From the Guidelines
A biventricular pacemaker (CRT) is indicated for this patient with persistent left bundle branch block (LBBB) and a wide QRS complex, accompanied by progressive first-degree atrioventricular (AV) block with a prolonged PR interval, as it can improve cardiac efficiency, reduce heart failure hospitalizations, and mortality. The patient's condition, characterized by LBBB and a wide QRS complex, indicates significant electrical dyssynchrony, which can lead to inefficient ventricular contraction. The prolonged PR interval further compromises cardiac output due to AV conduction disease.
Key Considerations
- The presence of LBBB with a QRS duration ≥150 ms is a strong predictor of benefit from CRT, as evidenced by the significant reduction in mortality and heart failure hospitalizations in patients with these characteristics 1.
- The 2022 AHA/ACC/HFSA guideline recommends CRT for patients with LVEF ≤35%, sinus rhythm, LBBB with a QRS duration ≥150 ms, and NYHA class II, III, or ambulatory IV symptoms on GDMT, to reduce total mortality, reduce hospitalizations, and improve symptoms and QOL.
Clinical Decision
Based on the most recent and highest quality evidence, CRT is recommended for this patient. The procedure should be performed by a cardiac electrophysiologist, and the patient should continue heart failure medications as prescribed. Regular device checks every 3-6 months are necessary, and patients should avoid vigorous arm movements on the implant side for about 4-6 weeks post-procedure.
Additional Considerations
- Optimal outcomes with CRT require effective placement of ventricular leads, ongoing HF management with neurohormonal antagonists and diuretic therapy, and in some cases, later optimization of device programming, especially atrioventricular (A-V) and interventricular (V-V) intervals 1.
- The patient's LVEF, NYHA class, and QRS duration should be assessed to ensure they meet the guideline criteria for CRT implantation, and the procedure should be performed only after any appropriate waiting period has concluded, during which GDMT has been applied 1.
From the Research
Indications for Biventricular Pacemaker (Cardiac Resynchronization Therapy, CRT)
The indication for a Biventricular Pacemaker (Cardiac Resynchronization Therapy, CRT) in a patient with persistent Left Bundle Branch Block (LBBB) and a wide QRS complex, accompanied by progressive first-degree atrioventricular (AV) block with a prolonged PR interval, can be considered based on the following points:
- Patients with heart failure and reduced ejection fraction with LBBB can benefit from CRT, as it reduces heart failure hospitalizations and all-cause mortality 2.
- LBBB is a strong predictor of response to CRT, and patients with true complete LBBB tend to have a greater response to CRT 3.
- The presence of a wide QRS complex is an indicator for CRT, and LBBB area pacing (LBBAP) has been shown to be effective in narrowing the QRS complex and improving left ventricular function 4, 5, 6.
- Progressive first-degree AV block with a prolonged PR interval may also be an indication for CRT, as it can lead to ventricular dyssynchrony and reduced cardiac function.
Key Considerations
Some key considerations for CRT in this patient population include:
- The feasibility and safety of LBBAP as an alternative to biventricular pacing (BVP) 4, 5, 6.
- The potential for greater electrical resynchronization with LBBAP compared to BVP 5, 6.
- The importance of evaluating the patient's response to CRT and adjusting the therapy as needed to optimize outcomes 2, 3.
Patient Selection
Patient selection for CRT is crucial, and the following factors should be considered: