Acute Effects of First Generation Calcium Antagonists on Left Ventriular Diastolic Functions in Healthy Individuals and in Essential Hypertension Patients

The acute effects of sublingual nitedipine (10 mg), IV verapamil (0.15 mg/kg and maximal 10 mg), and oral diltiazem (30-60 mg) on left ventricular diastolic functions in mild and moderate hypertensive cases (total 32 cases) and in 17 healthy individuals were studied. Drug administrations were made at 72 hours intervals. Pulse and blood pressure were measured, and two-dimensional, M-mode, and continous Doppler echocardiograms were taken by standard techniques, during baseline and presumed period of peak effect of each drug. The parameters of total mitral flow, early diastolic flow (E wave), and Iate diastolic flow (A wave) were determined. In hypertensive patients, nifedipine increased the mitral and atrial mean (MVM, AVM) and peak (E, A) flow velocities (p<0.0005, for each of them). It did not change the ratio of E/ A. Because of a 20 % increase attained in AVM and 11 % in MVM compared to baseline, it raised the supplementary effect of atrial filling on total filling (AFV /TFV %) (8 %, p<0.025). Verapamil increased MVM and E (6 %, 10 %, p<0.05, p<0.0005 respectively), and did not affect Iate diastolic filling. Hence, it decreased the rate of E/A (10 %. P<0.005) but did not affect AFV/ TFV %. Diltiazem decreased the flow velocities of A wave in this group, the rate of E/A (10 %, p<0.005) was increased, and AFV /TFV % (7 %, p<0.025) was decreased. In healthy individuals, nifedipine increased AVM (22 %, p<0.05) and thus raised AFV /TFV % (20 %, p<0.025). Verapamil did not effect the transmitral flow velocities. Diltiazem caused a decrease in MVM by 7 %, in AVM by 12% and in A by 5 % (p<0.005), p<0.025), p<0.025, respectively) but had no effect on the rate of E/A and AFV/TFV %. Hence, all three drugs affected the left ventricular diastolic functions in a different manner and the effects of these drugs are different in hypertensive than normotensive individuals.