Long-term clinical effect of hemodynamically optimized cardiac resynchronization therapy in patients with heart failure and ventricular conduction delay.
OBJECTIVE
We sought to compare the short- and long-term clinical effects of atrial synchronous pre-excitation of one (univentricular) or both ventricles (biventricular), that provide cardiac resynchronization therapy (CRT).


BACKGROUND
In patients with heart failure (HF) who have a ventricular conduction delay, CRT improves systolic hemodynamic function. The clinical benefit of CRT is still being investigated.


METHODS
Forty-one patients were randomized to four weeks of first treatment with biventricular or univentricular stimulation, followed by four weeks without treatment, and then four weeks of a second treatment with the opposite stimulation. The best CRT stimulation was continued for nine months. Cardiac resynchronization therapy was optimized by hemodynamic testing at implantation. The primary end points were exercise capacity measures. Data were analyzed by two-way repeated-measures analysis of variance.


RESULTS
The left ventricle was selected for univentricular pacing in 36 patients. The clinical effects of univentricular and biventricular CRT were not significantly different. The results of each method were pooled to assess sequential treatment effects. Oxygen uptake during bicycle exercise increased from 9.48 to 10.4 ml/kg/min at the anaerobic threshold (p = 0.03) and from 12.5 to 14.3 ml/kg/min at peak exercise (p < 0.001) with the first treatment, and from 10.0 to 10.7 ml/kg/min at the anaerobic threshold (p = 0.2) and from 13.4 to 15.2 ml/kg/min at peak exercise (p = 0.002) with the second treatment. The 6-min walk distance increased from 342 m at baseline to 386 m after the first treatment (p < 0.001) and to 416 m after the second treatment (p = 0.03). All improvements persisted after 12 months of therapy.


CONCLUSIONS
Cardiac resynchronization therapy produces a long-term improvement in the clinical symptoms of patients with HF who have a ventricular conduction delay. The differences between optimized biventricular and univentricular therapy appear to be small for short-term treatment.
Auricchio
Angelo
A
Department of Cardiology, University Hospital, Magdeburg, Germany. angelo.auricchio@medizin.uni-magdeburg.de
Stellbrink
Christoph
C
Sack
Stefan
S
Block
Michael
M
Vogt
Jürgen
J
Bakker
Patricia
P
Huth
Christof
C
Schöndube
Friedrich
F
Wolfhard
Ulrich
U
Böcker
Dirk
D
Krahnefeld
Olaf
O
Kirkels
Hans
H
D001145:Arrhythmias, Cardiac / Q000150:complications / Q000628:therapy*; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D016896:Treatment Outcome