Absolute survival after cardiac resynchronization therapy according to baseline QRS duration: a multinational 10-year experience: data from the Multicenter International CRT Study.
BACKGROUND
In the major trials of cardiac resynchronization therapy (CRT), the survival benefit of the therapy, relative to control subjects, increases with QRS duration. In the non-CRT heart failure population, however, a wide QRS duration is associated with a shorter survival. Relative survival benefit from a therapy, however, is not synonymous with a longer absolute survival. We sought to determine whether baseline QRS duration relates to the absolute survival after CRT.


RESULTS
In this prospective, longitudinal, observational study, 3,319 consecutive patients undergoing CRT (QRS 120-149 ms 26%, QRS 150-199 ms 58%, and QRS ≥200 ms 16%) were assessed in relation to mortality over 10 years. Overall mortality rates (per 100 patient-years) were 9.2%, 9.3%, and 13.3% in the 3 groups, respectively (all P < .001). Cardiac mortality rates were 6.2, 6.0, and 9.9 per 100 patient-years, respectively (all P < .001). Compared with the QRS 120-149 ms group, cardiac mortality was highest in the QRS ≥200 ms group (hazard ratio [HR] 1.72 [95% CI 1.35-2.19], P < .001), independent of age, gender, New York Heart Association class, presence of atrial fibrillation, heart failure etiology, and left ventricular ejection fraction. Median survival after CRT was longest in patients with a width of QRS 120-149 ms and shortest in patients with a QRS ≥200 ms (P < .001). In multivariable analyses, a QRS ≥200 ms emerged as a powerful independent predictor of both overall (HR 1.44 [95% CI 1.07-1.94], P = .017) and cardiac mortality (HR 1.59 [95% CI 1.14-2.24], P = .007).


CONCLUSIONS
At long-term follow-up, absolute overall and cardiac survival after CRT is similar in patients with a preimplant QRS duration of 120 to 149 ms and 150 to 199 ms but markedly shorter in patients with a QRS ≥200 ms.
Electrophysiology and Pacing Unit, Humanitas Research Hospital IRCCS, Rozzano-Milano, Italy. Electronic address: maurizio.gasparini@humanitas.it.
Maurizio
M
Gasparini
Department of Cardiology, University Hospital Rennes, Rennes, France.
Christophe
C
Leclercq
Department of Medicine and Therapeutics, Division of Cardiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin New Territories, Hong Kong.
Cheuk-Man
CM
Yu
Fondazione Cardiocentro Ticino, Lugano, Switzerland.
Angelo
A
Auricchio
Valley Health System and Columbia University College of Physicians & Surgeons, New York, NY.
Jonathan S
JS
Steinberg
Department of Cardiology, Heart and Diabetes Centre NRV, Bad Oeynhausen, Germany.
Barbara
B
Lamp
Biometry and Clinical Epidemiology, Research Department, IRCCS Fondazione Policlinico San Matteo, Pavia, Italy.
Catherine
C
Klersy
Centre for Cardiovascular Sciences, University of Birmingham, Queen Elizabeth Hospital, Birmingham, United Kingdom.
Francisco
F
Leyva
D000368:Aged; D001208:Asia / Q000453:epidemiology; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002423:Cause of Death / Q000639:trends; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005060:Europe / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D008297:Male; D009656:North America / Q000453:epidemiology; D011446:Prospective Studies; D013318:Stroke Volume; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology