Fragmented QRS as a marker of conduction abnormality and a predictor of prognosis of Brugada syndrome

Hiroshi Morita, Kengo F. Kusano, Daiji Miura, Satoshi Nagase, Kazufumi Nakamura, Shiho T. Morita, Tohru Ohe, Douglas P. Zipes, Jiashin Wu

Research output: Contribution to journalArticle

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Abstract

Background - Conduction abnormalities serve as a substrate for ventricular fibrillation (VF) in patients with Brugada syndrome (BS). Signal-averaged electrograms can detect late potentials, but the significance of conduction abnormalities within the QRS complex is still unknown. The latter can present as multiple spikes within the QRS complex (fragmented QRS [f-QRS]). We hypothesized that f-QRS could indicate a substrate for VF and might predict a high risk of VF for patients with BS. Methods and Results - In study 1, we analyzed the incidence of f-QRS in 115 patients with BS (13 resuscitated from VF, 28 with syncope, and 74 asymptomatic). f-QRS was observed in 43% of patients, more often in the VF group (incidence of f-QRS: VF 85%, syncope 50%, and asymptomatic 34%, P<0.01). SCN5A mutations occurred more often in patients with f-QRS (33%) than in patients without f-QRS (5%). In patients with syncope or VF, only 6% without f-QRS experienced VF during follow-up (43 ± 25 months), but 58% of patients with f-QRS had recurrent syncope due to VF (P<0.01). In study 2, to investigate the mechanism of f-QRS, we studied in vitro models of BS in canine right ventricular tissues (n=4) and optically mapped multisite action potentials. In the experimental model of BS, ST elevation resulted from a large phase 1 notch of the action potential in the epicardium, and local epicardial activation delay reproduced f-QRS in the transmural ECG. Conclusions - f-QRS appears to be a marker for the substrate for spontaneous VF in BS and predicts patients at high risk of syncope.

Original languageEnglish
Pages (from-to)1697-1704
Number of pages8
JournalCirculation
Volume118
Issue number17
DOIs
StatePublished - Oct 21 2008

Fingerprint

Brugada Syndrome
Ventricular Fibrillation
Syncope
Action Potentials
Pericardium
Incidence
Canidae
Electrocardiography
Theoretical Models

Keywords

  • Arrhythmia
  • Death, sudden
  • Electrocardiography
  • Genes
  • Tachyarrhythmias

ASJC Scopus subject areas

  • Physiology (medical)
  • Cardiology and Cardiovascular Medicine

Cite this

Morita, H., Kusano, K. F., Miura, D., Nagase, S., Nakamura, K., Morita, S. T., ... Wu, J. (2008). Fragmented QRS as a marker of conduction abnormality and a predictor of prognosis of Brugada syndrome. Circulation, 118(17), 1697-1704. https://doi.org/10.1161/CIRCULATIONAHA.108.770917

Fragmented QRS as a marker of conduction abnormality and a predictor of prognosis of Brugada syndrome. / Morita, Hiroshi; Kusano, Kengo F.; Miura, Daiji; Nagase, Satoshi; Nakamura, Kazufumi; Morita, Shiho T.; Ohe, Tohru; Zipes, Douglas P.; Wu, Jiashin.

In: Circulation, Vol. 118, No. 17, 21.10.2008, p. 1697-1704.

Research output: Contribution to journalArticle

Morita, H, Kusano, KF, Miura, D, Nagase, S, Nakamura, K, Morita, ST, Ohe, T, Zipes, DP & Wu, J 2008, 'Fragmented QRS as a marker of conduction abnormality and a predictor of prognosis of Brugada syndrome', Circulation, vol. 118, no. 17, pp. 1697-1704. https://doi.org/10.1161/CIRCULATIONAHA.108.770917
Morita, Hiroshi ; Kusano, Kengo F. ; Miura, Daiji ; Nagase, Satoshi ; Nakamura, Kazufumi ; Morita, Shiho T. ; Ohe, Tohru ; Zipes, Douglas P. ; Wu, Jiashin. / Fragmented QRS as a marker of conduction abnormality and a predictor of prognosis of Brugada syndrome. In: Circulation. 2008 ; Vol. 118, No. 17. pp. 1697-1704.
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abstract = "Background - Conduction abnormalities serve as a substrate for ventricular fibrillation (VF) in patients with Brugada syndrome (BS). Signal-averaged electrograms can detect late potentials, but the significance of conduction abnormalities within the QRS complex is still unknown. The latter can present as multiple spikes within the QRS complex (fragmented QRS [f-QRS]). We hypothesized that f-QRS could indicate a substrate for VF and might predict a high risk of VF for patients with BS. Methods and Results - In study 1, we analyzed the incidence of f-QRS in 115 patients with BS (13 resuscitated from VF, 28 with syncope, and 74 asymptomatic). f-QRS was observed in 43{\%} of patients, more often in the VF group (incidence of f-QRS: VF 85{\%}, syncope 50{\%}, and asymptomatic 34{\%}, P<0.01). SCN5A mutations occurred more often in patients with f-QRS (33{\%}) than in patients without f-QRS (5{\%}). In patients with syncope or VF, only 6{\%} without f-QRS experienced VF during follow-up (43 ± 25 months), but 58{\%} of patients with f-QRS had recurrent syncope due to VF (P<0.01). In study 2, to investigate the mechanism of f-QRS, we studied in vitro models of BS in canine right ventricular tissues (n=4) and optically mapped multisite action potentials. In the experimental model of BS, ST elevation resulted from a large phase 1 notch of the action potential in the epicardium, and local epicardial activation delay reproduced f-QRS in the transmural ECG. Conclusions - f-QRS appears to be a marker for the substrate for spontaneous VF in BS and predicts patients at high risk of syncope.",
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AU - Morita, Hiroshi

