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Cardiovascular Engineering

Cardiovascular Engineering - Poster Session B

Poster H10 - Developmental Electroanatomical Adaptations in the Guinea Pig Hearts

Thursday, October 24, 2024
2:45 PM - 3:45 PM EST
Location: Exhibit Hall E, F & G

    Presenting Author(s)

  • KM

    Kathleen M. McLean (she/her/hers)

    Research Assistant
    Children's National Hospital
    Washington, DC, District of Columbia, United States

    • Co-Author(s)

  • Kazi T. Haq, PHD

    Staff Scientist
    Children's National Hospital, United States

  • SS

    Shatha Salameh

    Graduate Student
    Children's National Hospital, United States

  • LS

    Luther Swift

    Staff Scientist III
    Children's National Hospital, United States

    • Last Author(s)

  • NP

    Nikki Posnack

    Associate Professor
    Children's National Hospital, United States


Introduction:  Electroanatomical adaptations during the neonatal to adult phase have not been comprehensively studied in preclinical animal models. To explore the impact of age as a biological variable on cardiac electrophysiology, we employed neonatal and adult guinea pigs to conduct our research. Guinea pigs are a well recognized animal model for developmental research.

Materials and

Methods:  Healthy guinea pigs were categorized into three age groups (neonates, n=10; younger adults, n=13; and older adults, n=26). Electrocardiogram (ECG) recordings were collected in vivo from anesthetized animals (2–3% isoflurane). A Langendorff-perfusion system was employed for optical assessment of epicardial action potentials and calcium transients, using intact excised heart preparations. Optical data sets were analyzed and metric maps were constructed using Kairosight 3.0.

Results, Conclusions, and Discussions: The allometric relationship between heart weight and body weight diminishes with age, as it is strongest at the neonatal stage (R2 = 0.84) and completely abolished in older adults (R2 = 1E-06). Neonatal hearts exhibit circular activation waveforms, while adults show prototypical elliptical shapes. Neonatal conduction velocity (40.6±4.0 cm/s) is slower than adults (younger adults: 61.6±9.3 cm/s; older adults: 53.6±9.2 cm/s). Neonatal hearts have a longer action potential duration (APD) and exhibit regional heterogeneity (left apex; APD30: 68.6±5.6 ms, left basal; APD30: 62.8±3.6), which was absent in adult epicardium. With dynamic pacing, neonatal hearts exhibit a flatter APD restitution slope (APD70: 0.29±0.04) compared to older adults (0.49±0.04). Similar restitution characteristics are observed with extrasystolic pacing, with a flatter slope in neonatal hearts (APD70: 0.54±0.1) compared to adults (Younger adults: 0.85±0.4; Older adults: 0.95±0.7). Finally, neonatal hearts display unidirectional excitation-contraction coupling, while adults exhibit bidirectionality.

Acknowledgements (Optional):