Pulmonary atresia with intact ventricular septum: Second heart field derived myocardial and epicardial developmental clues

Coronary microvascular dysfunction in childhood: An emerging pathological entity and its clinical implications

Coronary microvascular dysfunction (CMD) encompasses a spectrum of structural and functional alterations in coronary microvasculature resulting in impaired coronary blood flow and consequent myocardial ischemia without obstruction in epicardial coronary artery. The pathogenesis of CMD is complex involving both functional and structural alteration in the coronary microcirculation. In adults, CMD is predominantly discussed in context with anginal chest pain or existing ischemic heart disease and its risk factors. The presence of CMD suggests increased risk of adverse cardiovascular events independent of coronary atherosclerosis. Coronary microvascular dysfunction is also known in children but is rarely recognized due to paucity of concommitent coronary artery disease. Thus, its clinical presentation, underlying mechanism of impaired microcirculation, and prognostic significance are poorly understood. In this review article, we will overview variable CMD reported in children and delineate its emerging clinical significance.

Possible Association of Pulmonary Atresia with In-Utero Coxsackievirus B Exposure

Gestational viral infection has been associated with congenital heart disease (CHD). Few studies, however, have studied the potential role of gestational Coxsackievirus B (CVB) exposure in the pathogenesis of CHD. We prospectively enrolled women with pregnancies affected by CHD to explore possible associations with in utero CVB exposure. Serum samples were obtained from 122 women referred for fetal echocardiography between 2006 and 2018. We quantified CVB IgG and IgM levels, with titers ≥ 15.0 U/mL considered positive and measured neutralizing antibodies for three CVB serotypes: CVB1, CVB3, and CVB4. Using data from the national enterovirus surveillance system, we compared the annual exposure rates for each serotype in our cohort to infections reported across the United States. 98 pregnancies with no genetic defects were included. Overall, 29.6% (29/98) had positive IgG and 4.1% (4/98) of women had positive CVB IgM titers. To explore first-trimester CVB exposure, we focused exclusively on the 26 women with positive IgG and negative IgM titers. 61.5% (16/26) had neutralizing antibodies against a single serotype and 38.5% (10/26) against multiple CVB serotypes. CVB4 neutralizing antibodies were the most common (65.4%, 17/26), followed by CVB3 (53.9%, 14/26) and CVB1 (30.8%, 8/26). Among these, 30.8% of babies presented pulmonary valve anomalies: 19.2% (5/26) pulmonary atresia, and 11.5% (3/26) pulmonary stenosis. 23.1% (6/26) of babies had coronary sinusoids. CVB exposure in our cohort mirrored that of reported infections in the United States. Our results suggest a possible association between gestational CVB exposure and specific CHD, particularly pulmonary valve anomalies and coronary sinusoids.

Pulmonary Atresia With Ventriculocoronary Arterial Connections and a Large Conoventricular Septal Defect

Ventriculocoronary arterial connections are typically found in patients with pulmonary atresia with an intact ventricular septum. This report describes a case of ventriculocoronary arterial connections in a patient with pulmonary atresia with a ventricular septal defect. Our case supports recent data suggesting a primary coronary artery developmental anomaly in pulmonary atresia. (Level of Difficulty: Advanced.)

Pulmonary atresia with intact ventricular septum and right ventricular dependent coronary circulation through the "vessels of Wearn"

We present an autopsy case of a male baby born at 35 weeks of gestation with pulmonary atresia with intact ventricular septum (PAIVS), who had coronary blood flow that was dependent on outflow from the right ventricle through the vessels described by Wearn. At 7 weeks of age, he underwent single ventricle palliation consisting of ligation of a patent ductus arteriosus and placement of a modified Blalock-Taussig shunt. The patient experienced a perioperative myocardial infarction, requiring extracorporeal membrane oxygenation. Progressive hemodynamic decline resulted in death 8 days after surgery. Autopsy revealed acute and remote infarctions in both ventricles and fibromuscular dysplasia of the subepicardial and intramural coronary arteries. In 1926, Grant first reported the association between PAIVS and secondary dysplasia of the heart vasculature and hypothesized that the high pressure resulted in dilation of the myocardial sinusoids. Confusion secondary to the unmeritorious dismissal of the myocardial sinusoids has obscured the pathogenesis of PAIVS and led to several publications suggesting second heart field abnormalities as a disease model for PAIVS. We discuss the pathogenesis of PAIVS, the ventriculocoronary arterial connections and the sinusoidal relationship to the vessels described by Wearn, and we attempt to correct the solecism plaguing the nomenclature of myocardial vasculature.

Multiple coronary artery-left ventricular fistulas causing sudden death in a young woman

Multiple coronary artery fistulae arising from right and left coronary arteries were found at autopsy in a 22-year-old woman, dying suddenly while playing football. This is the fifth pathologic description of this finding with biventricular involvement. We found microscopic evidence of postischemic scars and foci of myocardial calcifications in the left ventricular wall.