How Many Patients with Dilated Cardiomyopathy May Potentially Benefit from Cardiac Resynchronization Therapy? WOLFRAM GRIMM, JULIA SHARKOVA, REINHARD FUNCK, and BERNHARD MAISCH From the Department of Cardiology, Hospital of the Philipps-University of Marburg, Marburg, Germany. GRIMM, W., ET AL.: How Many Patients with Dilated Cardiomyopathy May Potentially Benefit from Cardiac Resynchronization Therapy? The clinical and electrocardiographic Marburg Cardiomyopathy database was analyzed to identify potential candidates for cardiac resynchronization therapy (CRT) with biventricular or left ventricular pacing among 566 patients with dilated cardiomyopathy (DCM). All of the following restrictive selection criteria were fulfilled by 38 patients (7%): NYHA functional class ≥ 3 (n = 193, 34%), left ventricular ejection fraction (LVEF) <30% (n = 238, 42%), sinus rhythm (n = 437, 77%), left bundle branch block (LBBB, n = 142, 25%), and QRS duration ≥ 150 ms (n = 136, 24%). In 78 of the 566 patients (14%) all of the following less restrictive selection criteria were fulfilled: NYHA functional class ≥3 (n = 193, 34%), LVEF < 35% in presence of any underlying rhythm (n = 326, 58%), QRS duration ≥ 120 ms with right or left bundle branch block (n = 223, 39%). Thus, between 7% and 14% of patients with DCM were candidates for CRT depending on the application of strict versus less restrictive selection criteria.(PACE 2003; 26[Pt. II]:155–157) cardiac resynchronization, biventricular pacing, dilated cardiomyopathy, congestive heart failure Introduction Despite considerable progress made in the past decade in the medical management of con- gestive heart failure in patients with dilated car- diomyopathy (DCM), disabling symptoms persist in many patients. Several recent studies have shown significant symptomatic and hemodynamic improvements by biventricular or left ventricu- lar pacing in patients with drug refractory heart failure and marked inter- and intraventricular conduction delays. 1-12 To determine the preva- lence of potential candidates for cardiac resyn- chronization therapy (CRT), we have analyzed the clinical, hemodynamic and electrocardiographic data of the prospective Marburg Cardiomyopathy database. Methods Patients Data from 566 consecutive patients with DCM included in the Marburg Cardiomyopathy database between 1991 and 2001 were analyzed. Cardiac catheterization, including coronary an- giography, had confirmed the absence of coronary artery stenosis ≥50%. Detailed echocardiographic examinations were performed at the time of enroll- ment by an experienced echocardiographer using a Sonotron VingMed imaging system (Sonotron, Address for reprints: Wolfram Grimm, M.D., Department of Cardiology, Philipps-University Marburg, Baldingerstraße, 35033 Marburg, Germany. Fax: +49-6421-286-8954; e-mail: Wolfram.Grimm@med.uni-marburg.de Oslo, Norway). Left ventricular (LV) end-diastolic diameter and ejection fraction (EF) were measured according to the guidelines of the American So- ciety of Echocardiography. All patients had an LVEF ≤ 50% by left ventriculography and echocar- diography, and an LV end-diastolic diameter ≥56 mm by echocardiography. No patient had clinical findings consistent with ischemic, valvular, hyper- tensive, or metabolic cardiomyopathy. The data available in the 566 patients were analyzed using restrictive versus less restric- tive selection criteria for CRT as previously suggested in the literature. 1-15 Restrictive crite- ria were defined as 1) New York Heart Asso- ciation (NYHA) functional class ≥3, 2) LVEF <30%, 3) left bundle branch block (LBBB) with a QRS duration ≥150 ms, and 4) sinus rhythm. Less restrictive criteria were defined as 1) NYHA class ≥3, 2) LVEF < 35%, 3) right or left bundle branch block with a QRS duration ≥120 ms, and 4) any underlying rhythm. Results The clinical characteristics of the 566 patients with DCM including baseline echocardiographic and electrocardiographic findings are summarized in Table I. QRS duration on the baseline 12-lead electrocardiogram was ≥120 ms in 223 (39%) and ≥150 ms in 136 (24%) patients (Fig. 1). All of the following restrictive selection criteria were fulfilled in 38 of the 566 patients (7%): NYHA functional class ≥ 3 in 193 patients (34%), LVEF < 30% in 238 (42%), sinus rhythm in 437 (77%), PACE, Vol. 26 January 2003, Part II 155