AU - Kusano, Kengo F.

AU - Miura, Daiji

AU - Nagase, Satoshi

AU - Nakamura, Kazufumi

AU - Morita, Shiho T.

AU - Ohe, Tohru

AU - Zipes, Douglas P.

AU - Wu, Jiashin

PY - 2008/10/21

Y1 - 2008/10/21

N2 - Background - Conduction abnormalities serve as a substrate for ventricular fibrillation (VF) in patients with Brugada syndrome (BS). Signal-averaged electrograms can detect late potentials, but the significance of conduction abnormalities within the QRS complex is still unknown. The latter can present as multiple spikes within the QRS complex (fragmented QRS [f-QRS]). We hypothesized that f-QRS could indicate a substrate for VF and might predict a high risk of VF for patients with BS. Methods and Results - In study 1, we analyzed the incidence of f-QRS in 115 patients with BS (13 resuscitated from VF, 28 with syncope, and 74 asymptomatic). f-QRS was observed in 43% of patients, more often in the VF group (incidence of f-QRS: VF 85%, syncope 50%, and asymptomatic 34%, P<0.01). SCN5A mutations occurred more often in patients with f-QRS (33%) than in patients without f-QRS (5%). In patients with syncope or VF, only 6% without f-QRS experienced VF during follow-up (43 ± 25 months), but 58% of patients with f-QRS had recurrent syncope due to VF (P<0.01). In study 2, to investigate the mechanism of f-QRS, we studied in vitro models of BS in canine right ventricular tissues (n=4) and optically mapped multisite action potentials. In the experimental model of BS, ST elevation resulted from a large phase 1 notch of the action potential in the epicardium, and local epicardial activation delay reproduced f-QRS in the transmural ECG. Conclusions - f-QRS appears to be a marker for the substrate for spontaneous VF in BS and predicts patients at high risk of syncope.

AB - Background - Conduction abnormalities serve as a substrate for ventricular fibrillation (VF) in patients with Brugada syndrome (BS). Signal-averaged electrograms can detect late potentials, but the significance of conduction abnormalities within the QRS complex is still unknown. The latter can present as multiple spikes within the QRS complex (fragmented QRS [f-QRS]). We hypothesized that f-QRS could indicate a substrate for VF and might predict a high risk of VF for patients with BS. Methods and Results - In study 1, we analyzed the incidence of f-QRS in 115 patients with BS (13 resuscitated from VF, 28 with syncope, and 74 asymptomatic). f-QRS was observed in 43% of patients, more often in the VF group (incidence of f-QRS: VF 85%, syncope 50%, and asymptomatic 34%, P<0.01). SCN5A mutations occurred more often in patients with f-QRS (33%) than in patients without f-QRS (5%). In patients with syncope or VF, only 6% without f-QRS experienced VF during follow-up (43 ± 25 months), but 58% of patients with f-QRS had recurrent syncope due to VF (P<0.01). In study 2, to investigate the mechanism of f-QRS, we studied in vitro models of BS in canine right ventricular tissues (n=4) and optically mapped multisite action potentials. In the experimental model of BS, ST elevation resulted from a large phase 1 notch of the action potential in the epicardium, and local epicardial activation delay reproduced f-QRS in the transmural ECG. Conclusions - f-QRS appears to be a marker for the substrate for spontaneous VF in BS and predicts patients at high risk of syncope.

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KW - Death, sudden

KW - Electrocardiography

KW - Genes

KW - Tachyarrhythmias

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