Introduction: Ischaemic stroke at young age carries an increased risk for mortality in comparison to the general population, but factors associated with mortality have been poorly studied. We studied the role of electrocardiogram in mortality risk stratification in young stroke patients.
Patients and methods: The Helsinki Young Stroke Registry encompasses 1008 patients aged <50 years with ischaemic stroke. We included 690 patients for this electrocardiogram substudy. Our endpoints were all-cause and cardiovascular mortality. Cox regression models - adjusted for clinical and demographic characteristics - were used to identify the electrocardiogram parameters associated with these endpoints.
Results: At a mean follow-up of 8.8 years, cumulative all-cause and cardiovascular mortality were 16.1 and 9.1%, respectively. Factors associated with both endpoints included diabetes (type 1 for all-cause, type 2 for cardiovascular mortality), heavy drinking, malignancy, as well as stroke severity and aetiology. Of the electrocardiogram parameters, higher heart rate (hazard ratio 1.35 per 10/min, 95% confidence interval 1.21-1.49), a shorter P-wave (hazard ratio 0.78 per 10 ms decrement, 0.64-0.92) and longer QTc interval (1.09 per 10 ms, 1.03-1.16) were associated with increased all-cause mortality. Only a higher heart rate (1.42 per 10/min, 1.24-1.60) was associated with death from cardiovascular causes.
Conclusions: A higher heart rate during the subacute phase after stroke is associated with an elevated risk of all-cause and cardiovascular mortality in young adults. A longer QTc interval is associated only with higher all-cause mortality. P-wave characteristics and their possible association with mortality need further studies.
Keywords: Electrocardiogram; mortality; prognosis; stroke; young stroke.