INFLUENCE OF INTRAVENOUS DILTIAZEM ON LEFT-VENTRICULAR FUNCTION IN PATIENTS WITH SEVERE CORONARY-ARTERY DISEASE AT REST AND DURING PACING, MONITORED BY COMPUTER-PROCESSED NUCLEAR PROBE AND TIP-MANOMETER DATA

The influence of intravenous diltiazem on hemodynamics and left ventri cular function indices was studied in 14 patients with severe coronary artery disease at rest and during atrial pacing. We used a tip manome ter catheter for recording left ventricular pressure tracings and a nu clear probe for measuring left ventricular volume changes. Infusion of diltiazem at rest resulted in an increase in left ventricular enddias tolic volume (+ 16%, p < 0.0001); allother parameters did not differ s ignificantly from baseline values. Angina pectoris occurred in all pat ients during atrial pacing before diltiazem infusion (ContrP); during pacing after diltiazem infusion (DiltP) only four patients became symp tomatic (at the same pacing rates). Other differences between the two pacing studied and their baseline measurement were mean arterial press ure (ContrP: +13%, p < 0.001; DiltP: +11% p < 0.001), pulmonary wedge pressure (ContrP: +54%, p = 0.019; DiltP: NS), left ventricular enddia stolic pressure (ContrP: +40%, p < 0.005; DiltP: NS), left ventricular enddiastolic volume (ContrP: -19%, p = 0.001; DiltP: -33%, p = 0.0001 ), left ventricular ejection fraction (ContrP: -20%, p = 0.039: DiltP: NS), maximum rate of rise of left ventricular systolic pressure (Cont rP: +22%, p = 0.00 1; DiltP: +20%, p = 0.03), time constant of relaxat ion (ContrP: +40%, p = 0.001; DiltP +8%, p = 0.047), stiffness constan t of the diastolic pressure-volume relationship (ContrP: +157%, p = 0. 0001; DiltP: +132%, p = 0.001), and left ventricular systolic work (Co ntrP: -35%, p = 0.0001; DiltP -46%, p = 0.0001). When comparing the da ta collected during pacing before and after diltiazem infusion, we fou nd a significant decrease in the time constant of relaxation (Tr) (-17 %, p = 0.023). The study results demonstrate that diltiazem has favora ble hemodynamic effects and that it reduces the ischemia-induced early diastolic relaxation disturbances in patients with coronary artery di sease.