High-rate episodes with simultaneous atrial and ventricular activation in a patient with permanent pacemaker implantation for complete heart block

Key Teaching Points•Symptomatic narrow QRS tachycardia is rare in a patient with complete heart block and permanent pacemaker.•If found, it should be meticulously evaluated to rule out sinus tachycardia.•Simple measures such as increasing beta-blocker may take care of a patient’s symptoms. •Symptomatic narrow QRS tachycardia is rare in a patient with complete heart block and permanent pacemaker.•If found, it should be meticulously evaluated to...