Hemodynamic and myocardial performance characteristics after verapamil use in congestive heart failure

SIRT1-FOXOs signaling pathway: A potential target for attenuating cardiomyopathy

Cardiomyopathy constitutes a global health burden. It refers to myocardial injury that causes alterations in cardiac structure and function, ultimately leading to heart failure. Currently, there is no definitive treatment for cardiomyopathy. This is because existing treatments primarily focus on drug interventions to attenuate symptoms rather than addressing the underlying causes of the disease. Notably, the cardiomyocyte loss is one of the key risk factors for cardiomyopathy. This loss can occur through various mechanisms such as metabolic disturbances, cardiac stress (e.g., oxidative stress), apoptosis as well as cell death resulting from disorders in autophagic flux, etc. Sirtuins (SIRTs) are categorized as class III histone deacetylases, with their enzyme activity primarily reliant on the substrate nicotinamide adenine dinucleotide (NAD (+)). Among them, Sirtuin 1 (SIRT1) is the most intensively studied in the cardiovascular system. Forkhead O transcription factors (FOXOs) are the downstream effectors of SIRT1. Several reports have shown that SIRT1 can form a signaling pathway with FOXOs in myocardial tissue, and this pathway plays a key regulatory role in cell loss. Thus, this review describes the basic mechanism of SIRT1-FOXOs in inhibiting cardiomyocyte loss and its favorable role in cardiomyopathy. Additionally, we summarized the SIRT1-FOXOs related regulation factor and prospects the SIRT1-FOXOs potential clinical application, which provide reference for the development of cardiomyopathy treatment.

Safety and Efficacy of Nondihydropyridine Calcium Channel Blockers for Acute Rate Control in Atrial Fibrillation with Rapid Ventricular Response and Comorbid Heart Failure with Reduced Ejection Fraction

The use of nondihydropyridine calcium channel blockers (NDCCBs) to achieve rate control in atrial fibrillation with the rapid ventricular rate (AF RVR) is not recommended in patients with comorbid heart failure with reduced ejection fraction (HFrEF) due to the concern for further blunting of contractility. However, these recommendations are extrapolated from data examining chronic NDCCB use in HFrEF patients, and comorbid AF was not analyzed. These recommendations also do not cite the hemodynamic effects or clinical outcomes of NDCCBs for acute rate control in HFrEF patients with AF RVR. It is our goal to open the discussion concerning the hemodynamic effects and safety profile of NDCCBs for acute rate control in this specific patient population. In the acute setting of AF RVR and HFrEF, there is a paucity of low-quality data on the safety and hemodynamic effects of NDCCBs, with mixed results. There has not been a clear signal toward adverse outcomes with NDCCBs, particularly for diltiazem. Data in this scenario is similarly limited for beta blockers, which provide the additional hemodynamic effect of the neurohormonal blockade, which provides a long-term mortality benefit to HFrEF patients. We support the cautious use of beta blockers as first-line therapy in clinical settings where an acute rate control strategy for AF RVR is warranted. We also support diltiazem as a reasonable second-line option, though the relative paucity of data calls for further research to validate this conclusion. Verapamil in this setting should be avoided until more data are available.

Effects of the novel T-type calcium channel antagonist mibefradil on human myocardial contractility in comparison with nifedipine and verapamil

Mibefradil (Ro 40-5967) is a novel nondihydropyridine calcium antagonist. The aim of our study was to compare the negative inotropic effects of the well-known 1,4-dihydropyridine nifedipine and the phenylalkylamine verapamil with those of mibefradil. Isometric force of contraction in response to these substances was determined in isolated, electrically driven left ventricular papillary muscle strips from failing human hearts (1 Hz, 37 degrees C). The hearts were obtained during cardiac transplantation (n = 9) and mitral valve-replacement operations (n = 9). The calcium antagonists studied significantly (p < 0.05) depressed basal force of contraction in a concentration-dependent manner. The effect started at concentrations > 0.001 microM for nifedipine and > 0.01 microM for verapamil, but only at concentrations > 10 microM for mibefradil. Only in the presence of nifedipine and verapamil was a significant rightward shift of the inotropic concentration--response curves to calcium and a depression of the maximal effects of calcium observed. With respect of the relation between the therapeutic active plasma concentration in vivo and the negative intropic potency in vitro, it became evident that the difference between therapeutically beneficial concentrations and potentially hazardous cardiodepressant activity increases from nifedipine to mibefradil. We conclude that this new generation of calcium antagonists, almost lacking cardiodepressant effects, could lead to a greater therapeutic index and greater safety in the treatment of cardiovascular diseases.

Use of intravenous diltiazem in patients with acute coronary artery disease

The use of calcium antagonists for the treatment of patients with unstable angina and acute myocardial infarction has been a promising area of both basic and clinical research. Despite consistently beneficial effects experimentally, the clinical extrapolation of these results has been less than ideal, especially in patients with evolving myocardial infarction. Calcium antagonists have in some instances failed to manifest benefit and at times have been shown to have negative effects. One reason for this could be the use of oral or sublingual preparations, which result in variable absorption, variable volumes of distribution, and variable clearance. For this reason, an intravenous preparation of one of the calcium antagonists, diltiazem, may be more beneficial. Such a preparation has been developed and its safety confirmed in patients without cardiovascular disease and in patients with acute infarction. Substantial benefit has been documented in patients with stable angina and during noncardiac surgery. Preliminary data in patients with unstable angina suggest that the drug is effective, although studies comparing intravenous diltiazem with other agents or with the oral preparation of diltiazem have not yet been reported. Experimental data in animals with acute infarction have demonstrated that administration of intravenous diltiazem after occlusion, but prior to reperfusion, elicits a marked increase in the degree of myocardial salvage induced by thrombolysis. This appears to be due to the inhibition of lipid peroxidation rather than alterations in coronary perfusion. Thus, it appears that the intravenous preparation may permit the more effective use of diltiazem in patients with acute coronary artery disease.

