Fragmented QRS complex as a predictor of exercise-related sudden cardiac death

Little is known about the association between electrocardiographic abnormalities and exercise-related sudden cardiac death. Therefore, our aim was to identify possible electrocardiographic findings related to exercise-induced sudden cardiac death.

The FinGesture study includes 3,989 consecutive sudden cardiac deaths in northern Finland between 1998 and 2012, out of whom a total of 647 subjects had a previously recorded electrocardiography acquired from the archives of Oulu University Hospital. In 276 of these cases the death was witnessed, and the activity at the time of death was either rest or physical exercise (PE); in 40 (14%) cases sudden cardiac death was exercise-related and in 236 (86%) cases death took place at rest. Fragmented QRS complex in at least two consecutive leads within anterior leads (V1-V3) was more common in the exercise-group compared to rest-group (17 of 40, 43% vs. 51 of 236, 22%, P  =  0.005). Pathologic Q wave in anterior leads was more common in the PE group (9 of 40, 23% vs. 26 of 236, 11%; P  =  0.044). Median QRS duration was prolonged in the exercise-group compared to the rest-group (100 milliseconds vs. 94 milliseconds, P = 0.047). QTc interval, the prevalence of inverted T-waves, or other electrocardiographic abnormalities did not differ significantly between the two groups.

As a conclusion, fragmented QRS complex in the anterior leads is associated with an increased risk of sudden cardiac death during PE.