Non-paroxysmal junctional tachycardia with type I exit block

Lead V1 shows a non-paroxysmal atrioventricular (AV) junctional tachycardia with type I (Wenckebach) exit block and underlying sinus rhythm. The patient mistakenly took three times the recommended dose of digoxin administered for mild congestive heart failure and presented with prolonged nausea and vomiting in an era before serum digoxin measurements. Stable sinus rhythm with a normal P–R …