Agreement is poor among current criteria used to define response to cardiac resynchronization therapy.

BACKGROUND: Numerous criteria believed to define a positive response to cardiac resynchronization therapy have been used in the literature. No study has investigated agreement among these response criteria. We hypothesized that the agreement among the various response criteria would be poor. METHODS AND RESULTS: A literature search was conducted with the keywords "cardiac resynchronization" and "response." The 50 publications with the most citations were reviewed. After the exclusion of editorials and reviews, 17 different primary response criteria were identified from 26 relevant articles. The agreement among 15 of these 17 response criteria was assessed in 426 patients from the Predictors of Response to Cardiac Resynchronization Therapy (PROSPECT) study with Cohen's kappa-coefficient (2 response criteria were not calculable from PROSPECT data). The overall response rate ranged from 32% to 91% for the 15 response criteria. Ninety-nine percent of patients showed a positive response according to at least 1 of the 15 criteria, whereas 94% were classified as a nonresponder by at least 1 criterion. kappa-Values were calculated for all 105 possible comparisons among the 15 response criteria and classified into standard ranges: Poor agreement (kappa< or =0.4), moderate agreement (0.4 or =0.75). Seventy-five percent of the comparisons showed poor agreement, 21% showed moderate agreement, and only 4% showed strong agreement. CONCLUSIONS: The 26 most-cited publications on predicting response to cardiac resynchronization therapy define response using 17 different criteria. Agreement between different methods to define response to cardiac resynchronization therapy is poor 75% of the time and strong only 4% of the time, which severely limits the ability to generalize results over multiple studies.

A juvenile murine heart failure model of pressure overload.

Persistent pressure overload can cause cardiac hypertrophy and progressive heart failure (HF). The authors developed a pressure-overload HF model of juvenile mice to study the cardiac response to pressure overload that may be applicable to clinical processes in children. Severe thoracic aortic banding (sTAB) was performed using a 28-gauge needle for 40 juvenile (age, 3 weeks) and 47 adult (age, 6 weeks) C57BL/6 male mice. To monitor the structural and functional changes, M-mode echocardiography was performed for conscious mice that had undergone sTAB and sham operation. Cardiac hypertrophy, dilation, and HF occurred in both juvenile and adult mice after sTAB. Compared with adults, juvenile HF is characterized by greater impairment of ventricular contractility and less hypertrophy. In addition, juvenile mice had significantly higher rates of survival than adult mice during the early postoperative weeks. Consistent with clinical HF seen in children, juvenile banded mice demonstrated a lower growth rate than either adult banded mice or juvenile control mice that had sham operations. The authors first developed a juvenile murine model of pressure-overload HF. Learning the unique characteristics of pressure-overload HF in juveniles should aid in understanding age-specific pathologic changes for HF development in children.

Aorto-right atrial tunnel: fetal heart failure, diagnosis, and treatment.

Aorto-right atrial tunnel (ARAT) is a rare clinical entity. Although it is a benign finding in most cases; it can present with significant right ventricular volume overload and congestive heart failure. This report describes the first fetal diagnosis of congenital aorto-right atrial tunnel and successful management of the heart failure by surgical intervention.

Acute pacing-induced dyssynchronous activation of the left ventricle creates systolic dyssynchrony with preserved diastolic synchrony.

INTRODUCTION: Patients with heart block have conventionally received a pacemaker that stimulates the right ventricular apex (RVA) to restore heart rate control. While RVA pacing has been shown to create systolic dyssynchrony acutely, dyssynchrony can also occur in diastole. The effects of acute RVA pacing on diastolic synchrony have not been investigated. RVA pacing acutely impairs diastolic function by increasing the time constant of relaxation, decreasing the peak lengthening rate and decreasing peak negative dP/dt. We therefore hypothesized that acute RVA pacing would cause diastolic dyssynchrony in addition to creating systolic dyssynchrony. METHODS AND RESULTS: Fourteen patients (13 +/- 4 years old) with non-preexcited supraventricular tachycardia underwent ablation therapy with subsequent testing to confirm elimination of the tachycardia substrate. Normal cardiac structure and function were then documented on two-dimensional echocardiography and 12-lead electrocardiography prior to enrollment. Tissue Doppler images were collected during normal sinus rhythm (NSR), right atrial appendage pacing (AAI), and VVI-RVA pacing during the postablation waiting interval. Systolic and diastolic dyssynchrony were quantified using cross-correlation analysis of tissue Doppler velocity curves. Systolic dyssynchrony increased 81% during RVA pacing relative to AAI and NSR (P < 0.01). Diastolic synchrony was not affected by the different pacing modes (P = 0.375). CONCLUSION: Acute dyssynchronous activation of the LV created by RVA pacing resulted in systolic dyssynchrony with preserved diastolic synchrony in pediatric patients following catheter ablation for treatment of supraventricular tachycardia. Our results suggest that systolic and diastolic dyssynchrony are not tightly coupled and may develop through separate mechanisms.

