Whether noninvasive optimization of AV and VV delays improves the response to cardiac resynchronization therapy

The Usefulness and Limitations of Impedance Cardiography for Cardiac Resynchronization Therapy Device Optimization

Identifying the optimal atrioventricular (AV) or interventricular (VV) delay is beneficial for patients using cardiac resynchronization therapy (CRT) devices. Ultrasonic echocardiography (UCG) has been the most commonly used method; however, it requires high technical knowledge. Impedance cardiography (ICG) can calculate stroke volume by measuring changes in transthoracic electric impedance. This study sought to assess the clinical utility of ICG in comparison with that of UCG for the optimization of CRT devices.Patients who underwent CRT device implantation were retrospectively analyzed. One week after implantation, optimization of AV delay (AVD) was performed in every patient with ICG (AVD-ICG) and UCG (AVD-UCG). VV delay (VVD) was then determined according to the optimal AVD using these two methods.Forty-two patients were enrolled. Average AVD-ICG was significantly shorter than AVD-UCG (128 ± 49 versus 146 ± 41 milliseconds, P = 0.018). Five patients (12%) had the same optimized AVD with two methods, and the difference between AVD-ICG and AVD-UCG was ≤ 20 milliseconds in 19 patients (45%). In the multivariate analysis, the presence of postoperative mitral regurgitation (MR) was an independent predictor of AVD-ICG/AVD-UCG mismatch, defined as a difference over 20 milliseconds (odds ratio = 10.71; 95% confidence interval = 1.72 to 66.72; P = 0.018). The results of optimized VVD were similar using both methods.ICG might be a promising tool for the rapid optimization of CRT devices. However, in patients with moderate-to-severe MR, ICG may not be able to optimize AVD.

The efficacy of left bundle branch area pacing compared with biventricular pacing in patients with heart failure: A matched case-control study

BACKGROUND

Left bundle branch area pacing (LBBAP) was reported to improve cardiac function by correcting complete left bundle branch block (CLBBB). Our study aimed to compare the efficacy of LBBAP and biventricular pacing (BIVP) in heart failure patients with CLBBB.

METHODS

Ten patients prospectively underwent LBBAP (LBB-CRT group) and 30 patients received BIVP (BIV-CRT group) were matched using propensity score matching. LBBAP was achieved by the trans-interventricular septum method. Echocardiography, electrocardiogram, NYHA classification, and blood B-type natriuretic peptide concentration were evaluated at preimplantation and at 6-month follow up. CRT response was defined as at least 15% decrease in left ventricular end-systolic volume.

RESULTS

In the LBB-CRT group, CLBBB were successfully corrected by LBBAP with no complications. QRS duration (QRSd) significantly decreased after implantation in both groups, and the decrease of QRSd in the LBB-CRT group was significantly greater than that in the BIV-CRT group (60.80 ± 20.09 vs. 33.00 ± 21.48 ms, p = .0009). The echocardiographic measurements including left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left ventricular ejection fraction significantly improved after 6 months in both groups. The response rate was significantly higher in LBB-CRT group than BIV-CRT group (100.00% vs. 63.33%, p = .038). The percentage of patients in New York Heart Association classification Grades I and II was significantly higher in the LBB-CRT group compared with that in the BIV-CRT group (median 1.5 vs. 2.0, p = .029) at 6-month follow-up.

CONCLUSIONS

It is effective and safe to correct CLBBB with LBBAP in heart failure patients. Compared with BIVP, LBBAP can better optimize electrical synchrony and improve cardiac function.

Delay optimization of multipoint pacing increases the cardiac index and narrows the QRS width

INTRODUCTION

The benefits of MPP delay optimization on hemodynamics and ventricular contraction synchronicity can be quantified with cardiac index (CI) and QRS width. A delay with the maximum CI and minimum QRS width may be the optimized settings for multipoint pacing (MPP).

METHODS

Twelve patients with advanced heart failure who received cardiac resynchronization therapy defibrillation with MPP at the Third People's Hospital of Chengdu from March 2016 to April 2019 were included. Interventricular and intraventricular delays were optimized through noninvasive cardiac output monitoring and a 12 lead ECG.

RESULTS

According to CI, the optimized left ventricular- left ventricular - right ventricular delay setting was mainly 25 ms-25 ms and 40 ms-40 ms. And the delay with the minimum QRS width was mainly in 5 ms-5 ms, 25 ms-25 ms, and 40 ms-25 ms. The optimal MPP configuration increased CI compared to the MPP setting that produced the minimum CI (4.5 ± 1.3 vs. 2.8 ± 1.0 L/min/m2, P < 0.001). The QRS width of the optimized MPP was narrower than the MPP setting that produced the maximum QRS width (127 ± 20 vs. 160 ± 29 ms, P < 0.001).

CONCLUSION

Delay optimization improves hemodynamic response and ventricular contraction synchronicity. The delay of 25 ms-25 ms may be the optimal setting for most MPP patients.