Anatomical considerations and clinical interpretation of the 12-lead ECG in the prone position: a prospective multicentre study

Figures

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  Figure 1. Central illustration: supine and prone back electrocardiogram lead location.

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  Figure 2. Assessment of the electroanatomic position of the heart. Difference in the distance from the centre of ventricular depolarization of the heart to the precordial electrodes in the supine and in prone position by chest magnetic resonance images. (A) Prone chest magnetic resonance imaging of a healthy volunteer. (B) Localization of the centre of ventricular depolarization (centre of the heart). (C) Measurement of the distance from the centre of the heart to the standard supine lead position (dotted arrows); see QRS morphology in supine position. (D) Measurement of the distance from centre of the heart to posterior prone lead position (dotted arrows represent the distance measured to standard lead position when supine; straight arrows show the difference in distance between anterior and posterior lead placement); see QRS morphology in prone back position. [Reproduced from ‘Frank E. Determination of the electrical centre of ventricular depolarization in the human heart. Am Heart J 1955;49:670–92’ with permission of the publisher].

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  Figure 3. 3D-computed tomography measurements: Axial (left), coronal (centre), sagittal (right), and 3-D volume rendered (bottom) chest images without contrast. Top panel showing the distance between the centre of the heart and the precordial leads in supine position. Central panel showing the distance between the centre of the heart and the precordial leads placed on patient’s back in prone position. Lower panel illustrating the distance between the centre of the heart and the precordial leads in prone anterior position (see Methods for details on measurements).

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  Figure 4. Prone back vs. supine position. Differences in QRS amplitude, Q waves, and T-wave abnormalities between prone and supine position. As multiple comparisons were performed, a Bonferroni test was used to get a correction of the type I error; a p ≤ 0.0008 was considered to be statistically significant.

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  Figure 5. Correlation between QRS amplitude and distance to electrodes. Scatter plots delineating the V1–V6 values and their relationship between QRS amplitude and lead position distance by Pearson’s correlation analysis. n = 8. As multiple comparisons were performed, a Bonferroni test was used to get a correction of the type I error; a p ≤ 0.0008 was considered to be statistically significant.