Tricuspid regurgitation in patients with repaired Tetralogy of Fallot and its relation to right ventricular dilatation.

In a cohort of 56 school-aged children with repaired tetralogy of Fallot, significant (moderate to severe) tricuspid regurgitation was common (32% of patients) and was related to both tricuspid annulus dilatation and structural valve abnormalities that were potentially related to previous surgery. Even after adjusting for pulmonary regurgitation, tricuspid regurgitation was significantly correlated with right ventricular volume (r= 0.39, p = 0.009), suggesting that tricuspid regurgitation as well as pulmonary regurgitation may contribute significantly to progressive right ventricular dilatation in this population.

Reduction of tricuspid annular doppler tissue velocities in pediatric heart transplant patients.

BACKGROUND: Orthotopic heart transplantation is a life-saving therapy for children with end-stage heart disease. However, 50% of these transplanted children die or require re-transplantation 12 years later. Progressive deterioration of cardiac function is a common feature of long-term survivors; however, quantitative evaluation of the state of the right ventricle has been lacking. Tissue Doppler imaging (TDI) has been used to measure alterations in right ventricular (RV) function in other illnesses. The purpose of this study was to quantitate abnormalities in tricuspid annular systolic and diastolic velocities as an indicator of RV dysfunction, and to evaluate if time since transplantation and the presence of tricuspid regurgitation are associated with quantitative changes in tricuspid annular velocities in pediatric heart transplant recipients. METHODS: TDI was performed and velocities recorded during systole and early and late diastole at the tricuspid annulus, septum and mitral annulus in transplanted patients and in a control group with normal hearts. Pulsed wave Doppler mitral and tricuspid inflows were also measured and the severity of tricuspid regurgitation was estimated using color flow mapping. Patients with biopsy evidence of active cellular rejection or left ventricular ejection fraction of <60% were excluded from study. RESULTS: Thirty-five patients were divided into a normal heart group (n = 14) and a transplant group (n = 21), aged from 1 to 23 years. Systolic and early diastolic velocities at the tricuspid annulus and septum in the transplant group were reduced significantly compared with the normal group (p < 0.05): tricuspid annular systolic, 5.8 +/- 1.4 vs 9.4 +/- 1.7 cm/sec; early diastolic, -6.4 +/- 2.6 vs -9.7 +/- 2.6 cm/sec; septum systolic, 3.9 +/- 1.5 vs 5.8 +/- 1.4 cm/sec; and early diastolic, -6.3 +/- 2.4 vs -9.1 +/- 2.5 cm/sec. Patients were divided into early (<5 years) and late (>5 years) term groups since transplantation. Tissue velocities at the tricuspid annulus in the late term group had further reduction in systole, 4.9 +/- 1.4 vs 6.4 +/- 1.1 cm/sec, and early diastole, -5.3 +/- 1.5 vs -7.1 +/- 2.9 cm/sec (p < 0.05). Patients with severe tricuspid regurgitation had systolic and early diastolic velocities at the tricuspid annulus that were further reduced. Left ventricular mitral inflow Doppler early/late diastolic ratios became significantly different from the normal group 5 years after transplantation (p < 0.05). CONCLUSIONS: TDI demonstrated that tricuspid annular systolic and early diastolic velocities were abnormal in children after transplantation and became significantly more abnormal with prolonged time after transplantation. These alterations were not dependent on the presence of severe tricuspid regurgitation but appeared to be exacerbated by its presence. Evidence of diastolic left ventricular dysfunction was not detected before 5 years after transplantation in this unselected group. A prospective study may be required to define the evolution and progression of right and left ventricular dysfunction in children after heart transplantation.

Results with the freestyle porcine aortic root for right ventricular outflow tract reconstruction in children.