Calcium antagonists and left ventricular function

Calcium antagonists impede the entry of calcium into myocytes and inhibit myocardial contraction. Calcium antagonists differ in their relative negative inotropic potency and can provoke baroreceptor stimulation that modulates left ventricular (LV) performance. Calcium antagonists are uniformly well tolerated in patients with normal LV function. Use of these agents in patients with suspected LV function impairment has yielded results ranging from hemodynamic improvement to clinical deterioration and increased mortality. Reports of clinical deterioration when calcium antagonists were combined with beta blockers underscore the importance of reflex adrenergic support for the myocardium. Although calcium antagonists are potent vasodilators and produce short-term hemodynamic improvement, they are not useful as primary treatment in patients with congestive heart failure (CHF). They may have a place in the treatment of coexistent problems in patients with LV dysfunction. Short-term use of calcium antagonists for myocardial ischemia or rapid atrial fibrillation is probably safe in the presence of LV dysfunction and overt CHF. Calcium antagonists appear to have a role in the treatment of patients with diastolic dysfunction of diverse etiologies.

Verapamil administration to patients with contraindications: is it associated with adverse outcomes?

STUDY OBJECTIVES

To determine if the use of verapamil in patients with contraindications is associated with adverse sequelae, thereby assessing whether process measures of the quality of care are correlated with patient outcomes.

DESIGN

Retrospective chart review comparing the incidence of adverse outcomes and drug failure in patients with and without contraindications to verapamil administration.

SETTING

University hospital emergency department.

PARTICIPANTS

All patients more than 12 years old who received IV verapamil during the study period.

MEASUREMENTS

The presence or absence of contraindications to verapamil, the occurrence of complications, and the frequency of drug failure were determined by chart review.

MAIN RESULTS

Patients with contraindications to verapamil experienced a significantly higher incidence of adverse outcomes and drug failures than those without contraindications. The presence of contraindicated rhythms, low pretreatment blood pressure, and signs of congestive heart failure were each specifically associated with an increased risk of adverse sequelae.

CONCLUSION

Verapamil should not be administered to patients with contraindications to its use. In this instance, quality assurance process measures correlate with patient outcomes.

Supraventricular tachyarrhythmias and rate-related hypotension: cardiovascular effects and efficacy of intravenous verapamil

IV verapamil is the preferred drug for the acute management of supraventricular tachyarrhythmias (SVTs) in the absence of contraindications to its use. SVT complicated by hypotension has been considered a relative contraindication for the use of IV verapamil. However, the efficacy of IV verapamil in the management of "rate-related" hypotension has not been specifically addressed. The purpose of this study was to assess the effects of IV verapamil in patients with SVTs and arterial hypotension. A retrospective and prospective study design was used. Inclusion criteria were SVT (QRS duration, less than 120 ms; R-R interval, regular or irregular), QRS rate of 140 or more, systolic blood pressure of 90 mm Hg or less, and normal mental status. We identified 21 episodes of SVT meeting inclusion criteria in 19 patients. SVT was due to atrioventricular node re-entry in 17, atrial fibrillation in three, and atrial flutter in one. There were seven men and 12 women, with a mean age (+/- SD) of 52 +/- 17 years. Systolic blood pressure before verapamil was 70 +/- 28 mm Hg, and QRS rate was 192 +/- 19. IV calcium was not administered before IV verapamil. After IV verapamil administration (mean dose, 6.5 +/- 4.3 mg), a positive response (conversion to sinus rhythm or ventricular rate of less than 120) was noted in 17 of 21 episodes (80%). Post-treatment systolic blood pressure increased to 98 +/- 16 mm Hg (P less than .005 vs pretreatment), and ventricular response rate decreased to 112 +/- 39 (P less than .001 by two-tailed paired t test).(ABSTRACT TRUNCATED AT 250 WORDS)

Mild heart failure: diagnosis and treatment

CHF afflicts 15 million persons worldwide despite advances made in its diagnosis and treatment. A thorough physical examination and basic, noninvasive evaluation are essential for establishing the diagnosis of heart failure and for designing an optimal, individualized treatment regimen. Although digitalis and diuretics continue to be used commonly for the treatment of CHF of all severities, the use of vasodilators and ACE inhibitors has increased dramatically, as they are used more widely and earlier in the course of the illness. Because the RAA system contributes significantly to the altered cardiovascular hemodynamics and symptomatology characteristic of heart failure, the ACE inhibitors provide a rational approach to therapy for many patients. Results of controlled clinical trials have shown that selected vasodilators and ACE inhibitors can improve survival in patients with CHF and that patients receiving ACE inhibitors show sustained improvement in clinical class, exercise tolerance, and hemodynamics. Thus the therapeutic spectrum available to the clinician dealing with patients with CHF has broadened substantively over the past decade.

Inotropic effect of nicardipine in patients with heart failure: assessment by left ventricular end-systolic pressure-volume analysis

