Electrical Resynchronization and Clinical Outcomes During Long-Term Follow-Up in Intraventricular Conduction Delay
Xueying Chen1, Xiao Li1, Yingnan Bai1
1Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases; National Clinical Research Center for Interventional Medicine, China.
Insights
Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) offers superior QRS duration reduction and improved heart function compared to biventricular CRT in patients with intraventricular conduction delay. This approach also led to fewer adverse clinical outcomes over 24 months.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) shows promise for improving cardiac function and reducing QRS duration.
- Limited data exists on the efficacy and feasibility of LOT-CRT in patients with intraventricular conduction delay (IVCD).
- This study addresses the need to compare LOT-CRT with traditional biventricular CRT (BiV-CRT) in IVCD patients.
Purpose of the Study:
- To assess and compare the efficacy and clinical outcomes of LOT-CRT versus BiV-CRT in IVCD patients.
- To evaluate the impact on QRS duration, left ventricular ejection fraction, and adverse clinical events.
Main Methods:
- A non-randomized study comparing LOT-CRT (n=30) and BiV-CRT (n=55) in consecutive IVCD patients indicated for CRT.
- Lead placement strategy was physician-dependent, guided by QRS complex and clinical assessment.
- Echocardiographic parameters and clinical data were collected at baseline and over a 2-year follow-up period.
Main Results:
- Both LOT-CRT and BiV-CRT demonstrated high success rates (96.8% and 96.4%, respectively).
- LOT-CRT achieved significantly greater QRS duration reduction (42.7 ms vs. 21.9 ms; P<0.001) and higher left ventricular ejection fraction at multiple follow-up points.
- The LOT-CRT group experienced significantly lower rates of heart failure rehospitalization and mortality over 24 months (HR, 0.33; P=0.035).
Conclusions:
- LOT-CRT appears to enhance ventricular electrical synchrony more effectively than BiV-CRT in IVCD patients.
- LOT-CRT may lead to superior clinical outcomes compared to BiV-CRT in this patient population.
- Further validation through randomized controlled trials is warranted.
Background:
Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) has shown encouraging results for QRS duration reduction and heart function improvement. However, the feasibility and efficacy of LOT-CRT have not been well established in intraventricular conduction delay patients. This study aims to assess and compare the efficacy and clinical outcome of CRT based on left bundle branch pacing, combined with coronary sinus left ventricular pacing (LOT-CRT) with CRT via biventricular pacing (BiV-CRT) in intraventricular conduction delay patients indicated for CRT.
Methods:
Consecutive patients with intraventricular conduction delay and CRT indications were assigned nonrandomized to LOT-CRT (n=30) or BiV-CRT (n=55). Addition of the left bundle branch pacing (or coronary venous) lead was at the discretion of the implanting physician guided by suboptimal paced QRS complex and on clinical grounds. Echocardiographic parameters and clinical characteristics were accessed at baseline and during 2-years' follow-up.
Results:
Success rate for LOT-CRT and BiV-CRT was 96.8% and 96.4%. LOT-CRT had greater reduction of QRS duration compared with BiV-CRT (42.7±17.4 ms versus 21.9±21.5 ms; P<0.001). Higher left ventricular ejection fraction was also achieved in LOT-CRT than BiV-CRT at 6-month (36.7±9.8% versus 30.5±6.4%; P<0.05), 12-month (34.8±7.6% versus 30.3±6.2%; P<0.05), 18-month (36.3±7.9% versus 28.1±6.6%; P<0.005), and 24-month follow-up (37±9.5% versus 30.5±7%; P<0.05). Adverse clinical outcomes including heart failure rehospitalization and mortality were lower in LOT-CRT group for 24 months follow-up (hazard ratio, 0.33; P=0.035).
Conclusions:
LOT-CRT improves ventricular electrical synchrony and may provide greater clinical outcomes as compared with BiV-CRT in intraventricular conduction delay patients. These findings need further evaluation in future randomized controlled trials.
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