Can atrioventricular septal defects exist with intact septal structures?

The hallmark of an atrioventricular septal defect (AVSD) is a common atrioventricular junction, giving rise to a trileaflet left atrioventricular valve. AVSDs have the potential for interatrial shunting alone, interventricular shunting alone, or both. AVSDs without interatrial or interventricular communications have been identified at postmortem examination, but there are no reports of AVSDs with intact septal structures diagnosed in life. Six patients are described with AVSD and intact atrial and ventricular septa diagnosed echocardiographically. This report shows that AVSDs can exist without interatrial or interventricular communications and that the characteristic feature of this condition, the common atrioventricular junction with a trileaflet left atrioventricular valve, can be diagnosed in life by using cross sectional echocardiography. AVSDs with intact septal structures may be more common than previously described.

Transcatheter closure of atrial septal defect preserves right ventricular function.

OBJECTIVES: To determine the effects of atrial septal defects (ASD) and their closure on systolic and diastolic right and left ventricular function; and by comparing surgical closure with transcatheter device closure, to establish differences attributable to cardiopulmonary bypass. DESIGN: Cross sectionally guided M mode echocardiographic ventricular long axis function was measured prospectively before and within one week after ASD closure by device in 17 patients and by surgery in 12 patients, and compared with 18 normal subjects. RESULTS: All indices of right ventricular function were impaired after surgery: mean total excursion, -1.89 cm (95% confidence interval (CI), -2.18 to -1.59); peak shortening rate, -9.09 cm/s (-10.82 to -7.35); peak lengthening rate, -9.26 cm/s (-11.09 to -7.43). Total excursion and peak lengthening rate were preserved after device closure, at -0.12 cm (-0.28 to 0.05) and 0.01 cm/s (-2.29 to 2.31), respectively. Left ventricular free wall function was unchanged after closure by either method, while all septal measurements were reduced after closure by either method (changes ranging from -3.51 to -0.32; 95% CI ranging from -4.90 to -0.13). CONCLUSIONS: Left ventricular free wall function is unaffected by ASD closure, whereas septal function is impaired, irrespective of the method of closure. Right ventricular function, both systolic and diastolic, is impaired by cardiopulmonary bypass but preserved after device closure. These findings support the transcatheter approach to ASD closure in anatomically suitable defects.

Abnormalities of right ventricular long axis function after atrial repair of transposition of the great arteries.

BACKGROUND: While volume derived global indices of right ventricle (RV) function are frequently abnormal after the Mustard procedure, the mechanism for these abnormalities is poorly understood. RV muscle fibres are predominantly arranged longitudinally and thus indices derived in the long axis may better describe RV function. METHODS: 20 survivors of the Mustard operation were studied (age 7.8-37.3 years, median 14.2 years). Long axis recordings from the apical four chamber view were obtained with the M mode cursor positioned through the lateral angle of the tricuspid valve annulus. M mode traces were recorded on paper and later digitised to derive total atrioventricular ring excursion, peak lengthening rate, and peak shortening rate. These data were averaged and compared with control data for the normal RV and left ventricle (LV). RESULTS: RV total atrioventricular ring excursion was lower than that for the RV (p < 0.0001) or LV (p < 0.005) of controls. Peak lengthening rate was lower than the normal RV (p < 0.0001) and LV (p < 0.0001) rates. Furthermore, peak shortening rate was less than that of normal RV (p < 0.0001) and normal LV (p < 0.005) controls. CONCLUSION: Systemic RV long axis function is notably reduced compared with that of either the normal subpulmonary RV or the systemic LV. This presumably reflects the response of the predominantly longitudinally arranged myocardial fibres to increased afterload. However, such measurements may provide a more sensitive marker for progressive changes in global function during long term follow up.

Echocardiographic and morphological correlations in tetralogy of Fallot.

