RIGHT AND LEFT-VENTRICULAR HEMODYNAMIC PERFORMANCE DURING SUSTAINED VENTRICULAR-TACHYCARDIA

Several factors may influence hemodynamic tolerance of a ventricular t achycardia (VT) episode but, to date, only VT rate has been used as a major detection criterion in selecting implantable cardioverter-defibr illator therapy algorithms. We examined hemodynamic changes during VT in humans and a possible correlation between left and right ventricula r hemodynamic indexes. Right ventricular hemodynamic indexes could ref lect systemic hemodynamics but previous studies have been inconclusive . Patients with coronary artery disease and a history of recurrent, su stained VT were studied. Aortic pressure and right and left ventricula r pressures were simultaneously recorded with 2 dual micromanometer-ti pped high-fidelity pressure catheters during sinus rhythm and during i nduced sustained monomorphic VT. Beat-to-beat analysis was performed u sing custom-made software. Nine patients (7 men, mean age 60 +/- 8 yea rs, mean election fraction 24 +/- 8%) with 11 VT episodes (mean cycle length 283 +/- 48 ms) were studied, During VT, left and right ventricu lar systolic pressures showed a mean decrease of 57% and 26%, respecti vely, with weak correlation (r = 0.67, p = 0.06) between both values. There was also an increase in mean left and right ventricular end-dias tolic pressures of 26% and 74%, respectively, and no correlation was s een (r = -0.2, p = 0.6). A significant correlation was found between c hanges in left and right ventricular maximal positive dP/dt (55% and 2 8% decrease, respectively (r = 0.69, p = 0.03) and between changes in left and right ventricular maximal negative dP/dt (64% vs 39% decrease , r = 0.71, p = 0.02). Most ventricular time parameters in both ventri cles differed significantly during VT compared with sinus rhythm; howe ver, only the decrease in right ventricular time to end-diastolic pres sure correlated with the decrease in left ventricular systolic pressur e, at the 10th VT beat (r = 0.8, p = 0.01). We conclude that left and right ventricles are hemodynamically unequally affected during rapid V T. Although right ventricular pressures cannot be reliably used to ass ess changes in the hemodynamic status of the left ventricle, additiona l parameters, such as dP/dt or changes in ventricular time intervals, should be further evaluated for inclusion in implantable cardioverter- defibrillator algorithms. (C) 1997 by Excerpta Medica, Inc.