Electrocardiographic Changes During Scuba Diving
Scuba diving and associated physiologic stressors (immersion-related preload changes, peripheral vasoconstriction, and exercise) can produce a range of ECG changes. (prodivecairns.com)
In professional divers, ECG abnormalities reported include sinus tachycardia, early repolarization, ventricular extrasystoles (PVCs), occasional ST elevation, and T-wave inversion. (pmc.ncbi.nlm.nih.gov)
Underwater breath-holding and apneic diving have also been associated with bradyarrhythmias and conduction abnormalities such as sinus bradycardia, sinus arrest, atrioventricular block, and idioventricular rhythm. (journals.physiology.org)
Abnormal ECG Findings Requiring Immediate Dive Termination and Cardiac Evaluation
Any ECG finding consistent with a serious arrhythmia should prompt immediate termination of diving and urgent cardiac evaluation because serious arrhythmias are incompatible with diving due to the risk of loss of consciousness underwater. (dan.org)
ECG findings that are considered abnormal and require refraining from further diving pending complete cardiac evaluation include the following.
- Ventricular tachycardia (VT). (dan.org)
- “Many types of atrial arrhythmia” associated with elevated risk of incapacitation or unconsciousness. (dan.org)
- R-on-T phenomenon. (dan.org)
- Multifocal PVCs. (dan.org)
- Nonsustained runs of ventricular tachycardia. (dan.org)
Syncope that occurs during or around diving should trigger immediate cessation of diving and cardiac evaluation, with concurrent consideration of post-dive and immersion-specific conditions. (dan.org)
For divers with any cardiac arrhythmia, complete medical evaluation by a cardiologist is recommended prior to any resumption of diving. (dan.org)
ECG Findings That Commonly Occur but Still Require Assessment for Significance
PVCs are common in healthy individuals, but identification of concerning PVC features (such as multifocality or R-on-T phenomenon) increases concern for underlying pathology and should trigger abstention from diving until evaluated. (dan.org)
ST elevation and early repolarization patterns may occur in divers, but clinically significant ischemic or pathologic patterns should be distinguished from benign variants through appropriate assessment. (pmc.ncbi.nlm.nih.gov)
Evaluation Pathway After Abnormal ECG Findings
A cardiology evaluation should include ECG interpretation and often additional testing such as electrolyte assessment and ambulatory monitoring when clinically indicated. (dan.org)
Divers and diving candidates with significant ECG abnormalities should undergo specialist review because abnormal findings warrant cardiology referral and further investigation. (duikgeneeskunde.nl)
Practical “Do-Not-Continue-Dive” Triggers
Immediate dive termination is indicated when the diver experiences symptoms of cardiovascular compromise associated with abnormal rhythm behavior, including syncope. (dan.org)
Any detection (by clinician assessment or monitoring) of ventricular tachycardia, R-on-T phenomenon, multifocal PVCs, or nonsustained VT runs should be treated as a do-not-continue-dive finding with urgent cardiac evaluation. (dan.org)