Cardiac repolarization and autonomic regulation during short-term cold exposure in hypertensive men: an experimental study.

• Published in: PLoS ONE
• Main Authors: Heidi Hintsala, Tuomas V Kenttä, Mikko Tulppo, Antti Kiviniemi, Heikki V Huikuri, Matti Mäntysaari, Sirkka Keinänen-Kiukaannemi, Risto Bloigu, Karl-Heinz Herzig, Riitta Antikainen, Hannu Rintamäki, Jouni J K Jaakkola, Tiina M Ikäheimo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science (PLoS) 2014
• Subjects: Medicine; R; Science; Q; Subarctic
• Online Access: https://doi.org/10.1371/journal.pone.0099973; https://doaj.org/article/70ee98c7a03540acb121bab928c34b4e

The aim of our study was to assess the effect of short-term cold exposure, typical in subarctic climate, on cardiac electrical function among untreated middle-aged hypertensive men.We conducted a population-based recruitment of 51 hypertensive men and a control group of 32 men without hypertension (age 55-65 years) who underwent whole-body cold exposure (15 min exposure to temperature -10°C, wind 3 m/s, winter clothes). Conduction times and amplitudes, vectorcardiography, arrhythmias, and heart rate variability (autonomic nervous function) were assessed.Short-term cold exposure increased T-peak to T-end interval from 67 to 72 ms (p<0.001) and 71 to 75 ms (p<0.001) and T-wave amplitude from 0.12 to 0.14 mV (p<0.001) and from 0.17 to 0.21 mV (p<0.001), while QTc interval was shortened from 408 to 398 ms (p<0.001) and from 410 to 401 ms (p<0.001) among hypertensive men and controls, respectively. Cold exposure increased both low (from 390 to 630 ms2 (p<0.001) and 380 to 700 ms2 (p<0.001), respectively) and high frequency heart rate variability (from 90 to 190 ms2 (p<0.001) and 150 to 300 ms2 (p<0.001), respectively), while low-to-high frequency-ratio was reduced. In addition, the frequency of ventricular ectopic beats increased slightly during cold exposure. The cold induced changes were similar between untreated hypertensive men and controls.Short-term cold exposure with moderate facial and mild whole body cooling resulted in prolongation of T-peak to T-end interval and higher T-wave amplitude while QTc interval was shortened. These changes of ventricular repolarization may have resulted from altered cardiac autonomic regulation and were unaffected by untreated hypertension.ClinicalTrials.gov NCT02007031.