Management of cardiac conduction abnormalities and arrhythmia in aircrew

Abstract

Cardiovascular diseases ⁱ are the most common cause of loss of flying licence globally, and cardiac arrhythmia is the main disqualifier in a substantial proportion of aircrew. Aircrew ⁱⁱ often operate within a demanding physiological environment, that potentially includes exposure to sustained acceleration (usually resulting in a positive gravitational force, from head to feet (+Gz)) in high performance aircraft. Aeromedical assessment is complicated further when trying to discriminate between benign and potentially significant rhythm abnormalities in aircrew, many of whom are young and fit, have a resultant high vagal tone, and among whom underlying cardiac disease has a low prevalence. In cases where a significant underlying aetiology is plausible, extensive investigation is often required and where appropriate should include review by an electrophysiologist. The decision regarding restriction of flying activity will be dependent on several factors including the underlying arrhythmia, associated pathology, risk of incapacitation and/or distraction, the type of aircraft operated, and the specific flight or mission criticality of the role performed by the individual aircrew.

Keywords: cardiac arrhythmias and resuscitation science; catheter ablation; ecg/electrocardiogram; electrophysiology; health care delivery.

Figure 1

Spectrum of ambulatory patient monitoring systems. From left to right, the duration of monitoring increases leading to an increase of the diagnostic yield.

Figure 2

Risks possibly associated with an accessory pathway. (A) During sinus rhythm there is conduction via the atrioventricular (AV) node and accessory pathway. The delta wave in the ECG represents the ventricular pre-excitation caused by the conduction via the accessory pathway. The size of the delta wave and the PR interval depend on the location of the accessory pathway and the conduction properties of the AV node and accessory pathway. (B) A retrograde conduction of the accessory pathway bears the risk of an orthodromic AV re-entrant tachycardia with antegrade conduction via the AV node and retrograde conduction via the accessory pathway. (C) During atrial fibrillation there is a risk of a fast conduction via the accessory pathway to the ventricles depending on the conduction properties of the accessory pathway. As most accessory pathways have no decremental conduction in contrast to the AV node, the conduction via the accessory pathway can be much faster than via the AV node. This can lead to ventricular fibrillation and sudden cardiac death.