Regional wall motion and abnormalities of electrical depolarization and repolarization in patients after surgical repair of tetralogy of Fallot

Biventricular stimulation improves right and left ventricular function after tetralogy of Fallot repair: acute animal and clinical studies

BACKGROUND

Optimal treatment of right ventricular (RV) dysfunction observed in patients after tetralogy of Fallot (TOF) repair is unclear. Studies of biventricular (BiV) stimulation in patients with congenital heart disease have been retrospective or have included patients with heterogeneous disorders.

OBJECTIVE

The purpose of this study was to determine the effects on cardiac function of stimulating at various cardiac sites in an animal model of RV dysfunction and dyssynchrony and in eight symptomatic adults with repaired TOF.

METHODS

Pulmonary stenosis and regurgitation as well as RV scars were induced in 15 piglets to mimic repaired TOF. The hemodynamic effects of various configurations of RV and BiV stimulation were compared with sinus rhythm (SR) 4 months after surgery. In eight adults with repaired TOF, RV and left ventricular (LV) dP/dt(max) were measured invasively during SR, apical RV stimulation, and BiV stimulation.

RESULTS

At 4 months, RV dilation, dysfunction, and dyssynchrony were present in all piglets. RV stimulation caused a decrease in LV function but no change in RV function. In contrast, BiV stimulation significantly improved LV and RV function (P < .05). Echocardiography and epicardial electrical mapping showed activation consistent with right bundle branch block during SR and marked resynchronization during BiV stimulation. In patients with repaired TOF, BiV stimulation increased significantly RV and LV dP/dt(max) (P < .05).

CONCLUSION

In this swine model of RV dysfunction and in adults with repaired TOF, BiV stimulation significantly improved RV and LV function by alleviating electromechanical dyssynchrony.

[Surgical management of congenital heart defects in adolescent and adult patients, between years 2001-2008]

The leading interventions due to congenital heart defects performed in adults are: (I) reconstructive operations, including: (a) newly diagnosed malformations, (b) previously adjudged to be inoperable defects, (c) so called "tardive" interventions due to pulmonary hypertension or right ventricle insufficiency. There is a growing number of (II) REDO operations, including: (a) correction of residual defects, (b) replacement of damaged or outgrown homografts, (c) recoarctation (aneurysm, dissection) of the aorta after surgical or catheter interventions, (d) Ross procedure, valve replacements due to previously performed aortic valvulotomy/valvuloplasty or corrections of different malformations (e.g. TGA).

PATIENTS AND RESULTS

166 of all 4496 operations were performed in adolescents and adults (age: 16-52 years, mean: 28 years) between years 2001-2008. The distribution of these interventions: Ia: 77, Ib: 15, Ic: 4, IIa: 11, IIb: 22, IIc: 9, IId: 28. Mortality rates were the following: 0 intraoperative, 4 early postoperative, 1 pulmonary hypertensive crisis, 1 malignant rhythm disturbances, 2 multi-organ failure.

CONCLUSIONS

The main risk factors are pulmonary hypertension and right ventricle failure. Complex surgical solutions do not mean extreme problems for a congenital cardiac surgeon, but earlier diagnosis and the use of ECMO during therapy may improve the results.

Tissue velocities, strain, and strain rate for echocardiographic assessment of ventricular function in congenital heart disease

During the last decade tissue Doppler and myocardial deformation imaging has been introduced to quantify myocardial function in patients with congenital heart disease. These methods could have potential benefits for patients where the anatomy makes it difficult to quantify ventricular function using M-mode or two-dimensional volumetric techniques. In this overview, the potential benefits as well as limitations of the techniques are discussed. Looking directly into the myocardium renders the techniques geometry-independent, allowing the quantification of right ventricular as well as univentricular systolic function. The limitations include the influence of variable loading conditions as well as different methodological problems.

Changes during exercise of ECG intervals related to increased risk for ventricular arrhythmia in repaired tetralogy of Fallot and their relationship to right ventricular size and function

PURPOSE

Our study aimed to assess pro-arrhythmogenic electrocardiographic changes during maximal physical exercise in patients operated for Tetralogy of Fallot (TOF).

METHODS

TOF patients prospectively underwent: 1) bicycle ergometry, 2) cardiac MRI, and 3) 24-hour Holter. ECG data was analyzed at rest, at 60% of peak exercise and at peak exercise. R-R duration, QRS-, QT- and JT-duration and dispersions were assessed. Changes of ECG parameters during exercise were calculated and correlated to RV volume, RVEF, RV wall-mass, PR-percentage and VO(2max). Exercise ECG data from healthy controls were used as reference.

RESULTS

Thirty-one patients (mean age at repair (SD) 0.8 (0.5) years, age at study 16 (5) years) and 25 controls (age 12 (2) years) were included. With exercise mean QTc and JTc dispersions increased in patients (p<0.001), but not in controls. At peak exercise JTc dispersion was larger in patients (p<0.01). QTc did not change with exercise in patients (p=0.14) and decreased in controls (p<0.05). At all levels of exercise mean QTc, QRS and QRS dispersion were larger in patients (all p<0.001). Significant associations were found for; 1) a larger increase of JTc dispersion with a higher PR-percentage, a larger RV volume, a larger RV wall-mass, 2) a larger QTc increase with a larger RV volume and worse RVEF.

