Source:  Eur Heart J. 2004 Apr;25(8):650-5.
Comment: Eur Heart J. 2004 Apr;25(8):626-8.
Title:   Chronic electrical stimulation during the absolute
         refractory period of the myocardium improves
         severe heart failure.
Authors: Stix G, Borggrefe M, Wolpert C, Hindricks G,
         Kottkamp H, Bocker D, Wichter T, Mika Y, Ben-Haim
         S, Burkhoff D, Wolzt M, Schmidinger H.
From:    Department of Cardiology, University of Vienna, AKH
         Wien, Waehringer Guertel 18-20, 1090 Vienna, Austria.
E-mail:  guenter.stix@univie.ac.at
PMID:    15084369

In experimental studies, nonexcitatory electrical stimulation
delivered at the time of absolute myocardial refractoriness
caused cardiac contractility modulation (CCM) with improved
systolic function. We studied CCM in patients with chronic HF.
	Twenty-five patients (23 males) with an average age of
62 years and class 3 CHF not responding to drug treatment
received CCM-generator implant. The underlying heart disease
was IDCM in 12 patients and CAD in 13 patients.
	Short-term CCM effectiveness with 7.73-V stimuli given
through 2 right ventricular leads was evaluated by measuring
the time derivative of left ventricular pressure (dP/dt). After
implant, the CCM generator was activated for 3 hours daily for
8 weeks.
	In 23 of 25 patients, the CCM system was implanted
successfully. CHF improved from class 3 to class 2 in 15
patients and to class one in 4 patients; EF improved from 22%
to 28%; the Minnesota Living with Heart Failure score improved
from 43 to 25. The 6-minute walk test increased from 411 to 465
meters.
	Nine patients (39%) had intermittent sensations
associated with CCM delivery. There were two (8%) non-device-
related deaths during follow-up.
	This suggests that CCM by delivery of intermittent
nonexcitatory electrical stimuli may improve ventricular
systolic function and symptoms in patients with drug-refractory
class 3 heart failure.