ECG Abnormalities and Stroke Incidence
ECG Abnormalities and Stroke Incidence
Poor heart rate modulation is a marker of increased sympathetic tone or poor modulation by the parasympathetic nervous system in response to short changes in cardiac output with breathing. Lower heart rate variability (HRV) is an early manifestation of some of the shared risk factors of stroke such as poor physical activity, emotional stress, diabetes, hypertension and end-stage renal disease. However, there is paucity n the literature with regards to HRV and incidence of stroke with one study reporting higher stroke rates in those with lower nighttime HRV. This association may be mediated by several pathways including a higher inflammatory milieu, hypercoagulation and risk of arrhythmias, including AF.
Primary repolarization abnormalities such as ST or T wave changes are associated with higher risk of CHD mortality; however, the prevalence of primary repolarization abnormalities is low and their association with stroke independent of CHD and LVH remains to be studied. They may be markers of cardiomyopathy in some patients and may contribute to risk reduction but this needs to be looked at further. Similarly, the association of bundle branch blocks with stroke incidence remains to be studied. Finally, an ECG finding of right ventricular strain needs careful attention, especially during the poststroke period, as it may represent a serious pulmonary embolism (Table 1).
Other ECG Markers
Heart Rate Variability & Heart Rate
Poor heart rate modulation is a marker of increased sympathetic tone or poor modulation by the parasympathetic nervous system in response to short changes in cardiac output with breathing. Lower heart rate variability (HRV) is an early manifestation of some of the shared risk factors of stroke such as poor physical activity, emotional stress, diabetes, hypertension and end-stage renal disease. However, there is paucity n the literature with regards to HRV and incidence of stroke with one study reporting higher stroke rates in those with lower nighttime HRV. This association may be mediated by several pathways including a higher inflammatory milieu, hypercoagulation and risk of arrhythmias, including AF.
Others
Primary repolarization abnormalities such as ST or T wave changes are associated with higher risk of CHD mortality; however, the prevalence of primary repolarization abnormalities is low and their association with stroke independent of CHD and LVH remains to be studied. They may be markers of cardiomyopathy in some patients and may contribute to risk reduction but this needs to be looked at further. Similarly, the association of bundle branch blocks with stroke incidence remains to be studied. Finally, an ECG finding of right ventricular strain needs careful attention, especially during the poststroke period, as it may represent a serious pulmonary embolism (Table 1).
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