CONCLUSION

During physical exercise inhomogeneity of repolarisation, known to predispose for re-entry ventricular arrhythmia, increases in repaired TOF. Larger inhomogeneity is found with more severe PR.

Health-related quality of life and right ventricular function in the midterm follow-up assessment after tetralogy of fallot repair

BACKGROUND

Few data are available on quality of life after surgical repair of tetralogy of Fallot (ToF), and on its relationship to right ventricle function.

METHODS

Patients with at least 1 year of follow-up evaluation after surgery were studied. Right ventricle function was evaluated by the Doppler-derived myocardial performance index (MPI), and health-related quality of life (HRQL) was assessed by the Child Health Questionnaire, Parent Form-50. Findings were compared with those for an age- and sex-matched group of healthy children.

RESULTS

The study enrolled 35 successfully repaired ToF patients with 4.9 years (range, 3-7 years) of follow-up evaluation after surgery and 36 healthy children. The MPI demonstrated right ventricle dysfunction in patients compared with controls (0.34; range, 0.26-0.49 vs 0.2; range, 0.13-0.27; p < 0.01), although HRQL for the psychosocial domain was similar between patients and healthy children (summary score, 47.9; range, 45-52 vs 47.5; range, 44.5-50; p = 0.17). A trend for poorer physical area results was observed in patients (summary score, 44; range, 31-52 vs 48.5; range, 45.7-51.7; p = 0.06). Neither physical nor psychosocial summary scores for HRQL had any correlation with right ventricle MPI.

CONCLUSIONS

Right ventricle dysfunction is present in postoperative ToF patients. The psychosocial domain of HRQL is preserved after surgery. A trend for worse results was observed in the physical domain. The right ventricle function is not related to quality of life after surgical repair of ToF.

Abnormal Right Ventricular Tissue Velocities After Repair of Congenital Heart Disease—Implications for Late Outcomes

BACKGROUND

Although repair of Tetralogy of Fallot (TOF) and transposition of the great arteries (TGA) has facilitated survival into adulthood, many survivors have residual haemodynamic abnormalities, including exercise intolerance and late right ventricular (RV) failure.

METHODS

We studied 40 asymptomatic adult subjects (31.3+/-1.5 years) after congenital heart disease (CHD) surgery during childhood, using tissue Doppler echocardiography (TDE). We compared systolic (S') and diastolic (E' for early filling) RV and LV velocities, with 40 age matched controls (29.5+/-1.0 years).

RESULTS

Both RV S' and E' velocities were significantly slower in the CHD group compared to controls (6.3+/-0.4 cm/s vs. 9.3+/-0.3 cm/s; 8.5+/-0.5 cm/s vs. 10.9+/-0.4 cm/s, respectively, p<0.001 for both). By contrast, LV S' and E' velocities were similar in both groups. Interestingly, in 50% of CHD subjects where RV function was reported as 'normal', both RV S' and E' velocities were significantly slower compared with controls (6.5+/-0.6 cm/s vs. 9.3+/-0.3 cm/s, p<0.0001 and 9.4+/-0.7 cm/s vs. 10.9+/-0.4 cm/s, p<0.05 respectively).

CONCLUSIONS

RV S' and E' velocities are frequently abnormal in asymptomatic survivors of TOF and TGA repair, even where RV function appears 'normal'. Hence TDE during follow up may be a sensitive means of detecting pre-clinical abnormalities in RV performance.

Comparison of echocardiographic and cardiac magnetic resonance imaging for assessing right ventricular function in adults with repaired tetralogy of fallot

Adults with repaired tetralogy of Fallot and significant chronic pulmonary regurgitation are at risk for progressive right ventricular (RV) dilatation and dysfunction. The assessment of RV function is important in the management in these patients. There is still a lack of an adequate geometric model to quantify RV function by echocardiography. The myocardial performance index (MPI) is a nonvolumetric method to quantify global ventricular function. In this study, the accuracy of MPI obtained by echocardiography to quantify RV function was assessed in 57 adults with repaired tetralogy of Fallot. The MPI measurement was compared with the RV ejection fraction (EF) derived by cardiac magnetic resonance imaging. There was a negative linear correlation between the MPI and the RVEF (r = 0.73, p <0.001). A MPI cutoff of > or =0.40 had a sensitivity of 81% and a specificity of 85% to diagnose a RVEF <35%. A MPI cutoff of <0.25 had a sensitivity of 70% and a specificity of 89% to identify patients with RVEFs > or =0.50. In a multivariate regression model, the MPI was not affected by the degree of pulmonary regurgitation, the presence of tricuspid regurgitation, or the QRS duration. In conclusion, the Doppler-derived MPI is a simple and reliable method for the evaluation of RV systolic function in adults with repaired tetralogy of Fallot.

