Transient ascending ST-segment depression and widening of the S wave in 3-channel Holter monitoring-A sign of dromotropic disturbance in the right ventricular outflow tract in the Brugada syndrome: A report of five cases

Background Brugada syndrome (BrS) is somewhat a challenging diagnosis, due to its dynamic pattern. One of the aspects of this disease is a significant conduction disorder located in the right ventricular outflow tract (RVOT), which can be explained as a consequence of low expression of Connexin-43. This decreased conduction speed is responsible for the typical electrocardiographic pattern. Opposite leads located preferably in inferior leads of the electrocardiogram may show a deep and widened S wave associated with ascending ST segment depression. Holter monitoring electrocardiographic (ECG) aspects is still a new frontier of knowledge in BrS, especially in intermittent clinical presentations. Methods We describe, as an exploratory analysis, five case series of intermittent type 1 BrS to demonstrate the appearance of ascending ST segment depression and widening of the S wave, during 3-channel 24h-Holter monitoring (C1, C2 and C3) with bipolar leads. Results In the five cases described, the ST segment depression was observed mainly in C2, but in some cases also in C1 and C3. Only case 1 presented concomitant intermittent elevation of the ST segment in C1. All cases were intermittent. Conclusion The recognition of an ECG pattern with ascending ST-segment depression and widening of the S wave in 3-channel Holter described in this case series should raise a suspicion of the BrS and suggests the counterpart of a dromotropic disturbance registered in the RVOT and/or reciprocal changes.