TY - GEN
T1 - Contribution of the Slow Delayed Rectifier K+Current to Pacemaker Activity of the Human Sinoatrial Node
AU - Verkerk, Arie O.
AU - Wilders, Ronald
N1 - Publisher Copyright: © 2022 Creative Commons.
PY - 2022
Y1 - 2022
N2 - The slow delayed rectifier K+ current (IKs) is present in sinoatrial node (SAN) cells of various species, but data on the contribution of IKs to SAN pacemaker activity are not consistent. Yet, sinus bradycardia is a common finding in case of gain-of-function mutations in the KCNQ1 gene, encoding the pore-forming α -subunit of the IKs channel. We carried out computer simulations of human SAN pacemaker activity using the Fabbri-Severi model of a single human SAN cell. Biophysical properties of IKs were updated, based on our recent patch clamp data on IKs channels expressed in HEK-293 cells. Under vagal tone, block of the original IKs of the Fabbri-Severi model had only a marginally small effect on action potential duration and diastolic depolarization, and thus cycle length. However, with the formulation of IKs based on our patch clamp data, block of IKs had a substantial effect on diastolic depolarization and cycle length, increasing pacing rate by 17%. A qualitatively similar, but less substantial effect was observed under control conditions and under \beta -adrenergic tone, with an increase in pacing rate of 5.2% in either case. Simulation of a gain-of-function mutation in KCNQ1 revealed a strong bradycardic effect during vagal tone. We conclude that IKs contributes to human SAN pacemaker activity at all levels of autonomic tone.
AB - The slow delayed rectifier K+ current (IKs) is present in sinoatrial node (SAN) cells of various species, but data on the contribution of IKs to SAN pacemaker activity are not consistent. Yet, sinus bradycardia is a common finding in case of gain-of-function mutations in the KCNQ1 gene, encoding the pore-forming α -subunit of the IKs channel. We carried out computer simulations of human SAN pacemaker activity using the Fabbri-Severi model of a single human SAN cell. Biophysical properties of IKs were updated, based on our recent patch clamp data on IKs channels expressed in HEK-293 cells. Under vagal tone, block of the original IKs of the Fabbri-Severi model had only a marginally small effect on action potential duration and diastolic depolarization, and thus cycle length. However, with the formulation of IKs based on our patch clamp data, block of IKs had a substantial effect on diastolic depolarization and cycle length, increasing pacing rate by 17%. A qualitatively similar, but less substantial effect was observed under control conditions and under \beta -adrenergic tone, with an increase in pacing rate of 5.2% in either case. Simulation of a gain-of-function mutation in KCNQ1 revealed a strong bradycardic effect during vagal tone. We conclude that IKs contributes to human SAN pacemaker activity at all levels of autonomic tone.
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85152929969&origin=inward
U2 - https://doi.org/10.22489/CinC.2022.091
DO - https://doi.org/10.22489/CinC.2022.091
M3 - Conference contribution
VL - 2022-September
T3 - Computing in Cardiology
BT - 2022 Computing in Cardiology, CinC 2022
PB - IEEE Computer Society
T2 - 2022 Computing in Cardiology, CinC 2022
Y2 - 4 September 2022 through 7 September 2022
ER -