Reversible left-ventricular failure in angina pectoris

Usefulness of amlodipine for angina pectoris

Calcium antagonists are effective antianginal agents in the treatment of patients with stable exercise-induced angina pectoris. A series of randomized, double-blind, placebo-controlled studies with the novel, once-daily calcium antagonist amlodipine have been completed in a large number of patients with stable exercise-induced angina pectoris. Compared with placebo, once-daily amlodipine demonstrated a significant dose-related extension in exercise duration and workload accomplished, and reduction in number of anginal attacks and associated glyceryl trinitrate consumption. The clinical antianginal attributes of amlodipine were accompanied by significant reductions in electrocardiographic evidence of myocardial ischemia. In comparison with other antianginal drugs, once-daily amlodipine at a dosage range of 5-10 mg demonstrated antianginal activity comparable to thrice-daily diltiazem and once-daily nadolol. Amlodipine administered once daily achieves symptomatic and electrocardiographic amelioration of myocardial ischemic episodes induced by exercise in the majority of patients with stable angina pectoris. Amlodipine does not depress left ventricular pumping activity, and its side-effect profile does not differ substantially from that of placebo.

Therapeutic targets in ischaemic heart disease

The adequate treatment of a disease syndrome is dependent upon a clear definition of the symptomatic, pathological, physiological and prognostic targets against which therapy is to be deployed. The syndromes of ischaemic heart disease, including angina pectoris, are complex in origin, pathology, pathophysiology and natural history, and a complete clinical profile is difficult, if not impossible, to achieve in individual patients. The prime goals of pharmacotherapy in ischaemic heart disease are easy to define, but difficult to accomplish in practice. Relief of pain, breathlessness and fatigue are the prime clinical targets for pharmacotherapy. In view of their sinister significance, the electrophysiological indications of myocardial ischaemia, whether symptomatic or silent, are also crucial targets towards which therapy must be directed. Ischaemic heart disease is accompanied by a wide variety of regional and global abnormalities of myocardial contractile function associated with widespread reflex stimulation of the peripheral vascular system and neuroendocrine systems. Primarily, drug therapy must be directed at correction of these pathophysiological components of the syndrome. Longer term but no less essential goals in the treatment of ischaemic heart disease are the prevention of the clinical sequelae of the syndrome and its progression. A natural sequel of coronary artery obstructive disease is successive thrombotic events and loss of myocardium. Calcium antagonists, by preventing the increase in myocardial cytosolic calcium during acute ischaemic episodes, defer cell necrosis; in this respect, they are unique among currently available antianginal drugs. With regard to progression, the prime pathological cause of ischaemic heart disease is coronary atheroma.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic interactions of a new beta blocker, celiprolol, with nifedipine in angina pectoris

The hemodynamic consequences of blockade at both beta-adrenoceptors and slow calcium channels is of therapeutic importance for patients with angina pectoris. The hemodynamic interaction of a new cardioselective beta blocker, celiprolol, and nifedipine was examined in an acute hemodynamic study using three prospectively matched groups with angiographically confirmed coronary artery disease (n = 10/group). Patients were randomly allocated to intravenous celiprolol (8 mg), sublingual nifedipine (20 mg), or their combination. Rest and exercise (supine bicycle) hemodynamics were determined before and following each therapy. At rest, celiprolol did not alter pumping function; nifedipine reduced diastolic blood pressure and systemic vascular resistance index (SVRI), with a small increase in heart rate. Combination therapy reduced systemic arterial pressure and SVRI; heart rate and cardiac stroke volume index increased. During exercise celiprolol tended to reduce heart rate and cardiac index; nifedipine reduced exercise SVR and cardiac stroke work indices. Combination therapy reduced all components of blood pressure; cardiac stroke work and SVR indices fell. These hemodynamic data suggest that beta blockade with celiprolol may result in a slight depression of cardiac pumping during exercise; however, such effects are offset by the vasodilating actions of nifedipine (reflex sympathetic action offsetting cardiodepression). Thus the acute hemodynamic effects of this combination were seemingly safe in these patients; the longer term effects during maintained therapy should be further assessed.