Nicardipine, a new dihydropyridine calcium channel blocker, has been investigated for the treatment of coronary artery disease and heart failure. To assess the inotropic effect of nicardipine in humans independent of its vasodilator effect, equihypotensive doses of intravenous nitroprusside (mean infusion rate 65 +/- 13 micrograms/min) and nicardipine (mean dose 5.2 +/- 0.4 mg) were administered to 15 patients with heart failure (New York Heart Association functional classes II to IV, radionuclide left ventricular ejection fraction 0.15 +/- 0.02). Left ventricular micromanometer pressure and simultaneous radionuclide left ventricular volume were obtained at baseline, during nitroprusside infusion, during a second baseline period and during nicardipine infusion. Heart rate did not change significantly with either nitroprusside or nicardipine. Mean systemic arterial pressure decreased by an average of 21 mm Hg with both drugs. A greater decrease in left ventricular end-diastolic pressure occurred with nitroprusside (27 +/- 2 to 14 +/- 2 mm Hg, p less than 0.01) than with nicardipine (27 +/- 2 to 23 +/- 3 mm Hg, p less than 0.05), and pulmonary capillary wedge pressure decreased significantly only with nitroprusside. Cardiac index increased from 1.8 +/- 0.1 to 2.1 +/- 0.1 liters/min per m2 (p less than 0.05) with nitroprusside and to a greater extent from 1.7 +/- 0.1 to 2.4 +/- 0.1 liters/min per m2 (p less than 0.01) with nicardipine. Left ventricular ejection fraction increased with nicardipine (0.15 +/- 0.01 to 0.19 +/- 0.01, p less than 0.01), but not with nitroprusside. Peak positive first derivative of left ventricular pressure (dP/dt) decreased by 9% with both agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Verapamil. An updated review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension

Although verapamil is a well-established treatment for angina, cardiac arrhythmias and cardiomyopathies, this review reflects current interest in calcium antagonists as anti-hypertensive agents by focusing on the role of verapamil in hypertension. Verapamil is a phenylalkylamine derivative which antagonises calcium influx through the slow channels of vascular smooth muscle and cardiac cell membranes. By reducing intracellular free calcium concentrations, verapamil causes coronary and peripheral vasodilation and depresses myocardial contractility and electrical activity in the atrioventricular and sinoatrial nodes. Verapamil is well suited for the management of essential hypertension since it produces generalised systemic vasodilation resulting in a marked reduction in systemic vascular resistance and, consequently, blood pressure. Evidence from clinical studies supports the role of oral verapamil as an effective and well-tolerated first-line treatment for the management of patients with mild to moderate essential hypertension. Clinical studies have shown that verapamil is more effective the higher the pretreatment blood pressure and some authors have found a more pronounced antihypertensive effect in older patients or in patients with low plasma renin activity. Sustained release verapamil formulations are available for oral administration which, as a single daily dose, are as effective in lowering blood pressure over 24 hours as equivalent doses of conventional verapamil formulations given 3 times daily. As a first-line antihypertensive agent, oral verapamil is equivalent to several other calcium antagonists, beta-blockers, diuretics, angiotensin-converting enzyme (ACE) inhibitors and other vasodilators, and is not associated with many of the common adverse effects of these treatments. Verapamil may be preferred as an alternative first-line antihypertensive treatment to diuretics in elderly patients because it has similar efficacy in these patients without causing the adverse effects commonly linked with diuretic treatment. Furthermore, because verapamil does not cause bronchoconstriction, it may be used in preference to beta-blockers in patients with asthma or chronic obstructive airway disease. Reflex tachycardia, orthostatic hypotension or development of tolerance is not evident following verapamil administration. As a second- or third-line treatment for patients refractory to established antihypertensive regimens, verapamil produces marked blood pressure reductions when combined with diuretics and/or ACE inhibitors, beta-blockers and vasodilators such as prazosin.(ABSTRACT TRUNCATED AT 400 WORDS)

Hemodynamic study of short- and long-term isradipine treatment in patients with chronic ischemic congestive heart failure

The acute hemodynamic effects of isradipine on cardiac performance, at rest and during exercise, were examined in nine male patients aged 37 to 69 years with congestive heart failure due to ischemic heart disease. The effects of 10 mg oral isradipine were maximal after two to three hours with significant decreases in blood pressure as well as in systemic and pulmonary vascular resistances, and an increase in cardiac output. There were no significant changes in heart rate or pulmonary capillary wedge pressure. For the same 50-watt bicycle workload pre- and post-drug, the addition of isradipine was associated with lower systemic and pulmonary vascular resistances (systemic vascular resistance, 805 +/- 70 versus 975 +/- 70; p less than 0.01; pulmonary vascular resistance, 144 +/- 27 versus 207 +/- 35 dynes.sec.cm-5; p less than 0.01), and lower pulmonary artery pressures (54 +/- 6/23 +/- 3 versus 66 +/- 7/27 +/- 3 mm Hg; p less than 0.01) during exercise. In a double-blind 12-week trial, body weight decreased during isradipine treatment (71.6 to 68.9 kg; p less than 0.01), but there were no significant changes in exercise duration, radionuclide ejection fraction, or cardiothoracic ratio, and no serious side effects were encountered. These results suggest that isradipine is worthy of further evaluation in long-term treatment of chronic ischemic congestive heart failure.

Calcium antagonists and heart failure

The systemic vasodilatory actions of the calcium antagonists make them potentially attractive for use as afterload reducing agents in patients with left ventricular failure. However, unlike other vasodilator drugs, these drugs also exert a direct negative inotropic effect on the myocardium. Clinical data suggest a limited role for the calcium antagonists as vasodilator therapy in patients with heart failure.

Clinical and hemodynamic effects of long-term administration of gallopamil in patients with coronary artery disease and normal or impaired left ventricular function

The hemodynamic and clinical profiles of gallopamil, a new calcium antagonist, were evaluated in 20 patients with severe coronary artery disease in a placebo-controlled, single-blind study. The patients were divided into 2 groups depending on baseline ejection fraction (greater than 45 or less than or equal to 45%) and underwent nuclear ventriculography, both at rest and during bicycle exercise under electrocardiographic monitoring, after 3 weeks of therapy (50 mg 3 times daily) and the 1-week run in and washout placebo periods. The mean anginal weekly frequency per patient was significantly reduced, from 3.4 to 0.5 (p less than 0.001). The left ventricular ejection fraction, cardiac volumes, ejection and filling indexes at rest and for the same workload were not altered in the population as a whole or in each of the 2 groups. The rate pressure product during exercise was reduced for the same workload from 18.0 +/- 5.0 X 10(3) to 16.8 +/- 4.7 X 10(3), while the regional ejection fraction in ischemic regions was not significantly changed. Individual variations of ventriculographic parameters in both groups were not related to basal values. Gallopamil increased the total duration of exercise from 432 +/- 201 to 537 +/- 188 s (p less than 0.001). Six patients did not complain of angina and their exercise was interrupted because of muscular weakness. The hemodynamic and clinical responses did not differ when the results in the population as a whole and in each of the 2 groups were compared. Gallopamil was effective and well tolerated, even in patients with very depressed cardiac function.

