Acceleration-dependent aberrancy

A 73 yo is admitted due to shortness of breath. Is this ventricular tachycardia (VT)?

Figure 1 - ECG case

The 12 lead ECG shows an irregular wide complex tachycardia (WCT) with a left axis deviation and left bundle branch block (LBBB) configuration. One striking feature on the 12L is the negative concordance. However, this is not VT by the Brugada algorithm and the aVR algorithm. Looking at V1 and V6 criteria, it is not VT.

 

Figure 2 - Morphological Criteria Discriminating VT from SVT from Garner J and Miller J.

Figure 3 - Telemetry

Observing it at a different time and at slower rate revealed narrowing of the QRS. This is acceleration-dependent aberrancy (LBBB). Underlying rhythm is AF. Longer observations are often needed to discover that LBBB is rate-related. This is now the beauty of telemetry monitoring.

Further investigation also revealed that the patient had non-ischemic cardiomyopathy with EF about 20. So, an AICD is offered.

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