Atrial pacing every other beat: Is it pacemaker malfunction?

Area of Science:

• Cardiology
• Cardiac Electrophysiology
• Cardiovascular Surgery

Background:

• Hypertrophic obstructive cardiomyopathy (HOCM) is a complex cardiac condition often requiring surgical intervention.
• Patients with HOCM may have implanted devices like dual-chamber implantable cardioverter-defibrillators (ICDs) for arrhythmia management.
• Post-operative electrocardiogram (ECG) interpretation is crucial for monitoring cardiac function and device performance after complex cardiac surgery.

Observation:

• A 45-year-old female with HOCM and a dual chamber ICD underwent complex cardiac surgery.
• Postoperatively, on the 5th day, electrocardiogram (ECG) revealed a distinct pattern.
• The ECG demonstrated intermittent electronic atrial pacing alongside a consistent monomorphic wide QRS rhythm.

Findings:

• The observed ECG pattern suggests a specific interaction between the implanted device and the heart's native rhythm post-surgery.
• Atrial pacing every other complex indicates the device is functioning as programmed but potentially encountering conduction delays.
• Monomorphic wide QRS complexes point towards supraventricular or ventricular origin, influenced by the pacing and underlying cardiac condition.

Implications:

• Understanding this ECG pattern is crucial for accurate diagnosis and management of post-operative cardiac patients with ICDs.
• This case highlights the importance of vigilant ECG monitoring after complex cardiac surgeries.
• Further investigation may be needed to determine the precise electrophysiological mechanisms and optimize device settings.