Regular paperCardiac contractility modulation by electric currents applied during the refractory period in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy
Section snippets
Patient recruitment:
The present study included patients with either ischemic or idiopathic dilated cardiomyopathy and ejection fraction ≤35%, who were referred for an electrophysiologic study or implantation of a pacing device, and who were willing and able to provide written informed consent. Long-term HF medications were maintained at the time of the study, including digoxin, an angiotensin-converting enzyme inhibitor, diuretics, and β blockers. Patients with atrial fibrillation, frequent ventricular premature
Results
Table 1lists demographic and baseline hemodynamic data for the 24 patients enrolled in the study. Etiology of HF was ischemic in 9 patients (37%) and idiopathic in 15 (63%). On average, ejection fraction was 28 ± 6% and New York Heart Association class was 2.7 ± 0.6. As expected, average QRS duration was higher in protocol 3 patients. Indexes of isovolumetric (dP/dtmax) and ejection-phase (pulse pressure) systolic function decreased to a similar degree in patients from all 3 protocols.
Discussion
The present study demonstrated the feasibility of enhancing global LV performance by applying nonexcitatory electric currents to a region of the ventricular myocardium. The CCM signals were shown to induce a 9% increase in dP/dtmax and a 10% increase in aortic pulse pressure during epicardial delivery to the left ventricle. Comparable systolic enhancement was also obtained by applying the CCM current to the RV septum, raising the possibility that direct stimulation of the left ventricle may not
Acknowledgements
We wish to express our appreciation to the patients and to the technicians and nurses of the electrophysiologic and cardiac pacing unit for their dedication and outstanding support.
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