Blood Pressure Severity Modifies the Association Between Atrial Cardiopathy and Stroke Mortality

BackgroundElectrocardiographic (ECG) markers of atrial cardiopathy (AC) are associated with stroke mortality, but whether this association is modified by blood pressure (BP) is unknown. MethodsWe analyzed 7,191 adults free of cardiovascular disease from the Third National Health and Nutrition Examination Survey who underwent baseline ECG. AC was defined by three ECG markers: prolonged P-wave duration ([&ge;]120 ms), abnormal P-wave axis (<0{degrees} or >75{degrees}), and deep terminal negativity of the P wave in V1 (<-100 V). AC burden (per additional AC marker) and AC presence ([&ge;]1 vs. 0 markers) were examined in relation to stroke mortality using Cox proportional hazards models. Participants were stratified by BP as normal/elevated (<130/80 mmHg), stage 1-2 hypertension (130-159/80-99 mmHg), or severe hypertension ([&ge;]160/100 mmHg). Interaction by BP category was assessed. ResultsDuring a median follow-up of 13.8 years, 183 stroke deaths occurred. In multivariable adjusted model, AC burden was associated with a 41% higher risk of stroke mortality (HR (95%CI): 1.41 (1.13-1.77)). This association was significantly modified by BP (interaction P=0.003). The HRs (95% CIs) per additional AC marker were 0.88 (0.52-1.49), 1.39 (1.03-1.88), and 2.94 (1.82-4.75) for normal/elevated BP, stage 1-2 hypertension, and severe hypertension, respectively. A similar pattern of associations was observed for AC presence, although the interaction with BP was not statistically significant. ConclusionsECG-defined AC burden was independently associated with stroke mortality, with substantially stronger associations among individuals with severe hypertension, supporting BP as an important modifier of its prognostic significance.