Cardiogenic Shock, Acute Severe Mitral Regurgitation and Complete Heart Block After Cavo-Tricuspid Isthmus Atrial Flutter Ablation

Radiofrequency (RF) ablation is the first-line management of cavo-tricuspid isthmus dependent atrial flutter. It has been performed with 95% success rate. Adverse events are very rare. We report the first case of acute severe mitral regurgitation (MR) and complete heart block developed after successful atrial flutter ablation. A 62-year-old female with mild MR presented with palpitations. Surface electrocardiogram was suggestive of isthmus dependent atrial flutter. A duodecapolar mapping catheter showed an atrial flutter with cycle length of 280 ms. An 8 mm tipped Thermistor RF ablation catheter was placed at the cavo-tricuspid isthmus. RF energy was delivered as the catheter was dragged to the inferior vena cava. Temperature limit was 60 °C; the power output limit was 60 W. The patient converted to sinus rhythm with the first ablation line. Bi-directional block was recorded. Two additional ablation lines lasting 60 - 120 s were delivered. The patient started having chest pain and developed complete heart block with no escape rhythm. She became hypotensive and was immediately paced from the right ventricle. There were no signs of pericardial tamponade. Emergent bedside echo demonstrated severe MR with a retracted posteromedial mitral valve leaflet. She was 100% paced and EKG changes could not be assessed. Based on the sudden onset chest pain, hypotension, complete heart block and acute severe MR after ablation, the right coronary artery occlusion was suspected. She was immediately transferred to the catheterization laboratory. Coronary angiography revealed a total occlusion of the posterolateral branch from the right coronary artery. Balloon angioplasty and coronary artery stenting was performed. Complete heart block subsequently resolved. Subsequent bedside echocardiogram showed marked improvement of the MR. Patients with smaller body size have smaller hearts and more likely to have injury from RF current. Higher energy penetrates deeper and causes more tissue damage. The use of lower temperature limits (55 °C) and lower energy (60 W) for small, elderly, and female patients is encouraged.