Demonstration of exercise-induced painless myocardial ischemia in survivors of out-of-hospital ventricular fibrillation

To ascertain if myocardial ischemia is the mechanism of out-of-hospital ventricular fibrillation (VF), left ventricular (LV) function was assessed at rest and during submaximal exercise in 15 patients who survived out-of-hospital VF. They were separated into asymptomatic (9 patients, group A) and symptomatic (6 patients, group S) groups for a history of angina or myocardial infarction. Both groups had significant (at least 70% diameter stenosis) coronary artery disease. At catheterization no patient had angina during exercise, but 12 of 15 had ST depression or increased ST depression (group A, 1.9 +/- 1.4 mm; group S, 1.1 +/- 1.2 mm) and 11 had abnormal wall motion. From rest to exercise, patients in group S had increased LV end-diastolic pressure (from 21 +/- 9 to 37 +/- 11 mm Hg, p = 0.009) and volume (from 100 +/- 25 to 107 +/- 26 ml/m2, p = 0.006), with no significant change in LV ejection fraction (from 40 +/- 13 to 42 +/- 12%). In group A LV end-diastolic pressure increased from 19 +/- 4 to 31 +/- 8 mm Hg (p = 0.001), but neither end-diastolic volume nor ejection fraction changed significantly (from 83 +/- 13 to 92 +/- 23 ml/m2 and from 55 +/- 13% to 46 +/- 13%, respectively). Thus, patients with coronary artery disease who survive out-of-hospital VF may have evidence of myocardial ischemia during exercise without pain. Painless ischemia may have a role in out-of-hospital VF.

Immediate and long-term effects of nicardipine, at rest and during exercise, in patients with coronary artery disease

Haemodynamic effects of nicardipine were studied in 12 patients with documented coronary artery disease. Following nicardipine 10 mg, given intravenously to patients at rest, the heart rate increased, mean arterial pressure decreased, cardiac index increased, and systemic vascular resistance decreased significantly. Compared with the control exercise values, significant increases in heart rate and cardiac index and significant decreases in mean arterial pressure, systemic vascular resistance, and left ventricular end diastolic pressure occurred when nicardipine, 10 mg i.v., was given to the patients during exercise. All 12 patients complained of angina during the exercise phase, but following treatment with nicardipine, 10 mg i.v., only four patients reported angina when exercising to the same level. Exercise capacity on oral nicardipine treatment tended to increase whilst the ejection fraction response to exercise did not change. Thus, nicardipine was a potent vasodilator, which produced a marked reduction of systemic vascular resistance and left ventricular end diastolic pressure during exercise.

Effects of nicardipine on cardiac volume at rest and during exercise-induced angina

The action of nicardipine on cardiac volume, both at rest and during exercise-induced angina, was evaluated in 12 patients with angiographically-proven coronary artery disease. Nicardipine given to patients at rest reduced systemic vascular resistance and mean arterial pressure and increased heart rate and cardiac index. The left ventricular filling pressure, ejection fraction (EF), end-diastolic and end-systolic volumes were unchanged. During supine bicycle exercise, the reduction in systemic arterial blood pressure following nicardipine increased cardiac and stroke index and attenuated the rise in left ventricular filling pressure observed in the control exercise. The effects of nicardipine on EF, end-diastolic and end-systolic cardiac volumes were dependent on the baseline cardiac reserve. In patients with EF less than 50%, nicardipine improved EF and left ventricular exercise volumes.

Hemodynamic effects of nifedipine during upright exercise in stable angina pectoris and either normal or severely impaired left ventricular function

The immediate effects of sublingual nifedipine (20 mg) were evaluated in 18 men with stable, exercise-related angina pectoris and angiographically confirmed coronary artery obstructions, stratified at the time of left ventricular (LV) angiography according to the degree of LV dysfunction supine at rest (Group 1: n = 9, left ventricular end-diastolic pressure [LVEDP] less than 20 mm Hg; Group 2: n = 9, LVEDP greater than 20 mm Hg). At rest, in the upright posture in both groups, nifedipine reduced the systemic vascular resistance (p less than 0.01). The systemic arterial mean (p less than 0.05) and diastolic (p less than 0.01) pressures were reduced despite an increase in the cardiac output (p less than 0.05). Heart rate was increased only in Group 1 (p less than 0.05). Pulmonary artery occluded pressure was unchanged in both groups. During upright bicycle exercise in all patients, compared to control measurements, systemic arterial pressure (p less than 0.01) and vascular resistance (p less than 0.05) were similarly reduced, while exercise cardiac output response and LV filling pressure did not change after nifedipine. Heart rate was increased in Group 1 (p less than 0.05) and decreased in Group 2 (p less than 0.05). Stroke volume during exercise after nifedipine decreased 1 ml/m2 in Group 1 (p greater than 0.05) and increased 2 ml/m2 in Group 2 (p greater than 0.05) compared to control measurements; the between-group difference in the exercise heart rate and stroke volume responses after nifedipine were significant at the 5% level.(ABSTRACT TRUNCATED AT 250 WORDS)

