Factors affecting left ventricular function after correction of tetralogy of Fallot.

To investigate the possible causes of left ventricular dysfunction after total correction of tetralogy of Fallot, 84 patients, aged 1 1/2 to 16 years, were studied by left ventricular cineangiography both before and a mean of 4.6 months after operation. Left ventricular ejection fraction and mean velocity of circumferential fibre shortening were calculated; using multivariate analysis the results were correlated with age at operation, the degree of hypoxia and polycythaemia before operation, occurrence of hypoxic spells, and the duration of operative procedures (cardiopulmonary bypass and aortic cross clamping). The postoperative left ventricular ejection fraction was decreased slightly or moderately in 46% of patients. The variable most significantly associated with altered left ventricular function was a history of hypoxic spells. Age, the degree of chronic hypoxia, and polycythaemia did not correlate significantly with left ventricular function indices. Although no correlation was found between the duration of cardiopulmonary bypass and left ventricular ejection fraction, bypass times exceeding 120 minutes were associated with decreased ejection fractions; this was statistically significant and independent of the variable "hypoxic spells". Thus repeated episodes of acute hypoxia and long operative procedures appear to have a deleterious effect on left ventricular function in tetralogy of Fallot.     

Left ventricular function after total correction of tetralogy of Fallot

Conflicting data are available concerning left ventricular (LV)function in patients after total correction of tetralogy ofFallot (TOF). The response to afterload stress determined bymethoxamine challenge and the peak systolic blood pressure-end-systolicvolume relationship were evaluated echocardiographically in20 postoperative TOF patients (age range 9 to 15 years, mean12±2). All patients were without significant residualshunts or pulmonary stenosis. Results were compared with thosein 10 control subjects (age range 9 to 15 years, mean 11±2).The TOF group had higher mean end- diastolic (76·9±14·4vs 66·2±7·2 ml. m P<0·05) andmean end-systolic (36·7±8 vs 29·6±3·9ml. m^–2 P<0·05 volumes than controls. Strokevolume index (SVI) and LV ejection fraction were similar inthe two groups. In normal subjects, mnethoxamine caused a decreasein SVI in seven Out of 10 patients and a mild increase in three;the mean value of SVI at rest was not significantly differentfrom the mean value at peak pressor effect (36·5±4·4vs 35·9±4·0 ml. m^–2, P=NS). In theTOF group, methoxamine induceda reduction in SVI in all patients,the mean value of SVl at peak pressor effect was significantlylower than the mean value at rest (31·3±5·4vs 40·2±6·9 ml. m^–2 P<0·001).Ejection fraction decreased in both groups with the afterloadchallenge, but in the TOF patients the reduction was significantlyhigher than in the normal subjects (from 53±4 to 38±5%vs from 55±3 to 49±3%, P<0·001). Peaksystolic blood pressure-end- systolic volume relationships wereconstructed. The slope (m) of the relationship was significantlylower in the TOF group than in the control subjects (2·85±0·77vs 6·21+0·58, p<0·001);in the TOE groupm was below the 95% confidence limit in all studied patients.There was a significant correlation between aortic oxygen saturationpreoperatively and the slope of the peak systolic pressure-end-systolicvolume relation. Thus, LV function after successful total correctionof TOFmay be abnormal, with larger than normal LV size and decreasedcontractile function.     

Left ventricular function after total correction of tetralogy of Fallot.

Conflicting data are available concerning left ventricular (LV) function in patients after total correction of tetralogy of Fallot (TOF). The response to afterload stress determined by methoxamine challenge and the peak systolic blood pressure-end-systolic volume relationship were evaluated echocardiographically in 20 postoperative TOF patients (age range 9 to 15 years, mean 12 +/- 2). All patients were without significant residual shunts or pulmonary stenosis. Results were compared with those in 10 control subjects (age range 9 to 15 years, mean 11 +/- 2). The TOF group had higher mean end-diastolic (76.9 +/- 14.4 vs 66.2 +/- 7.2 ml.m-2 P less than 0.05) and mean end-systolic (36.7 +/- 8.5 vs 29.6 +/- 3.9 ml.m-2, P less than 0.05) volumes than controls. Stroke volume index (SVI) and LV ejection fraction were similar in the two groups. In normal subjects, methoxamine caused a decrease in SVI in seven out of 10 patients and a mild increase in three; the mean value of SVI at rest was not significantly different from the mean value at peak pressor effect (36.5 +/- 4.4 vs 35.9 +/- 4.0 ml.m-2, P = NS). In the TOF group, methoxamine induced a reduction in SVI in all patients; the mean value of SVI at peak pressor effect was significantly lower than the mean value at rest (31.3 +/- 5.4 vs 40.2 +/- 6.9 ml.m-2, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular systolic and diastolic function after total correction of tetralogy of Fallot

