Effect of long-term diltiazem treatment on central haemodynamics and exercise endurance in essential hypertension

The effects of long-term treatment with diltiazem on blood pressure,central haemodynamics and exercise endurance were studied in16 men (mean age 52 years) with essential hypertension. Intra-arterialpressureand heart rate (HR) were monitored continuously. Cardiac output(CO) was measured by Cardiogreen at rest (supine and sitting)and during 50 W, 100 Wand 150 W bicycle exercise. Haemodynamicmeasurements were repeated after continous bicycling at 150Wfor 20 min or until exhaustion. After 1 year on diltiazem (meandaily dose 278 mg) intra-arterial pressure was reduced (P <0001)in all situations (at rest sitting from 183/ 108 mmHg to 157/92mmHg (14%)) due to reduction in total peripheral resistance.HR was reduced at rest (7%) and during exercise (10%). Strokevolume tended to increase while CO was unchanged. Exercise timeat constant workload increased by 25%. After apeak level, intra-arterialpressure fell by 3% to 5% (P<0.05) due to a decrease in totalperipheral resistance both before and during diltiazem treatment.Stroke volume and CO remained unchanged during endurance exercisewhile HR showed a small increase. Thus, there was no reductionin the overall cardiac pump function after long-term diltiazemtreatment, and blood flow during exercise was maintained.