Abstract
Background
Cardiac resynchronization therapy (CRT) is used in selected heart failure patients with electrical cardiac dyssynchrony with a prolonged QRS duration and a left ventricle ejection fraction (LVEF) ≤35%. QRS duration post CRT implantation can probably predict responders and survivors. The aim of our study is to investigate the effect of QRS change on long-term survival post CRT implantation.
Methods
We performed a retrospective cohort study in patients receiving a CRT device in our tertiary referral center between January 2009 and January 2018. Clinical and electrocardiographic (ECG) data were collected at baseline, one week after CRT implantation, six months, and yearly during follow-up. The primary endpoint was death, left ventricle assisting device implantation, or heart transplantation. At the end, the cohort was dichotomized to the cut-off value of ≥15ms according current literature.
Results
The study population consisted of 219 patients of whom 145 (66%) patients were survivors and 74 (34%) non-survivors. Non-survivors were significantly older (63 vs. 68 years, p=0.001), male gender (67% vs. 82%, p=0.015), had more often diabetes mellitus (20% vs. 39%, p=0.002), chronic obstructive pulmonary disease (12% vs. 28%, p=0.003), an ischemic etiology of heart failure (42% vs. 61%, p=0.009) with previous myocardial infarction (29% vs 53%, p=0.001), previous revascularization (32% vs. 49%, p=0.019), atrial fibrillation (21% vs. 39%, p=0.004), worser NYHA class (p=0.008), and amiodarone use (10% vs. 22%, p=0.024). Blood urea nitrogen (BUN) (8.1 mmol/L vs. 10.4 mmol/L, p<0.001) and creatinine levels (96 μmol/L vs. 114 μmol/L, p=0.001) were also higher in the non-survivors group. Median QRS duration (168 ms IQR [154 to 182]) at baseline was comparable between survivors and non-survivors (170 ms vs. 166 ms, p=0.17). However, median QRS change one week after CRT implantation was significantly better in the survivors (−19 ms IQR [−30 to −2] vs. −6 ms IQR [−24 to +12], p=0.004). The QRS change at the last FU (median 5.1 years IQR [2.9 to 7.8] was consistently higher in the survivor group (−16 ms IQR [−29 to 0] vs. +1 ms IQR [−27 to +20], p=0.004). Dichotomized to ΔQRS narrowing of ≥15 ms after CRT implantation showed significantly better long-term survival (figure).
Kaplan-Meier curve
Conclusion
QRS narrowing cut-off of ≥15 ms post CRT implantation is strongly associated with the long term survival in chronic heart failure patients with reduced LVEF.
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