Tetralogy of fallot

Abstract

The optimal surgical approach and timing for patients with tetralogy of Fallot remain controversial. There are two options in current practice: a two-stage repair (an initial palliative aortopulmonary shunt at an early age followed by complete repair at an older age) or primary complete repair. There has been a trend towards primary repair at a young age, which can be attributed to advances in anesthetic and cardiac surgical techniques. Primary repair has several advantages. The correction can be done in one operation and shunt complications are avoided. Progressive right ventricular fibrosis, ventricular hypertrophy, and chronic hypoxia are avoided, which may reduce the incidence of late ventricular arrhythmias. However, surgical correction at a young age is associated with an increased incidence of transannular patching and consequent pulmonary regurgitation. Progressive pulmonary regurgitation is associated with late ventricular arrhythmias and sudden death. These consequences may be prevented by timely pulmonary valve replacement. Palliative procedures include an aortopulmonary shunt, balloon dilation of the right ventricular tract, and stent placement. Of these measures, the aortopulmonary shunt is preferred, as it results in a more predictable outcome. Complications associated with shunt placement include shunt occlusion, pulmonary artery distortion, and occasionally, volume overloading of the left ventricle and pulmonary circulation. Institutional and surgeon preferences exist for either surgical strategy, and ultimately are justifiable when they produce the best outcomes for the individual patient. The optimal surgical strategy has to be determined by large prospective randomized studies that compare the functional status of the pulmonary valve and the need for reoperation at long-term follow-up.

Myocardial hypertrophy after pulmonary regurgitation and valve implantation in pigs

“…Some studies however had limited improvement in survival rate and incidences of ventricular tachycardia [4,5]. Progressive fibrosis is suspected to play a pathological role in development of ventricular arrhythmias on long-term follow-up after primary repair [6,7]. Our porcine electrophysiological results warrant further investigationperhaps RV hypertrophy also can increase the arrhythmogenicity in the absence of excessive collagen.…”

“…The cellular mechanisms of the reverse remodelling process are not well understood. Fibrosis is believed to play a role in the refractory arrhythmias [6,7]. RV dilation and fibrosis can be associated with increased release of natriuretic peptides to plasma [8][9][10], whereas correction of RV volume overload might normalise peptide concentrations.…”

Arrhythmias and conduction abnormalities in children after repair of tetralogy of Fallot

“…The specificity of this surgical procedure and timing influenced the outcome in those children. Technical specificities of the procedure may damage specific areas of the conduction system and affect developing heart rhythm disturbances (8,9).…”