Daniel Forsha

Right Ventricular Mechanics using a Novel Comprehensive Three-View Echocardiographic Strain Analysis in a Normal Population

BACKGROUND Although quantitative right ventricular (RV) strain analysis may be useful in congenital and acquired heart disease populations with RV failure, a comprehensive, standardized approach is lacking. An 18-segment RV strain analysis obtained from three standardized RV apical echocardiographic images was used to determine the feasibility, normal values, and reproducibility of the method in normal adults. METHODS Forty healthy, prospectively enrolled volunteers with no cardiac histories and normal QRS durations underwent echocardiography optimized for strain analysis including three RV apical views. Two-dimensional speckle-tracking longitudinal strain analysis was performed using EchoPAC software. Eleven retrospectively identified subjects with RV disease were included as a pilot population. All had been imaged using the same protocol including the three RV apical views. RESULTS All control subjects had normal anatomic morphology and function by echocardiography. Feasibility of the RV strain analysis was good (adequate tracking in 696 of 720 segments [97%]). RV global peak systolic strain was -23 ± 2%. Peak strain was highest in the RV free wall and lowest in the septum. Dyssynchrony indices demonstrated no dyssynchrony using left ventricular criteria. Reproducibility of most strain measures was acceptable. This methodology identified important disease not seen in the four-chamber apical view alone in the pilot population of 11 patients with RV disease. Strain patterns and values were different from those in the control population, indicating that differences do exist from normal. CONCLUSIONS Eighteen-segment RV strain analysis is feasible, with strain measures falling into discrete ranges in this normal population. Those with RV disease illustrate the potential utility of this approach. These data indicate that this model can be used for more detailed studies evaluating abnormal RV populations, in which its full potential can be assessed.

Cardiovascular abnormalities in late-onset Pompe disease and response to enzyme replacement therapy

Purpose: We evaluated the prevalence of cardiovascular abnormalities and the efficacy and safety of enzyme replacement therapy in patients with late-onset Pompe disease.Methods: Ninety patients were randomized 2:1 to enzyme replacement therapy or placebo in a double-blinded protocol. Electrocardiograms and echocardiograms were obtained at baseline and scheduled intervals during the 78-week study period. Baseline cardiovascular abnormalities, and efficacy and safety of enzyme replacement therapy were described. Three pediatric patients were excluded.Results: Eighty-seven patients were included. Median age was 44 years; 51% were men. At baseline, a short PR interval was present in 10%, 7% had decreased left ventricular systolic function, and 5% had elevated left ventricular mass on echocardiogram (all in mild range). There was no change in cardiovascular status associated with enzyme replacement therapy. No significant safety concerns related to enzyme replacement therapy were identified.Conclusions: Although some patients with late-onset Pompe disease had abnormalities on baseline electrocardiogram or echocardiogram, those classically seen in infantile Pompe disease, such as significant ventricular hypertrophy, were not noted. Cardiovascular parameters were not impacted by enzyme replacement therapy, and there were no cardiovascular safety concerns. The cardiovascular abnormalities identified may be related to Pompe disease or other comorbid conditions.

Classic-Pattern Dyssynchrony and Electrical Activation Delays in Pediatric Dilated Cardiomyopathy

BACKGROUND Progressive heart failure leading to transplantation or death is common in pediatric dilated cardiomyopathy (DCM), and treatment options are limited. Select children with DCM have improved after cardiac resynchronization therapy (CRT), but predicting response is challenging. Nonetheless, considering the frequency of death or transplantation in this population, identifying any candidate would be valuable. Classic-pattern dyssynchrony (CPD) identifies mechanical dyssynchrony patterns consistent with underlying electrical activation delays and strongly predicts CRT response in adult DCM but has not been evaluated in pediatric DCM. The aim of this study was to test the hypothesis that CPD is present in a subgroup of patients with pediatric DCM and is associated with activation delays. METHODS Fifty-nine subjects with pediatric DCM (left ventricular end-diastolic diameter Z score > 2 and left ventricular ejection fraction < 40%) who underwent echocardiography with a functional protocol with apical images optimized for two-dimensional speckle-tracking strain analysis (EchoPAC) were retrospectively analyzed for CPD. Electrocardiograms were evaluated for activation delays (prolonged QRS duration and strict criteria for left bundle branch block [LBBB]). Forty control subjects with no cardiac disease and good imaging widows were also analyzed. RESULTS The mean age was 5.4 years (range, 1 day to 20 years); idiopathic DCM was most common (57%). Severe cardiomyopathy was present in 75% (end-diastolic diameter Z score > 4.6 and left ventricular ejection fraction < 32%). CPD was identified in seven subjects (12%), and prolonged QRS durations were present in 13 (22%), but only two subjects met strict criteria for LBBB. Six of seven subjects in the CPD group had prolonged QRS durations, and two of seven had LBBB. No control subjects had CPD. The CPD analysis was highly feasible and reproducible. CONCLUSIONS In this severely affected cohort, the small CPD subgroup is potentially important because their progressive disease may respond to CRT. CPD is associated with activation delays, although not necessarily strict LBBB. This has important potential implications for prospective evaluation of CRT in this disease.

