Impact of Prone Position on 12-Lead Electrocardiogram in Healthy Adults: A Comparison Study with Standard Electrocardiogram

Figure 3

The correlation between QRS vector loops and ECG tracing has been explained. From the centre of the x-y-z axes, QRS waveform circuits are initiated. Sequential 2-ms increments during ventricular depolarization are marked by arrows. On the ECG leads tracing, the amplitude of QRS complexes is consistent with the vertical direction of the vector loop at a specific location and time. (a) In the supine position, the horizontal vector loop showed that, at first, the ventricular depolarization loop was anteriorly and leftward directed towards the anterior chest precordial leads (V1 to V3), resulting in initial positive deflection in these leads. (b) In the prone position, the horizontal vector loop showed that the ventricular depolarization loop was initially oriented anteriorly and leftward away from precordial leads V1 to V3, which are positioned on the back of the patient, resulting in new Q wave emergence and low QRS amplitude.

(a)

(b)