A 23-year-old man was referred to our center for atrial flutter ablation. After arrhythmia termination sinus node dysfunction unmasked and persisted after 2 months drug-free follow-up. Secondary causes such as antiarrhythmic drug consumption, organic heart disease, or electrolyte disturbance could be excluded. Standard 12-lead ECG showed a coved-type ST elevation in V1-V3, which increased after flecainide provocative test. Following an unexpected sick sinus syndrome, a Brugada-type ECG should be noted.

Carcinoid heart disease is a well‐known complication of carcinoid syndrome that affects morbidity and mortality. Carcinoid heart disease may be asymptomatic in the early stages; therefore, patients with carcinoid syndrome should be screened to prevent misdiagnosis.

Coronary artery fistulas constitute a rare anomaly defined as an abnormal communication between a coronary artery and a great vessel or any cardiac chamber. The majority of these fistulas arise from the right coronary artery and the left anterior descending coronary artery; the circumflex coronary artery is rarely involved. We present an unusual case of a coronary artery fistula in a middle-aged woman who presented with symptoms of heart failure and abnormal auscultation. Echocardiography and conventional and computed tomography angiography showed that the coronary fistula originated from the left circumflex coronary artery and drained majorly into the right ventricle. Given the complex anatomy of the fistula, we managed it surgically rather than percutaneously. There were no complications early after surgery and at 1 year’s follow-up.