Utility of ECG Criteria in Idiopathic VT Patients

Study Questions:

How accurate are the criteria to diagnose ventricular tachycardia (VT) in patients with idiopathic VT?

Methods:

Electrocardiograms (ECGs) of 115 idiopathic VTs, 101 post-myocardial infarction (MI) VTs, and 111 wide QRS supraventricular tachycardias (SVTs) were analyzed using standard criteria. VT was diagnosed in patients when at least one criterion was met, SVT when no criteria were met, and indeterminate when there were conflicting criteria.

Results:

Standard ECG criteria more frequently diagnosed VT in the post-MI group than the idiopathic group (95% vs. 82%, respectively; p < 0.01). Diagnosis in only 12 of the 111 SVT patients (11%) met the criteria for VT. All patients in the idiopathic VT group with right branch bundle block morphology who did not meet VT criteria demonstrated an rsR’ pattern in V1 (consistent with SVT). Among idiopathic VT patients, Purkinje-associated VT had the lowest sensitivity for correct VT diagnosis in 13 of 23 patients (57%), septal sites of origin were correctly diagnosed in only 56 of 76 patients (74%), whereas nonseptal sites had a high sensitivity in 35 of 35 patients (100%; p < 0.005).

Conclusions:

Conventional ECG criteria have reduced sensitivity to distinguish VT from SVT with aberrancy in patients with idiopathic VT.

Perspective:

There are many criteria which aid in differentiating between VT and SVT with aberrancy. While they are thought to have high sensitivities and specificities, they were developed in cohorts with structural heart disease, especially ischemic heart disease, or unspecified cohorts. This study demonstrates that nearly 20% of idiopathic VTs may not be recognized as ventricular in origin based on the ECG, mainly because of the outflow or septal site of origin.

Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Prevention, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Acute Coronary Syndrome, Arrhythmias, Cardiac, Bundle-Branch Block, Catheter Ablation, Electrocardiography, Myocardial Infarction, Myocardial Ischemia, Secondary Prevention, Tachycardia, Supraventricular, Tachycardia, Ventricular


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