Characterization of morphology and function of the ‘neo-atria’ after a modified Mustard operation

Background: There is a pressing need to improve early and long-term results of the Mustard operation. A modification of the operation was introduced at the Aswan Heart Centre for this purpose which relies on creating new functional atria rather than the two rigid channels in the classical Mustard operation.Objectives: To evaluate the morphology and function of the neo-atria, shortly after modified mustard operation for a ‘neglected’ patient with TGA, VSD and severe pulmonary hypertension.Methods: A 6-year-old with neglected TGA, VSD and pulmonary hypertension presented with severe cyanosis, clubbing and haemoconcentration (Hb 22 g/dL), underwent the modified Aswan-Mustard operation (MAM) with rapid smooth postoperative recovery. Repeated 2D echograms and multi-slice CT scans, followed by 3D segmentation, were performed after the operation. The size, shape, and morphology of the neo-atria were measured and measurements of the patterns of instantaneous filling and emptying of the right and left ventricles were quantified.Results: The neo-systemic venous atrium consisted of three components with a combined volume of 78 mL/m2, all of which contributed to the reservoir, conduit, and importantly contractile function of the neo-atrium. The pulmonary venous atrium consisted of two components with a combined volume of 66 mL/m2. These measurements were made at atrial end diastole. The volumes of the systemic venous and the pulmonary venous diminished to 51 and 54 mL/m2, respectively, at the end atrial systole - indicating relatively preserved contractile functions.

Abstract 15658: Anatomical Characteristics of the Cavotricuspid Isthmus and Their Correlation With Obstructive Sleep Apnea

Introduction: Macro-reentrant arrhythmias involving the cavo-tricuspid isthmus (CTI) are common in patients with atrial fibrillation (AF). Bidirectional CTI block is the ablation strategy of choice, but it can be surprisingly difficult to obtain at times. Objective: Aim of this study was to systematically assess the characteristics of the CTI to determine its most common anatomical variants to be anticipated for ablation. Methods: This is a prospective observational study in which intracardiac echocardiography (ICE) was used to visualize the CTI of patients undergoing AF ablation. The presence of anatomical variants was recorded, and length was measured along the central CTI in atrial systole. CTI systolic shortening measured in sinus rhythm and defined as: [(diastolic length - systolic length)/(diastolic length)]x100. Results: 180 patients (65±9 years old, 31% female, 37% paroxysmal AF) are included in the study. Mean CTI length was 31±9 mm, with a systolic shortening of 25±13%. A prominent Eustachian ridge was present in 32%, a Chiari network in 11%, and at least one pouch-like recess in 35%, with a mean depth of 5.3±2.5 mm (Figure). A longer CTI was observed in patients with non-PAF compared with patients with PAF (33 vs. 27 mm, P<0.0001) and in patients with known obstructive sleep apnea (OSA; 37 vs. 32 mm, P=0.0077). Of note, after excluding patients with heart failure, ROC analysis showed that a CTI length ≥ 33 mm was predictive of the presence of OSA (67 % sensitivity and specificity, AUC = 0.71). Less CTI systolic shortening was observed in patients with non-PAF compared those with PAF (22 vs. 32%; P<0.0001). Conclusion: Anatomical variants of the CTI are common and should be anticipated in case of a challenging CTI ablation. A long CTI is associated with OSA and might warrant further clinical screening to identify this common AF comorbidity. CTI systolic shortening correlates with the type of AF and could represent a measure of right atrial contractility.

Phasic Compression of Left Circumflex Coronary Artery during Atrial Systole

Phasic coronary artery compression is typically associated with spasm or myocardial bridging. Compression caused by acquired anatomic changes to the surrounding heart chambers has been reported only infrequently. We present a possibly unique case of phasic compression of the proximal left circumflex coronary artery during atrial contraction in association with a dilated left atrium. A 55-year-old man with multiple cardiac risk factors presented with worsening exertional dyspnea. An electrocardiogram and echocardiogram revealed marked left atrial dilation and a left ventricular ejection fraction of 0.15 to 0.20 with elevated filling pressures. Angiograms showed compression of the proximal segment of the left circumflex coronary artery during late ventricular diastole: the compression occurred in phase with atrial systole, whereas good flow without compression was present during atrial diastole. We attributed this phenomenon to ballooning of the lateral region of the atrial wall toward the atrioventricular groove during atrial systole. The patient complied with antihypertensive therapy, and his status improved after one year. To identify coronary artery compression in the presence of abnormal chamber geometry and to guide the treatment of the contributing medical conditions, we recommend careful analysis of angiographic results.

