Absence Of Outflow Tract Obstruction Research Articles

Role of Computed Tomography in Pre- and Postoperative Evaluation of a Double-Outlet Right Ventricle.

Double-outlet right ventricle (DORV) is a type of ventriculoarterial connection in which both great arteries arise entirely or predominantly from the right ventricle. The morphology of DORV is characterized by a ventricular septal defect (location and relationship with the semilunar valve); bilateral coni and aortomitral continuity; the presence or absence of outflow tract obstruction; tricuspid-pulmonary annular distance; and associated cardiac anomalies. The surgical approach varies with the type of DORV and is based on multiple variables. Computed tomography (CT) is a robust diagnostic tool for the preoperative and postoperative assessment of DORV. Unlike echocardiography and magnetic resonance imaging (MRI), CT imaging is not limited by small acoustic window, need for anaesthesia and can be used in patients with metallic implants. Current generations CT scanners with high spatial and temporal resolution, wide detectors, high-pitch scanning mode, dose-reduction algorithms, and advanced three-dimensional post-processing tools provide a low-risk, high-quality alternative to diagnostic cardiac catheterization or MRI, and have been increasingly utilized in nearly every type of congenital heart defect, including DORV.

Impact of outflow tract obstruction in the management of atrial fibrillation in hypertrophic cardiomyopathy: insights from the national readmission database

Abstract Background Atrial fibrillation (AF) is commonly encountered in patients with Hypertrophic Cardiomyopathy (HCM). Presence of AF in this high risk population is detrimental due to its effect on hemodynamics, diastolic function and potential induction of ventricular tachyarrhythmias. For these reasons a rhythm control strategy is highly desirable, and yet catheter ablation of AF is consistently inefficacious with poorer overall outcomes. We hypothesize that in HCM presence of outflow tract obstruction by virtue of its effect on left atrial hemodynamics, altered circulatory flow patterns in the pulmonary veins, and stretch related triggered activities would create an arrhythmogenic substrate, and have significant impact on the outcomes of catheter ablation of AF. In this study, we aimed to evaluate AF ablation outcomes based on the presence or absence of outflow tract obstructions in patients with HCM. Methods We conducted a retrospective study using the AHRQ-HCUP National Readmission Database for the years 2016–17. All adults (≥18 years) with HCM undergoing AF ablation procedures were identified using ICD-9 codes. The cohort was divided into two groups; Obstructive HCM (Group A) and Non-Obstructive HCM (Group B) Multivariate regression analysis was utilized to adjust for confounders. Independent risk factors for in-hospital mortality were identified using a proportional hazards model. Complications were defined as per the Agency for Health Care Research and Quality guideline. Results From a total of 71,451,419 patients in the NRD registry, 97 patients with HCM were identified and formed the study cohort. When divided based on the presence or absence of outflow tract obstruction, there were 25 patients with Obstructive HCM and 72 patients with Non-obstructive HCM. Both groups were similar in clinical characteristics including CHADVASc scores and Charlson Comobidity indices as outlined in Table 1. Procedural outcome analysis revealed higher 30-day cardiac readmissions in the Obstructive HCM group compared to Non-obstructive HCM (25.2% vs 7.97%, p=0.049). The Obstructive HCM group had higher rates of atrial arrhythmias, 57.97%, compared to 32.44% in the non-obstructive HCM group, and heart failure exacerbations, 41.27% vs 25.82%. However, both indices did not reach statistical significance. The procedural complications rates tended to be higher in the non-obstructive HCM group, 10.8% vs. 5.6% in the Obstructive HCM group (p=0.54). Conclusions Presence of an obstructive component to HCM is associated with significantly increased short term cardiac readmissions predominantly driven by recurrent atrial arrhythmias and heart failure. These findings suggest negative influence of altered cardiac hemodynamics related to outflow tract obstruction on atrial arrhythmias. The arrhythmogenic substrate of HCM may therefore be different and less amenable to catheter ablation. HCM ablation outcomes Funding Acknowledgement Type of funding source: None

Patterns of cardiac dysfunction coinciding with exertional breathlessness in hypertrophic cardiomyopathy

