Long Term Follow-Up in a Patient with Arrhythmogenic Right Ventricular Dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited condition affecting predominantly the right ventricle (RV) with fatty or fibro-fatty substitution of myocytes, leading to segmental or global dilation. The fibrofatty replacement leads to ventricular arrhythmia and risk of sudden death in its early stages, and to right ventricular or biventricular failure in its later stages¹.

The disease starts usually in the subepicardium, expands to the subendocardium of the RV, and only rarely advances to the left ventricle (LV). The clinical manifestation of ARVD is unpredictable, and is probably connected with the chronological evolution of the myocardial injury. Accordingly, ARVD patients are sorted into 4 clinicopathological stages (phases): hidden phase (silent), arrhythmic phase, global dysfunction of the RV, and biventricular pump failure. Usually at the age of 30 to 40 years, ARVD patients report of exercise-induced palpitations because ventricular arrhythmias (VA) that arise in the RV². The majority of patients with ARVD usually remain in the second stage of the illness. At this stage, the disease is defined by segmental or global RV myocardial lesions with remaining normal myocardium³. Cardiac mortality in ARVD patients is caused by heart failure and sudden cardiac death (SCD). Those who have experienced ventricular tachycardia (VT), have an elevated SCD risk^4,5.

A 35-year-old patient with existing cardiovascular risk factors (overweight, dyslipidemia, former smoker) and Hashimoto's thyroiditis, with no personal history of cardiovascular disease and no family history of SCD, was referred to our hospital in February 2012 after a syncopal episode, that occured at rest and was preceded by dizziness and rapid palpitations. He reported dyspnea at medium exertion over a few months.

The ECG (Figure 1) showed sinus rhythm with frequent ventricular premature complexes (VPC) of left bundle branch block (LBBB) pattern, indicating an inferior RV origin; T wave inversions in the inferior and precordial leads, S waves in all precordial leads, and possible epsilon waves in leads DII, DIII, and aVF were noticed. Late ventricular potentials were also present (Figure 2).

Figure 1

Figure 2

ARVD was suspected at transthoracic echocardiography (TTE) assessment (Figure 3). Impaired, dilated, and excessive trabeculated RV with dilatation of the RV outflow tract were TTE's main findings.

Figure 3

Holter electrocardiography monitoring for 24 hours detected isolated supraventricular and ventricular premature complexes (episodes of ventricular bigeminy, couplets and triplets). Repeated resting ECG captured VPC and one episode of non-sustained ventricular tachycardia with a LBBB pattern. Coronary angiography showed normal coronary arteries.

We referred the patient to cardiac magnetic resonance imaging (MRI – Figure 4), which in the following years after the diagnosis of ARVD, magnetic resonance imaging was not performed again. Right and left ventricular function was assessed by transthoracic echocardiography. RV function remained the same, did not alter progressively during the follow-up. The LV had normal wall motion and function (LV ejection fraction =70%), but presented focal areas of late gadolinium enhancement in the basal segment of the lateral-inferior wall.

Figure 4

One year later the patient was hospitalized for several appropriate therapies delivered by the ICD, including anti-tachycardia pacing (ATP) initiated and shocks. The ECG at admission showed sustained ventricular tachycardia originating from the basal RV free wall, with a rate of 162 beats per minute (bpm) (Figure 5).

Figure 5

After the reinitiation of amiodarone, an electrophysiologic study was performed but VT was not induced (January 2014), so conventional VT ablation was not performed.

He was followed closely clinically, and after one year, only amiodarone was discontinued, the therapy with beta-blocker was continued. The patient played football as a hobby. We suggested him to avoid vigurous and competitive physical activity and to reduce exercise duration and dose per week.

Aerobic exercises and endurance training should be avoided by this category of patients.

Other restrictions included: smoking, alcohol and energy drinks.

In May 2019, seven years after the implant, the ICD was changed due to End of Life (EOL) indication (Medtronic Protecta XT). One year later he was re-admitted for recurrent VT episodes with appropriate therapy delivered by the ICD (Figure 6; 4 episodes in one week, failed ATP, the VT was terminated by internal shock delivery). Radiofrequency (RF) catheter ablation was performed using a three-dimensional (3D) mapping system (Carto-3).

Figure 6

The 3D electroanatomic CARTO map was achieved in sinus rhythm and substrate ablation was performed (voltage and activation map was done). „Normal” endocardial regions were described as those with an amplitude in bipolar electrogram of 1.5 mV, „scars” were defined as areas having an amplitude of 0.5 mV, and “abnormal” region was defined as having a bipolar electrogram amplitude of 0.5 to 1.5 mV. Substrate ablation target besides the voltage criteria, included critical sites (delayed, split and fragmented electrograms)⁶. During cathether manipulation VT was induced (Figure 7), but activation map was not achievable due to unstable hemodynamics of the patient (electrical cardioversion was performed immediately after syncope occurred).

Figure 7

The endpoint of each application was signal attenuation / complete elimination of these potentials. Programmed RV stimulation was performed after the completion of ablation, up to 4 extrastimuli at 2 different RV sites were used. The procedure was successful as no VT was inducible.

ARVD is a progressive disorder that often leads to RV failure in the long term. Adapted treatment strategies in ARVD plan to suppress or effectively end the recurrent VA, and to prevent SCD by antiarrhythmic pharmacotherapy, catheter ablation, or an ICD⁷. In our patient, incidental EKG findings after episodes of palpitations led to the discovery of a potentially life-threatening disease and to subsequent ICD implantation and antiarrhythmic therapy. The patient experienced after implantation many episodes of recurrent VTs and ICD shocks, initially with successful antiarrhythmic therapy; we can also speculate that drastically reduction in exercise led to a period of no arrhythmia. The special medical requirement of avoiding excessive physical activity was efficient, followed by clinical improvement. Thus the patient understood the risk of aggravation of his condition in case of continuing sustained physical activity. There are limited data published regarding the amount of exercise that may worsen the outcome. Yet, the evolution led finally to RF catheter ablation indication which was successfully performed. This case illustrates successful follow-up and survival in a life-threatening disease as ARVD. Close follow-up and complex attitude permitted an almost normal life course in a young patient.

However, due to progressive nature of ARVD recurrence rates are not insignificant, and ablation does not eliminate the need for ICD placement^8,9. There are few data and case reports in long term follow-up of ARVD patients.