Calcium Channel Antagonists

Calcium-channel blockers have antianginal, vasodilatory, and antihypertensive properties. 32 Calcium antagonists have not been shown to reduce mortality rate after AMI. In fact, they may be harmful to some patients with cardiovascular disease.4 Nifedipine is the most studied of the calcium-channel blockers for the treatment of AMI. This short-acting dihydropyridine has been associated with a nonsignificant increase in mortality rate when given during or shortly after AMI in several clinical trials.43 Immediate-release nifedipine may be harmful as a result of a coronary "steal" syndrome in which coronary perfusion pressure is reduced through disproportionate dilatation of the coronary arteries adjacent to the ischemic zone and/or reflex activation of the sympathetic nervous system with a resultant increase in myocardial oxygen demand.

Diltiazem has also been found to be associated with increased mortality rate, particularly for patients with congestive heart failure. 44 Similarly, studies evaluating verapamil have not found mortality-rate benefits.32 Verapamil is detrimental for patients with congestive heart failure or bradydysrhythmias. There are no data supporting the use of second-generation dihydropyridines (amlodipine and felodipine) for treatment of AMI.

The ACC/AHA guidelines state that "these agents are still used too frequently in patients with acute MI and that beta-adrenoreceptor blocking agents are a more appropriate choice."4 Verapamil and diltiazem are considered potentially beneficial for use in patients with ongoing ischemia or atrial fibrillation with rapid ventricular response who do not have congestive heart failure, left ventricular dysfunction, or atrioventricular block, and b-adrenergic antagonists are contraindicated. 424

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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