Figure 2.

Pharmacologic Effects of Nondihydropyridine Calcium-Channel Blockers on the Pathomechanisms of Obstructive Hypertrophic Cardiomyopathy

This drug class blocks the calcium influx into the SA and AV nodes resulting to negative effects on: 1) chronotropy leading a decrease in heart rate that causes prolongation of the diastolic phase, ultimately mitigating the obstructive effects on the LVOT; and 2) inotropy causing a decrease in myocardial oxygen demand and LVOT obstruction, both ultimately leading to the decrease of patient-felt symptoms. However, diltiazem is known to have a systemic vasodilating effect that may lead to a paradoxical increase in LVOT obstruction. AV = atrioventricular; LVOT = left ventricular outflow tract; SA = sinoatrial.