Atrial standstill disease progression documented after 13 years follow-up

A 22-year-old woman returned to our clinic complaining of asymptomatic intermittent episodes of narrow complex tachycardia. We initially saw the patient at the age of nine for a lipothymia, followed by headache, dizziness and marked asthenia 3 days after a flu-like episode. She was bradycardic, and the electrocardiogram (ECG) revealed a slow junctional escape rhythm (40 bpm) without P waves (an ECG performed at the age of 5 years was unremarkable). Transesophageal ECG and 24-h Holter ECG monitoring confirmed the persistent absence of any atrial activity (fixed junctional bradycardia). Transthoracic echocardiography revealed the lack of any atrial mechanical activity in the presence of normal ventricular function. An electrophysiologic (EP) study revealed the lack of right and left atrial spontaneous electrical activity, with a supra Hiss escape rhythm (HV interval 40 ms).