PubMed · 7094283
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J M Loeb. 1982. Sinus node in SIDS.. https://pubmed.ncbi.nlm.nih.gov/7094283/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
The hibernating myocardium refers to the presence of persistent myocardial and left ventricular dysfunction at rest, due to reduced coronary blood flow. This left ventricular dysfunction represents an endogenous adaptive mechanism which prevents irreversible cell damage. The dysfunction in hibernating myocardium improves following restoration of coronary blood flow. A key concept in hibernating myocardium is that the reduction in contractile function induced by ischaemia has a protective effect. By reducing oxygen demand the myocardium maintains its viability in the setting of limited oxygen supply. The hibernating myocardium is a new metabolic state that is a consequence of an ischaemic condition, but the hibernating cardiomyocytes are not necessarily ischaemic. There are no adequate animal models for chronic hibernation. However, there are models for acute hibernation both in intact beating hearts and in isolated hearts. In these models a stable reduction in mechanical function for some hours has been demonstrated, whereas metabolic indicators of ischaemia improve during sustained low-flow ischaemia.
OBJECTIVES: This study considers the array of pulmonary-systemic connections made by the levoatriocardinal vein. The primary and associated lesions that play a role in forming this vein are examined, and echocardiography is discussed as a method for its rapid identification. BACKGROUND: The levoatriocardinal vein is a pulmonary-systemic connection that provides an alternative egress for pulmonary venous blood in left-sided obstructive lesions. It is thought to result from the persistence of anastomotic channels that connect the capillary plexus of the embryonic foregut to the cardinal veins. Only 12 cases of levoatriocardinal vein have been reported since its first description in 1926. A comprehensive description of the morphology and echocardiographic identification of this lesion has been unavailable because of its rarity. METHODS: A retrospective study was performed in 13 patients with a levoatriocardinal vein from the University of California, San Francisco. Echocardiographic findings were compared with those obtained by angiography or at necropsy. In addition, the details of 12 previously published case reports were reviewed. Age at presentation, primary obstruction to pulmonary venous return, integrity of the atrial septum and origin and drainage of the levoatriocardinal vein were compared. RESULTS: Patient age at presentation was < 2 years, with most patients presenting before age 6 months. Variations of the hypoplastic left heart syndrome accounted for the majority of primary defects encountered, although multiple but less severe left-sided lesions were seen. The atrial septum was functionally intact in most patients. The levoatriocardinal vein, defined echocardiographically, originated predominantly from the smooth-walled left atrium and drained to the superior vena cava or innominate vein; however, variations of this pattern existed. CONCLUSIONS: As a physiologic entity, the levoatriocardinal vein provides a mechanism for decompression of pulmonary venous return primarily in patients with left ventricular inflow obstruction. A levoatriocardinal vein is thought to form when the atrial septum fails to provide an alternate egress for left atrial blood. However, when a septal defect or alternative shunt occurs in conjunction with a levoatriocardinal vein, the clinical presentation may be postponed. Echocardiography provides a rapid, noninvasive modality for identifying the pulmonary-systemic connection, which may masquerade as the vertical vein in anomalous pulmonary venous connection or act as an occult source of left to right shunting in patients undergoing surgery for hypoplastic left heart syndrome.