Haemodynamic effects of disopyramide in patients after open-heart surgery.

Abstract

SUMMARY Disopyramide phosphate was administered intravenously in a dose of 1-2 mg/kg body weight over one minute to nine patients after open-heart surgery and coronary artery bypass grafting. The haemodynamic changes were studied during and for 30 minutes after drug administration. Heart rate was unchanged throughout the study. During infusion the only significant changes were an increase in systemic blood pressure and systolic impedance signifying a direct increase in peripheral arterial resistance. Systemic blood pressure remained significantly higher for 10 minutes and systolic impedance for 30 minutes. Immediately after infusion max. dPower/dT, a measure of ventricular contractility, was significantly depressed for 15 minutes. Both cardiac output and aortic flow were significantly depressed for 30 minutes. DPTI/TTI, an estimate of subendocardial supply/demand ratio, showed an insignificant increase throughout the study.This study shows that intravenous disopyramide starts acting within 45 seconds of the start of infusion, directly increases peripheral arterial resistance, has a brief negative inotropic action, and does not reduce subendocardial blood flow.

Negative inotropic effects of disopyramide on guinea‐pig papillary muscles

“…Furthermore, this inhibitory action of disopyramide may also be involved in more marked negative inotropic effects reported in patients with pre-existing left ventricular abnormalities (Hills et al, 1976;Jensen et al, 1976;Sutton, 1976;Davies et al, 1979;Hulting & Rosenhamer, 1979;Naqui et al, 1979;Scheinman et al, 1980;Gottdiener et al, 1983;Greene et al, 1983;Marrott et al, 1983;Cameron et al, 1984).…”

“…In addition, a negative inotropic effect of disopyramide has been identified in animal experiments (Nayler, 1979;Walsh & Horwitz, 1979;Abdollah et al, 1984;Beltrame et al, 1984) and has been detected by echocardiography (Martin et al, 1980;Pollick et al, 1982;Holt et al, 1983), radionuclide angiography (Wisenberg et al, 1984) and during cardiac catheterisation (Thadani et al, 1981) in normal volunteers. In some haemodynamic studies on patient groups, the effects of disopyramide on myocardial performance have been minimal (Marrott et al, 1976;Sutton, 1976), but in patients with preexisting left ventricular function abnormalities, negative inotropic effects are more marked (Hills et al, 1976;Jensen et al, 1976;Sutton, 1976;Davies et al, 1979;Hulting & Rosenhamer, 1979;Naqui et al, 1979;Scheinman et al, 1980;Gottdiener et al, 1983;Greene et al, 1983;Marrott et al, 1983;Cameron et al, 1984). However, the mechanisms of the negative inotropic effects of disopyramide have not been clarified.…”

An equation to predict the changes in peak left ventricular pressure in hypertrophic obstructive cardiomyopathy after treatment: Application to the administration of disopyramide

“…5) suggests that the pressure-reducing effect of disopyramide is not mainly caused by its negative inotropic action. It has been reported that disopyramide increases systemic resistance [7,26,27], while other negative inotropic drugs, such as [3-blocking agents and calcium inhibitors, do not show the same effect. Indeed, the systemic resistance increased in our study.…”

Effect of disopyramide on isolated aortic ring of the rat

“…In anaesthetized dogs, DP produces an increase in arterial blood pressure that is not blocked by phenoxybenzamine (Walsh & Horwitz, 1979). Haemodynamic studies in man have shown that DP increases peripheral vascular resistance and decreases cardiac output (Navqui et al, 1979). As DP has a negative inotropic effect, the elevation of arterial blood pressure may be due to an increase in peripheral vascular resistance.…”

“…Discussion The intravenous injection of DP in patients without signs of cardiac failure produces an increase in diastolic and mean arterial pressure (Navqui et al, 1979). In anaesthetized dogs, DP produces an increase in arterial blood pressure that is not blocked by phenoxybenzamine (Walsh & Horwitz, 1979).…”