Baseline QRS duration did not predict clinical response to CRT (179±30 ms in responders vs 171±32 ms in nonresponders, NS), and individual QRS shortening varied highly.
Cohort (n=61)
Does QRS duration at baseline or its reduction after CRT predict clinical response in patients with end-stage heart failure?
Baseline QRS duration and its shortening after CRT do not reliably predict individual clinical response to CRT in patients with end-stage heart failure.
Despite current selection criteria (NYHA Class III-IV, LVEF 120 ms with LBBB), 30% of patients do not benefit from cardiac resynchronization therapy (CRT). The use of QRS duration as selection criteria for CRT has not been evaluated systematically yet. Accordingly, the value of QRS duration at baseline (and reduction in QRS duration after CRT) to predict responders was studied. Patients were evaluated at baseline and after 6 months of CRT for NYHA Class, quality of life score, and 6-minute walk test. QRS duration was evaluated before, directly after implantation, and after 6 months of CRT. Sixty-one patients were included; 45 (74%) patients were classified as responders (improvement of NYHA Class, 6-minute walking distance and quality of life score) and 16 (26%) as nonresponders. QRS duration at baseline was similar between the two groups: 179 +/- 30 ms versus 171 +/- 32 ms, NS. Directly after implantation, QRS duration was reduced from 179 +/- 30 ms to 150 +/- 26 ms (P 10 ms had a high sensitivity (73%) with low specificity (44%); conversely, a > 50 ms reduction in QRS duration was highly specific (88%) but not sensitive (18%) to predict response to CRT. No optimal cutoff value could be defined. QRS duration at baseline is not predictive for response to CRT; responders exhibit a significant reduction in QRS duration after CRT, but individual response varies highly, not allowing adequate selection of responders.
Molhoek et al. (Mon,) conducted a cohort in End-Stage Heart Failure (n=61). Baseline QRS duration and QRS shortening was evaluated on Clinical response to CRT (improvement of NYHA Class, 6-minute walking distance and quality of life score). Baseline QRS duration did not predict clinical response to CRT (179±30 ms in responders vs 171±32 ms in nonresponders, NS), and individual QRS shortening varied highly.