A smartphone ECG is helping athletes trace exercise-related arrhythmias, giving them access to diagnoses, treatments and peace of mind that traditional monitors can’t, Australian researchers say.

Their six-case report saw iECG Alivecor Kardia detect arrhythmias in five athletes with exercise-induced symptoms and rule them out in another.

The portable and non-invasive device led to diagnoses from rare cardiac events occurring in specific, high-intensity exercise situations that weren’t otherwise captured via Holter monitor or replicated in stress electrocardiograms. It helped patients get targeted treatment and gave one athlete the confidence to continue exercising, according to the researchers from the Olympic Park Sports Medicine Centre, Melbourne and the University of Sydney.

Published in European Heart Journal – Case Reports their paper mapped outcomes for an amateur middle-distance runner, two semi-elite ultra-endurance runners, two elite cricketers and an elite non-endurance athlete aged 16–48.

All had normal ECG, Holter monitor, CT coronary angiography and echocardiogram results on testing, except for the middle-distance runner who had moderately-dilated right ventricle and left atrium on echo. Yet, all complained of exercise-related rapid palpitations, diaphoresis, light-headedness, dyspnoea, and presyncope/syncope. One participant also had weakness post-presumed myopericarditis illness, and a couple had post- or non-exercise-related symptoms.

On iECG, however, there was evidence of wide-complex tachycardia and return to sinus rhythm, paroxysmal supraventricular tachycardia, atrial fibrillation, atrial flutter and normal traces during symptoms.

Ablations were done in three patients who had subsequent concealed postero-septal accessory pathway causing atrioventricular (AV) re-entrant tachycardia, AV junctional tachycardia and persisting dual AV nodal pathway due to concealed bypass tract, and atrial flutter on subsequent electrophysiology study. Meanwhile, one patient was put on the pill-in-the-pocket regime and one was yet to undergo electrophysiology study or ablation. The final patient, the ultra-endurance runner who was normal on iECG, was “comfortable that symptoms [were] not cardiac” after talking to a cardiologist and agreed to continue running at shorter distances.

Implications for practice

Although athletes are generally very fit and regular exercise is associated with improved health outcomes, intense exercise can increase arrhythmia risk and, in rare cases, sudden cardiac death, the authors wrote.

“In all cases, the iECG was valuable in obtaining a provisional diagnosis to determine the best course of investigation and treatment, where other diagnostic methods failed.”

One patient even had a loop recorder at one stage, which can capture more arrhythmias than traditional monitors but ultimately proved unhelpful since it resulted in infection and had to be removed.

“Perhaps just as important was the device’s utility in detecting no arrhythmia during symptoms … building on previous examples in collegiate athletes,” they noted. 

“These cases highlight how convenient, inexpensive and easy to use the device can be for athletes and clinicians to record traces during specific episodes of symptoms.”

Similar benefits may be obtained from other smartphone and smartwatch ECGs with sufficient trace quality and at low legal risk to clinical practice if used within TGA-approved indications — especially under the supervision of a treating condition, they suggested.

“Whether definitive ablation procedures, medications or observation strategies were used, the identification or exclusion of an arrhythmia allowed for targeted treatment tailored to the diagnosis and the presenting athlete.”

“This provided a sense of reassurance for all cases, which may give other clinicians and athletes confidence the device will assist in reaching a diagnosis to guide treatment,” they concluded.