Key result
Catheter ablation of WPW does not alter JTc intervals despite shortening QRS and QTc.
Why the study?
In patients with Wolff-Parkinson-White syndrome, preexcitation precludes accurate assessment of ventricular repolarization using the QTc interval. Whether the JTc interval remains unchanged despite depolarization abnormalities in WPW patients, as previously demonstrated in long QT syndrome, required testing.
Does catheter ablation of ventricular preexcitation alter the JTc interval compared to QRS and QTc intervals in patients with Wolff-Parkinson-White syndrome?
Cohort (n=29)
Does catheter ablation of ventricular preexcitation alter the JTc interval compared to QRS and QTc intervals in patients with Wolff-Parkinson-White syndrome?
The JTc interval remains constant before and after catheter ablation of accessory pathways in WPW syndrome, demonstrating its utility as a depolarization-independent measure of ventricular repolarization.
JTc may aid repolarization assessment in WPW; leaves open prospective validation before clinical adoption.
In patients with Wolff-Parkinson-White syndrome (WPW), preexcitation precludes accurate assessment of the ventricular repolarization by the QTc. In patients with long QT syndrome, it has been demonstrated that the JTc does not change when depolarization abnormalities develop. We hypothesized that this phenomenon should also be applicable to WPW patients. To test this, we assessed the surface ECG of 29 patients (16 males, 13 females) with WPW pre- and postablation. The QRS, QT, and JT intervals were measured pre- and postablation at 50 mm/s paper speed in leads II and V2. QTc and JTc were calculated according to Bazett's formula. The average age was 12.8 +/- 4.9 years (range 1.5-21). All patients had no residual preexcitation on postablation ECG. Early and late follow-up ECGs were obtained at 32 +/- 34 days and 388 +/- 197 days postablation, respectively. Both the QRS and the QTc intervals shortened significantly on the postablation versus preablation ECGs (QRS: 115 +/- 23 ms vs 89 +/- 15 ms, respectively; P < 0.0001), QTc: 454 +/- 26 vs 423 +/- 23, respectively; P < 0.0001). The preablation JTc interval did not change, postablation (319 +/- 21 vs 323 +/- 23, respectively; P > 0.2). Also, the JTc interval did not change between early and late follow-up, postablation. JTc is an independent measure of repolarization, not related to depolarization. JTc may be a useful tool in assessing repolarization in patients with WPW and other depolarization abnormalities.
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Salim et al. (1995) conducted a cohort in Wolff-Parkinson-White syndrome (WPW) (n=29). Catheter ablation of Wolff-Parkinson-White syndrome (postablation state) vs. Preablation ECG state (with ventricular preexcitation) was evaluated on Corrected JT interval (JTc) calculated according to Bazett's formula (p=> 0.2). Catheter ablation of WPW shortened QRS (89 vs 115 ms, P<0.0001) and QTc (423 vs 454 ms, P<0.0001), while JTc remained unchanged (323 vs 319 ms, P>0.2).
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