the septum and anteroapical areas with thallium-201 injected during exercise was compared to results of coronary arteriography. Septal MPI defect was found in 92.3% of patients with obstruction of the proximal LAD, 27.7% of patients with obstruction of LAD distal to first septal perforator, 0% in patients with obstructions involving right or circumflex arteries, and in 10.5% of patients without coronary disease. Anteroapical MPI defects were found with similar frequency in the three groups with obstructive coronary disease. Septal MPI defect had a sensitivity of 92.3% and specificity of 85.4% in the diagnosis of proximal LAD disease. Normal septal perfusion with thallium-201 virtually excluded proximal LAD disease.

Adult↗
PubMed1981

Provocation of myocardial ischemic events during initiation of vasodilator therapy for severe chronic heart failure. Clinical and hemodynamic evaluation of 52 consecutive patients with ischemic cardiomyopathy.

Although hydralazine provokes myocardial ischemic events in hypertensive patients not in heart failure by producing reflex tachycardia, the frequency of and mechanisms underlying ischemic events when this drug is administered as a vasodilator agent to patients with heart failure is unknown. The responses to hydralazine in 52 consecutive patients with severe chronic heart failure secondary to coronary artery disease were reviewed. Twelve patients (23 percent) had 16 ischemic events during the initial administration of hydralazine (angina at rest in 12 and myocardial infarction in 4); these generally occurred in the absence of significant tachycardia and hypotension. Thirty-five of the 52 patients received nitroprusside (8 of whom had ischemic events with hydralazine), but this drug provoked ischemia in only 1 of the 35 although it resulted in greater decreases in systemic arterial pressure than occurred with hydralazine. In patients with ischemic event only with hydralazine, left ventricular filling pressure decreased 14.6 mm Hg with nitroprusside but only 3.9 mm Hg with hydralazine (probability [p] less than 0.01). Provocation of ischemia with hydralazine may therefore be due to the relative preservation of elevated left ventricular preload with this drug, since ischemic events are not in common with nitroprusside despite greater decreases in systemic pressures.

Adult↗
PubMed1981

Quantification of valve regurgitation by radionuclide angiography before and after valve replacement surgery.

Radionuclide gated cardiac blood pool imaging was used to quantify the severity of valve regurgitation in 20 patients, by calculating the ratio of left ventricular to right ventricular stroke counts (end-diastolic minus end-systolic counts in right and left ventricular regions of interest). This ratio (the stroke index ratio) was substantially higher in patients with aortic and mitral regurgitation (3.91 +/- 1.45) than in a control group of 10 patients without regurgitation (1.32 +/- 0.15), p less than 0.001. The stroke index ratio correlated closely (r = 0.947) with measurements of regurgitant fraction derived from simultaneous determinations of total and forward stroke volumes during cardiac catheterization. After aortic and mitral valve replacement in 18 patients, the stroke index ratio decreased from 4.03 +/- 1.46 to 1.38 +/- 0.23 (p less than 0.001), a value not significantly different from that observed in patients without regurgitation. All three patients with residual postoperative regurgitation had a stroke index ratio greater than 2 standard deviations above the mean values for the control group (greater than 1.62), whereas the remaining 15 patients, who had no evidence of regurgitation, had values within the normal range. Therefore, radionuclide gated blood pool scanning provides a noninvasive method of quantifying valve regurgitation and assessing the results of medical or surgical interventions.

Adult↗
PubMed1981

Coronary flow studies in patients with left ventricular hypertrophy of the hypertensive type. Evidence for an impaired coronary vascular reserve.

Increased myocardial blood flow occurs in ventricular hypertrophy, but flow per 100 grams of myocardium remains normal. The increase in flow may be obtained at the expense of the existing coronary vascular reserve or by an increase in the vascular bed. The coronary vascular reserve was studied by analyzing the hyperemic reaction to selective injection of contrast agent into the coronary arteries in 25 patients: a control group (9 patients) with chest pain syndrome, normal coronary arteries and a normal left ventricle (Group I) and 16 patients with aortic stenosis, left ventricular hypertrophy and normal coronary arteries (Group II). The hyperemic response in Groups I and II was 73.3 +/- 2.2 and 65.8 +/- 9.1 percent, respectively (difference not significant). Group II was subdivided into two groups: Group IIA had five patients with a left ventricular mass of less than 200 g (mean 158.8 +/- 25.9); this group had a hyperemic response of 102.3 +/- 9.9 percent. Group IIB had 11 patients with a left ventricular mass of more than 200 g (mean 308.9 +/- 22.5) and a hyperemic response of 49.27 +/- 10.42 percent. The hyperemic response was correlated with the diastolic left ventricular-aortic gradient (r = +0.64, p less than 0.001), left ventricular mass (r = -0.51, p less than 0.01) and aortic diastolic pressure (r = +0.636, p less than 0.001). Group I had a left ventricular mass similar to that of Group IIA (124.9 +/- 9 and 158.8 +/- 26 g, respectively) but a lower hyperemic response (73.3 +/- 2 and 102.3 +/- 10 percent, respectively). These data suggest that severe left ventricular hypertrophy is associated with a reduction in coronary vascular reserve; it is speculated that this decrease in the vascular reserve capacity may be related to the ischemic component of hypertrophic heart disease.

