Spontaneous type 1 Brugada syndrome patients exhibited significantly higher QRS dispersion (34 vs. 24 ms) and (QRSd × Tpeak − Tend)/QRS (25 vs. 19 ms) compared to non-type 1 patients.
Observational (n=51)
No
Do patients with spontaneous type 1 Brugada syndrome have higher dispersion measures of conduction and repolarization compared to those with non-type 1 patterns?
Higher levels of dispersion in conduction and repolarization are found in type 1 compared to non-type 1 Brugada syndrome patients, which may explain the higher incidence of ventricular arrhythmias in the type 1 group.
Absolute Event Rate: 34% vs 24%
p-value: p=0.03
Background: Brugada syndrome (BrS) is a cardiac ion channelopathy that predisposes affected individuals to sudden cardiac death. Type 1 BrS is thought to take a more malignant clinical course than non-type 1 BrS. We hypothesized that the degrees of abnormal repolarization and conduction are greater in type 1 subjects and these differences can be detected by electrocardiography (ECG). Methods: Electrocardiographic data from spontaneous type 1 and non-type 1 BrS patients were analyzed. ECG parameters were measured from leads V1 to V3. Values were expressed as median lower quartile-upper quartile and compared using Kruskal-Wallis ANOVA. Results: Compared to non-type 1 BrS patients (n=29), patients with spontaneous type 1 patterns (n=22) showed similar (P>0.05) heart rate (73 64-77 vs. 68 62-80 bpm), QRS duration (136 124-161 vs. 127 117-144 ms), uncorrected QT (418 393-443 vs. 402 386-424 ms) and corrected QT intervals (457 414-474 vs. 430 417-457 ms), JTpeak intervals (174 144-183 vs. 174 150-188 ms), Tpeak - Tend intervals (101 93-120 vs. 99 90-105 ms), Tpeak - Tend/QT ratios (0.25 0.23-0.27 vs. 0.24 0.22-0.27), Tpeak - Tend/QRS (0.77 0.62-0.87 vs. 0.77 0.69-0.86), Tpeak - Tend/(QRS x QT) (0.00074 0.00034-0.00096 vs. 0.00073 0.00048-0.00012 ms-1), index of Cardiac Electrophysiological Balance (iCEB, QT/QRS, marker of wavelength: 3.14 2.56-3.35 vs. 3.21 2.85-3.46) and corrected iCEB (QTc/QRS: 3.25 2.91-3.73 vs. 3.49 2.99-3.78). Higher QRS dispersion was seen in type 1 subjects (QRSd: 34 24-66 vs. 24 12-34 ms) but QT dispersion (QTd: 48 39-71 vs. 43 22-94 ms), QTc dispersion (QTcd: 52 41-79 vs. 46 23-104 ms), JTpeak dispersion (44 23-62 vs. 45 30-62 ms), Tpeak - Tend dispersion (28 15-34 vs. 29 22-53 ms) or Tpeak - Tend/QT dispersion (0.06 0.03-0.08 vs. 0.08 0.04-0.12) did not differ between the two groups. Type 1 subjects showed higher (QRSd x Tpeak - Tend)/QRS (25 19-44 vs. 19 9-30 ms) but similar iCEB dispersion (0.83 0.49-1.14 vs. 0.61 0.34-0.92) and iCEBc dispersion (0.93 0.51-1.15 vs. 0.65 0.39-0.96). Conclusion: Higher levels of dispersion in conduction and repolarization are found in type 1 than non-type 1 BrS patients, potentially explaining the higher incidence of ventricular arrhythmias in the former group.
Tse et al. (Thu,) conducted a observational in Brugada syndrome (n=51). Spontaneous type 1 Brugada pattern vs. Non-type 1 Brugada pattern was evaluated on QRS dispersion (p=0.03). Spontaneous type 1 Brugada syndrome patients exhibited significantly higher QRS dispersion (34 vs. 24 ms) and (QRSd × Tpeak − Tend)/QRS (25 vs. 19 ms) compared to non-type 1 patients.