ABSTRACT
Background: Patients who are diagnosed with dextrocardia, a rare congenital heart condition in which the heart points toward the right side of the chest, need their specific situs classification (eg, solitus, inversus, ambiguus) ascertained to optimize their care and outcomes. In this report, we discuss the perioperative anesthetic management of a patient presenting with dextrocardia. Case Report: A 44-year-old African American female with a history of hypertension, hyperlipidemia, gastroesophageal reflux disease, and diabetes mellitus type 2 was admitted for shortness of breath, dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea. The patient had been diagnosed with dextrocardia in 2003 at an outside hospital and was asymptomatic prior to this presentation. Chest x-ray revealed bilateral perihilar vascular congestion with bibasilar atelectasis and suspected small bilateral pleural effusions consistent with new-onset congestive heart failure. Preoperative 2-dimensional transthoracic echocardiography revealed an ostium secundum-type atrial septal defect (ASD) with mild left-to-right atrial shunting. The patient's ASD was repaired using a pericardial patch. Conclusion: The anesthetic management of patients presenting with dextrocardia is complex. Preoperative cardiac transthoracic echocardiography can identify cardiac lesions or aberrant anatomy associated with dextrocardia. Proper placement of electrocardiogram electrodes is necessary to avoid false-positive results for perioperative ischemia. Central line access must be adjusted to anatomic variations. Clinicians should have high suspicion for associated pulmonary hypertension and should limit sedatives preoperatively to minimize the cardiovascular effects of hypoxia and/or hypercarbia on the pulmonary vasculature. Finally, high clinical suspicion for respiratory complications should be maintained, as dextrocardia has been associated with respiratory complications secondary to primary ciliary dyskinesia in approximately 25% of patients.
ABSTRACT
We examined the interactions of calmodulin with neuronal gap junction proteins connexin35 (Cx35) from perch, its mouse homologue Cx36, and the related perch Cx34.7 using surface plasmon resonance. Calmodulin bound to the C-terminal domains of all three connexins with rapid kinetics in a concentration- and Ca2+-dependent manner. Dissociation was also very rapid. K(d)'s for calmodulin binding at a high-affinity site ranged from 11 to 72 nM, and K(1/2)'s for Ca2+ were between 3 and 5 microM. No binding to the intracellular loops was observed. Binding competition experiments with synthetic peptides mapped the calmodulin binding site to a 10-30 amino acid segment at the beginning of the C-terminal domain of Cx36. The micromolar K(1/2)'s and rapid on and off rates suggest that this interaction may change dynamically in neurons, and may occur transiently when Ca2+ is elevated to a level that would occur in the near vicinity of an activated synapse.
