Arrhythmic Risk Evaluation during Exercise at High Altitude in Healthy Subjects: Role of Microvolt T‐Wave Alternans

Gibelli, G; Fantoni, Cecilia; Anzà, Claudio; Cattaneo, Paolo; Rossi, Andrea; Montenero, A. S.; Baravelli, Massimo

doi:10.1111/j.1540-8159.2008.01178.x

Cited by 10 publications

(7 citation statements)

References 39 publications

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“…Increased sympathetic activity reduces the ventricular fibrillation threshold14 and is able to provoke ventricular arrhythmias 15. Exposure to environmental stressors such as cold water6,16 but also high altitude17 per se leads to enhanced sympathetic activity which is further accentuated by exercise 18. The increase in the number of PVCs during cold water exposure, therefore, raises some concerns in regard to the safety of cold water immersion and exercise.…”

Section: Discussionmentioning

confidence: 99%

Haemodynamic and arrhythmic effects of moderately cold (22°C) water immersion and swimming in patients with stable coronary artery disease and heart failure

Schmid

Morger

Noveanu

et al. 2009

European J of Heart Fail

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Section: Discussionmentioning

confidence: 99%

Haemodynamic and arrhythmic effects of moderately cold (22°C) water immersion and swimming in patients with stable coronary artery disease and heart failure

Schmid

Morger

Noveanu

et al. 2009

European J of Heart Fail

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“…Despite enhanced sympathetic activity, MTWA testing during exercise at HA was negative in all participants. 38 The authors concluded that there is a low risk of dangerous arrhythmias in healthy trained subjects during exercise under hypobaric hypoxia conditions. The possibility, however, of an increased arrhythmic risk in patients with heart diseases favouring arrhythmias, remains an issue yet to be properly addressed in future studies.…”

Section: Arrhythmias and Implantable Devicesmentioning

confidence: 99%

Clinical recommendations for high altitude exposure of individuals with pre-existing cardiovascular conditions

Parati

Agostoni

Basnyat

et al. 2018

European Heart Journal

151

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Take home figureAdapted from Bärtsch and Gibbs2 Physiological response to hypoxia. Life-sustaining oxygen delivery, in spite of a reduction in the partial pressure of inhaled oxygen between 25% and 60% (respectively at 2500 m and 8000 m), is ensured by an increase in pulmonary ventilation, an increase in cardiac output by increasing heart rate, changes in vascular tone, as well as an increase in haemoglobin concentration. BP, blood pressure; HR, heart rate; PaCO2, partial pressure of arterial carbon dioxide.

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“…Heightened sympathetic activity associated with rapid ascent to elevated altitude and subsequent exercise may increase the frequency and duration of supraventricular and ventricular arrhythmias in healthy volunteers (Alexander 1999;Faulhaber et al 2007;Gibelli et al 2008). Because of this, we examined our healthy subjects until the 3rd week of their stay at elevated altitude, i.e.…”

Section: Discussionmentioning

confidence: 99%

Circadian and ultradian extrasystole rhythms in healthy individuals at elevated versus lowland altitudes

Kujaník

Mikulecký²

2010

Int J Biometeorol

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We defined chronobiologic norms for supraventricular and ventricular single extrasystoles (SV and VE, respectively) in healthy older males in lowland areas. The study was extended to higher altitudes, where hypobaric hypoxia was expected to increase extrasystole frequency, while perhaps not changing rhythmicity. In healthy men (lowland n = 37, altitude n = 22), aged 49-72 years, mean numbers of SVs and VEs were counted over a 24-h period. Cosinor regression was used to test the 24-h rhythm and its 2nd-10th harmonics. The resulting approximating function for either extrasystole type includes its point, 95% confidence interval of the mean, and 95% tolerance for single measurement estimates. Separate hourly differences (delta) between altitude and lowland (n = 59) were also analysed. Hourly means were significantly higher in the mountains versus lowland, by +0.8 beats/h on average for SVs, and by +0.9 beats/h for VEs. A relatively rich chronogram for VEs in mountains versus lowland exists. Delta VEs clearly display a 24-h component and its 2nd, 3rd, 4th and 7th harmonics. This results in significantly higher accumulation of VEs around 8.00 a.m., 11.00 a.m. and 3.00 p.m. in the mountains. The increase in extrasystole occurrence in the mountains is probably caused by higher hypobaric hypoxia and resulting sympathetic drive. Healthy men at elevated altitudes show circadian and several ultradian rhythms of single VEs dependent on the hypoxia level. This new methodological approach--evaluating the differences between two locations using delta values--promises to provide deeper insight into the occurrence of premature beats.

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Arrhythmic Risk Evaluation during Exercise at High Altitude in Healthy Subjects: Role of Microvolt T‐Wave Alternans

Abstract: In spite of an enhanced sympathetic activity, MTWA testing during exercise at high altitude was negative in all participants. Healthy trained subjects during exercise under hypoxia seem to be at low risk for dangerous arrhythmias.

Cited by 10 publications

References 39 publications

Haemodynamic and arrhythmic effects of moderately cold (22°C) water immersion and swimming in patients with stable coronary artery disease and heart failure

Haemodynamic and arrhythmic effects of moderately cold (22°C) water immersion and swimming in patients with stable coronary artery disease and heart failure

Clinical recommendations for high altitude exposure of individuals with pre-existing cardiovascular conditions

Circadian and ultradian extrasystole rhythms in healthy individuals at elevated versus lowland altitudes

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