The Impact of Age and Gender on Cardiac Resynchronization Therapy Outcome OMEED ZARDKOOHI, M.D., VEENA NANDIGAM, M.D., LORNE MURRAY, M.D., E. KEVIN HEIST, M.D., PH.D., THEOFANIE MELA, M.D., MARY ORENCOLE, R.N., A.N.P., JEREMY N. RUSKIN, M.D., and JAGMEET P. SINGH, M.D., PH.D. From the Cardiac Arrhythmia Service, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts Background: Cardiac resynchronization therapy (CRT) outcome varies significantly among patients. We aimed to determine the impact of age, gender, and heart failure etiology on the long-term outcome of patients receiving CRT. Methods: A total of 117 patients with drug-refractory heart failure, New York Heart Association (NYHA) Class III or IV, and a wide QRS complex, who received CRT, were followed for one year. Long-term outcome was measured as a combined end point of hospitalization for heart failure and/or all cause mortality. Efficacy of CRT was compared between men and women, between older and younger patients, and between patients with ischemic and nonischemic heart disease. Time to the primary end point was estimated by the Kaplan-Meier method and comparisons were made using the Breslow-Wilcoxon test. Results: Baseline clinical characteristics were comparable between gender, age, and heart failure eti- ology subgroups. There was no significant difference in the combined end point between older versus younger (age > 70, (n = 71), versus age < 70, (n = 46), P = 0.52); both genders (men, n = 91 vs women, n = 26, P = 0.46) and etiology of the cardiomyopathy (ischemic (n = 79) vs nonischemic (n = 38), P = 0.12). Substratification of the genders by the etiology of the cardiomyopathy, showed that women with ischemic cardiomyopathy (IW, n = 10) had a trend to a worse outcome compared to the other groups i.e., nonischemic women (NIW, n = 16), ischemic men (IM, n = 69), and nonischemic men (NIM, n = 22), P = 0.04. After adjusting for potential covariates, a Cox regression analysis showed no significant difference between the groups (P = 0.61). Conclusions: CRT outcome appears independent of age, gender, and heart failure etiology in this single institution study. (PACE 2007; 30:1344–1348) age, gender, resynchronization, etiology, heart failure Introduction Congestive heart failure (CHF) is a common illness in the United States, affecting an estimated five million people and responsible for nearly two million hospitalizations per year. 1 Despite the success of pharmacological therapy for CHF, this disease continues to carry a high morbidity and mortality. In addition to standard medical ther- apy, cardiac resynchronization therapy (CRT) has emerged as an important therapeutic modality in patients with CHF and prolonged QRS duration, and has been shown to improve both survival and health-related quality of life in numerous clinical trials. 2,3 However, the individual response to CRT varies substantially, with up to one-third of pa- tients being nonresponders, with poor long-term Address for reprint: Jagmeet P. Singh M.D. Ph.D., GRB 109, Car- diac Arrhythmia Service, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114. Fax: 617-726-3852; e-mail: js- ingh@partners.org Received January 5, 2007; revised June 8, 2007; accepted July 21, 2007. clinical outcomes. 2,4 To better target CRT to the appropriate patient population as clinical indica- tions for this therapy continue to expand, and im- prove cost-effectiveness, it is important to read- ily identify the preimplant characteristics that may impact clinical outcome. The purpose of this study was to determine the effect of age, gender, and heart failure etiology on the long-term clinical outcome of patients with heart failure and intraventricular conduction de- lay on maximum medical therapy receiving CRT. Methods This was a single-center, longitudinal obser- vational study that included 117 consecutive pa- tients with drug-refractory heart failure who re- ceived CRT at our institution. The following se- lection criteria for CRT were applied: New York Heart Association (NYHA) Class III or IV, left ven- tricular ejection fraction (LVEF) < 35%, and QRS duration >120 ms. All patients were on optimal medical therapy for CHF before CRT. The etiology was considered ischemic in the presence of coronary stenosis greater than 50% in at least one major coronary artery (left main, C 2007, The Authors. Journal compilation C 2007, Blackwell Publishing, Inc. 1344 November 2007 PACE, Vol. 30