Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Apr 1988
Comparative StudyComparison of the effects of right atrial, right ventricular apex and atrioventricular sequential pacing on myocardial oxygen consumption and cardiac efficiency: a laboratory investigation.
As the impact of cardiac pacing on myocardial energetics has not yet been established, this laboratory investigation was undertaken to evaluate the effects of right atrial (AP), right ventricular apex (VP) and atrioventricular sequential pacing (AVP) on cardiac energetics in a closed-chest model. Ninety-two pacing interventions were performed in ten anesthetized mongrel dogs with normal loading conditions and contractile states. The energetic effects of pacing were assessed in terms of myocardial oxygen consumption (MVO2), its hemodynamic determinants and cardiac efficiency. ⋯ AP has beneficial effects on cardiac energetics because it improves the relationship between mechanical performance of the heart and its energy requirements. AVP results in a higher efficiency than VP due to superior hemodynamics, despite MVO2 levels comparable to those of VP. The mechanism of energy waste with right ventricular apex pacing is probably related to an asynchronous contraction in the ventricular myocardium due to a nonphysiological spread of excitation.