P wave analysis with wavelets identifies hypertensive patients at risk of recurrence of atrial fibrillation: A case-control study and 1year follow-up

J Electrocardiol. Sep-Oct 2015;48(5):845-52. doi: 10.1016/j.jelectrocard.2015.07.012. Epub 2015 Jul 14.


Aims: Hypertension is a major risk factor for atrial fibrillation (AF); however, reliable non-invasive tools to assess AF risk in hypertensive patients are lacking. We sought to evaluate the efficacy of P wave wavelet analysis in predicting AF risk recurrence in a hypertensive cohort.

Methods: We studied 37 hypertensive patients who presented with an AF episode for the first time and 37 age- and sex-matched hypertensive controls without AF. P wave duration and energy variables were measured for each subject [i.e. mean and max P wave energy along horizontal (x), coronal (y) and sagittal (z) axes in low, intermediate and high frequency bands]. AF-free survival was assessed over a follow-up of 12.1±0.4months.

Results: P wave duration (Pdurz) and mean P wave energy in the intermediate frequency band across sagittal axis (mean2z) were independently associated with baseline AF status (p=0.008 and p=0.001, respectively). Based on optimal cut-off points, four groups were formed: Pdurz<83.2ms/mean2z<6.2μV(2) (n=23), Pdurz<83.2ms/mean2z≥6.2μV(2) (n=10), Pdurz≥83.2ms/mean2z<6.2μV(2) (n=22) and Pdurz≥83.2ms/mean2z≥6.2μV(2) (n=19). AF-free survival decreased (Log Rank p<0.0001) from low risk (Pdurz<83.2ms/mean2z<6.2μV(2)) to high-risk group (Pdurz≥83.2ms/mean2z≥6.2μV(2)). Patients presenting with longer and higher energy P waves were at 18 times higher AF risk compared to those with neither (OR: 17.6, 95% CI: 3.7-84.3) even after adjustment for age, sex, hypertension duration, left atrial size, beta-blocker, ACEi/ARBs and statin therapy.

Conclusions: P wave temporal and energy characteristics extracted using wavelet analysis can potentially serve as screening tool to identify hypertensive patients at risk of AF recurrence.

Keywords: Atrial fibrillation; Hypertension; Orthogonal ECG; P wave wavelet analysis.

MeSH terms

  • Atrial Fibrillation / diagnosis*
  • Atrial Fibrillation / epidemiology*
  • Case-Control Studies
  • Causality
  • Comorbidity
  • Diagnosis, Computer-Assisted / methods
  • Diagnosis, Computer-Assisted / statistics & numerical data
  • Disease-Free Survival
  • Electrocardiography / methods*
  • Electrocardiography / statistics & numerical data
  • Female
  • Greece / epidemiology
  • Humans
  • Hypertension / diagnosis*
  • Hypertension / epidemiology*
  • Incidence
  • Male
  • Middle Aged
  • Recurrence
  • Reproducibility of Results
  • Risk Assessment / methods
  • Sensitivity and Specificity
  • Wavelet Analysis*