Ultrasonic strain rate and strain imaging of the right ventricle in children before and after percutaneous closure of an atrial septal defect

This study examined the influence of preload alterations on systolic right ventricular (RV) velocities and deformation indices in patients with atrial septal defect (ASD). A total of 21 patients with ASD underwent 2-dimensional echocardiography and color Doppler myocardial imaging scan before and 24 hours after transcatheter ASD closure. The data were compared with those obtained from 30 healthy age-matched children. Longitudinal peak systolic velocities, peak systolic strain rate (SR), and end-systolic strain (epsilon) were calculated in the midsegment of the RV free wall and the septum. In patients with ASD, higher RV peak systolic velocities were recorded, which returned to normal values after closure of the defect. In contrast, RV deformation indices in the patients with ASD were not different from normal values. These RV indices did not change significantly after ASD closure. We found a significantly decreased septal function after percutaneous ASD closure. This may be attributed to the device within the atrial septum, affecting deformation of the interventricular septum. In conclusion, RV longitudinal systolic deformation indices were not significantly influenced by chronic ventricular volume overload and sudden abolishment of this volume overload. These findings suggest that SR/epsilon are relatively load-stable measures of contractile function in the clinical setting. In contrast, myocardial velocities are clearly load dependent.

Doppler Tissue Imaging Evaluation of Right Ventricular Function at Rest and During Dobutamine Infusion in Patients After Repair of Tetralogy of Fallot

BACKGROUND

Reliable, non-invasive evaluation of right ventricular function, especially in congenital heart disease, is challenging.

OBJECTIVES

The aim of this study was to evaluate Doppler tissue imaging (DTI) parameters of lateral tricuspid annular motion, mean rate of pressure rise during RV contraction (mean dP/dt) and indexed right ventricular (RV) stroke volume (RVSVi) as RV function indices in repaired tetralogy of Fallot (TOF).

METHODS

DTI evaluation was performed in 25 repaired-TOF patients, aged 11+/-6, at rest and during dobutamine infusion and 20 controls at rest.

RESULTS

TOF patients had lower (P<0.05) peak systolic velocity (Sa) (11.4+/-4 vs. 13.7+/-3.1 cm/s), early diastolic velocity (Ea) (11+/-3.1 vs. 16.3+/-3.5 cm/s) and Sa/time from onset of QRS to Sa (Sa/Q-Sa) (68.8+/-26.4 vs. 92.3+/-29.4 cm/s2) versus controls. Dobutamine increased (P<0.01) Sa (11.4+/-2.8-17.7+/-4.7 cm/s), Ea (11+/-3.1-15.6+/-3.9 cm/s), late diastolic velocity (Aa) (8.4+/-2-14.8+/-5 cm/s), Sa/Q-Sa (68.8+/-26.4-17 6.8+/-84.5 cm/s2), mean dP/dt (180+/-74-537+/-37 2 mmHg/s), and RVSVi (7.8+/-3.9-11.9+/-5.6 L/min/m2). RVSVi increase correlated (P<0.01) with that in Sa (r=0.6), Ea (r=0.5), Sa/Q-Sa (r=0.71), and mean dP/dt (r=0.57) while mean dP/dt increase correlated strongly with Sa/Q-Sa increase (r=0.88).

CONCLUSION

DTI evaluation of tricuspid annular motion during dobutamine infusion in repaired TOF correlates with dP/dt and RV stroke volume and may help in assessing RV function and reserve.

Indications and timing of pulmonary valve replacement after tetralogy of Fallot repair

Surgical management of tetralogy of Fallot results in anatomic and functional abnormalities in the majority of patients. Although right ventricular volume load due to severe pulmonary regurgitation can be tolerated for years, there is now evidence that the compensatory mechanisms of the right ventricular myocardium ultimately fail and that if the volume load is not eliminated or reduced the dysfunction might be irreversible. In light of that data and with better understanding of risk factors for adverse outcomes late after tetralogy of Fallot repair, many centers are now recommending early pulmonary valve replacement before symptoms of heart failure develop. This article reviews the pathophysiology of chronic right ventricular volume load after tetralogy of Fallot repair and the risks and benefits of pulmonary valve replacement. Finally, recommendations for timing and indications for pulmonary valve replacement are given.

Physiopathology of right ventricular failure

The physiopathology of right ventricular failure after repair of tetralogy of Fallot is complex. While primarily reflecting chronic volume overload resulting from pulmonary regurgitation, its determinants reflect a varied contribution of different boundary conditions. The competence of the outflow tract, right ventricular afterload, and the integrity of right ventricular diastolic performance are all crucial elements to the long-term responses of the right ventricle. When adverse, chronic right ventricular volume overload may lead to exercise intolerance, congestive cardiac failure, and both atrial and ventricular arrhythmia. Indeed, there appears to be a close relationship between the mechanical properties of the right ventricle and its electrical stability. In this chapter the determinants of pulmonary incompetence and its secondary effects on right ventricular function and performance, and mechano-electric interactions will be discussed.