Left ventricular (LV) systolic and diastolic function was assessed in 12 patients after total correction of tetralogy of Fallot (age range 5 to 18 years, mean 10) and compared with 10 control patients. Only 1 patient had a shunt before total correction that was performed at a mean age of 3.5 years, (range 0.3 to 8). At cardiac catheterization the following indexed LV parameters were measured: end-diastolic and end-systolic volumes, wall mass, ejection fraction, stroke volume and end-diastolic and end-systolic pressures and stresses. The rate-corrected mean velocity of fiber shortening was calculated. LV diastolic operant chamber stiffness and myocardial stiffness were calculated from simultaneous diastolic pressures and volumes in mid- and late diastole using monoexponential formulas. The 2 groups were compared by unpaired t tests. The tetralogy group had higher mean end-diastolic (93 vs 74 ml/m2), end-systolic (29 vs 19 ml/m2) and stroke (64 vs 55 ml/m2) volumes than controls. Rate-corrected mean velocity of fiber shortening was lower in the tetralogy group (1.07 vs 1.24). Myocardial stiffness was higher in the tetralogy group (16 vs 11). Other indexes were not significantly different. Thus, LV function after total correction of tetralogy of Fallot may be abnormal with larger than normal LV size, decreased contractile function and increased myocardial stiffness.     

Right and left ventricular systolic function late after repair of tetralogy of Fallot

Right ventricular (RV) dysfunction has adverse effects on long-term outcome in patients with repaired tetralogy of Fallot (TOF). We employed serial radionuclide angiography (RNA) to examine RV and left ventricular (LV) systolic function in adults late after TOF repair and its relation to clinical outcome. We reviewed 10-year records of 95 patients (53 men) with TOF followed in our clinic (mean age at repair 12.6 ± 10.5 years, mean age at last follow-up 37.7 ± 9.8 years) who underwent at least 2 RNAs between 1987 and 1997. Most patients were well by the end of the study (80% were New York Heart Association class I, 17% were class II, and 3% were in class III). Sixteen patients experienced sustained tachyarrhythmias (8 had atrial; 8 patients had ventricular). One patient died suddenly. Fifteen patients underwent RV outflow reoperations (15 underwent pulmonary valve replacement; 7 had relief of RV outflow obstruction); RV systolic function during exercise in these 15 patients was significantly impaired before and returned to similar levels after surgery, compared with the rest of the patients. Overall, RV and LV function remained stable in the whole group at a mean interval of 5.7 ± 2.2 years between first and last RNA. This group of closely followed adults with TOF remained well over 10 years with a low incidence of sudden death and stable RV and LV systolic function, despite a relatively large number of RV outflow reoperations. Aggressive intervention for right-sided hemodynamic abnormalities may have contributed to this outcome. Preserved ventricular function may herald a favorable long-term outlook in this group.     

Successful ablation of ventricular tachycardia after correction of tetralogy of Fallot

We present a case of a patient who, after correction of tetralogy of Fallot (TOF), experienced runs of ventricular tachycardia (VT). Mapping of the aortic root showed that the critical component of the reentry was located within the noncoronary cusp. The potential explanations of such an unusual isthmus location may be the presence of myocardial extensions in the aortic root or the close vicinity of the right ventricle (RV) to the noncoronary cusp, since in TOF the aorta overrides the RV. Our case highlights the advantage of using electroanatomic mapping systems together with intracardiac echocardiography in such complex cases.     

