Short P‐Wave Duration is a Marker of Higher Rate of Atrial Fibrillation Recurrences after Pulmonary Vein Isolation: New Insights into the Pathophysiological Mechanisms Through Computer Simulations

Figures

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  Figure 1. Electroanatomical mapping of a left atrial in a patient with a short P wave (86 ms) in anterio‐posterior, postero‐anterior, and left anterior oblique view. The earliest left atrial breakthrough occurred in the mid septum 33 ms after P wave onset as determined on surface ECG; the local electrogram and activation is visible on the catheter mapping (Pentaray – P 15‐16) of the right panel. Latest left atrial activation is on the lateral side of the left atrium close to the mitral valve ring; the local electrogram and activation is visible on the catheter mapping (Pentaray – P 1‐12) of the left panel. AP indicates antero posterior view; LAO, left anterior oblique view; MAP 1‐2, distal electrode pair of the ablation catheter; P, Pentaray mapping; PA, postero anterior view.

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  Figure 2. Atrial fibrillation recurrence according to P‐wave duration. A, Atrial fibrillation recurrence rate per 100 person‐year and P‐wave duration (grouped according to predefined cut‐offs of P wave); dots indicate the rate per 100 person years, whiskers indicate the 95% CIs of the rates. B, Shape of the risk of atrial fibrillation after pulmonary vein ablation in relationship to P‐wave duration. The shape of the risk of recurrence of AF over P‐wave duration is shown, computed using fractional polynomial. For this purpose, the linear predictor (y axis) derived by a Cox model using fractional polynomial is plotted against P‐wave duration (x axis). The best fit for this model includes a power 2 and a power 3 term. There is no physical interpretation of the values on the y axis. AF indicates atrial fibrillation.

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  Figure 3. Atrial fibrillation recurrence‐free survival after pulmonary vein isolation (blanking period of 3 months) according to the P‐wave duration. Blue line: P‐wave duration <110 ms; red line: P‐wave duration ≥110 to 139 ms; green line: P‐wave duration ≥140 ms.

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  Figure 4. Effect of adenosine administration on P‐wave duration. A 9% reduction of P‐wave duration was observed on the beat preceding a complete atrioventricular block. The non‐conducted P wave was slightly shorter than the previous one however, its morphology was marginally different as well. Also, the time from P‐wave onset to most distal coronary sinus was shorter during the adenosine challenge.

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  Figure 5. In‐silico simulation of the effect of adenosine. A, action potential in control and adenosine showed a triangular shape, with action potential duration 90 reducing from 312 ms to 149 ms from control to adenosine case (52% reduction). B, simulated P wave in lead II showed a reduction in duration from 103 ms to 96 ms (7% reduction). C through F, effect of an increase of sodium channels conductance from 0% to 100%. C, resting action potential shape. D, conduction velocity in a 1‐dimensional fiber strand. E, Action potential duration 90. F, P‐wave duration in lead II. A 100% increase in sodium conductance yielded a 26% increase of conduction velocity, a 28% reduction in action potential duration 90 and a 22% reduction in P‐wave duration.