Brugada - Lead I Is Your Friend (or Enemy)

A large or wide S-wave in lead I (>/= 1mV or 40ms) in patients with Brugada syndrome conferred a hazard ratio of 39.1 for V-fib/sudden cardiac death.  Next time you see a Brugada pattern, look at lead I closely.

J Am Coll Cardiol. 2016 Mar 29;67(12):1427-40. doi: 10.1016/j.jacc.2016.01.024.

A New Electrocardiographic Marker of Sudden Death in Brugada Syndrome: The S-Wave in Lead I.

Calò L1, Giustetto C2, Martino A3, Sciarra L3, Cerrato N2, Marziali M3, Rauzino J4, Carlino G5, de Ruvo E3, Guerra F6, Rebecchi M3, Lanzillo C3, Anselmino M2, Castro A7, Turreni F7, Penco M5, Volpe M4, Capucci A6, Gaita F2.

Author information:

1Division of Cardiology, Policlinico Casilino, ASL Rome B, Rome, Italy. Electronic address:

2Division of Cardiology, University of Torino, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Torino, Italy.

3Division of Cardiology, Policlinico Casilino, ASL Rome B, Rome, Italy.

4Department of Clinical and Molecular Medicine, School of Medicine and Psychology, Sapienza University of Rome, Ospedale S. Andrea and IRCCS Neuromed, Pozzilli (Isernia), Italy.

5Department of Cardiology, University of L'Aquila, L'Aquila, Italy.

6Cardiology Clinic, Ospedali Riuniti Umberto I-Lancisi-Salesi, Ancona, Italy.

7Division of Cardiology, Policlinic Sandro Pertini, ASL Rome B, Rome, Italy.



Risk stratification in asymptomatic patients remains by far the most important yet unresolved clinical problem in the Brugada syndrome (BrS).


This study sought to analyze the usefulness of electrocardiographic parameters as markers of sudden cardiac death (SCD) in BrS.


This study analyzed data from 347 consecutive patients (78.4% male; mean age 45 ± 13.1 years) with spontaneous type 1 BrS by ECG parameters but with no history of cardiac arrest (including 91.1% asymptomatic at presentation, 5.2% with a history of atrial fibrillation [AF], and 4% with a history of arrhythmic syncope). Electrocardiographic characteristics at the first clinic visit were analyzed to predict ventricular fibrillation (VF)/SCD during follow-up.


During the follow-up (48 ± 38 months), 276 (79.5%) patients remained asymptomatic, 39 (11.2%) developed syncope, and 32 (9.2%) developed VF/SCD. Patients who developed VF/SCD had a lower prevalence of SCN5A gene mutations (p = 0.009) and a higher prevalence of positive electrophysiological study results (p < 0.0001), a family history of SCD (p = 0.03), and AF (p < 0.0001). The most powerful marker for VF/SCD was a significant S-wave (≥0.1 mV and/or ≥40 ms) in lead I. In the multivariate analysis, the duration of S-wave in lead I ≥40 ms (hazard ratio: 39.1) and AF (hazard ratio: 3.7) were independent predictors of VF/SCD during follow-up. Electroanatomic mapping in 12 patients showed an endocardial activation time significantly longer in patients with an S-wave in lead I, mostly because of a significant delay in the anterolateral right ventricular outflow tract.


The presence of a wide and/or large S-wave in lead I was a powerful predictor of life-threatening ventricular arrhythmias in patients with BrS and no history of cardiac arrest at presentation. However, the prognostic value of a significant S-wave in lead I should be confirmed by larger studies and by an independent confirmation cohort of healthy subjects.

PMID: 27012403 [PubMed - in process]

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