Heart rate implicated in death among acute stroke patients with atrial fibrillation
The mean heart rate during acute stroke period factors in mortality but not stroke recurrence in patients with atrial fibrillation (AF) hospitalized for acute ischaemic stroke, a study has found. Heart rate variability has no effect on both outcomes.
Researchers used data from multicentre prospective stroke registry database and identified 3,622 ischaemic stroke patients (mean age, 74 years) who had AF and were hospitalized within 48 hours of stroke onset. They collected heart rate information in the acute stroke period, which was categorized as early (within 24 hours of hospitalization; n=2,046) and late (72 hours to 7 days from onset; n=1,576) stages.
In the entire cohort, 102 patients (5.0 percent) had a stroke recurrence and 440 (21.5 percent) died during the first year after stroke.
In the early acute stroke stage analysis, mean heart rate showed a statistically significant nonlinear J-shaped association with mortality (p<0.04 for quadratic and overall effect) but not with stroke recurrence (p>0.1 for quadratic and overall effect). Similar associations were observed in the late acute stroke stage analysis.
The nonlinear and overall effects of the coefficients of variation of heart rate were not significant for mortality and stroke recurrence.
According to the researchers, the findings can be partially explained by the knowledge that the increased risk of death in patients with elevated heart rates and in those with the lowest extreme of mean heart rate may be attributed to decreased heart function.