BACKGROUND: The ideal choice for valved reconstruction of the right ventricular outflow tract (RVOT) in children is undetermined. This study explores the Freestyle porcine aortic root for these patients. METHODS: From January 1998 to December 2002, 56 patients ages 1.6 to 29.9 years old (mean 11.8 years old) underwent RVOT reconstruction using a Freestyle porcine aortic root. The patients averaged 1.9 prior operations (range 0 to 5) for tetralogy of Fallot +/- pulmonary atresia (28 patients), critical pulmonary stenosis (10 patients), Ross procedure (5 patients), pulmonary atresia/intact ventricular septum (4 patients), complete atrioventricular septal defect +/- tetralogy of Fallot (4 patients), and others (5 patients). At time of RVOT reconstruction, 42 patients (75%) had additional procedures including the following: tricuspid or mitral repair (24 patients), pulmonary arterioplasty +/- Glenn (12 patients), ventricular septal defect closure (5 patients), aortic valve replacement (3 patients), placement of a cardioverter/defibrillator or pacemaker (3 patients), and others (8 patients). RESULTS: One patient developed mediastinitis; another was treated for Candida endocarditis (his excised homograft unexpectedly grew Candida). All patients are well on follow-up from 2 to 60 months (mean 30 +/- 20 months) with no deaths. The patient with endocarditis underwent conduit replacement for recurrent pulmonary stenosis 3.5 years postoperatively. Echocardiography revealed mild or no pulmonary insufficiency in 93%. The calculated mean peak systolic RVOT gradient by echocardiography was 19.7 +/- 15.4 mm Hg. CONCLUSIONS: These data demonstrate excellent results with the Freestyle bioprosthesis for RVOT reconstruction in children. This valve may serve as a readily available alternative to homograft valves in RVOT reconstruction, particularly since early insufficiency seems to be less problematic. Questions of long-term durability and significance of echocardiographic stenosis remain unanswered.

One hundred pulmonary valve replacements in children after relief of right ventricular outflow tract obstruction.

BACKGROUND: Surgical repair of obstructive lesions of the right ventricular outflow tract (RVOT) in children commonly creates pulmonary valve incompetence that may eventually require pulmonary valve replacement (PVR). We reviewed our experience with PVR late after RVOT reconstruction. METHODS: We performed 100 PVRs in 93 children 1.1 months to 22.4 years (median 8) after RVOT reconstruction. Children with right ventricular to pulmonary artery conduits and primary PVRs were excluded. Age at PVR was 4.5 months to 27.9 years (median 9.5 years). Initial diagnosis was tetralogy of Fallot and variants, 62; critical pulmonary stenosis, 15; pulmonary atresia with intact ventricular septum, 7; and others, 9. Eleven patients had a redo PVR. A total of 62 PVRs were homografts; 38 were porcine valves. RESULTS: There was one early death. On follow-up of 5 months to 12.4 years (mean 4.9 years) there were no late deaths although 1 child underwent cardiac transplantation. Actuarial freedom from redo PVR at 8 years was 100% for porcine valves but 70% for homograft valves (p = 0.17). For children younger than 3 years at PVR, freedom from reoperation was 76% at 1 year and 39% at 8 years compared with freedom from redo PVR at 8 years of 100% for children older than 3 years. On latest echocardiogram 97% of porcine valves had mild or no pulmonary regurgitation compared with 72% of homograft valves. CONCLUSIONS: PVR after RVOT reconstruction can be performed with low risk. Porcine valves may be superior to homograft valves although this advantage may be due to older age at time of PVR.

De Vega tricuspid annuloplasty for systemic tricuspid regurgitation in children with univentricular physiology.

BACKGROUND AND AIM OF THE STUDY: Significant tricuspid valve regurgitation (TR) is problematic in children with univentricular physiology and a systemic tricuspid valve occasionally requiring tricuspid (systemic atrioventricular) valve replacement. Since 1998, the De Vega tricuspid annuloplasty technique has been applied for TR in these children. METHODS: Twelve children (median age 2.2 years; range: 6 months to 17 years) with moderate or severe systemic TR underwent a De Vega tricuspid annuloplasty during a bidirectional Glenn anastomosis (n = 3), Fontan procedure (n = 8) or aortic valve replacement late after a Fontan procedure (n = 1). Nine patients (75%) had prior Norwood palliation for hypoplastic left heart syndrome. Four patients had simultaneous repair of an abnormal tricuspid valve in addition to the De Vega procedure. RESULTS: There were no deaths during a mean follow up of 2.0 +/- 1.4 years (range: 6 months to 5.1 years). One child required pacemaker implantation early after operation, and one child with a Glenn anastomosis underwent cardiac transplantation 21 months postoperatively. In the remaining 11 patients, the most recent echocardiogram showed mild or no TR in eight children, mild-to-moderate TR in one child, and moderate TR in two children. No child had symptomatic TR (including the two with moderate TR), significant tricuspid stenosis, or late pacemaker implantation. CONCLUSION: The De Vega tricuspid annuloplasty safely provides excellent relief of systemic TR in children with univentricular physiology, with a majority of patients (73%) having mild or less residual TR at follow up examination. This simple technique is preferred to tricuspid (systemic) valve replacement in these children.

