Effective nonapical left ventricular pacing with quadripolar leads for cardiac resynchronization therapy

Background: Current guidelines recommend avoiding apical left ventricular (LV) pacing for cardiac resynchronization therapy (CRT). Aims: We investigated the feasibility of nonapical pacing with the current quadripolar LV lead technology. Methods: We analyzed consecutive patients who received CRT with an LV quadripolar lead. The post­­implantation position of each electrode of the LV lead was designated as basal, mid, or apical. The pacing capture threshold (PCT) and phrenic nerve stimulation (PNS) threshold were assessed for each electrode. Results: We enrolled 168 patients. A total of 8 CRT defibrillators were from Biotronik (with Sentus OTW QP leads), 98 were from Boston Scientific (with 21 Acuity X4 Spiral and 77 Acuity X4 Straight leads), and 62 from St. Jude Medical (with Quartet leads). The median (interquartile range) number of electrodes at nonapical segments per patient was 3 (1–4) with Biotronik Sentus leads, 4 (3–4) with spiral ­design Boston Scientific leads, 4 (3–4) with straight Boston Scientific leads, and 3 (3–4) with St. Jude Medical Quartet leads (P = 0.045). Three patients (38%) with Biotronik Sentus leads, 21 (100%) with spiral ­design Boston Scientific leads, 69 (90%) with straight ­design Boston Scientific leads, and 49 (79%) with St. Jude Medical Quartet leads (P < 0.001) had at least 1 electrode located at nonapical segments linked with a PNS ­PCT safety margin of more than 2 V. During the 6­month follow ­up, PNS was detected in 4 patients and was eliminated with reprogramming. No significant changes in PCT were detected during follow ­up. Conclusions: Quadripolar leads allowed nonapical pacing with acceptable electrical parameters in the majority of CRT recipients, although differences were found among the currently available devices

Adherence to 2016 European Society of Cardiology guidelines predicts outcome in a large real-world population of heart failure patients requiring cardiac resynchronization therapy

Background Professional guidelines are based on the best available evidence. However, patients treated in clinical practice may differ from those included in reference trials. Objective The aim of this study was to evaluate the effects of cardiac resynchronization therapy (CRT) in a large population of patients implanted with a CRT device stratified in accordance with the 2016 European heart failure (HF) guidelines. Methods We collected data on 930 consecutive patients from the Cardiac Resynchronization Therapy MOdular REgistry. The primary end point was a composite of death and HF hospitalization. Results Five hundred sixty-three (60.5%) patients met class I indications, 145 (15.6%) class IIa, 108 (11.6%) class IIb, and 114 (12.3%) class III. After a median follow-up of 1001 days, 120 (14.7%) patients who had an indication to CRT had died and 71 (8.7%) had been hospitalized for HF. The time to the end point was longer in patients with a class I indication (hazard ratio 0.55; 95% confidence interval 0.39–0.76; P = .0001). After 12 months, left ventricular (LV) end-systolic volume had decreased by ≥15% in 61.5% (320/520) of patients whereas in 57.5% (389/676) of patients the absolute LV ejection fraction improvement was ≥5%. Adherence to class I was also associated with an absolute LV ejection fraction increase of >5% (P = .0142) and an LV end-systolic volume decrease of ≥15% (P = .0055). Conclusion In our population, ∼60% of patients underwent implantation according to the 2016 European HF guidelines class I indication. Adherence to class I was associated with a lower death and HF hospitalization rates and better LV reverse remodeling