Clinical Aspects and Ablation of Ventricular Arrhythmias in Tetralogy of Fallot

Abstract OBJECTIVES The long-term outcome of tetralogy of Fallot (TOF) is determined by progressive right ventricular (RV) dysfunction through pulmonary regurgitation (PR) and the risk of malignant arrhythmia. Although mechano-electrical coupling in TOF is well-known, its time effect on the inducibility of arrhythmia remains ill-defined. The goal of this study was to investigate the mechano-electrical properties at different times in animals with chronic PR. METHODS PR was induced by a transannular patch with limited RV scarring in infant pigs. Haemodynamic assessment included biventricular pressure–volume loops after 3 (n = 8) and 6 months (n = 7) compared to controls (n = 5). The electrophysiological study included endocardial monophasic action potential registration, intraventricular conduction velocity and induction of ventricular arrhythmia by burst pacing. RESULTS Progressive RV dilation was achieved at 6 months (RV end-diastolic volume 143 ± 13 ml/m2—RV end-systolic volume 96 ± 7 ml/m2; P < 0.001), in association with depressed RV contractility (preload recruitable stroke work-slope: 19 ± 1 and 11 ± 3 Mw.ml−1.s−1 for control and 6 m; P < 0.001) and left ventricular contractility (preload recruitable stroke work-slope: 60 ± 13 and 40 ± 11 Mw.ml−1.s−1 for control and 6 m; P = 0.005). Concomitant to QRS prolongation, monophasic action potential90-duration and dispersion at the RV and left ventricle were increased at 6 months. Intraventricular conduction was delayed only in the RV at 6 months (1.8 ± 0.2 and 2.4 ± 0.6 m/s for group 6M and the control group; P = 0.035). Sustained ventricular arrhythmias were not inducible. CONCLUSIONS In animals yielding the sequelae of a contemporary operation for TOF, mechano-electrical alterations are progressive and affect predominantly the RV after midterm exposure of PR. Because ventricular arrhythmias were not inducible despite significant RV dilation, the data suggest that the haemodynamic RV deterioration effectively precedes the risk of inducing sustained arrhythmia after TOF repair and opens a window for renewed stratification of contemporary risk factors of ventricular arrhythmias in patients operated on with currently used pulmonary valve- and RV-related techniques.

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QRS PROLONGATION DOES NOT PREDICT MALIGNANT VENTRICULAR ARRHYTHMIAS AND SUDDEN DEATH IN PATIENTS FOLLOWING NEONATAL TETRALOGY OF FALLOT REPAIR

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(13)60521-5 ◽

2013 ◽

Vol 61 (10) ◽

pp. E521

Author(s):

Benjamin R. Blevins ◽

Neha Joshi ◽

Maully Shah

Keyword(s):

Sudden Death ◽

Tetralogy Of Fallot ◽

Ventricular Arrhythmias ◽

Qrs Prolongation ◽

Tetralogy Of Fallot Repair

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Prognostic Factors for Late Ventricular Arrhythmias after Repair of Tetralogy of Fallot

Asian Cardiovascular and Thoracic Annals ◽

10.1177/021849239700500105 ◽

1997 ◽

Vol 5 (1) ◽

pp. 20-24

Author(s):

Fumikazu Nomura ◽

Seiichiro Ikawa ◽

Keishi Kadoba ◽

Masataka Mitsuno ◽

Yoshiki Sawa ◽

...

Keyword(s):

Pulmonary Artery ◽

Right Ventricular ◽

Tetralogy Of Fallot ◽

Ventricular Arrhythmias ◽

Right Atrial ◽

Age At Surgery ◽

Group A ◽

Group B ◽

The Right

During a median follow-up period of 9 years (ranging from 9 months to 25 years), 24-hour ambulatory electrocardiographic studies were undertaken in 155 patients after repair of tetralogy of Fallot. The patients were divided into two groups. Group A consisted of 76 patients in whom the right ventricular approach was used and group B comprised 79 patients whose repair was through the right atrium. A transannular patch was employed in all patients in group A and in none of the patients in group B. Age at surgery was between 1 and 37 years (median age 4.8 years). During follow-up, 37 patients (48.6%) in group A had significant ventricular arrhythmias (Lown grade 2 or higher) and 13 patients (15.4%) in group B had significant ventricular arrhythmias. A close relationship was observed between age at surgery and Lown grade (R2 = 0.374, p < 0.001) and between follow-up duration and Lown grade (R2 = 0.514, p < 0.001), especially when the two groups were analyzed separately (R2 = 0.502, 0.476, p < 0.001). In contrast, no significant relationship was observed between the ratio of right ventricular to left ventricular pressure and Lown grade or between right ventricular systolic pressure and Lown grade. Discriminant analysis revealed risk factors associated with postoperative ventricular arrhythmias are follow-up duration (partial F = 3.22, p < 0.01), right ventricular to pulmonary artery pressure gradient (partial F = 3.35, p < 0.01), and operative method (partial F = 2.4, p < 0.05). Despite antiarrhythmic therapy, 11 of 22 late postoperative deaths occurred suddenly, presumably from ventricular arrhythmias. In this series of patients, the right atrial and pulmonary artery approach significantly reduced the risk of life-threatening ventricular arrhythmias after repair of tetralogy of Fallot.

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