Radionuclide assessment of right and left ventricular exercise reserve after total correction of tetralogy of Fallot

First pass radionuclide angiocardiography under conditions of rest and exercise was utilized to evaluate a group of 16 postoperative patients who had undergone total surgical correction of tetralogy of Fallot. Functional data were related to thallium-201 myocardial imaging at rest, a noninvasive means of detecting right ventricular hypertrophy. All 16 patients were asymptomatic and 15 demonstrated normal right ventricular ejection fraction (equal to or greater than 45 percent) at rest. However, 13 patients manifested abnormal right ventricular ejection fraction responses to exercise (normal response is an absolute increment in an ejection fraction of 5 or greater percent). For the entire group, right ventricular ejection fraction at rest was 55 ± 2 percent, whereas at exercise it was 52 ± 2 percent (p = not significant). In contrast, left ventricular ejection fraction responses were normal in all patients. Thallium-201 imaging revealed substantial right ventricular uptake consistent with residual right ventricular hypertrophy, which was quantifiable in all patients. Thus, abnormalities in right ventricular performance during exercise may be detected readily by this radionuclide approach in these postoperative patients despite their asymptomatic clinical status and generally normal right ventricular performance at rest.     

Usefulness of left ventricular volume in assessing tetralogy of Fallot for total correction

Ninety-one patients with tetralogy of Fallot underwent intracardiac repair between 1978 and 1981. One patient died from left-sided heart failure. Retrospective analyses of this death revealed a significant decrease of the left ventricular (LV) end-diastolic volume index (EDVI) of 21 ml/m2 (36% of normal). Results of early postoperative hemodynamic studies after total correction of this anomaly suggested that an EDVI of 30 ml/m2 is the minimal requirement for adequate cardiac output postoperatively. Based on these data, 3 patients with decreased LV volume with EDVI of around 30 ml/m2 were challenged with the primary repair with success, although they required atrial pacing and catecholamine support postoperatively to maintain adequate left atrial pressure and cardiac output. From these results, it is recommended that patients with tetralogy of Fallot and an EDVI of 30 ml/m2 or more can be considered as candidates for the primary repair, but that patients with an EDVI of less than 30 ml/m2 should be palliated once by systemic-to-pulmonary arterial shunt procedures. Subsequent total correction should be performed after sufficient LV growth for those patients.     

Sustained ventricular tachycardia 7 years after complete correction of tetralogy of Fallot

The authors report a case of sustained ventricular tachycardia which occurred seven years after complete surgical correction of Fallot's tetralogy in a 13 year old girl. This arrhythmia was well tolerated haemodynamically, showed right-sided delay and was associated with mitral valve prolapse. After reviewing the literature, several physiopathological mechanisms are discussed: --the role of residual intraventricular conduction defects in sustaining the tachycardia; --the role of the ventriculotomy scar or of other associated lesions (mitral valve prolapse in this case) in the genesis of ventricular extrasystoles; --the postoperative haemodynamic status in the tolerance of the arrhythmias. This is a rare complication with an incidence of less than 2% of survivors followed-up over long periods. There is a risk of sudden death in 38% of these patients with ventricular arrhythmias which justifies Holter monitoring and ECG stress testing for their detection.     

Cardiac function after radical correction of tetralogy of Fallot in infants

A total of 20 patients (mean age 8.9 months) were examined after total correction of Fallot's tetralogy, 9 of them underwent transannular plasty and 11, separate right ventricular outflow tract plasty. Two-dimensional and Doppler echocardiographies were used to measure cardiac index, end-diastolic and end-systolic volumes, ejection fraction of the left and right ventricles, regurgitation fraction on the pulmonary and tricuspid valves, right ventricular-pulmonary artery pressure gradient. The study of the immediate postoperative period indicated that the pattern of its course was affected by the type of right ventricular outflow tract plasty, however, its function (ejection fraction) remained diminished in the periods up to 12 months of the operation. Pulmonary valve regurgitation was found to be one of the factors contributing to its diminution.     

