Rapid ventricular tachycardia in patients with tetralogy of Fallot and implantable cardioverter-defibrillator: Insights from the DAI-T4F nationwide registry

BACKGROUND

In repaired tetralogy of Fallot (TOF), little is known about characteristics of patients with rapid ventricular tachycardia (VT). Also, whether patients with a first episode of nonrapid VT may subsequently develop rapid VT or ventricular fibrillation (VF) has not been addressed.

OBJECTIVES

The objectives of this study were to compare patients with rapid VT/VF with those with nonrapid VT and to assess the evolution of VT cycle lengths (VTCLs) overtime.

METHODS

Data were analyzed from a nationwide registry including all patients with TOF and implantable cardioverter-defibrillator (ICD) since 2000. Patients with ≥1 VT episode with VTCL ≤250 ms (240 beats/min) formed the rapid VT/VF group.

RESULTS

Of 144 patients (mean age 42.0 ± 12.7 years; 104 [72%] men), 61 (42%) had at least 1 VT/VF episode, including 28 patients with rapid VT/VF (46%), during a median follow-up of 6.3 years (interquartile range 2.2-10.3 years). Compared with patients in the nonrapid VT group, those in the rapid VT/VF group were significantly younger at ICD implantation (35.2 ± 12.6 years vs 41.5 ± 11.2 years; P = .04), had more frequently a history of cardiac arrest (8 [29%] vs 2 [6%]; P = .02), less frequently a history of atrial arrhythmia (11 [42%] vs 22 [69%]; P = .004), and higher right ventricular ejection fraction (43.3% ± 10.3% vs 36.6% ± 11.2%; P = .04). The median VTCL of VT/VF episodes was 325 ms (interquartile range 235-429 ms). None of the patients with a first documented nonrapid VT episode had rapid VT/VF during follow-up.

CONCLUSION

Patients with TOF and rapid VT/VF had distinct clinical characteristics. The relatively low variation of VTCL over time suggests a room for catheter ablation without a backup ICD in selected patients with well-tolerated VT.

Long-term follow-up of a patient with type 2 Timothy syndrome and the partial efficacy of mexiletine

We report a detailed case of type 2 TS due to a p.(Gly402Ser) mutation in exon 8 of the CACNA1C gene. The patient shows a marked prolongation of repolarization with a mean QTc of 540 ms. He shows no structural heart disease, syndactyly, or cranio-facial abnormalities. However, he shows developmental delays, without autism, and dental abnormalities. The cardiac phenotype is very severe, with a resuscitated cardiac arrest at 2.5 years of age, followed by 26 appropriate shocks during nine years of follow-up. Adding mexiletine to nadolol resulted in a reduction of the QTc and a slight decrease in the number of appropriate shocks.

5204Primary prevention of sudden cardiac death in patients with tetralogy of Fallot with implantable cardioverter defibrillator: insights from the DAI-T4F study

Background

Ventricular arrhythmias and sudden death are feared late complications in patients with tetralogy of Fallot. Selection of candidates for primary prevention implantable cardioverter defibrillator (ICD) remains challenging in this population. Non-sustained ventricular tachycardia (NSVT), altered left ventricular ejection fraction (LVEF), positive programmed ventricular stimulation, and enlarged QRS are currently used for risk stratification.

Purpose

To identify high-risk patients with tetralogy of Fallot in the setting of primary prevention of sudden cardiac death.

Methods

The DAI-T4F study is a large ongoing national French registry including all patients with tetralogy of Fallot and ICD (NCT03837574). Information have been collected prospectively since 2010 with annual update. Baseline patient characteristics and clinical events during the follow-up were analyzed with central adjudication. Cox proportional hazard models were used to identify factors associated with appropriate ICD therapies.

Results

Among 134 patients enrolled, 47 (35.1%) underwent ICD implantation for primary prevention (median age 49.1 years, 76.6% males). At baseline, 20 (42.6%) patients had NSVT, 17 (36.2%) had severe altered LVEF ≤35%, 16 (34.0%) had positive programmed ventricular stimulation, and 16 (34.0%) had QRS duration ≥180ms. Overall, 20 (42.6%), 15 (31.9%), and 6 (12.8%) patients had respectively one, two, or ≥ three of these risk factors. Six (12.8%) patients were implanted for other indications. During a median (IQR) follow-up duration of 5.3 (2.1–8.0) years, 14 (29.8%) patients had at least one appropriate ICD therapy. The annual incidence of appropriate ICD therapies were 2.8%, 4.6%, 6.3%, and 8.6% in patients with none, one, two, or ≥ three of these factors (p for trend = 0.145). None of predictors, considered isolated, was significantly associated with ICD appropriate therapies. Patients with non-sustained ventricular tachycardia (NSVT) and positive programmed ventricular stimulation had a significant increased risk of ICD appropriate therapies (HR=3.8, 95% CI: 1.1–14.3, p=0.035), as well as patients with NSVT and QRSd ≥180 ms (HR=7.2, 95% CI: 1.6–32.7, p=0.003). No patient with severe altered LVEF without other risk factor had appropriate ICD therapy. Patients with congestive heart failure and/or altered LVEF had a higher risk of non-sudden death or cardiac transplantation (HR=14.4, 95% CI: 1.8–112.7, p<0.001). Seventeen (36.2%) patients experienced at least one ICD-related complication.

Conclusions

Our data illustrate that specific risk stratification and primary prevention for sudden cardiac death in patients with tetralogy of Fallot may be improved. The value of a severely altered LVEF appears low in the absence of other risk factors, and combination of different predictors is essential. The high rate of complications as well as consideration of competing risk situation have to be integrated in the benefit-risk equation.

Mitral valve replacement with a pulmonary autograft: long-term follow-up in an infant

A 7-month-old boy with a complete atrioventricular septal defect presented with severe left atrioventricular valve regurgitation 4 months after complete repair. As the valve was unsuitable for the repair and the annulus was too small to accommodate a mechanical prosthesis, the modified mitral Ross operation was performed. The long-term outcome was uneventful for 12 years. The mitral Ross procedure is an old-described technique in which classically the pulmonary autograft is encased in a prosthetic conduit preventing any growth potential. On the contrary, the modified technique used in this case shows that the long-term function can be obtained. This procedure may be a valuable option when mitral valve replacement is necessary in infants.