Alpha- and beta-blockade in angina pectoris

Angina pectoris encompasses a clinically diverse group of syndromes in which the common factor is myocardial ischaemia resulting from an imbalance between oxygen requirement and delivery. Anginal pain is most frequently precipitated by exercise, but may occur without any apparent cause at rest. Fixed obstructions in the coronary vessels, often attended by thickening of the overlying coronary artery media, are the most frequent cause of ischaemic cardiac pain. The resulting myocardial fibrosis impairs efficient filling and emptying of the ventricles, further aggravating the functional embarrassment resulting from the reduced coronary blood flow. In stable coronary heart disease the increased energy demands during exercise are associated with the rapid development of a haemodynamic profile characteristic of acute left ventricular failure. This results in further substantial increases in pressure work, wall stress and oxygen consumption of the left ventricle. The reflex sympathoadrenal consequences of these primary haemodynamic changes lead to further mechanical and electrical embarrassment of the ischaemic heart. Increased stimulation of beta 1- and beta 2-receptors in the heart increases heart rate and contractility and thereby myocardial oxygen demand. Increased stimulation of alpha-receptors in the peripheral veins and arteries indirectly increases left ventricular oxygen demand still further by increasing preload and afterload, respectively. The reduced blood flow to the endocardium enhances its sensitivity to increased sympathoadrenal stimulation and facilitates initiation of arrhythmias. Blockade of all adrenergic activity, particularly in the myocardium, coronary arteries and peripheral blood vessels should, therefore, help alleviate the myocardial ischaemia. There is a rational argument for the use of alpha-blockade in coronary heart disease, particularly in conjunction with beta-blockade. Attenuation of the risk of coronary spasm and ventricular arrhythmias and reduction of pressure work and left ventricular afterload are amongst the potential attributes of alpha-blockade. Alone, however, their utility is severely limited by the risks of hypotension and reduction in coronary perfusion pressure and reflex oxygen-wasting tachycardia. Alone, alpha-adrenoceptor antagonists have no place in the treatment of angina pectoris. beta-Adrenoceptor blocking drugs competitively inhibit catecholamines at both cardiac and peripheral vascular beta-adrenergic receptors. Their main advantage is that they reduce many of the important determinants of myocardial oxygen consumption, particularly by reducing the heart rate during exercise.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative haemodynamic dose-response effects of intravenous propranolol and pindolol in patients with coronary heart disease

To determine whether the depression of left ventricular pumping activity associated with beta-blockade alone could be offset by a substantial degree of partial agonist activity, the haemodynamic dose-response effects of intravenous propranolol and pindolol were compared in a randomised between-group saline controlled study in twenty patients with angiographically proven coronary artery disease. The intravenous doses of propranolol (2-16 mg) and pindolol (0.2-1.6 mg) used were selected on the basis of published reports of equivalence in terms of exercise blockade of chronotropic beta-adrenoceptors. Following four intravenous boluses of each drug, administered according to a cumulative log-dosage schedule, there was a log-linear increase in the plasma concentrations of each drug. The range of plasma concentrations achieved were those which have been shown to be associated with substantial attenuation of sympathetic stimulation of cardiac beta-adrenoceptors. At rest propranolol resulted in dose-related linear reductions in heart rate and cardiac output and linear increases in left heart filling pressure and systemic vascular resistance compared with saline-controlled measurements. The only statistically significant change at rest after pindolol was a small increase in the left heart filling pressure. The calculated systemic vascular resistance was increased after propranolol but unchanged after pindolol. During supine bicycle exercise the systolic blood pressure increased less after propranolol than after saline or pindolol. The increments in all other measured haemodynamic variables during exercise were equally influenced by the two drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative haemodynamic dose response effects of propranolol and labetalol in coronary heart disease

The immediate haemodynamic dose response effects of beta blockade (propranolol: 2 to 16 mg) were compared with those of combined alpha beta blockade (labetalol: 10 to 80 mg) in a randomised study of 20 patients with stable angina pectoris. After control measurements, the circulatory changes induced by four logarithmically cumulative intravenous boluses of each drug in equivalent beta blocking doses were evaluated at rest, after which comparison of the effects of the maximum cumulative dose of each was undertaken during a four minute period of supine bicycle exercise. Propranolol, at rest, induced significant dose related reductions in heart rate and cardiac output, with reciprocal increases in the systemic vascular resistance and pulmonary artery occluded pressure; systemic arterial pressure was unchanged. Labetalol was followed by significant dose related decreases in systemic blood pressure and vascular resistance associated with a significant increase in cardiac output; heart rate and pulmonary artery occluded pressure were unchanged. The slope of the left ventricular pumping function curve relating output to filling pressure from rest to exercise was significantly depressed by propranolol but unchanged after labetalol. The less deleterious effects on left ventricular haemodynamic performance after alpha beta blockade in contrast to beta blockade alone in ischaemic heart disease may be attributable to the concomitant reduction in left ventricular afterload associated with the alpha blocking activity of labetalol.