Report of the National Heart, Lung, and Blood Institute Working Group on Research in Adult Congenital Heart Disease

The Working Group on research in adult congenital heart disease (ACHD) was convened in September 2004 under the sponsorship of National Heart, Lung, and Blood Institute (NHLBI) and the Office of Rare Diseases, National Institutes of Health, Department of Health and Human Services, to make recommendations on research needs. The purpose of the Working Group was to advise the NHLBI on the current state of the science in ACHD and barriers to optimal clinical care, and to make specific recommendations for overcoming those barriers. The members of the Working Group were chosen to provide expert input on a broad range of research issues from both scientific and lay perspectives. The Working Group reviewed data on the epidemiology of ACHD, long-term outcomes of complex cardiovascular malformations, issues in assessing morphology and function with current imaging techniques, surgical and catheter-based interventions, management of related conditions including pregnancy and arrhythmias, quality of life, and informatics. After research and training barriers were discussed, the Working Group recommended outreach and educational programs for adults with congenital heart disease, a network of specialized adult congenital heart disease regional centers, technology development to support advances in imaging and modeling of abnormal structure and function, and a consensus on appropriate training for physicians to provide care for adults with congenital heart disease.

Cardiac resynchronization therapy for adult congenital heart disease patients with a systemic right ventricle: analysis of feasibility and review of early experience

AIMS

Patients with a systemic right ventricle (RV) frequently develop heart failure and may benefit from cardiac resynchronization therapy (CRT). We aimed to assess the proportion of unselected patients with a systemic RV eligible for CRT and to review available data on the effect of CRT in congenital heart disease patients.

METHODS AND RESULTS

Adhering to criteria derived from landmark CRT trials, we determined the eligibility of patients with a systemic RV for CRT. Seventy-five transposition of the great arteries (TGA) patients (age 29.5+/-10.2 years) and 49 patients with congenitally corrected (cc) TGA (age 36.2+/-12.8 years) were studied. Full criteria for CRT were met in 4.0% of the TGA patients and 4.1% of the ccTGA patients. Including New York Heart Association class 2 patients, 9.3% of TGA and 6.1% of ccTGA patients were eligible for CRT.

CONCLUSION

Four to 9% of unselected patients with a systemic RV appear to be potential candidates for CRT. Although large clinical studies are currently lacking, available data consistently demonstrate that CRT improves haemodynamics in congenital heart disease patients and warrants further investigation.

Usefulness of exercise-induced changes in plasma levels of brain natriuretic peptide in predicting right ventricular contractile reserve after repair of tetralogy of Fallot

Elevated levels of brain natriuretic peptide (BNP) have been associated with ventricular dysfunction, and exercise tests have been used for assessing cardiac contractile reserve. We examined the relation between BNP and right ventricular (RV) contractile reserve during exercise in patients after repair of tetralogy of Fallot (TOF). A total of 45 patients, 26 of whom underwent repair of TOF at 2 to 3 years of age and 19 age-matched healthy children, were studied. Plasma levels of BNP were measured at baseline and at maximal exercise. Echocardiography combined with tissue Doppler imaging (TDI) was performed at rest and during supine bicycle submaximal exercise. The peak value of the first derivation of RV pressure (peak dP/dt) was measured by the continuous-wave Doppler method. The severity of pulmonary regurgitation (PR) (mild, moderate, or severe) was based on color Doppler findings. Plasma BNP levels were significantly higher in patients with TOF than in controls (44 +/- 34 vs 6 +/- 4 pg/ml, p <0.01). Exercise was associated with increased plasma BNP levels in both groups. A larger increment in BNP was noted in patients with TOF than in normal subjects (15 +/- 12 vs 2 +/- 2 pg/ml, p <0.01). The peak systolic myocardial velocity (Sa) and peak dP/dt values increased significantly in both groups during exercise; however, the magnitude of increase in both of these values was significantly less in patients with TOF than in controls (36 +/- 19% vs 70 +/- 19% and 42 +/- 11% vs 81 +/- 12%, respectively; p <0.01). There were significant correlations between the increment in BNP and changes in Sa and peak dP/dt values (r = -0.67 and -0.53, p <0.01, respectively), and the severity of PR (r = 0.74, p <0.01). Thus, exercise increases plasma levels of BNP, and greater increases are associated with impaired RV contractile reserve in patients with TOF with various degrees of PR.

Late Complications of Repair of Tetralogy of Fallot and Indications for Pulmonary Valve Replacement

With increasing follow-up of patients after surgical repair of tetralogy of Fallot, the long-term complications of chronic pulmonary regurgitation (PR), ventricular dilation, electrical inhomogeneity and myocardial scarring are becoming apparent. In this article we review the existing literature regarding the deleterious effects of chronic PR in these patients and the current data regarding the timing and mode of intervention.

The relationship between blood pressure, pulse pressure and right ventricular function following an atrial switch procedure for complete transposition of the great arteries

BACKGROUND

The pressure overload may be responsible for the failure of the systemic ventricle. No study so far has evaluated the association between arterial blood pressure values and right ventricular function in adults with atrially corrected complete transposition.

METHODS

This was a retrospective analysis. The studied population consisted of 60 patients with complete transposition, 11.5+/-2.7 years after atrial switch procedure, divided into subgroups according to the severity of systemic ventricular dysfunction (right ventricular ejection fraction < or = 0.40 vs. > 0.40), and the severity of perfusion abnormalities in the radionuclide study (absent or mild vs. moderate-to-severe).

