Re-thinking angina

William Heberden in 1772 published "some account of the disorder of the breast" which contains the essential elements of angina pectoris as we understand it today. The number of existing cases in the U.S. population today is 6.4 million. Myocardial ischemia manifested by angina pectoris can be either acute or chronic. Patients with chronic stable angina will be the focus of this supplement. The majority of patients are symptomatic but approximately 25% can be asymptomatic. The clinical manifestations of myocardial ischemia generally are chest discomfort, arrhythmias, and LV dysfunction. Myocardial ischemia is a result of imbalance between myocardial oxygen supply and myocardial oxygen demand. High grade coronary stenosis are the usual cause of decreased oxygen supply. The classic hemodynamic factors increasing myocardial oxygen demand include hypertension and increased heart rate due to tachyarrhythmias of any etiology. Exertion is the usual precipitating cause of chronic myocardial ischemia. New information has come forward indicating that myocardial ischemia is associated with disruption of cellular sodium and calcium homeostasis. Ischemia results in a rise of intracellular sodium concentration and thus sodium overload which then activates the sodium calcium exchanger and leads to increased intracellular calcium. When this occurs there is electrical instability and mechanical dysfunction which increases oxygen demand and decreases oxygen supply. The compound Ranolazine is thought to selectively inhibit the late sodium current and attenuates the abnormalities of ventricular repolarization and contractility associated with myocardial ischemia. This compound is the first new class of anti-anginal medication approved in 25 years which may provide physicians with additional therapy for chronic stable angina along with the other anti-angina agents, beta blockers, calcium antagonists and nitrates.