Abstract
Patients with heart failure who have undergone partial left ventriculotomy improve resting left ventricular systolic function, but have limited functional capacity. We studied systolic and diastolic left ventricular function at rest and during submaximal exercise in patients with previous partial left ventriculotomy and in patients with heart failure who had not been operated, matched for maximal and submaximal exercise capacity. Nine patients with heart failure previously submitted to partial left ventriculotomy were compared with 9 patients with heart failure who had not been operated. All patients performed a cardiopulmonary exercise test with measurement of peak oxygen uptake and anaerobic threshold. Radionuclide left ventriculography was performed to analyze ejection fraction and peak filling rate at rest and during exercise at the intensity corresponding to the anaerobic threshold. Groups presented similar exercise capacity evaluated by peak oxygen uptake and at anaerobic threshold. Maximal heart rate was lower in the partial ventriculotomy group compared to the heart failure group (119 +/- 20 vs 149 +/- 21 bpm; P < 0.05). Ejection fraction at rest was higher in the partial ventriculotomy group as compared to the heart failure group (41 +/- 12 vs 32 +/- 9%; P < 0.0125); however, ejection fraction increased from rest to anaerobic threshold only in the heart failure group (partial ventriculotomy = 44 +/- 17%; P = non-significant vs rest; heart failure = 39 +/- 11%; P < 0.0125 vs rest; P < 0.0125 vs change in the partial ventriculotomy group). Peak filling rate was similar at rest and increased similarly in both groups at the anaerobic threshold intensity (partial ventriculotomy = 2.28 +/- 0.55 EDV/s; heart failure = 2.52 +/- 1.07 EDV/s; P < 0.0125; P > 0.05 vs change in partial ventriculotomy group). The abnormal responses demonstrated here may contribute to the limited exercise capacity of patients with partial left ventriculotomy despite the improvement in resting left ventricular systolic function.
Highlights
Heart transplantation is considered to be the treatment of choice for patients with endstage heart failure secondary to left ventricular systolic dysfunction but, due to the limited availability of donors and certain contraindications, other surgical procedures have been proposed for the treatment of these patients [1]
In order to better understand the mechanisms associated with this limited exercise capacity, we studied the systolic and diastolic left ventricular function at rest and during submaximal exercise in patients with partial left ventriculotomy and in patients with heart failure who had not been operated, matched for maximal and submaximal exercise capacity
Left ventricular systolic and diastolic function was evaluated at rest and at the intensity corresponding to the anaerobic threshold in the sitting position, with the chest inclined at about 35 degrees and with the collimator positioned at a left anterior oblique projection
Summary
Heart transplantation is considered to be the treatment of choice for patients with endstage heart failure secondary to left ventricular systolic dysfunction but, due to the limited availability of donors and certain contraindications, other surgical procedures have been proposed for the treatment of these patients [1]. The surgical excision of part of the free wall of the left ventricle, with reduction of the radius, could improve wall stress with consequent improvement in function. Reports using this procedure demonstrated benefits in symptoms as well as improvement in resting left ventricular systolic function [2,3,4]. A subgroup of survivors improves clinically, with enhancement of quality of life, despite the persistence of limited exercise capacity
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