RESULTS

All patients had blood pressure values (systolic 109.1+/-11.7 mm Hg and diastolic 72.3+/-9.7 mm Hg) within the normal range. Systolic blood pressure values correlated inversely with right ventricular ejection fraction (r = -0.450; p < 0.001). Compared to patients with systolic blood pressure below median values, patients with "elevated" blood pressure had lower right ventricular ejection fraction (32.6+/-6.3 vs. 38.9.+/-7.2; p < or = 0.002) and more significant perfusion abnormalities (1.5+/-1.0 vs. 2.9+/-1.5; p < or = 0.001). In a multivariate backward logistic regression model age at surgery and at the time of the study, systolic blood pressure at rest predicted impaired right ventricular ejection fraction (p < 0.02). Greater pulse pressure at peak exercise female sex were associated with greater more severe perfusion abnormalities (p < 0.01).

CONCLUSIONS

There is a significant correlation between blood pressure values and indices of right ventricular dysfunction in patients who underwent an atrial switch procedure for complete transposition. Blood pressure values might be considered as a surrogate end point in these patients.

Quantitative analysis of right atrial performance after surgical repair of tetralogy of Fallot

We aimed to assess the right atrial performance in patients after surgical correction of tetralogy of Fallot, and to clarify the relationship between the pump function of the right atrium and right ventricular systolic function. We included in the study 50 asymptomatic patients following corrective surgery of tetralogy of Fallot, comparing them to 30 normal subjects. Right atrial areas were measured by echocardiography, and the active fractional area of emptying was expressed, in percentages, as the area measured at the onset of atrial contraction, minus the minimal area, divided by the area at the onset of atrial contraction. We used this value to assess the atrial pump function. Right atrial peak strain rates were measured by tissue Doppler imaging. Compared to controls, patients with tetralogy of Fallot had a significantly reduced right atrial active fractional area of emptying (p = 0.005), along with a reduced peak late diastolic strain rate (p = 0.002). Among 20 patients who underwent magnetic resonance tomographic examination, a relatively higher right atrial peak late diastolic strain rate was shown in patients with a right ventricular ejection fraction of less than 50% (p = 0.021). Right atrial performance is reduced in patients after surgical correction of tetralogy of Fallot. When facing right ventricular systolic dysfunction, nonetheless, the right atrial pump function may be relatively enhanced. Tissue Doppler derived strain rate can provide quantitative analysis of regional right atrial performance.

Assessment of right ventricular function during exercise with quantitative Doppler tissue imaging in children late after repair of tetralogy of Fallot

Doppler tissue imaging (DTI) has been developed to assess ventricular wall-motion velocity quantitatively for patients with various types of heart disease. This technique has a possibility of assessing right ventricular (RV) function reserve during exercise. To investigate RV function during exercise using DTI, 21 patients (9.3 +/- 3.3 years) who had undergone operation for tetralogy of Fallot at 1 to 3 years of age and 19 age-matched healthy children were studied. Echocardiography combined with DTI was performed at rest and during supine bicycle submaximal exercise. DTI of tricuspid annulus movement during systole (Sa) was obtained from a 4-chamber view. RV pressure was estimated by maximal tricuspid regurgitation (TR) velocity. The peak value of the first derivation of RV pressure (peak dP/dt) was measured from the continuous wave Doppler-derived TR profile. Adequate spectral Doppler recordings of TR were obtained in all participants. However, 9 healthy children and 2 patients with tetralogy of Fallot were excluded from the study because of an inability to determine the entire spectral TR velocity envelope during exercise. Therefore, data were analyzed in 29 participants. At rest, the mean RV pressure for patients was higher than that in control subjects (27 +/- 4 vs 18 +/- 3 mm Hg, P <.01). The mean Sa and RV peak dP/dt for patients were lower than those in control subjects (6.7 +/- 1.6 vs 8.8 +/- 1.7 cm/s and 464 +/- 77 vs 550 +/- 80 mm Hg/s, P <.01, respectively). Sa and RV peak dP/dt in the two groups increased significantly during exercise. However, the magnitude of increases in Sa and peak dP/dt was significantly less for patients than in control subjects (37 +/- 16 vs 66 +/- 19% and 42 +/- 10 vs 80 +/- 13%, P <.01, respectively). The magnitude of increase in Sa correlated with that in RV peak dP/dt (r = 0.84, P <.01). Results of DTI show high correlation with RV peak dP/dt during exercise. This technique has a potential as a useful indicator of the effect of exercise on RV systolic function. An insufficient increase in Sa suggests impaired response to exercise of RV in patients with tetralogy of Fallot.

Myocardial acceleration during isovolumic contraction as a new index of right ventricular contractile function and its relation to pulmonary regurgitation in patients after repair of tetralogy of Fallot

BACKGROUND

Myocardial acceleration during isovolumic contraction (IVA) by Doppler tissue imaging has been proposed to be a new index of right ventricular contractile function that is unaffected by ventricular shape or loading conditions.

OBJECTIVES

We sought to assess the use of IVA to evaluate right ventricular contractile function.

