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

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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.