Vasodilator and inotropic drugs for the treatment of chronic heart failure: distinguishing hype from hope

During the past 10 years, more than 80 orally active vasodilator and inotropic agents have been tested in the clinical setting to evaluate their potential utility in the treatment of chronic heart failure. Although the initial reports of all of these drugs suggested that each represented a major therapeutic advance, only three agents--digoxin, captopril and enalapril--have produced consistent long-term hemodynamic and clinical benefits in these severely ill patients. Most of the other drugs that have been tested have not (to date) distinguished themselves from placebo therapy in large-scale, controlled trials, even though these agents produce hemodynamic effects that closely resemble those seen with digitalis and the converting-enzyme inhibitors. These observations suggest that the hemodynamic derangements that characteristically accompany the development of left ventricular dysfunction cannot be considered to be the most important pathophysiologic abnormality in chronic heart failure. Although cardiac contractility is usually depressed in this disease, positive inotropic agents do not consistently improve the clinical status of these patients. Similarly, although the systemic vessels are usually markedly constricted, drugs that ameliorate this vasoconstriction do not consistently relieve symptoms, enhance exercise capacity or prolong life. Hence, correction of the central hemodynamic abnormalities seen in heart failure may not necessarily provide a rational basis for drug development, and future advances in therapy are likely to evolve only by attempting to understand and modify the basic physiologic derangements in this disorder.

Calcium channel antagonists. Part IV: Side effects and contraindications drug interactions and combinations

With the correct selection of drug and patient, the calcium antagonists as a group can be remarkably effective at relatively low cost of serious side effects. Almost all side effects are dose related. Minor side effects include those caused by vasodilation (flushing and headaches), constipation (verapamil), and ankle edema. Serious side effects are rare and result from improper use of these agents, as when intravenous verapamil (or diltiazem) is given to patients with sinus or atrioventricular nodal depression from drugs or disease, or nifedipine to patients with aortic stenosis. The potential of a marked negative inotropic effect is usually offset by afterload reduction, especially in the case of nifedipine which actually has the most marked negative inotropic effect. Yet caution is required when even calcium antagonists, especially verapamil, are given to patients with myocardial failure unless caused by hypertensive heart disease. Drug interactions of calcium antagonists occur with other cardiovascular agents such as alpha-adrenergic blockers, beta-adrenergic blockers, digoxin, quinidine, and disopyramide. The most marked interaction with digoxin is that with verapamil, which may raise digoxin levels by over 50%. Combination therapy of calcium antagonists with beta-blockers is increasingly common, and is probably safest in the case of dihydropyridines. Other combinations being explored are those with angiotensin-converting enzyme inhibitors and diuretics.

Calcium channel antagonists. Part III: Use and comparative efficacy in hypertension and supraventricular arrhythmias. Minor indications

The major antihypertensive mechanism of calcium antagonists is by decreasing the systemic vascular resistance, modified by the counter-regulatory responses of the baroreflexes and the renin-angiotensin-aldosterone system. In severe hypertension, the concept that calcium overload of the vascular myocyte could precipitate or aggravate peripheral vasoconstriction provides a logical basis for the use of these agents as first choice therapy; nifedipine, especially, has been well tested. As monotherapy for mild to moderate hypertension each of the three first-generation agents compares well with beta-blockers. Calcium antagonists may have a special role in the therapy of certain patient groups (elderly, black) or in those subjects whose life style involves intense physical or mental exertion (hemodynamics better maintained than with beta-blockade) or in patients with early end-organ damage such as left ventricular hypertrophy or renal insufficiency. However, the goal blood pressure may not be reached during monotherapy so that drug combinations may be required. Further indications for these compounds are as follows. Verapamil and diltiazem are frequently used in supraventricular tachycardias including acute and chronic atrial fibrillation. In the arrhythmias of the Wolff-Parkinson-White syndrome, there is the potential danger of provocation of anterograde conduction. Further indications for calcium antagonists, still under evaluation, include congestive heart failure (controversial), hypertrophic cardiomyopathy (verapamil), primary pulmonary hypertension (high doses required), Raynaud's phenomenon (nifedipine and diltiazem effective), peripheral vascular disease (proof not yet documented), cerebral insufficiency and subarachnoid hemorrhage (nimodipine promising), migraine, exertional bronchospasm, renal disease, atherosclerosis (experimental), and primary aldosteronism (nifedipine inhibits aldosterone release). Second-generation agents include dihydropyridines, such as nitrendipine, nicardipine, felodipine, amlodipine, nisoldipine, nimodipine, and isradipine. From these will be selected agents that are longer acting and provide higher vascular selectivity. New preparations of existing agents include slow-release formulations of nifedipine, verapamil, and diltiazem. Minor side effects include those caused by vasodilation (flushing and headaches), constipation (verapamil), and ankle edema. Serious side effects are rare and result from improper use of these agents, as when intravenous verapamil is given to patients with sinus or atrioventricular nodal depression from drugs or disease, or nifedipine to patients with aortic stenosis. The potential of a marked negative inotropic effect is usually offset by afterload reduction, especially in the case of nifedipine. Yet caution is required when calcium antagonists, especially verapamil, are given to patients with myocardial failure unless caused by hypertensive heart disease. Drug interactions of calcium antagonists occur with other cardiovascular agents such as alpha-adrenergic blockers, beta-adrenergic blockers, digoxin, quinidine, and disopyramide.(ABSTRACT TRUNCATED AT 400 WORDS)

Calcium channel blockers

The calcium channel blockers initially were approved for the treatment of classical and variant angina pectoris. Recent studies indicate that these agents also are useful in such diverse conditions as pulmonary and systemic hypertension, hypertrophic cardiomyopathy, arrhythmias, asthma, Raynaud's syndrome, esophageal spasm, myometrial hyperactivity, cerebral arterial spasm, and migraine.