METHODS

In all, 22 pediatric patients with pulmonary regurgitation (PR) after repair of tetralogy of Fallot (TOF) (8 +/- 3 years) and 27 age-matched children were examined. The degree of PR (mild, moderate, and severe) for patients with TOF was on the basis of pulsed and color Doppler findings. Using Doppler tissue imaging, the peak myocardial velocities during early diastole, late diastole, systole, and isovolumic contraction were recorded.

RESULTS

Compared with healthy children, Doppler tissue imaging velocities for patients with TOF showed decreased myocardial velocities during early diastole (P =.007), late diastole (P <.0001), systole (P <.0001), and isovolumic contraction (P <.0001). Patients with TOF had a lower IVA when compared with healthy children (P <.0001). There was a stepwise decrease in the IVA from mild to severe PR. We found a significant relationship between the IVA and the degree of PR (r = -0.86, P <.0001).

CONCLUSION

The analysis of IVA allows the assessment of right ventricular contractile function for patients with repaired TOF and various degrees of PR.

Right ventricular strain rate and strain analysis in patients with repaired tetralogy of Fallot: possible interventricular septal compensation

BACKGROUND

Indices such as strain rate (SR) and strain (epsilon) are free of geometric assumptions and, thus, may provide new insights into right ventricular (RV) function and compensatory mechanisms in repaired tetralogy of Fallot (TOF).

METHODS

All those with postoperative (>1 year) TOF had echocardiography evaluation of SR and epsilon indices along the RV lateral free wall (RVFW) and the interventricular septum (IVS) in the apical 4-chamber view. Pulmonary regurgitation, pulmonary stenosis, QRS duration, RV ejection fraction, and RV dimension were also measured and compared with control subjects.

RESULTS

There were 15 patients with TOF (7 +/- 4 years old) 6 +/- 3 years remote from surgical repair and 25 control subjects (10 +/- 5 years old). In the patients with TOF, systolic and diastolic SR and epsilon in the RVFW were significantly reduced but were normal in the IVS. In the RVFW, reduced systolic SR and epsilon correlated with reduced RV ejection fraction (r = -0.7 [P <.01] and -0.6 [P <.03], respectively), and poorer early diastolic SR correlated with poorer RV ejection fraction (r = 0.7, P <.01).

CONCLUSIONS

In patients with postoperative TOF, systolic and diastolic RV SR and epsilon were impaired in the RVFW but preserved in the IVS. We speculate that IVS myocardial function is preserved as a compensatory mechanism for impaired RVFW function.

Right ventricular myocardial dysfunction in adult patients late after repair of tetralogy of fallot

AIM OF THE STUDY

To detect in adult patients late after repair of Tetralogy of Fallot (TOF) possible correlation between myocardial parameters assessed at rest by Tissue Doppler (TD) and cardiac performance during physical effort.

METHODS

Doppler echo, treadmill test and pulsed TD of both mitral and tricuspid annulus were performed in 25 healthy subjects and in 40 adult patients who had undergone surgery for TOF at a mean age of 1.4+/-0.5 years. Exclusion criteria were echocardiographic evidence of residual pulmonary, either stenosis or regurgitation. By use of TD, the following parameters were assessed: systolic peak velocities (Sm), pre-contraction time, contraction time, early (E(m)) and late (A(m)) diastolic velocities, E(m)/A(m) ratio, relaxation time. By treadmill test, we measured: maximal heart rate (HR), systolic blood pressure (SBP), rate-pressure product, maximal workload, time duration of the exercise.

RESULTS

the two groups were comparable for left ventricular measurements and for all transmitral and transtricuspid Doppler indexes, while tricuspid ring diameter was increased in TOF. TD analysis showed in TOF lower S(m), E(m) and E(m)/A(m) ratio and prolonged PCT(m) and Rt(m) at tricuspid annulus level, despite comparable TD mitral annulus indexes. By treadmill test, TOF showed reduced time of exercise, number of METS reached and rate-pressure product. Multiple linear regression models evidenced in TOF independent positive association between tricuspid Em velocity and time of exercise (p<0.0001), achieved METS at peak effort (p<0.001) and rate-pressure product (p<0.001). An E(m) peak velocity of tricuspid annulus lower than 0.13 m/s showed 90% sensitivity and 93% specificity in identifying TOF patients unable to perform maximal exercise test.

CONCLUSIONS

despite normal Doppler parameters, adult patients late after correction of TOF showed impaired right ventricular myocardial function. In these patients pulsed TD may be taken into account as a valuable supporting tool to predict the effort response and possibly to assess long-term follow-up of cardiac functional reserve.

Predicting late sudden death from ventricular arrhythmia in adults following surgical repair of tetralogy of Fallot

Tetralogy of Fallot was the first complex congenital cardiac defect to undergo open repair. The life expectancy and quality of life of those surviving surgery is now good, although late survival is compromised by the occurrence of sudden death. The emergence of successful methods for both the prevention of arrhythmias (including valve replacements and electrophysiological ablation) and the treatment of arrhythmias when they occur (including implantable defibrillators), has meant the identification of those at risk is of even greater importance. This paper reviews the predictive methods currently available to the practising physician caring for these increasingly common patients.

