A Simple Electrocardiogram Marker for Risk Stratification of Ischemic Stroke in Low-resources Settings

Background

Because of economic constraints, identification of patients at high risk for ischemic stroke who may benefit from further evaluation and aggressive control of their risk factors carries a special importance in low-resources settings. We sought to examine the use of the negative component of the P wave in V₁ in the standard electrocardiogram, referred to as P-wave terminal force (PTF), as a risk stratification tool of ischemic stroke in Africans living in Malawi, a sub-Saharan African country where stroke is a strongly emerging health problem.

Methods

This was a case-comparison study where 92 patients with ischemic stroke were compared with an equal number of subjects in an age- and sex-matched comparison group. The sensitivity and specificity of abnormal PTF, defined as PTF greater than or equal to 4mm-s, to diagnose ischemic stroke were calculated. Univariate and multivariable logistic regression analysis was used to estimate the odds of ischemic stroke associated with abnormal PTF.

Results

Abnormal PTF was present in 54% of patients with stroke compared with only 17% of the comparison group (P < .001). The specificity and sensitivity of PTF was 82% and 54%, with positive and negative predictive values of 76% and 64%, respectively. PTF was associated with ischemic stroke in a univariate analysis (odds ratio [OR] 5.7; 95% confidence interval [CI] 2.9-11.1), a multivariate analysis adjusting for common ischemic stroke risk factors (OR 2.8; 95% CI 2.4-3.4), and even with further adjustment for echocardiographically measured left atrial size (OR 2.1; 95% CI 1.9-2.4).

Conclusions

PTF greater than or equal to 4mm-s is associated with the risk of ischemic stroke in Africans independently from ischemic stroke risk factors. Given its reasonable sensitivity and specificity to predict ischemic stroke, PTF greater than or equal to 4mm-s could be used as a risk stratification tool to discriminate between patients at high and low risk of ischemic stroke, and subsequently identify patients who may benefit from further evaluation and aggressive control of their risk factors.

Key Words: Stroke, risk stratification, electrocardiogram, sub-Saharan Africa, Africans, low-resources settings