Molsidomine in the treatment of patients with angina pectoris

Molsidomine, a new long-acting vasodilator, was administered intravenously (0.03 mg per kilogram of body weight) to two groups of six patients with stable anginapectoris. In the first group, studied during exercise-induced angina, the drug shortened the duration of pain and reduced electrocardiographically measured ST-segment depression, mean systemic arterial pressure, and mean pulmonary wedge pressure. Cardiac output and heart rate remained unchanged. In the second group, studied during pacing-induced angina, the drug reduced both left ventricular pressures and angiographically estimated ventricular volumes and improved the ejection fraction. In a double-blind crossover comparison with a placebo, molsidomine (2 mg three times daily) reduced the frequency of anginal attacks and the consumption of nitroglycerin tablets in 14 patients. During exercise testing on a treadmill a statistically significant reduction in ST-segment depression lasted for up to six hours. These studies suggest that molsidomine acts like nitroglycerin but its effects last longer. We conclude that molsidomine is effective in preventing the symptoms of angina pectoris. (N Engl J Med 302:1-6, 1980).

Left ventricular function after aortocoronary bypass surgery

Aortocoronary bypass operations without additional myocardial surgery or valve replacement were performed at Ullevål Hospital in 190 patients during the period May 1971 to Dec. 1975. Postoperatively re-examination was made by left-heart catheterization in 124 patients at a mean interval of 18.2 months and right-heart catheterization in 108 patients at a mean interval of 16.0 months after surgery. The mean postoperative values for PCVP at rest, PCVP during exercise, LVEDP before contrast and LVEDP after contrast were significantly lower than the mean pre-operative values. The difference between pre- and postoperative values were largest in patients with elevated PCVP or LVEDP values before surgery, whereas in patients with low pre-operative values the mean values after surgery were unchanged or increased. The results indicate that marked improvement of left ventricular function may occur after aortocoronary bypass operations, even in patients with signs of ventricular failure at rest. A stress test is, however, of importance in evaluating the haemodynamic consequences of coronary surgery. No difference was found in patients with single versus patients with double or triple shunts. Post-operative shunt occlusion was found in 44 of 258 grafts at re-examination. No difference was found between patients with all shunts patent and patients with one or more shunts occluded as regard to mean postoperative PCVP and LVEDP values.

Left ventricular pressure responses in post-angiographic angina

Alterations in left ventricular end-diastolic pressure and in dp/dt observed in ten patients with coronary heart disease who developed angina pectoris following left ventricular cineangiography were compared with those of six other patients who developed angina spontaneously and with patients who underwent left ventricular cineangiography without experiencing angina. In the patients with post-angiographic angina there was a greater increase in end-diastolic pressure than that seen in the other patients, but there was no significant change in dp/dt. Changes in left ventricular pressure associated with post-angiographic angina would appear to reflect the combined effects of increased preload provided by the contrast material and of ventricular dysfunction including diminished compliance associated with angina. A rise in end-diastolic pressure greater than 20 mmHg following left ventricular cineangiography should alert the physician that the patient may be having myocardial ischemia.

Comparison of adrenergic beta-receptor antagonists in angina pectoris

The symptomatic, electrocardiographic, and circulatory effects of intravenous and oral preparations of propranolol, oxprenolol, and practolol were compared in 16 patients with uncomplicated angina pectoris precipitated by exertion. The method of study included treadmill exercise, double-blind assessment, single-blind analysis, with placebo control and randomized serial comparison of each drug in each patient. The doses used were selected to give the same near-maximum suppression of the heart rate response to exercise. The symptomatic, electrocardiographic, and circulatory response of each patient to both preparations of each of the three drugs was similar. Exercise tolerance was increased in two-thirds, unchanged in one-sixth, and significantly worsened in one-sixth of the studies. Electrocardiographic evidence of myocardial ischaemia was conspicuously reduced by all three drugs in most studies irrespective of their symptomatic effects. Though the exclusive choice of patients, the single dose design of the trial, and the treadmill method of assessment limit the general application of these results, they do clearly indicate that in doses that induce equal suppression of the exercise heart rate these three drugs have similar distinct anti-anginal activity. Their ancillary pharmacological properties are probably of little importance in this respect. Equally, the similarity in the symptomatic, circulatory, and electrocardiographic response to the intravenous and oral preparations suggests that metabolic breakdown products are probably of therapeutic importance only in so far as they antagonize beta-receptor activity.

Comparison of adrenergic beta-blocking drugs in angina pectoris

The symptomatic, electrocardiographic, and haemodynamic effects of two adrenergic beta-blocking drugs, oxprenolol and propranolol, have been compared in equipotent intravenous doses in six patients with uncomplicated angina pectoris during treadmill exercise. The method of comparison included double-blind assessment and analysis with placebo control and randomized serial comparison in each patient. Both drugs produced an equal amelioration in symptoms in most of the patients. This was closely correlated with improvement in the electrocardiographic changes and a significant reduction in the exercising heart rate and systemic arterial pressure. This method of double-blind combined subjective and objective assessment carries distinct advantages in the comparative assessment of drug treatments in angina pectoris.