Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives

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Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives. / Busch, Stephen; Davies, Hannah; Van Diepen, Sean et al.
In: Journal of Applied Physiology, Vol. 124, No. 4, 04.2018, p. 930-937.

Research output: Contribution to journalArticlepeer-review

HarvardHarvard

Busch, S, Davies, H, Van Diepen, S, Simpson, L, Sobierajski, F, Riske, L, Stembridge, M, Ainslie, P, Willie, C, Hoiland, R, Moore, J & Steinback, C 2018, 'Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives', Journal of Applied Physiology, vol. 124, no. 4, pp. 930-937. https://doi.org/10.1152/japplphysiol.00774.2017

APA

Busch, S., Davies, H., Van Diepen, S., Simpson, L., Sobierajski, F., Riske, L., Stembridge, M., Ainslie, P., Willie, C., Hoiland, R., Moore, J., & Steinback, C. (2018). Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives. Journal of Applied Physiology, 124(4), 930-937. https://doi.org/10.1152/japplphysiol.00774.2017

CBE

Busch S, Davies H, Van Diepen S, Simpson L, Sobierajski F, Riske L, Stembridge M, Ainslie P, Willie C, Hoiland R, et al. 2018. Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives. Journal of Applied Physiology. 124(4):930-937. https://doi.org/10.1152/japplphysiol.00774.2017

MLA

VancouverVancouver

Busch S, Davies H, Van Diepen S, Simpson L, Sobierajski F, Riske L et al. Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives. Journal of Applied Physiology. 2018 Apr;124(4):930-937. Epub 2017 Dec 21. doi: 10.1152/japplphysiol.00774.2017

Author

Busch, Stephen ; Davies, Hannah ; Van Diepen, Sean et al. / Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives. In: Journal of Applied Physiology. 2018 ; Vol. 124, No. 4. pp. 930-937.

RIS

TY - JOUR

T1 - Chemoreflex Mediated Arrhythmia during Apnea at 5050m in Low but not High Altitude Natives

AU - Busch, Stephen

AU - Davies, Hannah

AU - Van Diepen, Sean

AU - Simpson, Lydia

AU - Sobierajski, Frances

AU - Riske, Laurel

AU - Stembridge, Mike

AU - Ainslie, Philip

AU - Willie, Christopher

AU - Hoiland, Ryan

AU - Moore, Jonathan

AU - Steinback, Craig

PY - 2018/4

Y1 - 2018/4

N2 - Peripheral chemoreflex mediated increases in both parasympathetic and sympathetic drive under chronic hypoxia may evoke brady-arrhythmias during apneic periods. We determined if: a) voluntary apnea unmasks arrhythmia at low (344m) and high (5050m) altitude, b) if high altitude natives (Nepalese Sherpa) exhibit similar cardiovagal responses at altitude; and c) if brady-arrhythmias at altitude are partially chemoreflex mediated. Participants were grouped as Lowlanders (n=14; age=27±6yrs) and Nepalese Sherpa (n=8; age=32±11yrs). Lowlanders were assessed at 344m and 5050m while Sherpas were assessed at 5050m. Heart rate (HR) and rhythm (Lead-II ECG) were recorded during rest and voluntary end-expiratory apnea. Peripheral chemoreflex contributions were assessed in Lowlanders (n=7) at altitude after 100% oxygen. Lowlanders had higher resting HR at altitude (70±15 vs. 61±15 bpm;P<0.01) that was similar to Sherpas (71±5 bpm;P=0.94). High-altitude apnea caused arrhythmias in 11 of 14 Lowlanders (junctional rhythm (n=4), 3° atrio-venticular block (n=3), sinus pause (n=4)) not present at low altitude and larger marked bradycardia (nadir -39±18 bpm; P<0.001). Sherpas exhibited a reduced bradycardia response during apnea compared to Lowlanders (P<0.001) and did not develop arrhythmias. Hyperoxia blunted bradycardia (nadir -10 ±14bpm; P<0.001 compared to hypoxic state) and reduced arrhythmia incidence (3 of 7 Lowlanders). Degree of bradycardia was significantly related to hypoxic ventilatory response (HVR) at altitude and predictive of arrhythmias (P<0.05). Our data demonstrates apnea-induced brady-arrhythmias in Lowlanders at altitude but not in Sherpa (potentially through cardio-protective phenotypes). The chemoreflex is an important mechanism in genesis of brady- arrhythmias and the HVR may be predictive for identifying individual susceptibility to events at altitude.

AB - Peripheral chemoreflex mediated increases in both parasympathetic and sympathetic drive under chronic hypoxia may evoke brady-arrhythmias during apneic periods. We determined if: a) voluntary apnea unmasks arrhythmia at low (344m) and high (5050m) altitude, b) if high altitude natives (Nepalese Sherpa) exhibit similar cardiovagal responses at altitude; and c) if brady-arrhythmias at altitude are partially chemoreflex mediated. Participants were grouped as Lowlanders (n=14; age=27±6yrs) and Nepalese Sherpa (n=8; age=32±11yrs). Lowlanders were assessed at 344m and 5050m while Sherpas were assessed at 5050m. Heart rate (HR) and rhythm (Lead-II ECG) were recorded during rest and voluntary end-expiratory apnea. Peripheral chemoreflex contributions were assessed in Lowlanders (n=7) at altitude after 100% oxygen. Lowlanders had higher resting HR at altitude (70±15 vs. 61±15 bpm;P<0.01) that was similar to Sherpas (71±5 bpm;P=0.94). High-altitude apnea caused arrhythmias in 11 of 14 Lowlanders (junctional rhythm (n=4), 3° atrio-venticular block (n=3), sinus pause (n=4)) not present at low altitude and larger marked bradycardia (nadir -39±18 bpm; P<0.001). Sherpas exhibited a reduced bradycardia response during apnea compared to Lowlanders (P<0.001) and did not develop arrhythmias. Hyperoxia blunted bradycardia (nadir -10 ±14bpm; P<0.001 compared to hypoxic state) and reduced arrhythmia incidence (3 of 7 Lowlanders). Degree of bradycardia was significantly related to hypoxic ventilatory response (HVR) at altitude and predictive of arrhythmias (P<0.05). Our data demonstrates apnea-induced brady-arrhythmias in Lowlanders at altitude but not in Sherpa (potentially through cardio-protective phenotypes). The chemoreflex is an important mechanism in genesis of brady- arrhythmias and the HVR may be predictive for identifying individual susceptibility to events at altitude.

KW - Hypoxia

KW - Arrhythmia

KW - Chemoreflex

KW - Apnea

U2 - 10.1152/japplphysiol.00774.2017

DO - 10.1152/japplphysiol.00774.2017

M3 - Article

VL - 124

SP - 930

EP - 937

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 4

ER -