Systemic ventricular function in patients with transposition of the great arteries after atrial repair: a tissue Doppler and conductance catheter study

OBJECTIVES

The aim of this study was to assess the utility of tissue Doppler echocardiography in the setting of repaired transposition of the great arteries when the right ventricle (RV) functions as the systemic ventricle.

BACKGROUND

Myocardial acceleration during isovolumic contraction, "isovolumic myocardial acceleration" (IVA), has been validated as a sensitive non-invasive method of assessing RV contractility. Although traditional indexes may be less valid for the abnormal RV, the relative insensitivity of IVA to an abnormal load makes it a potentially powerful clinical tool for the assessment of RV disease.

METHODS

We examined 55 controls and 80 patients (mean age 22 years) with transposition, who had undergone atrial repair at age 8 (0.3 to 72) months. A subgroup of 12 underwent cardiac catheterization. The RV systolic function was derived by analysis of pressure-volume relationships and IVA both at rest and during dobutamine stress. In all 80, myocardial velocities were sampled in the RV free wall.

RESULTS

During dobutamine (10 microg/kg/min for 10 min), the increase of IVA mirrored the increase in end-systolic elastance (r = 0.69, p < 0.02). In the group as a whole, IVA was reduced compared with the subpulmonary RV and the systemic left ventricle of controls. There was abnormal wall motion in 44 patients, which was associated with reduced IVA. Diastolic myocardial velocities were also abnormal but unrelated to the presence of wall motion abnormalities.

CONCLUSIONS

The IVA can accurately assess changes in RV contractile function in patients with an RV as the systemic ventricle. Global long-axis RV function is reduced in patients with transposition, and this is associated with abnormal regional function.

Longitudinal strain quantitates regional right ventricular contractile function

The assessment of contractile function of the right ventricle (RV) is an important clinical issue, but this remains difficult because of its complex anatomy and structure. We thought to investigate whether new Doppler-derived myocardial deformation indexes may quantify regional contractile RV function during varying loading conditions. In nine pigs, ultrasonic crystals were inserted longitudinally in the RV inflow and outflow tracts to assess regional contractile function. The same RV segments and the interventricular septum were imaged using apical echocardiographic views. Regional function was assessed using two parameters: 1) systolic strain (SS), representing the relative magnitude of segmental systolic shortening; and 2) its temporal derivative, peak systolic strain rate (SR), i.e., the maximal velocity of segmental shortening. Data were acquired at baseline and during partial pulmonary artery constriction (PAC) and inferior vena cava occlusion (IVCO). SS decreased significantly after PAC and IVCO in both the inflow and outflow tracts but only during IVCO in the septum. SR was less sensitive to loading variations in all segments. A significant correlation was found between SS values derived from sonomicrometry and myocardial Doppler in RV segments (r = 0.84, P < 0.001). Thus regional strain and SR provide complementary information on the heterogeneous RV contractile function and can be accurately and noninvasively quantified using Doppler myocardial imaging.

Regional cardiac wall motion abnormalities during and shortly after anthracyclines therapy

BACKGROUND

Tissue Doppler imaging (TDI) is a new non-invasive ultrasound technique that enables quantitative assessment of regional myocardial wall motion. A previous study of survivors of childhood malignancies demonstrated abnormalities of regional diastolic wall motion abnormalities many years after treatment with anthracyclines. The purpose of the present study was to investigate this phenomenon during and shortly after treatment.

PROCEDURE

A total of 60 patients, age range 4.4-16.0 years, were included in this study: 43 early survivors, with a mean follow-up duration of 2.1 (range 0.3-5.2) years from end of anthracycline treatment, were evaluated retrospectively. Seventeen other patients were evaluated before, during, and 6 months after the end of anthracycline therapy. All patients received moderate cumulative doses of anthracyclines (range 120-450 mg/m2). Echocardiographic examination was performed using standardized conventional and TDI techniques.

RESULTS

Of the early survivors, 26 (60%) demonstrated regional LV free wall motion abnormalities. In the prospective group, serial echocardiographic studies revealed three patients (18%) with regional abnormalities of LV free wall motion before starting chemotherapy, but 14 (82%) at the end of treatment. Six months later, however, the incidence decreased to 61% of the survivors. Subject and treatment characteristics, as well as LV wall diameters and fractional shortening were not significantly different for children with or without free wall motion abnormalities. Regional wall motion abnormalities were also seen in the interventricular septum, although this was less frequent.

CONCLUSIONS

Regional diastolic wall motion abnormalities are common during and shortly after anthracyclines therapy but may be transient. The authors recommend simultaneous use of both conventional echocardiography & TDI for the monitoring of anthracycline-induced cardiotoxicity.

ECG predictors of ventricular arrhythmias and biventricular size and wall mass in tetralogy of Fallot with pulmonary regurgitation

BACKGROUND

In patients with the tetralogy of Fallot, QRS prolongation predicts malignant ventricular arrhythmias. QRS prolongation may result from right ventricular dilatation. The relation of ECG markers to biventricular wall mass and volumes has not been assessed.

OBJECTIVE

To investigate the relations of surface ECG markers of depolarisation and repolarisation to right and left ventricular volume and biventricular wall mass.

