Wide Complex Tachycardia
Updated: Aug 19
David Didlake EMT-P, RN, ACNP
@DidlakeDW
An adult male self-presented to the ED with palpitations and the following ECG.
The patient was very uncomfortable, dyspneic, and displayed an SpO2 90% on RA. He denied any known history of CAD, but did report ASCVD risk factors to include HTN, HLD, and DM.
Of interest, he specified that he awoke earlier that morning in his usual state of health, developed chest discomfort, then developed palpitations.
I interpreted the ECG as VT with two primary etiological possibilities:
1. Abrupt plaque ulceration of Type 1 ACS leading to VT.
2. Baseline fibrotic substrate from dilated cardiomyopathy leading to VT.
From a clinical standpoint I reconciled the first possibility as more probable since the chest discomfort came first.
Despite the otherwise stable NIBP he was deemed acutely ill and we elected to pursue DCCV over any Rx therapy. Here is the ECG after 200J.
Readers of the Smith ECG Blog will probably recognize this as a very subtle inferior OMI. Ultimately the patient went to Cath and was found to have multi-vessel obstructive coronary disease with an acute LCX culprit vessel, which was stented.
Corresponding echocardiogram demonstrated LV systolic dysfunction with an EF 30%.
The VT vs SVT with Aberrancy debate is beyond the scope of this particular blog post. Helpful tools to differentiate a WCT ECG include the Smith ECG Blog, and the Life in The Fast Lane blog. Examples provided below.
Here’s a recent article from the JACC that not only summarizes previous WCT ECG research (eg, Brugada, Vereckei, etc), but presents a novel algorithm that may perform better.
In any case, I think the important takeaway point is that VT has a longer initial activation sequence because of slow myocardial conduction, as opposed to brisk antegrade electrical transmission using the bundle branches (which would be more typical of SVT with aberrancy).
Addendum
I would like to add this stellar publication regarding the differential diagnosis of WCT on the 12 Lead ECG. Pay attention to the fact that it addresses pre-test probability from the start.
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