Left-ventricular Non-compaction Cardiomyopathy Presenting With Atrial Flutter With Rapid Ventricular Response.

Left ventricular non-compaction cardiomyopathy (LVNC) is a rare genetic cardiomyopathy characterized by prominent trabeculations and deep recesses that predispose to arrhythmias and heart failure. We describe a 42-year-old man with persistent tachycardia and exertional fatigue found to have CTI-dependent atrial flutter with 2:1 conduction. Transesophageal echocardiography showed severe biventricular dysfunction with an ejection fraction of 15%, and cardiac MRI confirmed LVNC with a non-compacted to compacted ratio of 3.3. After successful ablation and normal coronary angiography, he was diagnosed with LVNC. This case highlights an unusual presentation of LVNC with typical atrial flutter and underscores the value of cardiac MRI in diagnosing unexplained atrial arrhythmias.