Left ventricular function during and after right ventricular pacing
Maher Nahlawi, MD,
Michael Waligora, MD,
Stewart M. Spies, MD,
Robert O. Bonow, MD, FACC,
Alan H. Kadish, MD, FACC and
Jeffrey J. Goldberger, MD, FACC*
Division of Cardiology, Department of Medicine, Northwestern University, Chicago, Illinois, USA
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Figure 1 Time line depicting study protocol. Electrocardiograms, blood pressure, and gated blood pool scans were obtained at each time point indicated by the vertical arrows. Between studies, pacemakers were programmed to result in either normal atrioventricular (AV) conduction (AAI) or ventricular pacing (DDD mode with short AV delay), as indicated by the programmed mode. The mode during testing is indicated on top. MTVP = mid-term ventricular pacing for at least one week; STVP = short-term ventricular pacing for 2 h.
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Figure 2 Plot of individual values of left ventricular ejection fraction obtained at the baseline evaluation after at least one week of atrial pacing with normal atrioventricular conduction (BASE), during short-term (after 2 h) ventricular pacing (STVP), and during mid-term (after at least one week) ventricular pacing (MTVP).
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Figure 3 Plot of individual values of left ventricular ejection fraction obtained at the baseline evaluation after at least one week of atrial pacing with normal atrioventricular conduction (BASE), during mid-term (after at least one week) ventricular pacing (MTVP), and immediately after cessation of MTVP (immediately post-MTVP).
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Figure 4 Plot of mean ± SD values of left ventricular ejection fraction obtained in all 12 subjects at the baseline evaluation after at least one week of atrial pacing with normal atrioventricular conduction (BASE), during mid-term (after at least one week) ventricular pacing (MTVP), and 0, 2, 5, 8, 24, and 32 h after cessation of MTVP. *p < 0.007 compared with BASE;  p < 0.02 compared with 0 h after cessation of ventricular pacing.
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