Multiplane Transesophageal Echocardiographic Evaluation of Defects of the Atrioventricular Septum: The Crux of the Matter.

The availability of multiplane transesophageal probes has dramatically facilitated visualization of complex cardiac anatomy, with full dynamic tracking of anatomic contiguity. This report describes the unique applicability of multiplane transesophageal echocardiography (TEE) for visualization and assessment of a spectrum of congenital cardiac defects involving the cardiac crux, including the atrioventricular septum, inlet muscular septum, and the atrioventricular valves. With further evolution and progressive miniaturization of these probes, the use of this echocardiographic modality will hopefully encroach into the young infant age range, permitting enhanced preoperative and perioperative depiction of complex congenital cardiac anatomy. (ECHOCARDIOGRAPHY, Volume 13, November 1996)

Tricuspid Valve Aneurysm Formation in a Child with Suspected Endocarditis.

Aneurysms of the aortic and mitral valve are a known complication of infective endocarditis in adults. We report an unusual case of tricuspid valve endocarditis in a child with resultant aneurysm formation as its presenting finding after a brief clinical course. (ECHOCARDIOGRAPHY, Volume 13, January 1996)

Clinical Validation of Digital Image Compression Levels for Fetal Echocardiograms for Telemedicine.

BACKGROUND: Digital telephone transmission of dynamic fetal echocardiographic sequences requires wide bandwidths. To reduce the transmission of nonessential information present in echocardiographic images, compression algorithms have been used and validated for adult echocardiography. The level of compression that retains all diagnostic clinical information must be determined and validated for fetal echocardiographic studies. The purpose of this study was to validate levels of image compression that are diagnostic for fetal echocardiography. METHODS: Twenty previously recorded fetal echocardiograms representing two normal and 18 congenitally abnormal hearts were looped, digitized, and compressed at differing ratios. Images were reviewed in a blinded manner by four experts. Images were scored for diagnosis, diagnostic quality, and technical quality. RESULTS: Forty-four images were viewed. Experts correctly diagnosed 87% of images. There were no images of unacceptable diagnostic quality at a compression ratio of 300 (0%) and 2% at compression ratio of 600:1. CONCLUSIONS: Digital image compression of 300:1 was diagnostic for fetal congenital heart diseases with a variety of defects using cine-looped images. These data support the use of compressed fetal images for telephone transmission with a low bandwidth.

Initial Experience with an Internally Rotating Transthoracic Three-Dimensional Echocardiographic Probe and Image Acquisition on a Conventional Echocardiogram Machine.

Three-dimensional echocardiography has required motorized external scanning devices that move a standard echo transducer to obtain data sets before reconstruction. These transducer holders are susceptible to axis alignment errors and transducer movement. The use of a three-dimensional workstation makes acquisition cumbersome. An internally rotating 5-MHz "omniplane" transthoracic transducer, specifically designed for three-dimensional echocardiography, and an integrated three-dimensional acquisition software package that allows single machine acquisitions were validated in 50 pediatric patients. Children were 1 day to 16 years old and had 22 different cardiac pathological conditions imaged. Ninety-eight of the 104 (94%) data sets collected were successfully reconstructed in three dimensions. Acquisitions took 3-6 minutes depending on the increment of internal rotation. Minimum total study time to set up and complete the acquisition was 12 minutes. The new probe and software makes three-dimensional acquisitions and reconstructions of consistently high quality, rapid, reliable, and user friendly.

Measures of dyssynchrony in the left ventricle of healthy children and young patients with dilated cardiomyopathy.

