Haemodynamic effects of intravenous diltiazem at rest and exercise in patients with coronary artery disease

The acute effects of intravenous diltiazem on exercise performancewere studied in 10 patients with coronary artery disease. Haemodynamicmeasurements were made at rest and during exercise before andafter 0-5 mgkg^–1 of diltiazem. Diltiazem prolonged theduration of exercise (+2.85 min, P>0.001) and delayed theonset of ischaemic ST depression or angina in all patients.The highest tolerated heart rate and pressure rate product wereincreased in all but one patient after diltiazem. At rest diltiazem decreased mean arterial pressure (–10.8%,P>0.005), systemic vascular resistance (SVR) (-11.8%, P>005)and left ventricular stroke work index (SWI) (–14.1%,P>0.005). During exercise under diltiazem therapy, at the level achievedbefore the drug, the pulmonary capillary wedge pressure (-30%,P>0005) and the SVR (–13.6%, P>0.02) were lowered,the SWI (+13%, P>0.01) was increased: at the end of exerciseonly the SVR (14%, P>0.05) was reduced. Two patients experiencedangina on lying down and one had orthostatic hypotension afterexercise with diltiazem. This study indicates that intravenousdiltiazem is a potentially useful agent for the treatment ofangina by reducing myocardial oxygen demand at rest and by improvingleft ventricular performances on exercise.