Effects on hemodynamics and left ventricular ejection fraction of intravenous bepridil for impaired left ventricular function secondary to coronary artery disease

To define the hemodynamic effects of bepridil in patients with depressed left ventricular (LV) function, 22 patients with an LV ejection fraction (EF) of 0.45 or less were studied before and after 2 mg/kg (n = 11) and 4 mg/kg (n = 11) of intravenous bepridil. Maximal hemodynamic effects were evident between 15 and 30 minutes after drug infusion. After 2 mg/kg, heart rate decreased 9% (p less than 0.01), cardiac index 17% (p less than 0.01), LV dP/dt max 16% (p less than 0.01), stroke work index 14% (p less than 0.01) and mean aortic pressure 8% (difference not significant). Right atrial pressure increased 8% (not significant), pulmonary arterial wedge pressure 24% (p less than 0.01) and systemic vascular resistance 17% (p less than 0.01). After administering 4 mg/kg of bepridil the changes in heart rate, cardiac index, right atrial pressure, LV dP/dt max, mean aortic pressure and systemic vascular resistance were almost identical to those after the smaller dose. The larger dose produced a 40% (p less than 0.01) increase in pulmonary arterial wedge pressure and a 22% decrease in stroke work index (p less than 0.01), but only the change in wedge pressure was significantly greater (p less than 0.01) than that produced by the lower dose. Radionuclide-determined LVEF decreased 6% (p less than 0.05), from 0.33 +/- 0.14 after 2 mg/kg and 11% (p less than 0.05) from 0.27 +/- 0.11 after 4 mg/kg of bepridil. The data indicate that bepridil exerts significant negative inotropic and chronotropic effects in patients with impaired LV function.

Hazards of intravenous verapamil for sustained ventricular tachycardia

In 11 of 25 patients (44%) with sustained ventricular tachycardia (VT) who received intravenous verapamil (5 to 10 mg), acute severe hypotension or loss of consciousness developed, necessitating immediate cardioversion. Comparison of these 11 patients with the 14 who did not have adverse effects after verapamil revealed no significant difference in age, heart disease, ejection fraction, blood pressure before verapamil administration, other oral or intravenous drugs use, verapamil dose or VT characteristics (rate and morphologic pattern). Although most patients with severe adverse effects after verapamil had prior myocardial infarction, deterioration also occurred in patients without coronary disease and in patients with a normal left ventricular ejection fraction. VT terminated after verapamil infusion in 6 patients. No single electrocardiographic morphologic pattern characterized these patients. A control group of 25 patients presenting with hemodynamically stable VT who received other antiarrhythmic agents was examined. Hypotension developed in only 1 patient during acute therapy and did not require emergency cardioversion. Thus, although verapamil may terminate VT, severe adverse effects occur much more often. Use of verapamil to differentiate supraventricular tachycardia with aberrant conduction from ventricular tachycardia is hazardous.

Chronic renal and neurohumoral effects of the calcium entry blocker nisoldipine in patients with congestive heart failure

Nisoldipine, a calcium entry blocker, was given to 10 patients with congestive heart failure. During a 2 month follow-up period, 7 of the 10 patients were readmitted with pulmonary edema; daily furosemide doses were increased (128 +/- 87 to 192 +/- 135 mg/day, p less than 0.01), and plasma creatinine increased (1.5 +/- 0.5 to 1.8 +/- 0.6 mg/dl, p less than 0.05) (all values mean +/- SD). Despite this unfavorable clinical course, nisoldipine caused some beneficial chronic (1 month) hemodynamic effects. It decreased systemic vascular resistance (from 1,781 +/- 229 to 1,306 +/- 345 dynes X s X cm-5, p less than 0.01), decreased mean arterial pressure (from 88 +/- 0 to 74 +/- 4 mm Hg, p less than 0.001) and increased stroke volume index (from 27 +/- 6 to 33 +/- 9 ml/min per m2, p less than 0.02). Heart rate, pulmonary capillary wedge pressure and stroke work index did not change. However, nisoldipine's chronic renal and neurohumoral effects were not as favorable. These were assessed during a 5 hour water load (15 ml/kg body weight of 5% dextrose in water) and compared with the effects of a water load before therapy. Nisoldipine did not change creatinine clearance or sodium excretion, but decreased water excretion (from 58 +/- 35 to 46 +/- 40% of water load in 5 hours). Over this 5 hour study, mean plasma vasopressin was also higher with nisoldipine (1.9 +/- 2.3 versus 2.7 +/- 3.2 pg/ml, p less than 0.05), but mean plasma aldosterone was lower (67 +/- 31 to 47 +/- 27 mg/dl, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Improved left ventricular performance during exercise with verapamil or nifedipine in patients with chronic stable angina

