Case report: An irregular wide QRS rhythm with flutter waves and a positive precordial concordance.

We report a 69-year-old woman with persistent palpitation, a history of myocardial infarction. ECG showed irregular wide QRS tachycardia with positive precordial concordance and flutter waves, initially misdiagnosed as atrial flutter with accessory pathway. Direct current cardioversion restored sinus rhythm but failed to terminate tachycardia, revealing ventricular tachycardia (VT). Amiodarone resolved VT. This case highlights the challenge of differentiating wide QRS tachycardias, emphasizing QRS morphology and atrioventricular (AV) relationship analysis for accurate diagnosis.