Results:
Triggers
In patients with CAD the mean coupling interval (CI) between the extrastimuli and PVC1 (S-PVC1) was 237±75 ms and between PVC1- PVC2: 212±70 ms. The duration of QRS: PVC 1 187± 35 ms and PVC2 189±32 ms. In patients with BS, SPVC1: 277± 50 ms; PVC1-PVC2: 217± 28 ms; QRS duration PVC 1: 207± 32 ms; PVC2: 186± 33 ms. (Fig 1). Four QRS morphologies were observed : similar to stimulated QRS (IR); LBBB with late transition and superior axis; RBBB with superior left axis and LBBB with inferior axis. These morphologies appear both in PVC1 and PVC2. In Brugada Syndrome cases, the predominant morphologies were those with LBBB morphology, and in CAD cases, those with RBBB morphology predominated (Fig 1)
Tachysistolic stage
In this first phase, QRS morphologies are still observed, unlike the following phase where only sinusoidal waves can be seen. In the group with coronary arterial disease there is a predominant morphology with right bundle branch and superior axis. (Fig 2,3). In the Brugada Syndrome group, RBBB and superior axis morphologies are not distinguished; on the contrary, LBBB and inferior axis morphologies are predominant, together with others which are less common with LBBB and superior axis morphologies (Fig 4).
Sinusoidal stage
The phase after what we call tachysistolic, is characterized by sinusoidal complexes, where we can no longer distinguish QRS, which following Wigger´s description could correspond to Wigger´s convulsive incoordination phase. If we analyze this portion of the ECG we can distinguish complexes of great amplitude and others of smaller amplitude with notches; established VF is characterized by sinusoidal complexes with large amplitude and traces with an appearance of notches. These should not be confused with the final phase of VF where there are only low amplitude waves corresponding to a phase of disorganization. Notches in the sinusoidal complexes appeared in sustained VF, but not in non-sustained VF (Fig 5).