Tetralogy of Fallot associated with supramitral ring: "Paying for a near miss"

Abstract

A 13-year-old girl developed the features of congestive heart failure on day three of intracardiac repair of tetralogy of Fallot. A routine transthoracic echocardiography identified the missed supramitral ring (SMR), closely placed just above the mitral valve, the very reason for severe mitral stenosis and its implication in the present clinical deterioration. A rare association of SMR with tetralogy of Fallot may be missed narrowly because closely placed SMR can sometimes mask its hemodynamic effect when present with significant right ventricular outflow tract obstruction as in this case. <Learning objective: This case report highlights when a case of complex congenital heart disease is referred for intervention or surgery, it is better to be verified by a pediatric cardiologist. Tetralogy of Fallot (TOF) associated with supramitral ring (SMR) is reported as an anecdotal case report. Although it is a mistake, it may be possible to miss the SMR when it is associated with TOF. The reasons are threefold: (1) The rare association of SMR with TOF. (2) The close proximity of SMR to mitral valve. (3) Right ventricular outflow obstruction in TOF reduces flow across mitral valve i.e. a low cardiac output state.>.

Keywords: Echocardiography; Intracardiac repair; Supramitral ring; Tetralogy of Fallot.

Fig. 1

Two-dimensional (2D) echocardiography. (A) Color Doppler across right ventricular outflow tract (RVOT) showed mild residual RVOT gradient (40/23 mmHg) and moderate pulmonary valve regurgitation, adding volume overload to already pressure overloaded right ventricle. (B) 2D echocardiography showed mild tricuspid regurgitation with severe pulmonary arterial hypertension, right ventricular systolic pressure (RVSP) of 70 mmHg. (C) 2D echocardiograph in parasternal long-axis view showed very closely placed membranous supramitral ring (SMR), almost looks deceptively absent, a bit more echogenic valves (marked by an arrow). This controversy was resolved by the apical four-chamber view. (D) 2D echocardiograph in apical four-chamber view showed a distinct SMR, very closely placed just above the mitral valve as marked by arrows. (E) 2D echocardiograph with continuous wave Doppler interrogating mitral valve shows severe mitral stenosis, a gradient of 28/20 mmHg.