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Challenges in Clinical Electrocardiography
Apr 9, 2012

Wide QRS Tachycardia in a Young Patient—Discussion

Arch Intern Med. 2012;172(7):538-539. doi:10.1001/archinternmed.2012.19b

Figure 1, the presenting ECG, shows a regular ventricular rate of 240 beats/min and monomorphic, wide QRS tachycardia with left bundle-branch block (LBBB) configuration, right axis deviation, and QRS width greater than 160 milliseconds (ms), measured in V4. Although the exact electrocardiographic diagnosis of the arrhythmia is uncertain, the likely diagnosis of this wide QRS tachycardia of LBBB configuration with QRS width greater than 160 ms is ventricular tachycardia (VT).1,2 The possible causes of VT in this young patient include idiopathic dilated cardiomyopathy, ischemic cardiomyopathy, hypertrophic cardiomyopathy, right ventricular outflow tract VT, and arrhythmogenic right ventricular cardiomyopathy (ARVC).3-6 The last condition is also called arrhythmogenic right ventricular dysplasia.3-6 Coronary artery disease due to atherosclerosis or anomalous coronary artery anatomy is unlikely in this patient because he never had any typical chest pain and his exercise capacity by history was normal. Less likely diagnoses would be supraventricular tachycardia with aberrant ventricular conduction (this tachycardia is associated more commonly with right bundle-branch block [RBBB]), preexisting intraventricular conduction delay, or preexcitation.