Age-related changes in right and left ventricular function in tetralogy of Fallot

Age-related changes in right (RV) and left (LV) ventricular myocardium in tetralogy of Fallot (TF) are analyzed with regard to pre- and postoperative ventricular function. In RV, preoperative function was better in patients under 4 years of age in terms of ejection fraction and compliance, but no significant change was seen in LV function. Postoperatively, patients who underwent corrective surgery at age less than 4 years showed no significant difference compared to those at operative age above 4 years in terms of RV and LV functions at rest. However, stress tests for RV by isoproterenol and LV using methoxamine revealed some masked ventricular dysfunction in both ventricles in the older groups. The relationships between these functional abnormalities and previously described histological changes of right and left ventricular myocardium in TF are discussed.     

Reoperations after surgical correction of tetralogy of Fallot

Between 1970 and 1981, 40 patients (6%) were reoperated after surgical correction of Fallot's tetralogy. The average age of these patients was 7,5 years (range 2 months to 37 years). The usual anatomical form was present in 30 cases and severe forms accounted for the other 10 cases (pulmonary atresia with septal defect were excluded). The 40 patients were divided into 3 groups according to the anatomical lesions corrected at reoperation: Group I: 16 patients with a residual isolated VSD; Group II: 14 patients with one or two residual right heart anomalies (RRHA) but without a septal defect; Group III: 10 patients with a residual VSD and RRHA. The only clinical difference between the patients of these 3 groups was the delay of onset of symptoms: the patients with residual VSD (Groups I and III) often developed cardiac failure immediately, whilst in those without residual VSD (Group II) cardiac failure was usually observed secondarily. Four patients (10%) died early after reoperation (less than 1 month). Three others died later, two during a third operation. The total mortality was similar in the three groups. The surgical result was assessed clinically after an average follow-up of 4,5 +/- 3 years: patients with a residual isolated VSD (Group I) had the best long-term results. In 12 patients, M mode and 2D echocardiography showed normal left ventricular function but the ratio of end diastolic right ventricular and left ventricular dimensions was increased to an average of 0,72 +/- 0,2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development of left ventricular muscle in tetralogy of Fallot

Age-related changes of the muscle fiber diameter of the left ventricle were studied in 20 autopsied specimens of tetralogy of Fallot (TOF) and in 34 normal autopsied hearts. According to the amount of pulmonary blood flow, two groups were defined: In Group 1, TOF with a markedly decreased pulmonary blood flow. In Group 2, TOF with a moderately decreased pulmonary blood flow. In Group 1, the muscle fiber diameter was nearly normal at birth, but increased slightly and remained constant after one year, so that it was significantly less than normal. Moreover, histological observation revealed underdevelopment of the left ventricular muscle fibers in this group. In Group 2, the diameter increased with age in a manner similar to normal and, histologically, the muscle fibers were not different from normal ones except for those in one heart with left ventricular hypertrophy. The growth of muscle fibers in the left ventricle seems to depend on the volume of pulmonary blood flow, or the left ventricular inflow volume. If the left ventricular functional capacity correlates with the growth of muscle fibers, left ventricular dysfunction after the corrective operation may originate in the underdevelopment of muscle fibers. Surgical intervention is advisable before the retardation of muscle fiber growth has become apparent.     

Echocardiographic study of right and left ventricular dimension and left ventricular function in patients with tetralogy of Fallot before and after surgery.

Right and left ventricular dimensions and function were determined by one-dimensional echocardiography in patients with tetralogy of Fallot before and after corrective surgery. Thirty-five children (mean age: 5.9 years) were examined; 5 of them died immediately after operation; 5 had palliative operations only. The remaining 25 had repeat echocardiography 2 to 4 and/or 8 weeks after total correction. Compared with normal values, preoperative left ventricular dimensions were smaller than expected for body surface area (mean = 85.4% +/- 1.9 SEM, range 65 to 105% of normal); 21 values were below the 5th centile. Postoperatively, left ventricular dimensions increased significantly and reached normal values in most cases (mean = 103.2 +/- 2.0% SEM, range 81 to 121%). The main increase took place in the first 4 weeks (P less than 0.001; mean difference 0.7 +/- 0.14 cm). The 5 children who died after operation had smaller left ventricular dimensions than the survivors (P less than 0.01). Left ventricular function was evaluated by measuring mean circumferential fibre shortening, per cent shortening, and ejection fraction; they were normal in most patients and diminished only insignificantly after corrective surgery. Right ventricular dimensions were increased preoperatively but decreased significantly (P less than 0.001) postoperatively. Septal movement was normal in direction and excessive in displacement in most patients before operation; immediately after operation it became flat or showed paradoxical motion. Two months after operation 50 per cent of the children showed a return to normal septal movement. Early appearance of normal septal movement could be related to the presence of significant pulmonary stenosis. It is concluded that a high percentage of patients with tetralogy of Fallot have underdeveloped but normally functioning left ventricles which adapt well to the new postoperative state.     

