Effect of ethnicity and hypertension on atrial conduction: evaluation with high-resolution P-wave signal averaging

Abstract

Background: Measurements by P-wave signal-averaged electrocardiogram (P-SAECG) of P-wave duration and P-wave voltage integral are higher in patients with atrial fibrillation (AF) than in those with sinus rhythm. Hypertension is perhaps the most common cardiovascular antecedent cause of AF, and particularly a disproportionate cause of morbidity and mortality among blacks. The purpose of this study was to examine the effect of hypertension and ethnicity on P-SAECG parameters in patients without AF.

Hypothesis: It was hypothesized that P-SAECG parameters can identify hypertensives, and are disproportionately higher in hypertensive blacks.

Methods: In all, 234 normotensives and 84 hypertensives underwent P-SAECG analysis. In an ancillary study group of 34 hypertensive black men, the relationship between severity of hypertension and measured parameters of P-SAECG was evaluated.

Results: Mean filtered P-wave duration and total P-wave voltage integral for normotensives of both ethnic groups were similar. Hypertensive blacks had greater increase in P-wave duration (138 +/- 16 vs. 132 +/- 12ms;p < 0.01, N42:42) and total P-wave voltage integral (922 +/- 285 vs. 764 +/- 198 microV-ms; p < 0.001) than white hypertensives. Filtered P-wave duration and total P-wave voltage integral increased with severity of hypertension.

Conclusions: Patients at very early stages of hypertension have demonstrable evidence of prolonged atrial conduction by P-SAECG and, thus, cardiac electrical remodeling. P-wave duration and total P-wave voltage integral increase with severity of hypertension. Hypertensive blacks manifest a greater increase in P-SAECG parameters than whites. This may portend an increased cardiovascular risk for black patients with hypertension.