Intracardiac ultrasound to detect aneurysm in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy is a genetic disorder characterized by fibrofattty replacement of the right ventricular myocardium. In the revised 2010 Task Force Criteria, a major criteria for ARVD/C is the presence of RV aneurysm by 2D echo. Our report demonstrates that intracardiac ultrasound can detect RV aneurysms and also focal absence of trabeculations which brings additional value to the diagnosis of ARVD/C. A 26-year-old male patient suffering from multiple sustained episodes of ventricular tachycardia was implanted with an internal cardiac defibrillator after confirmation of the disease by cardiac magnetic resonance imaging. Intracardiac ultrasound was performed using a 6F, 9 MHz catheter and the iLAB intravascular system (Boston Scientific). Images of right ventricular inflow tract, outflow tract, apex and pulmonary artery were taken and saved on videotape. ICE revealed loss of trabecular structure at the right ventricular outflow tract with an antero-septal aneurysm at this level. Intravascular ultrasound provides useful information on the presence of aneurysms and of tissue characterization.

A 26-year-old male patient was diagnosed with arrhythmogenic right ventricular cardiomyopathy/dysplasia by electrocardiographic features (presence of epsilon wave in lead V1–V3), echocardiography (right ventricular dilation) and cardiac resonance magnetic imaging. He presented a syncope and multiple episodes of ventricular tachycardia with a left-bundle branch block morphology and therefore was implanted with an internal cardiac defibrillator. A contrast-enhanced computed tomography showed a focal aneurysm of the right ventricular outflow tract which was further confirmed by intracardiac ultrasound. A 6F, 9 MHz catheter in combination with the iLAB intravascular system (Boston Scientific) [1] was used for imaging of the so-called ‘triangle’ of ARVD: inflow tract-outflow tract and apex of the right ventricle. Visualization of the pulmonary artery and right ventricular outflow tract was saved on videotape during pulling back of the catheter. By intracardiac ultrasound a focal aneurysm of the antero-septal wall of RVOT was identified, corresponding with that of contrast-enhanced computed tomography. Absence of trabeculations in the RVOT could be demonstrated at this level (Fig. 1). Catheter ablation of the right ventricular VT was performed with no-inducibility at the end of the procedure by programmed ventricular stimulation. There were no femoral or cardiac post-procedural complications.

Figure 1:

Intracardiac ultrasound of the right ventricular outflow tract and right ventricular apex in a patient with arrhythmogenic right ventricular dysplasia/cardiomyopathy. (A) At the level of the RVOT an aneurysm is present (red arrow) that was also identified during contrast-enhanced computed tomography. Lack of trabeculations is a marker of ARVD/C. (B) At the level of the apex, trabeculations are present (yellow arrow); in this particular patient the apex was not affected by dysplasia.

The ESC diagnosis of ARVD/C is based on morphological and functional changes of the right ventricle. In early stages patients are often asymptomatic but with a risk of death during effort which is still present. In late stages patients present symptomatic arrhythmias and structural changes of the right ventricle and RVOT are present. Structural changes include presence of aneurysm or motion abnormalities, and segmental or global dilation of the right ventricle [2]. Transthoracic echocardiography is the first line imaging technique but it has a low ability to demonstrate localized RVOT aneurysm [3, 4]. The ‘gold standard’ in the diagnosis is selective right ventricular angiography, but tissue characterization is not possible with this technique. From a pathological point of view it is known that loss of trabeculations is a typical finding in patients with ARVD/C [5]. Our report indicates that intracardiac ultrasound can demonstrate focal absence of trabeculations which adds additional value for ARVD/C diagnosis.