Echocardiographic study of right and left ventricular dimension and left ventricular function in patients with tetralogy of Fallot before and after surgery.

Right and left ventricular dimensions and function were determined by one-dimensional echocardiography in patients with tetralogy of Fallot before and after corrective surgery. Thirty-five children (mean age: 5.9 years) were examined; 5 of them died immediately after operation; 5 had palliative operations only. The remaining 25 had repeat echocardiography 2 to 4 and/or 8 weeks after total correction. Compared with normal values, preoperative left ventricular dimensions were smaller than expected for body surface area (mean = 85.4% +/- 1.9 SEM, range 65 to 105% of normal); 21 values were below the 5th centile. Postoperatively, left ventricular dimensions increased significantly and reached normal values in most cases (mean = 103.2 +/- 2.0% SEM, range 81 to 121%). The main increase took place in the first 4 weeks (P less than 0.001; mean difference 0.7 +/- 0.14 cm). The 5 children who died after operation had smaller left ventricular dimensions than the survivors (P less than 0.01). Left ventricular function was evaluated by measuring mean circumferential fibre shortening, per cent shortening, and ejection fraction; they were normal in most patients and diminished only insignificantly after corrective surgery. Right ventricular dimensions were increased preoperatively but decreased significantly (P less than 0.001) postoperatively. Septal movement was normal in direction and excessive in displacement in most patients before operation; immediately after operation it became flat or showed paradoxical motion. Two months after operation 50 per cent of the children showed a return to normal septal movement. Early appearance of normal septal movement could be related to the presence of significant pulmonary stenosis. It is concluded that a high percentage of patients with tetralogy of Fallot have underdeveloped but normally functioning left ventricles which adapt well to the new postoperative state.     

Hemodynamic studies after total correction of tetralogy of Fallot

Twenty patients were studied by right heart catheterization 5 to 23 months after complete surgical correction of tetralogy of Fallot. The ventricular septal defects had been closed with a polyvinyl sponge and a Teflon prosthesis had been used to widen the right ventricular outflow tract in each case.

Residual systolic gradients between the right ventricle and pulmonary artery were small. Fifteen patients had gradients of 15 mm. or less, and the highest found was 34 mm. Arterial oxygen saturation was normal at rest or with exercise, or both, in nearly all cases. Two patients had definite evidence of a persistent ventricular septal defect with a left-to-right shunt.

Pulmonic regurgitation was present in 13 patients. Despite elevated right ventricular end diastolic and right atrial pressures in some patients, clinical evidence of heart failure was absent in all at the time of catheterization.

A comparison was made of the right ventricular and pulmonary arterial pressure measurements obtained in the operating room upon completion of the cardiac repair with those made at catheterization. It was found that pressure measurements at surgery give a reliable indication of the effectiveness of relief of the right ventricular outflow stenosis.

The operation employed in these patients has relieved the physiologic abnormalities of tetralogy of Fallot. Pulmonic regurgitation is present in many of the patients but is tolerated well at present. The long-term effects of this new abnormality will become clear only after extended observation.     

Radical correction of tetralogy of Fallot after palliative operations

The experience in radical correction of tetralogy of Fallot in 120 patients after various palliative operations is generalized. Twenty-five patients (20.8%) died. From comparative evaluation of the different preceding operations, preference cannot be given to any of the anastomoses. From the standpoint of the subsequent radical correction, Potts' anastomosis is the most disadvantageous palliative intervention.