Impact of left ventricular pacing threshold on ventricular arrhythmia occurrence in cardiac resynchronization therapy
Jerko Ferri-Certić1, Dinko Zavrl-Džananović2, Luka Ležaić3
1Department of Cardiology, General Hospital Dubrovnik, Dubrovnik, Croatia.
Insights
High left ventricular pacing threshold during cardiac resynchronization therapy may indicate lower myocardial viability and predict ventricular arrhythmias in heart failure patients.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is a standard treatment for heart failure (HF).
- The impact of CRT on ventricular arrhythmias (VAs) remains debated.
- High left ventricular pacing thresholds (LVPT) and scar burden are linked to poorer outcomes in CRT patients.
Purpose of the Study:
- To investigate the relationship between intraoperative LVPT and VA occurrence in CRT patients.
- To assess if LVPT can predict VA development.
Main Methods:
- Eighty advanced HF patients undergoing CRT defibrillator implantation were assessed.
- Myocardial viability was evaluated using single-photon emission computed tomography.
- Intraoperative LVPT and LV lead position were recorded.
Main Results:
- LVPT showed an inverse correlation with regional myocardial viability (ρ -0.785, p<0.001).
- Ventricular arrhythmias (VAs) occurred in 33.7% of patients after a median follow-up of 36 months.
- Patients with VAs exhibited significantly higher intraoperative LVPT compared to those without VAs (p<0.001).
- Intraoperative LVPT emerged as a strong independent predictor of VAs in multivariate analysis.
Conclusions:
- Elevated intraoperative LVPT in CRT patients may suggest reduced myocardial viability at the LV lead site.
- Higher LVPT during CRT implantation is associated with an increased risk of developing ventricular arrhythmias.
Background:
Cardiac resynchronization therapy (CRT) is an established heart failure (HF) treatment option, however its effect on ventricular arrhythmias (VAs) is controversial. Regional scar burden and high left ventricular (LV) pacing threshold (PT) are associated with poor outcome in CRT patients. The aim of our study was to analyze the impact of intraoperative LVPT on VA occurrence.
Methods:
Eighty consecutive patients with advanced HF scheduled for a CRT defibrillator device [aged 63.3±10.9 years; New York Heart Association II-III 86.2%; 52 males (65%); 34 ischemic etiology (42.5%); 71 sinus rhythm (88.7%); QRS duration 168±25.7ms] were evaluated using single-photon emission computed tomography myocardial perfusion imaging. Regional myocardial viability was calculated as the mean tracer activity in the corresponding segments at the LV lead pacing site. Fluoroscopic position and intraoperative LVPT were determined at implant after the final LV lead position was determined.
Results:
LVPT was inversely associated with regional myocardial viability (ρ -0.785, p<0.001). After a median follow-up of 36 months (24-57) months VAs were registered in 27 patients (33.7%). Patients with VAs had higher median intraoperative LVPT compared to those without VAs [2.2V (1.9-2.8) vs. 0.8V (0.6-1.2), p<0.001]. In a multivariate logistic regression model intraoperative LVPT was identified as a strong independent predictor of VAs.
Conclusion:
Increased intraoperative LVPT during CRT could be associated with lower regional myocardial viability at LV lead location. CRT patients with higher LVPT could have an increased risk of VA occurrence.
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