Incidence of cardiac dysrhythmias occurring during centrifuge training.

High-G training has been reported to provoke dysrhythmias in many subjects. These reports have been based on small subject groups. Students attending aeromedical professional courses at the USAF School of Aerospace Medicine are offered the opportunity to participate in high-G centrifuge training on the Armstrong Laboratory centrifuge, during which ECG monitoring is routinely performed. This study documents the incidence of dysrhythmias in this large group of subjects. The pertinent information from the records of 1,180 training sessions from 1984-91 were transcribed to a database on a personal computer. Dysrhythmias were recorded in 552 (47%) of the training sessions. Ventricular ectopy occurred in 480 (41%) of the sessions, and supraventricular dysrhythmias appeared in 127 (11%). In 53 (4.5%) of the sessions, training either was or would have been terminated because of the dysrhythmia. Session-terminating dysrhythmias included: 26 ventricular tachycardias (2.2%), including 18 triplets (1.5%); 9 ventricular couplets (0.8%); 8 episodes of too-frequent ventricular premature beats (0.7%); 4 of supraventricular tachycardia (0.3%), including 2 with aberrant conduction (0.2%); 2 of aberrantly conducted beats (0.2%); and 4 of anomalous bradycardia (0.3%). Centrifuge training can provoke serious dysrhythmias in ostensibly healthy individuals, and ECG monitoring of aircrew undergoing such training is recommended for their safety. Because some of these dysrhythmias are disqualifying for aircrew duties, the need for a more lenient aeromedical disposition policy must be considered.