26 Aug CRT-D: Cardiac Resynchronization plus Defibrillator – Predicting Who Does Best
MedicalResearch.com Interview with:
Dr Pamela N Peterson MD
Denver Health Medical Center, CO
MedicalResearch.com: What are the main findings of the study?
Answer: We assessed the outcomes of mortality, rehospitalization, and procedural complications among 24,169 patients in the NCDR-ICD Registry with left ventricular systolic dysfunction receiving a cardiac resynchronization device in addition to an implantable defibrillator for the primary prevention of sudden cardiac death between 2006 and 2009. After stratification by the QRS complex morphology and duration on the ECG and adjustment for measured differences in other characteristics, patients with left bundle branch block (LBBB) and QRS durations of at least 150 msec had significantly lower rates of mortality and rehospitalization at 3 years compared with patients with non-LBBB QRS morphology and/or QRS duration of 120-149 msec. Rates of mortality and readmission were generally highest in patients with non-LBBB and QRS duration of 120-149 msec. Rates of procedural complications at 30- and 90-days were similar across strata of QRS morphology and duration.
MedicalResearch.com: Were any of the findings unexpected?
Answer: Generally, longer QRS duration and LBBB QRS morphology are markers of adverse prognosis in patients with LV systolic dysfunction. In this cohort of patients who received CRT-D therapy, patients with both LBBB and wider QRS actually experienced better outcomes.
MedicalResearch.com: What should clinicians and patients take away from your report?
Answer: These findings support current guideline recommendations for patient selection for CRT-D therapy, with an emphasis on QRS duration and morphology as important criteria in identifying patients who may have better outcomes with this therapy. The strongest guideline recommendations for CRT in patients with LVSD are for those patients with LBBB and QRS complexes of at least 150 msec—those who in our study had the best outcomes. This study is also important because it provides information about outcomes in patients in contemporary practice who receive device therapy outside of the relatively rarified context of randomized trials. However, because there was no comparison group, we could not determine the relative associations between CRT-D vs. ICD therapy alone in any of the patient groups. Thus, one should not conclude that this study provides insights into the possible effectiveness of CRT-D in any specific patient group.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Answer: More refined data that helps clinicians, patients, and policy makers identify those who will derive the most benefit from relatively expensive technologies like CRT-D will be important to optimizing care quality and efficiency. Both trials and observational observational studies that assess the comparative effectiveness of CRT-D in patients for whom the benefits of the therapy are less clear (e.g. those with non-LBBB QRS morphology or shorter QRS duration) will be important to informed patients election for this therapy.
QRS Duration, Bundle-Branch Block Morphology, and Outcomes Among Older Patients With Heart Failure Receiving Cardiac Resynchronization Therapy
Peterson PN, Greiner MA, Qualls LG, Al-Khatib SM, Curtis JP, Fonarow GC, Hammill SC, Heidenreich PA, Hammill BG, Piccini JP, Hernandez AF, Curtis LH, Masoudi FA.
Division of Cardiology, Department of Medicine, Denver Health Medical Center, Denver, CO 80204, USA
JAMA. 2013 Aug 14;310(6):617-26. doi: 10.1001/jama.2013.8641.