Evaluation of the Specificity of Morphological Electrocardiographic Criteria for the Differential Diagnosis of Wide QRS Complex Tachycardia in Patients With Intraventricular Conduction Defects

BACKGROUND: Although several ECG criteria have been described for the differential diagnosis of tachycardias with a wide QRS complex, their applicability in patients with preexisting intraventricular conduction defects (IVCDs) has been questioned. The specificity of previously described criteria in this context is unknown. METHODS AND RESULTS: We analyzed prospectively the specificity of the QRS morphological criteria previously described in ECGs during sinus rhythm of 232 patients with IVCD. Only 5 of 12 analyzed criteria had a specificity > or = 0.90 among our patients: (1) a triphasic configuration (Rsr' or Rr') QRS complex in V1 in the presence of a right bundle-branch block morphology (BBBM); (2) a QS, QR, or R QRS pattern in V6 in the presence of a right BBBM; (3) any Q in V6 in the presence of a left BBBM; (4) a concordant pattern in all precordial leads; and (5) the absence of an RS complex in all precordial leads (particularly useful for left BBBM). The following criteria--QRS duration > 140 ms; a left axis with right BBBM, right superior axis with right BBBM, monophasic or biphasic R wave in V1 with right BBBM, and a relation R/S 30 ms in lead V1 or V2 with left BBBM, > 60 ms from QRS onset to S nadir with left BBBM, a notched downstroke S wave with left BBBM, and an R-to-S interval > 100 ms in one precordial lead--had a specificity of 0.43, 0.54, 0.87, 0.80, 0.85, 0.78, 0.66, 0.69, and 0.63 (0.84 in right BBBM), respectively. CONCLUSIONS: Most of the previously described morphological criteria favoring ventricular tachycardia are present in a substantial percentage of patients with IVCD during sinus rhythm. These findings suggest a limited applicability of these criteria in this subset of patients.