Right ventricular echocardiographic indices predict poor outcomes in infants with persistent pulmonary hypertension of the newborn

AIMS Infants with persistent pulmonary hypertension of the newborn (PPHN) have elevated pulmonary vascular resistance that can lead to right ventricular (RV) failure and death. Clinicians must decide which infants will fail conventional therapy and require transfer to extra corporeal membrane oxygenation (ECMO) centres, but accurate echocardiographic predictors have not been identified. We assessed echocardiographic measurements of RV pressure and function in predicting progression to death or ECMO in infants with PPHN. METHODS AND RESULTS Echocardiograms for infants ≥35-week gestation with a clinical diagnosis of PPHN were retrospectively reviewed. Traditional and strain echocardiographic measures were compared for those with or without the primary outcome of ECMO/cardiovascular death. Receiver operator curves identified cut points for measures that were significantly different. Of the 86 subjects analysed, 25 (29%) of the patients had the primary outcome of ECMO/death. The ECMO/death group had diminished tricuspid annular plane systolic excursion (TAPSE; P = 0.002) and RV global longitudinal peak strain (GLPS; P = 0.03), a predominant right-to-left shunt across the patent ductus arteriosus (PDA; P = 0.05), and an elevated oxygenation index (OI; P < 0.001). Sensitivity/specificity for TAPSE <4 mm was 56 and 85%, and for GLPS greater than or equal to -9% was 52 and 77%. CONCLUSION TAPSE, GLPS, and right-to-left PDA shunting were associated with progression to death/ECMO. RV free wall strain was not associated with the outcome, suggesting that diminished global strain better reflects clinical outcomes in this group. These thresholds may assist in the decision-making to transfer high-risk infants to ECMO centres.

Evaluation of Right Ventricular Myocardial Mechanics Using Velocity Vector Imaging of Cardiac MRI Cine Images in Transposition of the Great Arteries Following Atrial and Arterial Switch Operations

OBJECTIVE The aim of the study was to determine right and left ventricle deformation parameters in patients with transposition of the great arteries who had undergone atrial or arterial switch procedures. SETTING Patients with transposition are born with a systemic right ventricle. Historically, the atrial switch operation, in which the right ventricle remains the systemic ventricle, was performed. These patients have increased rates of morbidity and mortality. We used cardiac MRI with Velocity Vector Imaging analysis to characterize and compare ventricular myocardial deformation in patients who had an atrial switch or arterial switch operation. DESIGN Patients with a history of these procedures, who had a clinically ordered cardiac MRI were included in the study. Consecutive 20 patients (75% male, 28.7 ± 1.8 years) who underwent atrial switch operation and 20 patients (60% male, 17.7 ± 1.9 years) who underwent arterial switch operation were included in the study. Four chamber and short-axis cine images were used to determine longitudinal and circumferential strain and strain rate using Vector Velocity Imaging software. RESULTS Compared with the arterial switch group, the atrial switch group had decreased right ventricular ejection fraction and increased end-diastolic and end-systolic volumes, and no difference in left ventricular ejection fraction and volumes. The atrial switch group had decreased longitudinal and circumferential strain and strain rate. When compared with normal controls multiple strain parameters in the atrial switch group were reduced. CONCLUSIONS Myocardial deformation analysis of transposition patients reveals a reduction of right ventricular function and decreased longitudinal and circumferential strain parameters in patients with an atrial switch operation compared with those with arterial switch operation. A better understanding of the mechanisms of right ventricle failure in transposition of great arteries may lead to improved therapies and adaptation.

A strategy for atrial septal defect closure in small children that eliminates long-term wall erosion risk

Objectives: To evaluate feasibility, efficacy, and safety of an approach to atrial septal defect (ASD) occlusion in children ≤20 kg that eliminates cardiac wall erosion risk. Background: Cardiac wall erosion is a potentially catastrophic complication of ASD device closure. The HELEX Septal Occluder (HSO) is a compliant device with no reports of erosion. The HSO is technically difficult to deploy in smaller children and cannot be used to close larger defects. To eliminate wall erosion risk, we use the HSO when feasible and surgery for larger defects. Methods: Retrospective review of ASD procedures performed in children ≤20 kg. Results: Between January 2006 and January 2011, 60 children underwent ASD closure. HSO placement was successful in 32 of 34 patients, and surgical closure was successful in all of 28 patients. Surgical patients were younger (35.1 ± 12.6 vs. 47.4 ± 15.3 months, P < 0.01) and smaller (15.3 ± 3.2 vs. 12.6 ± 4.3 kg; P < 0.01) with larger ASDs (15.8 ± 4.5 vs. 9.8 ± 3.0 mm; P < 0.01). No surgical patients demonstrated residual leak. Residual leak was seen in 14 of 32 (44%) HSO patients on postprocedure day #1 and in 1 of 26 (3.8%) with ≥6 months follow‐up. Indications for surgery included: deficient inferior/superior rims (n = 17), provider preference (n = 2), and HSO device not feasible (n = 9). Serious adverse events included device embolization with percutaneous retrieval (n = 1) and postpericardiotomy syndrome without intervention (n = 1). Conclusions: The HSO can be safely used in most children ≤20 kg. Our approach to ASD closure is associated with minimal morbidity and good short‐term results. This approach requires no more than a 15% increase in surgical referrals and eliminates risk of cardiac wall erosion.

Activation delay-induced mechanical dyssynchrony in single-ventricle heart disease

We present the case of an infant with a single functional ventricle who developed ventricular dysfunction and heart failure due to an electrical activation delay and dyssynchrony. Earlier recognition of this potentially reversible aetiology may have changed her poor outcome.

A Rare Coronary Collateral in Pulmonary Atresia and Intact Septum With Coronary Sinusoids

A neonate with pulmonary atresia and intract ventricular septum, ventriculocoronary sinusoids, bilateral coronary ostial atresia, and a rare collateral vessel between the descending thoracic aorta and the coronary system is described. The clinical course in this infant included extracorporeal life support and coil occlusion of the collateral in order to manage multiple ischemic events.