METHODS

37 Fallot patients (mean (SD) age 17 (9) years) were studied 14 (8) years after surgical repair; 34 had important pulmonary regurgitation. Left and right ventricular size was assessed from tomographic magnetic resonance imaging (MRI), and the amount of pulmonary regurgitation by velocity mapping MRI. QT, QRS, and JT duration and interlead dispersion markers were derived from a standard 12 lead ECG.

RESULTS

Mean QRS duration was significantly prolonged (133 (31) v 91 (11) ms in controls), as were dispersion of QRS (36 (17) v 20 (6) ms), QT interval (87 (48) v 42 (20) ms), and JT interval (93 (48) v 42 (19) ms). Biventricular volumes were increased (right ventricular end diastolic volume, 129 (41) v 70 (9) ml/m(2); left ventricular end diastolic volume, 83 (16) v 69 (10) ml/m(2)), as was right ventricular wall mass (24 (7) v 17 (2) g/m(2)). QRS duration correlated best with right ventricular mass (r = 0.55, p < 0.01).

CONCLUSIONS

In patients operated on for tetralogy of Fallot and with pulmonary regurgitation, ECG predictors of ventricular arrhythmias are influenced by several mechanical factors that may occur simultaneously. These include increased right ventricular volume, but also increases in left ventricular volume and in right and left ventricular wall mass.

Quantification of regional right and left ventricular function by ultrasonic strain rate and strain indexes after surgical repair of tetralogy of Fallot

The quantification of regional myocardial function in tetralogy of Fallot (TOF) by conventional M-mode and 2-dimensional echocardiography is difficult because of the complex right ventricular (RV) and altered left ventricular (LV) geometry. In 30 asymptomatic postoperative TOF patients (aged 4 to 16 years) with a low pressure in the right ventricle and with varying degrees of pulmonary regurgitation and in 30 aged-matched healthy children, the ultrasonic-derived regional deformation parameters peak systolic strain rate (SR) and systolic strain (epsilon) were acquired from ventricles and compared. In TOF RV free walls, SR, and epsilon were reduced in the basal, mid-, and apical segments and averaged -1.5 +/- 0.6 second(-1) for SR and -22 +/- 8% for epsilon, respectively (p <0.001 vs normals). Peak systolic SR of the basal RV free wall correlated significantly with the QRS duration of the electrocardiogram (r = 0.81, p <0.0001). Abnormalities in RV deformation were more marked in patients with transannular patches versus infundibular patches. In the septum there was a homogeneous reduction in SR and epsilon in the basal, mid-, and apical segments. These averaged -1.4 +/- 0.3 second(-1) for SR and -19 +/- 4% for epsilon, respectively (p <0.01 vs normals). Longitudinal SR and epsilon values of the 3 LV lateral wall segments (averaged SR = -1.6 +/- 0.4 second(-1), averaged epsilon = -20 +/- 5%; p <0.05 vs normals), and radial SR and epsilon of the LV posterior wall (SR = 3.3 +/- 0.9 second(-1); epsilon = 51 +/- 14%; p <0.05 vs normals) were significantly reduced. Thus, abnormalities in regional RV and LV systolic myocardial function in asymptomatic postoperative TOF patients were quantified by the deformation parameters SR and epsilon. RV deformation abnormalities are associated with electrical depolarization abnormalities.

Adrenergic nervous activity in patients after surgical correction of tetralogy of Fallot

OBJECTIVES

The study was done to define the role of the autonomic nervous system in postoperative tetralogy of Fallot.

BACKGROUND

Subsequent to surgical correction of tetralogy of Fallot, patients are at long-term risk of sudden death owing to ventricular electrical instability. The status of the sympathetic nervous system in these patients, known to play an important role in other patients at risk, remains unknown.

METHODS

We used (123)I metaiodobenzylguanidine (MIBG) with tomographic imaging, combined with assessment of heart rate variability (HRV), to evaluate the activity of the sympathetic nervous system. We analyzed 22 patients who had undergone total correction of tetralogy of Fallot: 13 with either no or minor ventricular arrhythmias, and 9 with sustained ventricular tachycardia or ventricular fibrillation.

RESULTS

Analysis of HRV revealed a reduction in vagal control and sympathetic dominance in all patients compared with a healthy control group of 20 subjects. A significant difference was found in the standard deviation of all the adjacent intervals between normal beats (SDNN) in patients with or without severe ventricular arrhythmias. A significant reduction in uptake of (123)I MIBG was demonstrated 30 min after IV injection, and a trend toward reduction after 5 h, associated with reduced washout indices. These data reflect a decrease in the number of nerve endings in the right and left ventricular walls, and an inhomogeneous distribution of the adrenergic nervous system. The uptake of MIBG was significantly reduced in the patients at risk of ventricular tachycardia or fibrillation.

CONCLUSIONS

Subsequent to surgical correction of tetralogy of Fallot, the positive correlation between myocardial uptake of MIBG, SDNN and the QRS dispersion confirmed the usefulness of analysis of the adrenergic nervous system to stratify patients at risk of life-threatening arrhythmias.