Quantitative Analysis of Hypertrophy in Cardiac Chambers in Cyanotic Tetralogy of Fallot.

Abstract

SUMMARYAlthough early total corrective repair for cyanotic tetralogy of Fallot is now safely performed at many institutions, long-term complications after surgical repair have been demonstrated. Therefore, the optimal procedure and timing for surgical treatment remain controversial. In the present study, we conducted a quantitative analysis of the hypertrophy of all four chambers of 87 autopsied hearts of cyanotic tetralogy of Fallot and 71 normal control hearts utilizing the myocardial mass index, and evaluated the progression of lesions with advancing age. In cyanotic tetralogy of Fallot, hypertrophy of the right ventricle progresses immediately after birth, with that of the right atrium developing soon after. The left side of the heart is normal or slightly atrophied which could be corrected by sufficient palliative intervention or total corrective repair. The growth curves of both ventricles were parallel to those of normal hearts for the period studied. Pulmonary atresia, palliative operation, and total corrective repair have been shown to have some influence on the morphological characteristics of hearts of cyanotic tetralogy of Fallot. ( SURGICAL approaches to cyanotic tetralogy of Fallot (TOF) continue to evolve and now many institutions favor early total corrective repair for TOF without initial palliative procedures. Meanwhile, life-threatening ventricular arrhythmias and severe right ventricular dysfunction have been demonstrated in the long-term after surgical repair. Therefore, the optimal procedure, including the combination with initial palliative surgery and the timing for the surgical treatment, has once again become controversial. In the present study, we conducted a quantitative analysis of hypertrophy of all four chambers of the hearts of patients with cyanFrom the Divisions of Cardiovascular Surgery,

Histopathology of the right ventricular outflow tract and the relation to hemodynamics in patients with repaired tetralogy of Fallot

“…Myocardial hypertrophy leads to myocardial ischemia, degeneration, and ultimately fibrosis. 3,9,[20][21][22] During surgery, these hearts are subjected to intentional ischemia during aortic crossclamping. Adequate myocardial protection still remains a challenge in cyanotic hearts.…”

“…Fibrosis, an irreversible change at tissue level compounded with RV muscular hypertrophy, further aggravates the already-stressed myocardial oxygen delivery and function. 21,22 Although it is impossible to relate an LCOS state directly to a specific myocardial morphologic alteration, such a relation is suggested by the presence of disorganization and degeneration in the heart muscle of adult TOF. 10,[19][20][21][22][23] We concur with other investigators in that the frequency of ventricular arrhythmia increases in older patients with TOF.…”

“…21,22 Although it is impossible to relate an LCOS state directly to a specific myocardial morphologic alteration, such a relation is suggested by the presence of disorganization and degeneration in the heart muscle of adult TOF. 10,[19][20][21][22][23] We concur with other investigators in that the frequency of ventricular arrhythmia increases in older patients with TOF. 10,[15][16][17] Necropsy studies have shown extensive endocardial thickening and perivascular fibrosis in adults with uncorrected TOF, unlike younger patients.…”