Does Cardiac Resynchronization Therapy Benefit Patients with Non-Left Bundle Branch Block Prolonged QRS Patterns?
Mark N Belkin1, Gaurav A Upadhyay2
1Center for Arrhythmia Care, Section of Cardiology, The University of Chicago Medicine, 5841 S. Maryland Avenue, MC 9024, Chicago, IL, 60637, USA.
Insights
Cardiac Resynchronization Therapy (CRT) utility in non-Left Bundle Branch Block (LBBB) patients is debated. Specific patient subgroups and advanced lead placement techniques show promise for improved CRT response.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac Resynchronization Therapy (CRT) is established for heart failure (HF) patients with Left Bundle Branch Block (LBBB).
- CRT use in non-LBBB patients, especially those with Right Bundle Branch Block (RBBB), is controversial due to high non-response rates.
Purpose of the Study:
- To assess the clinical utility and effectiveness of CRT in patients who do not have LBBB.
- To identify specific patient profiles within the non-LBBB population that may benefit from CRT.
Main Methods:
- Review of recent studies investigating CRT response in non-LBBB patient cohorts.
- Analysis of advanced imaging and mapping techniques for optimizing LV lead placement.
- Identification of patient characteristics associated with CRT non-response and response.
Main Results:
- Sub-populations of non-LBBB patients, including those with prolonged PR intervals (≥230 ms) or RBBB with left-sided delay, show potential CRT benefits.
- Significant right ventricular pacing burden is another factor influencing CRT response in non-LBBB patients.
- Advanced LV lead placement guided by electrical and mechanical mapping improves CRT outcomes by targeting dyssynchrony.
Conclusions:
- CRT may be beneficial for select non-LBBB patients, particularly when guided by advanced imaging and patient selection criteria.
- Optimized LV lead placement targeting electrical and mechanical dyssynchrony is crucial for maximizing CRT efficacy in non-LBBB populations.
Purpose Of Review:
We sought to assess the utility of CRT in patients with non-LBBB.
Recent Findings:
CRT has an established role as a device-based therapy for patients with HF with systolic dysfunction and intraventricular conduction disease, specifically LBBB. In modern practice, the use of CRT in non-LBBB patients remains controversial, with high rates of non-response for CRT in patients with RBBB, in particular. Recent studies have identified sub-populations of non-LBBB patients that respond to resynchronization, such as those with prolonged PR intervals (≥ 230 ms), with RBBB and concomitant left-sided delay and those with significant burden of right ventricular pacing. As technology has advanced to allow for detailed mapping of LV electrical and mechanical function, benefits have been found with placement of LV leads utilizing intra-procedural mapping to target areas of greatest electrical activation delay or mechanical dyssynchrony, leading to more widespread benefit through the more specific application of CRT.
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