Case Description

A 27-year-old male was admitted to our cardiac tertiary center because of increasing dyspnea and progressive exercise intolerance.

He had been followed up by different hospitals during his life.

At birth, he was diagnosed with transposition of great arteries with ventricular septal defect and pulmonary outflow tract obstruction.

At the age of 9 months, he underwent the Blalock-Hanlon atrial septectomy and at 3 years the Rastelli procedure with homograft implant, ventricular septal defect enlargement, and atrial septal defect closure.

At 12 and 15 years, he underwent percutaneous angioplasty of the conduit with the use of balloon expandable stents to relieve conduit stenosis, but with unsatisfactory results.

At 16 years, he underwent an uncomplicated right ventricle–pulmonary artery (RV–PA) conduit replacement.

At 21 years, during routine echocardiographic assessment he was found to have moderate conduit stenosis (peak gradient up to 45 mmHg).

At the age of 25 years, due to an episode of syncope and a 24-h Holter documenting a symptomatic pause related to second-degree atrioventricular block, he underwent a dual chamber pacemaker implant.

At 26 years, he had a hospital admission for congestive heart failure, despite taking high-dose diuretics treatment and intravenous inotropic drugs (dobutamine and later levosimendan).

On admission to our department, he had severe dyspnea on mild to minimal effort and peripheral edema. There was a third heart sound and a systolic murmur (grade 4/6) at the left sternal border. Percutaneous peripheral oxygen saturation was 96% and his blood pressure was 100/60 mmHg.

Electrocardiogram showed sinus rhythm at 80 bpm, QRS axis at −40 degrees on the frontal plane, and incomplete right bundle branch block (QRSd, 110 ms).

Transthoracic echocardiographic examination revealed left ventricle enlargement (left ventricular end-diastolic diameter, 65 mm; left ventricular end-systolic diameter, 60 mm), with severe global dysfunction (ejection fraction, 15%); massive mitral regurgitation; a restrictive transmitral flow pattern (E/E′:18); severe RV enlargement (RV end-diastolic diameter, 52 mm) with severe global dysfunction (tricuspid annular plane systolic excursion, 7 mm); and severe tricuspid regurgitation, with the systolic pulmonary artery pressure estimated to be 50 mmHg.

To confirm the anatomic and hemodynamic findings, the patient underwent cardiac catheterization. During angiography, severe RV–PA conduit stenosis was confirmed.

He was then scheduled for heart transplant assessment.

During hospitalization, telemetric electrocardiography and 24-h electrocardiographic Holter monitoring showed repeated symptomatic nonsustained ventricular tachycardia runs ( Fig. 2.1 ) and so he was started on amiodarone.

Electrocardiographic Holter monitoring traces showing nonsustained ventricular tachycardia runs.

Owing to the presence of potentially life-threatening ventricular arrhythmias, despite amiodarone treatment, as a bridge for heart transplant, we decided to implant a subcutaneous implantable cardioverter defibrillator (S-ICD), as an upgrade of the existing pacemaker to a transvenous ICD was considered to be a higher procedural risk ( Figs. 2.2–2.4 ).

Anteroposterior view of chest radiograph demonstrating the subcutaneous implantable cardioverter defibrillator and the permanent transvenous pacemaker.

Lateral view of chest radiograph demonstrating the subcutaneous implantable cardioverter defibrillator and the permanent transvenous pacemaker.

Complete healing of the wound at follow-up. Note the scar of the previous pacemaker (PMK) implant and the subcutaneous implantable cardioverter defibrillator (S-ICD) scar. A tattoo on the chest is masked to protect patient’s confidentiality.