What is 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?

From the Guidelines

A biventricular pacemaker (Cardiac Resynchronization Therapy, 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. The patient's condition, characterized by LBBB with a QRS duration ≥150 ms, is a strong indication for CRT, as it suggests significant electrical dyssynchrony that can be improved with CRT [1]. This recommendation is based on the latest guidelines from the American College of Cardiology and American Heart Association, which emphasize the importance of CRT in reducing total mortality, hospitalizations, and improving symptoms and quality of life (QOL) in patients with heart failure and LBBB [1].

Key Considerations for CRT Imbo

• The presence of LBBB with a QRS duration ≥150 ms is a key indicator for CRT, as it suggests significant electrical dyssynchrony [1].
• The patient's progressive first-degree AV block with a prolonged PR interval further contributes to atrioventricular dyssynchrony, making CRT an appropriate treatment option.
• CRT works by simultaneously pacing both ventricles, which resynchronizes ventricular contraction, improves cardiac output, and potentially reverses adverse cardiac remodeling.
• The procedure typically involves placing leads in the right atrium, right ventricle, and left ventricle (via the coronary sinus).
• Following implantation, the patient will need regular device checks every 3-6 months and should be monitored for improvement in symptoms and cardiac function.

Benefits of CRT

• Reduces heart failure hospitalizations and mortality in appropriate candidates with electrical dyssynchrony [1].
• Improves symptoms and quality of life (QOL) in patients with heart failure and LBBB [1].
• Can potentially reverse adverse cardiac remodeling and improve cardiac output.

Recommendation

The patient should be referred to a cardiac electrophysiologist for CRT device implantation, as this treatment has been shown to improve outcomes in patients with similar conditions [1]. Regular follow-up and monitoring will be necessary to assess the effectiveness of the treatment and make any necessary adjustments.

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:

• Cardiac resynchronization therapy (CRT) is an established treatment for patients with left ventricular systolic heart failure and intraventricular conduction delay resulting in wide QRS, including those with LBBB pattern on electrocardiogram (ECG) and evidence of clinical heart failure 2.
• The presence of conduction block, such as LBBB, is a key factor in determining the indication for CRT, and the presence of a wide QRS complex (≥150 ms) is a commonly applied criterion for LBBB 2.
• Biventricular pacing (BVP) is considered the gold standard for achieving CRT, but approximately 30%-40% of patients do not respond to BVP-CRT, and alternative approaches such as left bundle branch pacing (LBBP) have shown promising results 3.
• The patient's progressive first-degree AV block with a prolonged PR interval may also be a consideration for CRT, as it can contribute to ventricular dyssynchrony and reduced cardiac function 4.

Key Considerations

Some key considerations for the indication of CRT in this patient include:

• The patient's left ventricular ejection fraction (LVEF) and symptoms of heart failure, as CRT has been shown to improve LVEF and reduce symptoms in patients with LBBB and heart failure 5, 6.
• The patient's QRS duration, as a wider QRS complex is associated with greater benefit from CRT 2.
• The presence of other conduction abnormalities, such as first-degree AV block, which may affect the patient's response to CRT 4.

Alternative Approaches

Alternative approaches to BVP-CRT, such as LBBP and His-bundle pacing, have shown promising results in patients with LBBB and heart failure, and may be considered in patients who do not respond to BVP-CRT or have specific conduction abnormalities 3, 5, 6.