Lead V1 P wave Measurements in Relation to the Presence or Absence of Left Atrial Dilation.

<p>Left atrial dilation defined using established CMR normative cutoff (>15 cm²/m²) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099178#pone.0099178-Maceira1" target="_blank">[19]</a>.</p

Pulmonary Arterial Pressure.

<p>Pulmonary arterial systolic pressure (mean ± standard deviation) among population subgroups stratified based on lead V1 P wave area quartiles (≤1.92 | 1.93–2.70 | 2.71–3.65 | >3.65 mV·msec). Black bar = top P wave area quartile.</p

Mitral Regurgitation Severity.

<p>P wave area in lead V1 (mean ± standard deviation) in relation to MR severity on cine-CMR (<b>3A</b>) and echo (<b>3B</b>). Note that P wave area increased stepwise in relation to MR severity as measured by both modalities, with greatest magnitude of increase at a threshold of moderate-severe MR (black bars).</p

Multivariate Models for Prediction of Increased P wave Area in Lead V1* in Overall CMR Population.

<p>Multivariate Models for Prediction of Increased P wave Area in Lead V1* in Overall CMR Population.</p

Multivariate Models for Prediction of Increased P wave Area in Lead V1* in Echocardiography Sub-group.

<p>(*top P wave area quartile ≥3.5 mV·msec).</p

P wave and Left Atrial Area Quantification.

<p>Representative examples of LA quantification methods: For ECG (top), total P wave area was quantified based on geometric area (green shading) between the electrical waveform and the isoelectric line. Corresponding indices of amplitude (red line) and duration (blue line) were measured within the total P wave complex, as well as its positive and negative components. For CMR (bottom), LA area was measured by planimetry of chamber borders (green line) at ventricular end-systole. Note heterogeneity in P wave morphology among patients with LA enlargement: Whereas both patient examples demonstrate LA dilation by CMR, a bimodal P wave with large negative terminal component is present in <b>1A</b>, whereas a bifid but upright P wave is present in <b>1B</b>.</p

Clinical and Imaging Characteristics in Relation to the Presence or Absence of Left Atrial Dilation.

<p>Left atrial dilation defined using established CMR normative cutoff (>15 cm²/m²) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099178#pone.0099178-Maceira1" target="_blank">[19]</a>.</p><p>Numbers in boldface indicate p values <0.05.</p

Atrial Fibrillation/Flutter Risk as Stratified by LA Remodeling Indices.

<p>Kaplan-Meier plots relating baseline P wave area (5A) and body surface area indexed LA area (5B) to follow-up risk for AF/AFl. Note that both ECG and CMR indices demonstrated increased risk for AF/AFl among patients in the highest quartile of LA remodeling.</p