Associations of electrocardiographic P-wave characteristics with left atrial function, and diffuse left ventricular fibrosis defined by cardiac magnetic resonance: The PRIMERI Study

BACKGROUND Abnormal P-terminal force in lead V-1 (PTEv(1)) is associated with an increased risk of heart failure, stroke, atrial fibrillation, and death. OBJECTIVE Our goal was to explore associations of left ventricular (LV) diffuse fibrosis with left atrial (LA) function and electrocardiographic (ECG) measures of LA electrical activity. METHODS Patients without atrial fibrillation (n = 91; mean age 59.5 years; 61.5% men; 65.9% white) with structural heart disease (spatial QRS-T angle >= 105 degrees and/or Selvester ORS score >= 5 on ECG) but LV ejection fraction >35 /a underwent clinical evaluation, cardiac magnetic resonance, and resting ECG. LA function indices were obtained by multimodality tissue tracking using 2- and 4-chamber long-axis images. T-1 mapping and late gadolinium enhancement were used to assess diffuse LV fibrosis and presence of scar. P-prime in V-1 amplitude (PPaV1) and duration (PPdV1), averaged P-wave-duration, PR interval, and P-wave axis were automatically measured using 12 SLIM algorithm. PTFv1 was calculated as a product of PPaVi and PPdV1. RESULTS In linear regression after adjustment for demographic characteristics, body mass index, maximum LA volume index, presence of scar, and LV mass index, each decile increase in LV interstitial fibrosis was associated with 0.76 mV*ms increase in negative abnormal PTFv1 (95% confidence interval [CI] 1.42 to 0.09; P = .025), 15.3 ms prolongation of PPdV1 (95% CI 6.9 to 23.8; P = .001) and 5.4 ms prolongation of averaged P-duration (95% CI 0.9-10.0; P = .020). LV fibrosis did not affect LA function. PTFV1 and PPdv(1) were associated with an increase in LA volumes and decrease in LA emptying fraction and LA reservoir function. CONCLUSION LV interstitial fibrosis is associated with abnormal PTEvi, prolonged PPdV1, and P-duration, but does not affect LA function.