Second degree atrioventricular block

Area of Science:

• Cardiology
• Electrophysiology
• Aviation Medicine

Background:

• Second-degree atrioventricular (AV) block, specifically Type II or Type I with bundle branch block, poses a significant risk of progressing to higher degrees of AV block.
• Long-term outcomes for Type I AV block with narrow QRS complexes are debated, with some studies suggesting a benign course and others indicating a high rate of progression to complete heart block requiring pacemakers.

Purpose of the Study:

• To evaluate the risks associated with different types of second-degree AV block in the context of aviation medical certification.
• To clarify the prognosis of Type I AV block with narrow QRS complexes in aircrew.

Main Methods:

• Review of existing long-term follow-up studies on patients with Type I AV block and narrow QRS complexes.
• Analysis of risk stratification for different subtypes of second-degree AV block relevant to aviation safety.

Main Results:

• Type II AV block and Type I AV block with wide QRS complexes are associated with a high risk of progression and should preclude medical certification for flying.
• Aircrew with Type I second-degree AV block and narrow QRS complexes require thorough evaluation but may be deemed fit for multi-crew operations.

Conclusions:

• The risk stratification for second-degree AV block subtypes is crucial for determining fitness for aviation duties.
• While Type II or wide QRS AV blocks are disqualifying, Type I AV block with narrow QRS warrants careful individual assessment for aircrew.