DOI: 10.1161/circ.148.suppl_1.14390 ISSN: 0009-7322

Abstract 14390: Interatrial Block in the Presence of Lipomatous Hypertrophy of the Interatrial Septum

Abdulaziz Malik, Kevin John, Mohamad Wahoud, Basel Humos, Guy Rozen, Jennifer Chee, Munther Homoud, Christopher Madias
  • Physiology (medical)
  • Cardiology and Cardiovascular Medicine

Introduction: Interatrial block (IAB) from disruption of conduction through Bachmann’s bundle results in atrial electromechanical dysfunction. Delay in conduction and alteration in the pattern of atrial activation causes P-wave lengthening (≥120 ms) and characteristic biphasic P-waves in the inferior ECG leads. IAB has been associated with atrial arrhythmia and risk of stroke. Generally, the anatomic substrate for IAB is a fibrotic atrial myopathy; however, intertrial masses have also been associated with IAB. Lipomatous hypertrophy of the interatrial septum (LHIS) constitutes an anatomical barrier that could similarly lead to IAB.

Hypothesis: The presence of LHIS is associated with an increased prevalence of IAB.

Methods: A query of the echocardiography database at our institution from 2017 to present revealed 312 subjects with LHIS. Data collection included demographic characteristics, ECG and echocardiographic parameters. Prevalence of IAB and associated clinical variables were assessed.

Results: The mean age was 72 years (56% male). In the total group IAB was present in 131 patients (42%). Comparison between the group with IAB versus without IAB was notable for a higher prevalence of stroke in those with IAB (24 subjects versus 16; p value = 0.013). The prevalence of atrial fibrillation was not statistically different between the two groups, but atrial flutter was noted to be more prevalent in those with IAB (16 subjects vs 9; p value = 0.018). Hypertension and male sex were also associated with IAB.

Conclusions: Subjects with LHIS have a high prevalence of IAB, likely consequent to localized disruption in conduction through Bachmann’s bundle. We demonstrate a higher prevalence of atrial flutter and stroke in those with LHIS and IAB. These results highlight the importance of LHIS as a potential cause of IAB that can contribute to atrial structural remodeling and electromechanical dysfunction associated with atrial arrhythmia and stroke.

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