ediastinal irradiation in patients with cancer is known to cause cardiovascular complications such as constrictive pericarditis, valvular dysfunction, coronary artery disease, cardiomyopathy, and conduction system disorders. [1][2][3][4][5][6] Although rarely, multiple complications might occur in a single patient. Here, we report a case of a patient who underwent mediastinal irradiation for the treatment of breast cancer 20 years ago and developed paroxysmal atrioventricular (AV) block, manifested as recurrent syncope, high-grade coronary artery ostial stenoses, pre-valvular right ventricular outflow tract (RVOT) stenosis, and constrictive pericarditis.
Case ReportA 67-year-old woman presented to the emergency department with a history of recurrent syncope and a subsequent trauma-related scalp laceration. She did not experience any prodromal symptoms, such as palpitation, chest pain, or vagal symptoms immediately before the syncopal episode. She was diagnosed with left-sided breast cancer 20 years ago and had undergone a left radical mastectomy with lymph node dissection and mediastinal irradiation. There has been no recurrence of her cancer to date. On the physical examination, jugular venous engorgement was observed, and a grade II/VI ejection murmur was audible at the right parasternal border, second intercostal space. The skin of the left-sided anterior chest wall changed cicatricial because of previous surgery and radiation. An electrocardiogram (ECG) demonstrated a sinus rhythm with 136 ms of normal PR interval, a complete left bundle branch block with 147 ms of QRS width, and left axis deviation ( Fig 1A). A chest radiography showed mild cardiomegaly with an enlarged right cardiac border because of right atrial enlargement. On echocardiography, heavy calcification of aortic valve annulus, enlargement of both atria, thickened pericardium, and hypertrophied and stenotic RVOT were observed (Figs 1B, C). There was flow acceleration at the subvalvular RVOT on Doppler study (Figs 1D,E), and the systolic pressure gradient measured by right catheterization was 22 mmHg. The respiratory variation of pulsed wave Doppler recordings in mitral inflow was compatible with constrictive pericarditis (Fig 1F). As to syncope evaluation, a Holter ECG monitor and tilting test were negative, but a treadmill ECG showed significant ST depression during exercise. Therefore, we performed an electrophysiologic study and coronary angiography. Sinus node function and AH/HV intervals were normal (Fig 2A), and carotid sinus massage did not reveal a bradyarrhythmia. A ventricular arrhythmia was not inducible by programmed ventricular stimulation. Because coronary angiography showed significant bilateral coronary ostial stenoses, stents were deployed successfully in the left and right coronary artery ostia ( Figs 2D,E). However, the patient still experienced recurrent syncope and pre-syncope episodes of unknown cause (Fig 3). Therefore, we implanted a loop recorder (Reveal plus, Medtronic Inc, Minneapolis, MN, USA) on the right chest wal...