To examine the effects of chronic oral therapy with verapamil, 120 mg three times a day, and nifedipine, 20 mg four times daily, on left ventricular ejection fraction and regional wall motion at rest and exercise, 10 patients with chronic stable angina pectoris underwent serial rest and exercise radionuclide angiography. Pre drug control study revealed a resting left ventricular ejection fraction (LVEF) of 0.62 +/- 0.08, falling to 0.54 +/- 0.12 at peak exercise (p less than 0.05). Wall motion score deteriorated from a resting value of 13.8 +/- 2.3 to 10.6 +/- 1.8 (p less than 0.01) with exercise. Patients were subsequently randomized to verapamil or nifedipine for 4 weeks each in an open-labeled crossover design. Rest and exercise radionuclide angiography were repeated at the end of each 4-week period. Neither verapamil nor nifedipine had a significant effect on resting LVEF (verapamil LVEF = 0.61 +/- 0.10, nifedipine LVEF = 0.64 +/- 0.02). Likewise, they had no significant effect on resting wall motion score (verapamil = 14.2 +/- 2.2, nifedipine = 14.4 +/- 1.6). Both verapamil and nifedipine significantly increased LVEF at peak exercise (verapamil = 0.63 +/- 0.09, nifedipine = 0.65 +/- 0.08, p less than 0.05 vs pre drug control) and improved peak exercise wall motion score (verapamil = 13 +/- 1.9, nifedipine = 13.8 +/- 1.6, p less than 0.05 vs pre drug control). Both drugs significantly reduced maximal ST depression at peak exercise and prolonged exercise duration. Episodes of angina and nitroglycerin use were also significantly reduced. In summary, verapamil and nifedipine improved left ventricular performance at exercise in patients with angina pectoris.

Hemodynamic effects of PN 200-110 (isradipine) in congestive heart failure

PN 200-110 (isradipine), a dihydropyridine derivative, is a newly available calcium antagonist with potent vasodilatory properties. To determine if PN 200-110 might benefit patients with congestive heart failure (CHF), its acute hemodynamic effects were evaluated in a group of 12 patients with severe CHF. Measurements of cardiac performance were obtained after oral administration of placebo and 15 mg of PN 200-110. Placebo resulted in no significant changes in any of the variables. PN 200-110 decreased mean arterial pressure from 94 +/- 14 (mean +/- standard deviation) to 77 +/- 7 mm Hg (p less than 0.001) and increased both cardiac index from 2.1 +/- 0.4 to 2.8 +/- 0.6 liters/m2 (p less than 0.01) and stroke volume index from 26 +/- 7 to 36 +/- 10 ml/m2 (p less than 0.001). Systemic vascular resistance was reduced from 1,726 +/- 563 to 1,099 +/- 370 dynes s cm-5 (p less than 0.01). Neither heart rate nor pulmonary artery wedge pressure changed significantly. Of the 7 patients discharged receiving PN 200-110, 6 improved clinically and there was evidence of a substantial reduction in cardiothoracic ratio on chest x-ray in some patients. No serious side effects were encountered. Vasodilation with PN 200-110 can improve cardiac performance acutely in patients with CHF. Although this clinical experience is encouraging, carefully performed long-term trials must be done to determine the value of this drug in the management of patients with CHF.

The haemodynamic effects of nifedipine, verapamil and diltiazem in patients with coronary artery disease. A review

Of the 3 most widely used calcium antagonists--nifedipine, verapamil and diltiazem--nifedipine is the most potent arterial vasodilator. Increases in cardiac output and coronary blood flow following nifedipine administration result in part from the afterload reduction. Reflex adrenergic stimulation produces an increase in heart rate and masks a direct inhibitory effect on myocardial contractility. The negative inotropic action of nifedipine is observed during intracoronary administration or may be made apparent by concurrent beta-blocker therapy. While verapamil is also a potent vasodilator, negative inotropic and dromotropic properties are more apparent in therapeutically used dosages. Reflex sympathetic activation is also triggered by verapamil, with an offsetting of the negative inotropic effects such that little change in cardiac output results. A decrease in myocardial oxygen consumption, with or without a decrease in coronary sinus blood flow, has regularly been observed following verapamil administration. Reduced oxygen demand appears to be a major mechanism of its antianginal effect. The heart rate X systolic pressure product is decreased both by the fall in arterial pressure and, particularly after oral administration, by a decrease in heart rate. Diltiazem produces similar haemodynamic and electrophysiological effects to those of verapamil but has less potency in inducing arterial dilatation and more of a tendency to slow the heart rate. Diltiazem does not appear to cause significant increases in coronary blood flow or bring about improvement in ejectional and isovolumic indices of myocardial contraction - evidence of its intrinsic negative inotropic effect.

Hemodynamic effects of verapamil in left ventricular valvular volume overload

The hemodynamic consequences of aortic and mitral insufficiency may be influenced by the high systemic vascular resistance often seen in these patients. Since the calcium antagonists have been shown to reduce systemic vascular resistance, we evaluated the effects of intravenous verapamil in 23 patients. In 11 patients with aortic insufficiency, verapamil resulted in a 20% increase in cardiac index (p less than 0.001), 18% increase in forward stroke volume index (p less than 0.001), and a 24% decrease in regurgitant fraction (p less than 0.005). In the 12 patients with mitral insufficiency, verapamil resulted in a 19% increase in both cardiac index (p = 0.004), and forward stroke volume index (p less than 0.001), while there was a 19% decrease in regurgitant fraction (p less than 0.02). Left ventricular end-systolic stress decreased significantly in both groups as did end-diastolic stress in the mitral insufficiency group. There was no significant change in several measures of contractile performance, though the end-systolic stress-to-volume index ratio fell significantly (p less than 0.04) in the mitral insufficiency group. Our findings suggest that the vasodilatory effects of intravenous verapamil predominate over the negative inotropic effects in patients with aortic and mitral insufficiency. Verapamil may be of use in patients intolerant to other vasodilators, patients with concomitant ischemic heart disease, or those with supraventricular arrhythmias.