Left atrial strain rate estimates PCWP

<p><span>Objective: </span>Raised left atrial (LA) pressure is a common pathway for many pathologies and is known for its complications. It has a direct effect on LA cavity size and potentially also its function. We hypothesized that raised LA pressure, as shown by pulmonary capillary wedge pressure (PCWP), correlates with severity of global LA deformation abnormalities during atrial systole (LASRa).</p><p>Design and Patients: We prospectively studied 46 consecutive patients, mean age 61 +/-13 years, 17 males, of various etiologies who underwent right heart catheterization and simultaneous Doppler echocardiography using spectral, tissue Doppler and speckle tracking echocardiography techniques for assessing LA structure and function.</p><p><span>Results: </span>PCWP correlated with direct measurements of LA structure and function: LA volume (r= 0.43, p&lt;0.01) and LASRa (r=0.79, p&lt;0.001). PCWP correlated also with other indirect measures of LA pressure such as E/A (r=0.65, p&lt;0.001), E wave deceleration time (r=0.54, p&lt;0.001), E/e’ (r=0.49, p&lt;0.001) and LA systolic filling fraction (r=0.52, p&lt;0.001). However, LASRa together with LA systolic filling fraction, had the highest areas under the curve (0.83 and 0.87, respectively) for identifying patients with PCWP &gt; 15 mmHg.</p><p><span>Conclusion: </span>PCWP correlates with LA deformation rate during atrial systole and to a higher extent than conventional Doppler measures of raised LA pressures. These findings should have significant clinical implications in correctly identifying breathless patients due to raised LA pressure.</p><p> </p>

Left atrial deformation parameters in patients with non-alcoholic fatty liver disease: a 2D speckle tracking imaging study

The presence of the metabolic syndrome is a strong predictor for the presence of NASH (non-alcoholic steatohepatitis) in patients with NAFLD (non-alcoholic fatty liver disease). In the present study, we assessed LA (left atrial) deformation parameters in patients with NAFLD using 2D-STE (speckle tracking echocardiography) and to investigate if any changes exist between subgroups of the NAFLD. A total of 55 NAFLD patients and 21 healthy controls were included in the study. The diagnosis of NAFLD was based on liver biopsy. After patients were categorized into groups according to histopathological analysis (simple steatosis, borderline NASH, definitive NASH), all patients underwent echocardiography with Doppler examination. In the 2D-STE analysis of the left atrium, LA-Res (peak LA strain during ventricular systole), LA-Pump (peak LA strain during atrial systole), LA-SRS (peak LA strain rate during ventricular systole), LA-SRE (peak LA strain rate during early diastole) and LA-SRA (peak LA strain rate during atrial systole) were obtained. LA-Res, LA-Pump and LA-SRA were lower in the NAFLD group than in the control group. LA-Res was found to be significantly lower in NAFLD subgroups compared with healthy subjects (43.9±14.2 in healthy controls compared with 31.4±8.3 with simple steatosis, 32.8±12.8 with borderline NASH and 33.8±9.0 with definitive NASH). LA-Pump was significantly lower in the NAFLD group (18.2±3.1 in healthy controls compared with 13.3±4.7 with borderline NASH and 14.4±4.7 with definitive NASH). There were significant differences in LA-SRA between healthy controls compared with simple steatosis and borderline NASH (−1.56±0.36 compared with 1.14±0.38 and 1.24±0.32 respectively). Correlation analysis showed significant correlation of LA-Res values with E (early diastolic peak velocity)/Em (early diastolic mitral annular velocity) ratio (r=−0.50, P≤0.001), with LAVI (LA volume index; r=−0.45, P≤0.001) and with Vp (propagation velocity; r=0.39, P≤0.001). 2D-STE-based LA deformation parameters are impaired in patients with NAFLD with normal systolic function. Although LA-Res and pump function parameters might be useful in estimating LV (left ventricular) filling pressure in the NAFLD patient group, it could not be used for differentiating the subgroups.