Key result
Higher pacing rates induce incomplete relaxation in ~50% of normal EF myocardium, linked to increased LV mass.
Why the study?
Diastolic dysfunction and LV hypertrophy are linked, and tachycardia can induce heart failure symptoms in asymptomatic patients, motivating evaluation of tachycardia on myocardial contractility and relaxation in patients with normal ejection fraction.
Does increasing pacing rate induce incomplete relaxation and diastolic resting tone in myocardium from patients with normal ejection fraction?
Population
LV biopsy samples obtained during coronary bypass surgery from patients with normal ejection fraction
Comparison
Electrical pacing at rates from 60 to 180 beats/min
Design
Ex vivo myocardial tissue study
Authors
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Tachycardia may impair diastolic relaxation in preserved-EF myocardium; leaves open in vivo HFpEF relevance and therapeutic implications.
Does increasing pacing rate induce incomplete relaxation and diastolic resting tone in myocardium from patients with normal ejection fraction?
Tachycardia induces incomplete relaxation and increased resting tone in a subset of human myocardium with normal ejection fraction, potentially explaining tachycardia-induced diastolic dysfunction and reduced exercise tolerance.
Selby et al. (2011) studied Normal ejection fraction (n=14). Increasing pacing rates vs. Lower pacing rates was evaluated on Incomplete relaxation and diastolic resting tone. Increasing pacing rates induced incomplete relaxation in 7 of 14 myocardial preparations from patients with normal ejection fraction, associated with increased LV mass and left atrial volume.
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