Left Ventricular Pressure-Volume Relationships Before and After Cardiomyoplasty in Patients With Heart Failure

Abstract

Background The aim of this study was to elucidate whether beneficial effects of cardiomyoplasty (CMP) in patients with dilated cardiomyopathy are the result of a decrease in existing ventricular dilatation or a prevention of further dilatation. Methods and Results Combined micromanometer-conductance catheters were used to evaluate left ventricular pressure-volume relationships in six patients with dilated cardiomyopathy before and at 6 and 12 months after CMP. Acute changes in preload and afterload were induced by a standardized leg-tilting intervention and a bolus infusion of nitroglycerin. After CMP, end-diastolic volume (EDV) decreased from 138±10 to 103±18 mL/m 2 ( P <.01) at 6 months and to 83±17 mL/m 2 ( P <.01) at 12 months. End-diastolic pressure (EDP) decreased from 20.2±6.4 to 13.9±7.7 mm Hg ( P <.01) at 6 months after CMP. Peak ejection rate and ejection fraction increased at 6 months after CMP from 594±214 to 799±214 mL/s ( P <.05) and from 26.6±4.7% to 40.1±8.3% ( P <.05), respectively. Peak −dP/dt decreased at 12 months after CMP from −842±142 to −712±168 mm Hg/s ( P <.05). Leg-tilting before CMP increased EDP from 20.2±6.4 to 25.6±5.2 mm Hg ( P <.01), end-systolic pressure (ESP) from 118±17 to 122±17 mm Hg ( P <.05), and τ from 50.8±2.8 to 53.8±2.3 ms ( P <.05). Six months after CMP, leg-tilting also increased EDV from 103±18 to 110±22 mL/m 2 ( P <.05) and ESV from 62±14 to 66±14 mL/m 2 ( P <.05). Before CMP, nitroglycerin decreased EDP from 20.2±6.4 to 10.4±3.8 mm Hg ( P <.01), ESP from 118±17 to 96±11 mm Hg ( P <.05), ESV from 100±11 to 89±7 mL/m 2 ( P <.05), and τ from 50.8±2.8 to 44.5±3.7 ms ( P <.05). Six months after CMP, nitroglycerin decreased EDP, ESP, and τ to similar values. Conclusions Our findings show that up to 1 year after CMP, marked decreases in left ventricular volume are present. Our measurements suggest that CMP actively reduced the dilated ventricle but did not prevent a higher EDV on an increased venous return. The latissimus dorsi muscle wrap contraction results in better synchronization of contraction and more rapid emptying of the left ventricle.