BACKGROUND: Doppler tissue imaging may help identify children with dyssynchrony who could benefit from resynchronization therapy. However, few studies have quantified dyssynchrony measures in children; no study has investigated the relationship among age, heart rate, and dyssynchrony measures in children; and no study has quantified cross-correlation delay in children. The aim of this study was to test the hypotheses that measures of left ventricular dyssynchrony would correlate with age, primarily because of the correlation between heart rate and age, and that children with cardiomyopathy would have left ventricular dyssynchrony. METHODS: Sixty healthy children and 11 children with dilated cardiomyopathy were prospectively enrolled. Seven dyssynchrony measures were quantified: septal-to-lateral delay, peak velocity difference, the standard deviations of times to peak in 12 segments in systole and diastole, and cross-correlation delay in systole, diastole, and the whole cycle. RESULTS: The seven dyssynchrony measures were either not correlated with age or only weakly correlated with age after correcting for heart rate using Bazett's formula. Septal-to-lateral delay, peak velocity difference, and the standard deviation of times to peak in 12 segments in systole showed dyssynchrony in 57% to 85% of normal controls, compared with 20% for cross-correlation delay in the whole cycle and 3% for the standard deviation of times to peak in 12 segments in diastole. Cross-correlation delay in systole, cross-correlation delay in diastole, cross-correlation delay in the whole cycle, and the standard deviation of times to peak in 12 segments in diastole were elevated in children with dilated cardiomyopathy compared with controls. CONCLUSIONS: Echocardiographic dyssynchrony measures should be corrected for heart rate using Bazett's formula in children. Time-to-peak Doppler tissue imaging dyssynchrony measures classify many healthy children as having abnormalities with the timing of left ventricular contraction, which suggests that the methodology is not accurate in children. In preliminary studies, cross-correlation dyssynchrony measures show elevated systolic and diastolic measures of dyssynchrony in children with dilated cardiomyopathy compared with controls, which deserves further investigation to help identify children who may benefit from resynchronization therapy.

Variability in tissue Doppler echocardiographic measures of dyssynchrony is reduced with use of a larger region of interest.

BACKGROUND: Doppler tissue imaging (DTI)-based dyssynchrony parameters failed to predict response to cardiac resynchronization therapy (CRT) in the multicenter Predictors of Response to Cardiac Resynchronization Therapy (PROSPECT) trial. Large variability during the interpretation of DTI data was one of several factors thought to contribute to this failure. In this study, the authors hypothesized that using larger regions of interest (ROIs) to generate velocity curves from Doppler tissue images would significantly reduce the variability of DTI dyssynchrony parameters. METHODS: The variability of 3 ROI sizes (6 x 6, 18 x 6, and 30 x 6 mm) was compared in 30 patients undergoing CRT. Variability due to manual ROI placement was determined for each ROI size by placing 3 ROIs in each myocardial segment, 6mm apart from one another. Thus, 3 velocity curves were generated for each segment and each ROI size. Four published dyssynchrony parameters were calculated from all permutations of the 3 ROI positions per segment. A mean modified coefficient of variation was calculated for each parameter and ROI size. RESULTS: The 6 x 6 mm ROI had a mean coefficient of variation of 27%. The 18 x 6 and 30 x 6 mm ROIs had significantly lower coefficients of variation (17% and 14%, respectively) than the 6 x 6 mm ROI (P < .01 for both). The 30 x 6 mm ROI also reduced the diagnostic inconsistency of dyssynchrony parameters by 44% (P = .024) compared with the 6 x 6 mm ROI. CONCLUSION: Using a 30 x 6 mm ROI instead of a 6 x 6 mm ROI to quantify tissue Doppler dyssynchrony reduces variability by 47% and diagnostic inconsistency by 44%. The authors recommend using a 30 x 6 mm ROI in future trials to minimize variability.

Real-time three-dimensional echocardiographic acquisition and quantification of left ventricular indices in children and young adults with congenital heart disease: comparison with magnetic resonance imaging.

BACKGROUND: Echocardiographic assessment of left ventricular (LV) contractility and dimensions is important in the management of patients with congenital heart disease. Conventional two-dimensional measures are limited because of volume or pressure-overloaded right ventricles that may distort the septal planes. Real-time three-dimensional echocardiography (RT3DE) has overcome these limitations; however, postprocessing image reconstruction and analysis are required. We compared LV indices calculated by new online RT3DE software with those obtained by magnetic resonance imaging (MRI) in patients with congenital heart disease. METHODS: Twelve patients (ages 1-33 years, median age = 15.9 years) with congenital heart disease underwent RT3DE and cardiac MRI. End-diastolic and end-systolic LV volumes, stroke volume, ejection fraction, and mass were calculated online using biplane method-of-discs and semiautomated border detection echocardiographic techniques. RESULTS: All RT3DE volumes correlated strongly with MRI (r = 0.93-0.99, P < .001). Ejection fraction had a lower correlation (r = 0.69, P = .013). There was no significant underestimation or overestimation of MRI values by RT3DE. Both biplane method-of-discs and semiautomated border detection echocardiographic techniques had excellent volume correlation (r = 0.94-0.99, P < .001). Interobserver variability was 7%. CONCLUSIONS: Combined RT3DE acquisition and analysis machines can accurately assess the LV in patients with congenital heart disease, thus impacting clinical management and perhaps obviating the need for MRI in some cases.