Tiapamil, a new calcium antagonist: hemodynamic effects in patients with acute myocardial infarction

The afterload reduction and myocardial oxygen sparing that results after administration of calcium antagonists suggests a possible role for these drugs in intervention after onset of acute myocardial infarction, but their use in this setting is limited by the possibility that left ventricular failure will develop. Tiapamil is a new verapamil congener. The hemodynamic effects of this drug (1 mg/kg followed by 25 micrograms/kg/min over 36 hr) were studied in 30 patients randomly assigned in a double-blind manner to a tiapamil or control group within 12 hr of the onset of acute myocardial infarction as diagnosed by Swan-Ganz catheterization and gated blood pool scans. Tiapamil reduced heart rate from 83 +/- 20 beats/min (mean +/- SD) before to 74 +/- 19 beats/min after drug (over an average 36 hr), arterial pressure from 128 +/- 22/87 +/- 14 to 118 +/- 16/74 +/- 11 mm Hg, rate-pressure product from 10,695 +/- 3492 to 8800 +/- 2550 units, and systemic vascular resistance from 1732 +/- 351 to 1400 +/- 350 dynes X sec X cm-5. Tiapamil also increased stroke volume index from 34.7 +/- 12.1 to 41.6 +/- 12.0 ml/m2, left ventricular ejection fraction from 50.1 +/- 14.8% to 56.4 +/- 17.4% (at 24 hr), left ventricular end-diastolic volume index from 71.3 +/- 23.1 to 80.5 +/- 23.7 ml/m2, and peak diastolic filling rate (an index of diastolic relaxation) from 2.1 +/- 0.9 to 2.6 +/- 0.8 end-diastolic volumes/sec (p less than .05 for all changes). Cardiac index, wedge pressure, left ventricular end-systolic volume, and PR interval remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of calcium antagonists in ventricular dysfunction

Calcium antagonists are now widely used in a variety of cardiocirculatory disorders, many of which are associated with varying levels of depressed myocardial function. Thus, the hemodynamic effects of calcium antagonists in patients with normal as well as depressed ventricular function are clinically relevant. None of the 3 agents verapamil, nifedipine or diltiazem exerts significant negative inotropic effects in patients with relatively normal myocardial function, although increases in left ventricular end-diastolic pressure may occur with verapamil and possibly diltiazem. In a setting in which ischemia, hypertension or arrhythmias contribute to cardiac failure, all 3 agents may ameliorate myocardial decompensation if they reverse the precipitating causes. In patients with depressed myocardial function, the effects of diltiazem are not known; verapamil may depress myocardial function, especially if the ventricular filling pressure is increased. Nifedipine generally has little depressant action in this setting and usually improves cardiac function, especially if the sympathetic reflexes are intact. However, hemodynamic deterioration after nifedipine administration has been reported. Thus, the available data do not support the use of calcium antagonists as afterload-reducing agents in heart failure and suggest caution in the use of these agents in patients with impaired ventricular performance.

Hemodynamic effects of intravenous diltiazem with impaired left ventricular function

The acute hemodynamic effects of intravenous diltiazem were studied in 8 patients with coronary artery disease, left ventricular (LV) failure (New York Heart Association functional class III), a rest ejection fraction (EF) less than 40% or a cardiac index less than 2.4 liters/min/m2. Hemodynamic measurements and LV angiograms were performed at rest before and after the administration of diltiazem, 0.5 mg/kg, administered at a speed of 5 mg/min. Diltiazem treatment induced a decrease in heart rate from 68 +/- 12 to 55 +/- 9 beats/min (p less than 0.001). Mean aortic pressure decreased from 94 +/- 14 to 81 +/- 15 mmHg (p less than 0.05). Thus, the pressure-rate product significantly decreased under the influence of the drug, from 8,791 +/- 2,465 to 6,342 +/- 1,808 beats mm Hg/min, (p less than 0.001). Diltiazem induced no significant change of LV end-diastolic pressure, pulmonary wedge pressure, cardiac index and LV stroke work index. Systemic vascular resistance decreased (p less than 0.01), whereas pulmonary vascular resistance showed no change. End-systolic volume diminished (p less than 0.02), which accounts for the increase of stroke volume and ejection fraction (p less than 0.001). Disorders of regional contractility were not aggravated by diltiazem, and even improved in individual cases. Thus, intravenous diltiazem may be used safely in patients with heart failure. However, in view of the marked bradycardic effects seen in some cases, heart rate should be carefully monitored.

Management of patients with hypertension and angina pectoris

Management of patients with concomitant hypertension and angina pectoris mandates that the physician pay attention to the underlying pathophysiology. The heart, when exposed to years of hypertension, becomes "remodeled." Overall mass is enlarged, the walls are thickened, and initial cavity volume remains normal or relatively small. Left ventricular end-diastolic pressure rises in the setting of a hypertrophic noncompliant ventricle; coronary resistance and coronary perfusion pressure are increased; and coronary vascular reserve, even with widely patent coronary arteries, is decreased. Long-standing hypertension--a risk factor for coronary atherosclerosis--is often accompanied by epicardial coronary stenoses that aggravate these coronary abnormalities. In managing the patient with hypertension and angina pectoris, it is important to determine whether the angina occurs in the setting of hypertensive hypertrophic disease alone or coexists with coronary arterial stenoses. Also important to therapy is whether the ventricle is of normal size with good function or decompensated with dilatation and diminished function. The latter two anatomic considerations, namely, epicardial coronary patency and left ventricular cavity size, will influence the choice of an anti-ischemic regimen. For example, diuretic and nitrate therapy can be hazardous, and digitalis unnecessary, in the setting of a nondilated hypertrophic ventricle with hyperdynamic function. On the other hand, the combined use of beta blocking agents plus calcium antagonists is particularly effective in lowering blood pressure and in improving coronary blood flow. Finally, this combination has been shown to be rapidly effective and to have prolonged benefit in this setting. The choice of these latter agents is also affected by the underlying state of the ventricle. Calcium channel blocking agents without significant negative inotropic effect, such as nifedipine and nitrendipine, would be suitable in patients with decompensated ventricular function and dilated left ventricular cavities. Both of these drugs have been shown to increase cardiac output and contractility via a reflex effect and to have little or no direct negative inotropic effect. In contrast, verapamil has a direct negative inotropic effect. The final choice of agents must be tailored to the needs of the individual patient, and the physician also has to determine the role of specific agents in the natural history of hypertensive heart disease.