Adult↗
PubMed1981

Noninvasive detection of left ventricular dysfunction with a portable electrocardiographic gated scintillation probe device.

A comparison of left ventricular function data derived from a low cost, portable electrocardiographic gated scintillation probe (nuclear stethoscope) with conventional scintiangiographic data was performed in 68 patients. Ejection fraction correlation (r = 0.86, p less than 0.005) was better in patients with uniform wall motion than in those with regional asynergy (r = 0.68 p less than 0.01). Probe variables reflecting systolic emptying rates, diastolic filling rates and timing intervals, and relative volumes analyzed in combination provided 100 percent sensitivity, specificity, and predictive value in detecting abnormal left ventricular performance. The results suggest that radionuclide angiography with an electrocardiographic gated scintillation probe is a sensitive, rapid and relatively inexpensive portable method of screening for cardiac dysfunction with a yield similar to that from the more costly gamma camera derived scintiangiogram.

Electrocardiography↗
PubMed1981

Determinants of drug response in severe chronic heart failure. 1. Activation of vasoconstrictor forces during vasodilator therapy.

Vasodilator drugs activate neurohumoral forces that produce peripheral vasoconstriction and tachycardia and probably cause the rebound events observed upon abrupt withdrawal of therapy. To determine their role in limiting therapeutic vasodilator responses, these reactive forces were measured in 40 patients with severe chronic heart failure by quantifying the magnitude of rebound change (MRC) after nitroprusside withdrawal. Group 1 patients (n = 22), who had minimal reactive vasoconstriction (MRC less than or equal to 27%), showed marked hemodynamic effects with nitroprusside (4.5 microgram/kg/min) and isosorbide dinitrate (40 mg orally), associated with significant decreases in heart rate with both drugs (p less than 0.001). Despite administration of the same doses of both drugs, group 2 patients (n = 18), who had marked rebound changes (MRC greater than 27%), showed significantly smaller changes in cardiac index, systemic vascular resistance and mean arterial pressure (p less than 0.001), associated with no change or increases in heart rate. Rebound events were attenuated and the responses to nitroprusside and nitrates were enhanced in four patients in whom these drugs were readministered after pretreatment with i.v. phentolamine (0.3mg/min). We conclude that activation of neurohumoral forces can limit the hemodynamic responses to vasodilator administration; this supports the use of combination therapy of direct-acting vasodilators and neurohumoral antagonists in selected patients with severe chronic heart failure.

Administration, Oral↗
PubMed1980

Importance of left ventricular chamber size in determining the response to hydralazine in severe chronic heart failure.

To examine the importance of left ventricular chamber size in determing the response to vasodilator therapy, we performed echocardiography in 40 patients with chronic refractory heart failure before they were treated with oral hydralazine. The left ventricular end-diastolic dimension (LVEDD) correlated significantly with the per cent change in stroke volume (r = 0.77), left ventricular filling pressure (r = -0.68), and stroke work index (r = 0.87) during short-term drug administration. After 14 to 21 days of maintenance therapy, 15 of 24 patients with an LVEDD greater than or equal to 60 mm were improved, and one was worse; mean blood urea nitrogen decreased from 45.6 to 30.6 mg per deciliter in the 21 patients in this group who completed the study (16.3 to 10.9 mmol per liter) (P less than 0.001). In contrast, only two of 16 patients with an LVEDD less than 60 mm improved, whereas 10 showed clinical deterioration; blood urea nitrogen increased from 49.3 to 64.2 mg per deciliter in the 13 patients in this group who completed the study (17.6 to 22.9 mmol per liter) (P less than 0.01). These findings indicate that left ventricular chamber size is an important factor in the response to hydralazine in patients with severe chronic heart failure.

Administration, Oral↗