Electrical Signals Applied During the Absolute Refractory Period
An Investigational Treatment for Advanced Heart Failure in Patients With Normal QRS Duration
Thomas Lawo, MD*,
Martin Borggrefe, MD
,
Christian Butter, MD
,
Gerhard Hindricks, MD
,
Herwig Schmidinger, MD||,
Yuval Mika, PhD¶,
Daniel Burkhoff, MD, PhD¶,#,
Carlo Pappone, MD, PhD** and
Hani N. Sabbah, PhD,*
* Berufgenossenschaftliche Kliniken Bergmannnsheil, Bochum, Germany
Fakultät für klinische Medizin der Universität Heidelberg, Mannheim, Germany
Heart Center Brandenburg Bernau/Berlin, Bernau, Germany
Herzzentrum der Universität Leipzig, Leipzig, Germany
|| Department of Cardiology, University Clinic for Internal Medicine II, Vienna, Austria
¶ IMPULSE Dynamics USA, Orangeburg, New York
# Columbia University, New York, New York
** Fondazione Centro S. Raffaele de Monte Tabor, Milano, Italy
Henry Ford Health System, Detroit, Michigan
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Figure 1 (A) Cardiac contractility modulating (CCM) signals employed in clinical study are biphasic pulses delivered after a defined delay from detection of local electrical activation. (B) Effects of CCM signals on isometric force measured from trabecular muscle of an end-stage failing heart obtained at heart transplant (11,12). ECG = electrocardiogram.
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Figure 2 Effects of cardiac contractility modulating (CCM) signals on global function assessed by pressure-volume relations (left column) and on regional function in the anterior wall (middle column) and posterior wall (right column) assessed by pressure-segment length (SL) loops when signals are applied to the anterior wall (top row), posterior wall (middle row), and simultaneously to both walls (bottom row). Baseline shown in blue; measurements during CCM signal application shown in red. LV = left ventricular. Used with permission from Mohri et al. (33).
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Figure 3 (A) Acute effects of cardiac contractility modulating (CCM) signals on dP/dtmax in patients with heart failure. Average CCM effect (dashed line) was independent of QRS duration. (B) In patients with prolonged QRS duration, CCM effects were additive to those of biventricular pacing (BVP) (B) Reprinted from Pappone et al. (38) with permission from Excerpta Medica, Inc.
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Figure 4 Right anterior oblique (RAO) and left lateral oblique (LAO) fluoroscopic images of electrode placement during OPTIMIZER System implant. One lead is placed in the right atrium (RA), and two leads are placed on the right ventricular septum (RV1, RV2) approximately mid-way between the base and apex, one near the anterior and one near the posterior interventricular groove. The LAO caudal view shows the electrode tips point toward the left side of the patient’s body, into the septum. A micromanometer (Millar) is placed temporarily to measure physiologic response to acute cardiac contractility modulating signal application.
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Figure 5 Holter monitor analysis available from the first 22 patients exposed to cardiac contractility modulating signals for eight weeks showed no significant change in ambient ectopy quantified by either the average total number of premature ventricular contractions (PVCs) per hour of the average number of runs of tachycardia consisting of four or more consecutive beats of ventricular tachycardia (VT) (41).
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Figure 6 Results of a feasibility study suggest improvements over time in New York Heart Association (NYHA) functional classification, Minnesota Living With Heart Failure Questionnaire (MLWHFQ) score, and ejection fraction over the eight-week course of the study (41).
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Copyright © 2005 by the American College of Cardiology Foundation.