The effect of antiarrhythmic agents on myocardial contractility and arrhythmia frequency

Most patients requiring antiarrhythmic therapy for ventricular arrhythmias have underlying organic heart disease which causes left ventricular dysfunction. Treatment of these patients' arrhythmias requires knowledge of the hemodynamic as well as antiarrhythmic effects of the available agents. These effects may differ during acute and chronic oral therapy. Several of the newer agents and quinidine are very effective in suppressing ventricular ectopic activity, allowing demonstration of drug effect during ambulatory monitoring. The clinical significance of this for prevention of sudden death has yet to be shown. However, prevention of ventricular tachycardia or fibrillation in the electrophysiology laboratory and suppression of ambient ectopy may generally be separate phenomena, as has been demonstrated for amiodarone.

Calcium ions, drug action and the heart--with special reference to calcium antagonist drugs

Calcium antagonists, of which the best known are verapamil, nifedipine and diltiazem, are a powerful group of cardioactive agents with a clinical spectrum of indications rather similar to those of beta-adrenoceptor blockade, including angina of effort, angina at rest, hypertension and supraventricular tachycardias (nifedipine is ineffective for the latter). In angina caused by coronary spasm, calcium antagonists are preferred to beta-blockade. Calcium antagonists have a basically different mode of action from beta-adrenoceptor blockade, although both ultimately act on the free cytoplasmic calcium ion concentration. Critical differences between the calcium antagonists are dependent on the individual properties of the calcium antagonists concerned. Different binding sites on the sarcolemma have been identified for nifedipine-like agents and verapamil, but with a different interaction with the nifedipine site. None of these sites might be relevant to the binding of calcium antagonists to the tissue of their therapeutic site of action (arterial smooth muscle for all; atrioventricular node for verapamil and diltiazem). As a group, calcium antagonists cause vascular dilation and do not cause bronchial constriction, in contrast to the beta-adrenoceptor blocking agents. In many patients, these diverse properties allow safe combination of calcium antagonists and beta-adrenoceptor blockers if due care is observed, especially in the case of nifedipine. The clinical differences between the effects of various calcium antagonists reflect: (i) the greater vasodilator capacity of nifedipine, so that at a given concentration the afterload effect dominates over possible effects on the nodal or myocardial tissue; (ii) the greater inhibition of vagal tone by nifedipine than by verapamil or diltiazem; and (iii) the greater inhibition of the atrioventricular node by verapamil and diltiazem. In angina of effort, calcium antagonists are now becoming the agents of first choice in some centers. Experimental use of calcium antagonists include the possible prevention of ventricular fibrillation, the inhibition of ischemic injury, the prevention of catecholamine mediated injury to the myocardium and decreased arterial calcinosis.

Vasodilator and inotropic therapy for severe chronic heart failure: passion and skepticism

Although substantial progress has been made in the last 5 years in the development of vasodilator and inotropic drugs for the management of patients with severe chronic heart failure, much of the enthusiasm that surrounded the introduction of many of these agents has subsequently been tempered by reports of drug failure or adverse reactions. In this review and analysis, currently available vasodilator and inotropic agents are critically and comparatively evaluated to assess their respective advantages and limitations. It is apparent that the ability of most of these drugs to produce substantial clinical benefits in patients with severe heart failure has probably been overstated. Therapy fails to achieve the desired clinical results all too frequently, possibly as the result of: the choice of an ineffective drug; the administration of an effective drug in subtherapeutic doses; the administration of an effective drug to improperly selected patients; the failure of initial hemodynamic benefits to be sustained; the occurrence of severe or serious adverse reactions; and the failure to alter concomitant therapy appropriately. The present analysis indicates that there is no uniformly effective or safe vasodilator or inotropic drug for patients with severe heart failure; all agents have important limitations. Of the available therapeutic choices, however, long-term converting enzyme inhibition appears to produce more consistent hemodynamic and clinical benefits with an acceptable degree of adverse reactions than other pharmacologic approaches for the management of these severely ill patients.

Acute hemodynamic effect of oral nifedipine in severe chronic congestive heart failure

The temporal hemodynamic effects of oral nifedipine after a single dose of 20 to 40 mg were evaluated in 11 patients with severe chronic congestive heart failure (left ventricular ejection fraction 0.22 +/- 0.7 [mean +/- standard deviation]). Nifedipine significantly reduced systemic vascular resistance, from 1,850 +/- 493 to 1,315 +/- 398 dynes s cm-5 at 1 hour (29%), to 1,410 +/- 246 at 3 hours and to 1,523 +/- 286 at 6 hours (p less than 0.05). Cardiac index increased 21%, from 2.07 +/- 0.46 to 2.51 +/- 0.83 liters/min/m2 at 1 hour, to 2.38 +/- 0.53 liters/min/m2 at 3 hours (p less than 0.05) and to 2.24 +/- 0.41 liters/min/m2 at 6 hours. The group response of stroke volume to nifedipine was smaller. A peak increase of 17% was seen 3 hours after initiation of therapy (22.6 +/- 7.2 versus 25.5 +/- 6.1 ml/m2). This difference did not reach statistical significance. Mean blood pressure declined significantly, from 94 +/- 20 to 80 +/- 13 mm Hg at 1 hour, to 83 +/- 15 mm Hg at 3 hours and to 86 +/- 17 mm Hg at 6 hours (p less than 0.05) and was associated with no significant change in heart rate. The marked decrease in blood pressure resulted in a decrease in rate-pressure product from 12,272 +/- 4,230 to 10,500 +/- 2,074 mm Hg/min at 1 hour, to 10,374 +/- 2,735 mm Hg/min at 3 hours and to 11,047 +/- 3,813 mm Hg/min at 6 hours (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)