ObjectiveThe commonest cause of breathlessness in hypertrophic cardiomyopathy (HCM) is left ventricular outflow tract (LVOT) obstruction which improves with its removal. However, in the absence of outflow tract obstruction, as in dilated cardiomyopathy, patients may be limited by similar symptoms, thus suggesting a potential common mechanism for the two conditions. We aimed to assess cardiac function at the time of symptoms in a group of unselected patients with HCM to identify other patterns of cardiac dysfunction which coincide with their breathlessness. MethodsWe studied 37 HCM patients (aged 55±15years, 13 female) with septal thickness >15mm and 17 controls (aged 58±12years, 12 female) using Doppler echocardiography, at rest and at peak dobutamine stress. Stress end points were symptoms, >20mmHg drop in systolic blood pressure, arrhythmia, or maximum dobutamine dosage of 40μg/kg/min. ResultsAt rest: LV systolic function was maintained (EF 68±7 v 76±12%, respectively), LVOT velocity raised (p<0.005), lateral and septal long axis amplitude reduced (p<0.05 and p<0.005, respectively) and dyssynchronous and QRS duration was also broader (p<0.005) in patients compared to controls. At peak stress: Overall LVOT velocities were higher in patients than controls (4.3±1.7 v 1.7±1.0m/s, p<0.005, respectively) due to systolic anterior movement of the mitral valve and mitral regurgitation developing. In the 15 patients who did not develop significant LVOT obstruction (velocity <4m/s), LV ejection time increased and peak systolic amplitude did not increase. In the 10 patients with neither LVOT obstruction nor restrictive filling, QRS duration prolonged by 12ms (p <0.05), post-ejection shortening worsened and peak systolic amplitude fell (p<0.005). Also, LV ejection time prolonged by 5s/min (p<0.05), filling time failed to increase as it did in controls (p<0.005) and Tei index was higher than controls (p<0.01). ConclusionExertional breathlessness in HCM is associated with LV outflow tract obstruction and functional mitral regurgitation in almost two thirds of patients. The remaining one third have either resistant restrictive physiology or dyssynchronous cavity at fast heart rate. Despite similar exercise limiting breathlessness in the three groups, means of management should be quite different.

Adenomyosis in the Adolescent Population: A Case Report and Review of the Literature

Background This report presents a rare cause of dysmenorrhea in the adolescent female and the usefulness of magnetic resonance imaging (MRI) with T2 weighted sequence in the identification of adenomyosis. Case Two adolescents who presented with persistent pelvic pain in the absence of outflow tract obstruction or biopsy confirmed endometriosis had MRI-findings consistent with adenomyosis. Summary and Conclusion In the adolescent female presenting with persistent dysmenorrhea, a diagnosis of adenomyosis is rare but should remain a possibility as one considers the differential diagnosis.

Low pressure/low flow voiding in younger men: psychological aspects.

Low pressure/low flow voiding in young and middle-aged males in the absence of outflow tract obstruction has been reported as being associated with anxiety and a high incidence of dyspepsia. To assess objectively the psychological basis of this condition, an unselected group of 50 men aged 25 to 55 years was evaluated by psychiatric interview, questionnaires and urodynamic tests. In addition, patients involved in an earlier study were psychologically evaluated. Low pressure/low flow voiding was demonstrated in three (6%) of the new patients. This voiding pattern was related to a long preceding history, stress-dependent symptoms and difficulty in voiding in public urinals. When compared with a control population, the experimental group scored significantly higher on measures of psychoneurosis. It is recommended that surgery be avoided in these patients and that simple behavioural therapy may be most appropriate.

Nonobstructive hypertrophic cardiomyopathy mimicking mitral stenosis: Documentation by echocardiography, phonocardiography and intracardiac pressure and sound recordings

The physical findings in hypertrophic cardiomyopathy with left ventricular outflow tract obstruction are well described. In the absence of outflow tract obstruction the findings are less distinctive. There have been several reported cases in which the cardiac findings have suggested the diagnosis of mitral stenosis. In this report we describe a patient whose auscultatory and roentgenographic findings more closely mimicked mitral stenosis. The patient had a loud first heart sound, mitral opening snap and an apical presystolic murmur; left atrial enlargement was present. Noninvasive studies, including phonocardiography, echocardiography and apex cardiography, strongly suggested the correct diagnosis of nonobstructive hypertrophic cardiomyopathy. The diagnosis and unusual auscultatory findings were confirmed by results of cardiac catheterization and intracardiac phonocardiography. The importance of recognizing this syndrome and the use of noninvasive methods to establish the diagnosis are stressed.

Familial Myocardial Disease with and without Obstruction to Left Ventricular Outflow

Right and left heart catheterization, including selective cineangiocardiography, was performed in 20 of the 33 patients examined in a large Negro family. Fifteen had features compatible with the diagnosis of idiopathic hypertrophic subaortic stenosis. Sudden death has not occurred in this family. Many of the patients were young and were totally unaware of the heart disease, although 11 had symptoms of dyspnea on exertion. A large number of individuals in this family were found to be affected by a familial form of heart disease with similar clinical manifestations, but with a wide spectrum of hemodynamic and cineangiocardiographic abnormalities ranging from no obstruction to ventricular outflow and only mild indentation of the ventricular cavity to obstruction and marked narrowing of both ventricular outflow tracts. The patients with obstruction of the left ventricular outflow tract were older than those without obstruction. Therefore, this study provides further evidence that in families with myocardial disease, the presence or absence of outflow tract obstruction is merely a different manifestation of the same basic cardiac disease. This study has also demonstrated distinct left ventricular abnormalities quite early in life suggesting that the disease may be of congenital origin and that obstruction may be a function of the duration of the disease.