Calcium antagonists heart failure

The cardiac effects of the calcium antagonists, ie, slowed rate (negative chronotropy) and decreased contractile force (negative inotropy), are prominent in isolated cardiac preparations. However, in the intact circulation, these effects may be masked by reflex compensatory adjustments to the hypotension that these agents produce. The negative inotropic activity of the calcium antagonists may be a problem in patients having heart failure, where contractility is already depressed, or in patients on concomitant -adrenoceptor blockers where reflex compensatory mechanisms are reduced. 

Patients with asymptomatic left ventricular systolic dysfunction and hypertension should be treated with P-blockers and ACE inhibitors. Those with heart failure secondary to left ventricular dysfunction and hypertension should be treated with drugs proven to also reduce the morbidity and mortality of heart failure, including P-blockers, ACE inhibitors, ARBs, aldosterone antagonists, and diuretics for symptom control as well as antihypertensive effect. In African-Americans with heart failure and left ventricular systolic dysfunction, combination therapy with nitrates and hydralazine not only affords a morbidity and mortality benefit, but may also be useful as antihypertensive therapy if needed.66 The dihydropyridine calcium channel blockers amlodipine or felodipine may also be used in patients with heart failure and left ventricular systolic dysfunction for uncontrolled blood pressure, although they have no effect on heart failure morbidity and mortality in these patients.49 For patients with heart failure and preserved ejection fraction, antihypertensive therapies that should be considered include P-blockers, ACE inhibitors, ARBs, calcium channel blockers (including nondihydropyridine agents), diuretics, and others as needed to control blood pressure.2,49... 

A randomized comparison of oral atenolol and bisoprolol in 334 patients with acute myocardial infarction was associated with drug withdrawal in 70 patients (21%) because of significant bradydysrhythmias, hypotension, heart failure, and abnormal atrioventricular conduction (40). Logistic regression analysis suggested that critical events were more likely to occur in patients who were pretreated with dihydropyridine calcium antagonists. 

Cohn JN, Ziesche S, Smith R, Anand I, Dunkman WB, Loeb H, Cintron G, Boden W, Baruch L, Rochin P, Loss L. Effect of the calcium antagonist felodipine as supplementary vasodilator therapy in patients with chronic heart failure treated with enalapril V-HeFT in. Vasodilator-Heart Failure Trial (V-HeFT) Study Group. Circulation 1997 96(3) 856-63. 

Nitrates are the drugs of choice in patients with left ventricular impairment, in whom they are of benefit when used in combination with hydralazine (3), and they should be used in preference to the calcium antagonists, which cause deterioration in myocardial function by an as yet unknown mechanism (4). In black patients with congestive heart failure taking ACE inhibitors and beta-block-ers, a combination of isosorbide dinitrate plus hydralazine significantly reduced total mortality (5). 

FIGURE 17-6. Algorithm for the treatment of atrial fibrillation and atrial flutter. Sx = symptoms AVN = AV node DCC = direct-current cardioversion CCB = calcium channel antagonist (verapamil or diltiazem) BB = jS-blocker ASA = aspirin OHD = organic heart disease AADs = antiarrhythmic drugs INR = international normalized ratio MVD = mitral valve disease CHF = congestive heart failure HTN = hypertension DM = diabetes mellitus. 

A. Use with extreme caution in patients with asthma, congestive heart failure, sinus node dysfunction, or other cardiac conduction disease and in those receiving calcium antagonists and other cardiac-depressant drugs. 

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