Effect of disabling biventricular pacing in patients with left ventricular assist device and cardiac resynchronization therapy
Authors: Sawicka M , Bielka A , Ratman K , Kalinowski M , Przybylowski P 
Published: October 2024

Abstract

Introduction
Taking into account the mechanism of the left ventricular assist device (LVAD) function, the cardiac resynchronization therapy (CRT) seems to be unnecessary and, according to the current reports, the left ventricular lead (LVL) should be disabled. However, observation of the patients suggests that deactivation of the left ventricle (LV) pacing leads to deterioration of the patients condition and progression of the heart failure (HF) symptoms.

Purpose
The study aimed to determine differences in survival of the patients with LVAD and maintained or disabled CRT, including patients subjected to heart transplantation, as well differences in left and right ventricle function, kidneys and liver condition, NTproBNP value, subjective exercise tolerance and frequency of HF exacerbation before and after CRT deactivation.

Methods
The study group involved 55 patients with LVAD and CRT devices, including 11 patients with disabled LV pacing. The statistical analysis concerned the comparison of groups with and without biventricular stimulation as well results within the group with disabled LVL before and after its deactivation. Analyzed data included laboratory results, echocardiographic parameters, number of HF exacerbation episodes and exercise tolerance by NYHA classification.

Results
Total CRT period did not differ in group with maintained and disabled CRT [24 (12-36)months vs. 30 IQR(12-48)months respectively; p=0,74]. The median period of CRT deactivation was 30 IQR(12-48) months after LVAD implantation. Time from LVAD implantation to heart transplantation differed significantly between patients with and without CRT [20 IQR(9-32)months vs. 49,5 IQR(46,5-62)months respectively; p=0,003]. LV disabling was connected with a significant increase of NTproBNP [3072 IQR(2287-6636) pg/ml vs. 2133 IQR(1618-3437) pg/ml before LVL deactivation; p=0,009), without an aggravation of the exercise intolerance by NYHA classification (p=0,11) or total number of HF exacerbation episodes (p=0,72). Lack of LV pacing was not related to change of concentration of creatinine (p=0,13), AST (p=0,89, ALT (p=0,5), bilirubin (p=0,06) and albumin (p=0,69) before and after LV deactivation. Comparison of echocardiographic parameters with and without CRT did not demonstrate significant differences in LV ejection fraction (p=0,37), LV end-diastolic diameter (p=0,33), TAPSE (p=0,72) and tricuspid regurgitation degree (p=0,39). Death-free survival from LVAD implantation has not differed in patients with and without CRT(p=0,08), similarly like death-free survival from heart transplantation (p=0,56), however with tendency to better outcome of patients with CRT till 12 months after the heart transplant.

Conclusion
CRT does not improve general health condition as well death-free survival in LVAD recipients, including patients subjected to heart transplantation, however with tendency to better outcome of patients with CRT till 12 months after the heart transplant.Death-free surival after LVADDeath-free survival after transplant