Long-term follow-up after cardiac resynchronization therapy-optimization in a real-world setting: A single-center cohort study

Cardiac Resynchronization Therapy beyond Nominal Settings: An IEGM-Based Approach for Paced and Sensed Atrioventricular Delay Offset Optimization in Daily Clinical Practice

Optimization of the atrioventricular (AV) delay has been performed in several landmark trials in cardiac resynchronization therapy (CRT), although it is often not performed in daily practice. Our aim was to study optimal AV delays and investigate a simple intracardiac electrogram (IEGM)-based optimization approach. 328 CRT patients with paired IEGM and echocardiography optimization data were included in our single-center observational study. Sensed (sAV) and paced (pAV) AV delays were optimized using an iterative echocardiography method. The offset between sAV and pAV delays was calculated using the IEGM method. The mean age of the patients was 69 ± 12 years; 64% were men, 48% had ischemic etiology of heart failure. During echocardiographic optimization, an offset of 73 ± 18 ms was found, differing from nominal AV settings (p < 0.001). Based on the IEGM method, the optimal offset was 75 ± 25 ms. The echocardiographic and IEGM-generated AV offset delays showed good correlation (R2 = 0.62, p < 0.001) and good agreement according to Bland-Altman plot analysis. CRT responders had a near zero offset difference between IEGM and echo optimization (-0.2 ± 17 ms), while non-responders had an offset difference of 6 ± 17 ms, p = 0.006. In conclusion, optimal AV delays are patient-specific and differ from nominal settings. pAV delay can easily be calculated from IEGM after sAV delay optimization.

Impact of ventricular arrhythmia management on suboptimal biventricular pacing in cardiac resynchronization therapy

BACKGROUND

Reduced biventricular pacing (BiVP) is a common phenomenon in cardiac resynchronization therapy (CRT) with impact on CRT-response and patients' prognosis. Data on treatment strategies for patients with ventricular arrhythmia and BiVP reduction is sparse. We sought to assess the effects of ventricular arrhythmia treatment on BiVP.

METHODS

In this retrospective analysis, the data of CRT patients with a reduced BiVP ≤ 97% due to ventricular arrhythmia were analyzed. Catheter ablation or intensified medical therapy was performed to optimize BiVP.

RESULTS

We included 64 consecutive patients (73 ± 10 years, 89% male, LVEF 30 ± 7%). Of those, 22/64 patients (34%) underwent ablation of premature ventricular contractions (PVC) and 15/64 patients (23%) underwent ventricular tachycardia (VT) ablation while 27/64 patients (42%) received intensified medical treatment. Baseline BiVP was 88.1% ± 10.9%. An overall increase in BiVP percentage points of 8.8% (range - 5 to + 47.6%) at 6-month follow-up was achieved. No changes in left ventricular function were observed but improvement in BiVP led to an improvement in NYHA class in 24/64 patients (38%). PVC ablation led to a significantly better improvement in BiVP [9.9% (range 4 to 22%) vs. 3.2% (range - 5 to + 10.7%); p =  < 0.001] and NYHA class (12/22 patients vs. 4/27 patients; p = 0.003) than intensified medical therapy. All patients with VT and reduced BiVP underwent VT ablation with an increase of BiVP of 16.3 ± 13.4%.

CONCLUSION

In this evaluation of ventricular arrhythmia treatment aiming for CRT optimization, both medical therapy and catheter ablation were shown to be effective. Compared to medical therapy, a higher increase in BiVP was observed after PVC ablation, and more patients improved in NYHA class.

CLINICAL TRIAL REGISTRATION

The study was registered at clinical trials.org in August 2019: NCT04065893.