Three years of cardiac resynchronization therapy: could superior benefits be obtained in patients with heart failure and narrow QRS?
OBJECTIVE
To examine the long-term effects of cardiac resynchronization therapy (CRT) in patients presenting with heart failure (HF) and QRS </= 120 ms.


METHODS
This was a prospective, longitudinal study of 376 patients [mean age = 65 years, mean left ventricular (LV) ejection fraction (EF) = 29%, mean QRS duration = 165 ms, mean distance covered during a 6-minute hall walk (6-MHW) = 325 m], who underwent successful implantation of CRT systems. The QRS duration at baseline was </= 120 ms in 45 patients (12%) who were not pre-selected by echocardiographic criteria of dyssynchrony, and > 120 ms in the remaining 331 patients. The baseline characteristics of the 2 groups were similar. We evaluated indices of cardiac function, percentage of responders, and survival rates over a mean 28-month follow-up.


RESULTS
Both groups experienced similar long-term increases in 6-MHW, and decreases in New York Heart Association functional class and LV end-systolic volume (all comparisons P < 0.0001 in both groups). Time interaction of changes in LVEF and percentage of responders were significantly different (P = 0.03 and P = 0.004, respectively), in favor of the narrow QRS group, where the changes were sustained and persisted at 2 and 3 years. The long-term death rate from HF was lower in the group with narrow than in the group with wide QRS complex (P = 0.04; log-rank test).


CONCLUSIONS
CRT confers considerable long-term clinical, functional, and survival benefits in patients presenting with HF and narrow QRS, not preselected by echocardiographic criteria of dyssynchrony. Caution is advised before denying CRT to these patients on the basis of QRS width only.
Gasparini
Maurizio
M
IRCCS Istituto Clinico Humanitas, Rozzano-Milano, Italy. maurizio.gasparini@humanitas.it
Regoli
François
F
Galimberti
Paola
P
Ceriotti
Carlo
C
Bonadies
Marika
M
Mangiavacchi
Maurizio
M
Andreuzzi
Bruno
B
Bragato
Renato
R
Pini
Daniela
D
Klersy
Catherine
C
Gronda
Edoardo
E
D000368:Aged; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left