Pacing and Cardiac Resynchronization Therapy
Prediction of response to cardiac resynchronization therapy using simple electrocardiographic and echocardiographic tools
1 Department of Pacemaker and Electrophysiology, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Mellat Park, Vali-E-Asr Avenue, PO Box 15745-1341, Tehran 1996911151, Iran; 2 Department of Research Laboratory, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; 3 Department of Echocardiography, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
Aims: To predict response to cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and intraventricular conduction delay.
Methods and results: The study population consisted of 82 consecutive HF patients with standard CRT indications. Patients were classified as responders, if they were alive without cardiac decompensation and experienced 
15% decrease in left ventricular end-systolic volume. Sixty-eight percent of the enrolled patients responded to CRT. When compared with non-responders, responders had a wider baseline QRS width (P = 0.001), more marked QRS shortening (
QRS) immediately after CRT (P = 0.001), and a better improvement in aortic velocity time integral (VTI) 24 h after CRT (P = 0.02). Moreover, there was a trend towards a greater baseline intraventricular dyssynchrony in the responder group (P = 0.07). By multivariable logistic regression, the baseline QRS width (OR: 0.95, 95% CI: 0.90–0.97, P = 0.001), QRS (OR: 1.038, 95% CI: 1.012–1.064, P = 0.003), and acute aortic VTI (OR: 0.81, 95% CI: 0.68–0.96, P = 0.017) emerged as independent predictors of response to CRT. Receiver operating characteristic curve analysis identified a QRS width >145 ms, QRS >20 ms, and aortic VTI >14 cm to predict responders.
Conclusion: A positive response to CRT was observed in 68% of the patients. Cardiac resynchronization therapy response is predictable using simple electrocardiographic and echocardiographic data.
Key Words: Cardiac resynchronization therapy, Heart failure, Response, Electrocardiography, Echocardiography
* Corresponding author. Tel: +98 21 2392 2163, Fax: +98 21 2204 8174, Email: majid.haghjoo{at}gmail.com
Manuscript submitted 10 June 2009. Accepted after revision 18 August 2009.