Chiladakis John, Kalogeropoulos Andreas, Zagkli Fani, Chouchoulis Konstantinos
Cardiology Department, Patras University Hospital, 26500 Rion, Patras, Greece.
Cardiology Department, Patras University Hospital, 26500 Rion, Patras, Greece.
J Electrocardiol. 2015 Jul-Aug;48(4):689-95. doi: 10.1016/j.jelectrocard.2015.04.009. Epub 2015 Apr 11.
We evaluated the effect of heart rate on the intrinsic and the ventricular-paced QRS duration in implanted device recipients with normal or reduced left ventricular ejection fraction (EF).
We studied 239 outpatients with preserved intrinsic ventricular activation and normal (n=92) or reduced (n=147) EF who had apical (RVA) or mid-septal (RVS) right ventricular lead position. The QRS duration was measured at baseline and during atrial-based pacing at increased heart rate to ensure intrinsic or ventricular-paced QRS activation.
The heart rate increase shortened the intrinsic QRS only in patients with normal EF, and further prolonged the ventricular-paced QRS in patients with reduced EF and either narrow or wide QRS (p<0.001), irrespective of RVA or RVS pacing (p<0.01).
Heart rate increase is associated with further QRS prolongation in patients with reduced EF, regardless of RVA or RVS pacing site.