AIMS: Our aim was to clarify the location and structure of the outlet septum relative to the free-standing subpulmonary infundibulum in the setting of tetralogy of Fallot and to examine its relationship to the other components of the subpulmonary outflow tract, determining their potential influence on clinical outcome. METHODS AND RESULTS: We studied prospectively 41 patients with tetralogy of Fallot (mean age 14 +/- 10.9 months) prior to surgical repair, and compared them with 15 patients undergoing closure of a ventricular septal defect associated with malalignment of the outlet septum but no subpulmonary infundibular stenosis (Eisenmenger ventricular septal defect), and 20 healthy controls. We also examined available autopsied hearts from cases with uncorrected tetralogy of Fallot (8) and Eisenmenger ventricular septal defect (13). Data were indexed for body surface area, and diameter of the tricuspid valve, respectively. The overall length of the subpulmonary infundibulum, including the extent of the muscular outlet septum, was significantly greater for patients with tetralogy of Fallot compared to normals (2.34 +/- 0.6 vs 1.46 +/- 0.34 cm/BSA0.5, P<0.001), whereas the difference between those with tetralogy of Fallot and an Eisenmenger ventricular septal defect was confined to the degree of narrowing of the subpulmonary outlet (0.43 +/- 0.22 vs 2.17 +/- 0.64 cm/BSA0.5, P<0.001). Within the tetralogy of Fallot group, there were linear relationships between deviation of the outlet septum (r= -0.61, P<0.005) and the diameter of the pulmonary valvar orifice (r=0.75, P<0.001), suggesting that growth of the pulmonary arteries may be related to this feature. When patients requiring a transannular patch as part of their surgical repair were compared with those not needing this procedure, differences were found in the diameter of the pulmonary valvar orifice and the pulmonary trunk, but not in the dimensions of the outlet septum. CONCLUSION: The position of the outlet septum in relationship to the remainder of the muscular subpulmonary infundibulum represents a hallmark of tetralogy of Fallot, permitting its differentiation from Eisenmenger ventricular septal defects and normal hearts.

Does restrictive right ventricular physiology in the early postoperative period predict subsequent right ventricular restriction after repair of tetralogy of Fallot?

OBJECTIVE: To assess the relation between immediate postoperative right ventricular (RV) diastolic physiology and subsequent diastolic function in patients after repair of tetralogy of Fallot. DESIGN: Serial prospective echocardiographic study early after surgical repair of tetralogy of Fallot and at mid-term follow up. SETTING: Tertiary referral centre. PATIENTS: 34 patients who had repair of tetralogy of Fallot between 1992 and 1995 were studied. MAIN OUTCOME MEASURES: Restrictive RV physiology defined as antegrade flow in the pulmonary artery in late diastole throughout the respiratory cycle. RESULTS: Sixteen of the 34 patients had early restrictive RV physiology. The need for transannular patch repair was an independent variable predictive of early restriction (odds ratio 4.3 (1.1-47), p < 0.05). Nine of 16 patients with early restriction also had restriction at follow up, while 15 of 16 patients without restrictive RV physiology continued without restriction. Early restriction was the only independent variable predictive of late restriction (odds ratio 6.0 (1.9-273), p = 0.01). CONCLUSIONS: Early and mid-term restrictive RV physiology after repair of tetralogy of Fallot is related to the repair type. Although evidence for this physiology tends to resolve in the first few days after operation, it is highly predictive of subsequent abnormalities of RV diastolic function. Similarly, normal RV diastolic physiology without restriction in the immediate postoperative period persists in the mid-term and may be associated with the long term problems of progressive RV dilatation.

Discrepancies in the measurement of isovolumic relaxation time: a study comparing M mode and Doppler echocardiography.

Mitral valve cusp separation on M mode echogram, the mitral valve opening artefact, and the onset of forward transmitral flow recorded by Doppler echocardiography have all been taken to mark the end of isovolumic relaxation, while its onset has been taken either as the aortic closure sound (A2) recorded phonocardiographically or the aortic closure artefact determined by Doppler technique. Possible differences in the measurement of the isovolumic relaxation time were studied when these landmarks were used in 44 healthy people, 14 patients with mitral stenosis, 21 patients with left ventricular hypertrophy, and 24 patients with dilated cardiomyopathy by recording M mode echograms of the mitral valve, and pulsed and continuous wave Doppler spectra of transmitral flow, with simultaneous electrocardiograms and phonocardiograms. A2 was effectively synchronous with the aortic artefact. However, when the onset of Doppler flow was regarded as the end of isovolumic relaxation, the interval was significantly longer than when mitral cusp separation on M mode echograms was used: by 25 (10) ms in healthy individuals, by 25 (15) ms in patients with left ventricular hypertrophy, and by 50 (35) ms in patients with dilated cardiomyopathy. In patients with mitral stenosis the interval was only 5 (5) ms longer. The mitral valve opening artefact consistently followed the onset of flow and corresponded much more closely to the E point on the M mode echogram. This shows that it occurred during the rapid filling period and well beyond isovolumic relaxation by any definition. Thus isovolumic relaxation time measured from A2 to the onset of transmitral flow or the mitral valve opening artefact differs from that derived from A2 to mitral valve cusp separation. These intervals cannot be used interchangeably to measure "isovolumic relaxation time".