Chronic Arrhythmias in the Setting of Heterotaxy: Differences between Right and Left Isomerism

Abstract

So-called heterotaxy affects lateralization of the thoracic and abdominal organs. Congenital malformations may be present in one of several organ systems. Cardiac involvement includes both structural and conduction abnormalities. Data regarding arrhythmias in heterotaxy come from case reports and small case series. We pooled available data to further characterize arrhythmias in heterotaxy. A systematic review of the literature for manuscripts describing arrhythmias in heterotaxy patients was conducted. Databases including PubMed, EMBASE, and Ovid were searched. Studies describing arrhythmias in patients with heterotaxy were included if they were in English and presented characteristics of the arrhythmias. Arrhythmia characteristics were abstracted and are presented as pooled data. Freedom from arrhythmia by age was then analyzed using Kaplan-Meier analysis. A total of 19 studies with 121 patients were included in the pooled analysis. Those with right isomerism were found to be more likely to have atrial flutter, atrial tachycardia, junctional tachycardia, and ventricular tachycardia. Those with left isomerism were more likely to have atrioventricular block, intraventricular conduction delay, sick sinus syndrome, and atrioventricular nodal reentry tachycardia. Median age of onset for all arrhythmias was 4 years with no difference by specific arrhythmia or isomerism. Those with right and left isomerism are at risk for different arrhythmias but are likely to develop arrhythmias at the same age. Those with left isomerism are more likely to require pacemaker placement due to atrioventricular block. Understanding these differences allows for focused surveillance of development of these arrhythmias.

Isomerism in the setting of the so-called “heterotaxy”: The usefulness of computed tomographic analysis

“…These patients are likely to have atrial tachycardias,[15] as was the case in our patient. In general, patients with right isomerism have more complex cardiovascular malformations than those with left isomerism,[12] again as shown in the present case.…”

“…[14] Those with left isomerism are also more likely to have sick sinus syndrome and junctional rhythm. [15] It is again paradoxical, therefore, that our patient demonstrated sick sinus syndrome, with an overall constellation of findings in keeping with left isomerism, but in the setting of usual arrangement of the atrial appendages.…”

Genetic Disturbances in Patients with Bodily Isomerism from a Single Center: Clinical Implications of Affected Genes and Potential Impact of Ciliary Dyskinesia

“…13 Twin atrioventricular nodes may also be present in either subset, this potentiating in many cases to arrhythmias. 14,15 The arrangement of the abdominal organs, however, although markedly different from the usual or mirrorimages lateralized arrangements, shows minimal evidence of isomerism. 8 The mechanism underscoring an isomeric formation of the thoracic organs is unclear, although emerging data indicates that isomerism may be the result of ciliary dyskinesia, with dyskinesia being found in at least twofifths of afflicted patients.…”

Cardiac Embryology and Molecular Mechanisms of Congenital Heart Disease: A Primer for Anesthesiologists

“…The presence of two atrioventricular conducting pathways when there are duplicated atrioventricular nodes increases susceptibility for supraventricular reentrant tachycardias while the lack of a normally situated sinus node can predispose patients to development of atrioventricular conduction blocks. Loomba et al 62 investigated the occurrence of chronic cardiac arrhythmias in heterotaxy patients. Comparing left and right isomerism, the authors found no significant differences in cardiac malformations and sinus node position.…”