PMID- 34113919
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20220423
IS  - 2666-5018 (Electronic)
IS  - 2666-5018 (Linking)
VI  - 2
IP  - 2
DP  - 2021 Apr
TI  - Pregnancy-induced increased heart rate is independent of thyroid hormones.
PG  - 168-173
LID - 10.1016/j.hroo.2021.03.001 [doi]
AB  - BACKGROUND: The heart rate increases by 10-20 beats per minute (bpm) throughout 
      pregnancy in women, reaching maximum heart rate in the third trimester. During 
      pregnancy, important changes in thyroid hormones also occur, with increases of up 
      to 50% in the levels of triiodothyronine (T(3)), the biological active thyroid 
      hormone. In addition, T(3) has been shown to regulate cardiac electrophysiology. 
      OBJECTIVE: Thus, in the present study the potential contribution of T(3) in 
      pregnancy-induced increased heart rate was explored. METHODS: We compared the 
      heart rate between nonpregnant and pregnant mice under control conditions and 
      after altering thyroid hormone levels with T(3) and propylthiouracil (PTU, an 
      antithyroid drug) treatments. RESULTS: Consistent with the clinical data, we 
      found a 58% rise in T(3) levels during pregnancy in mice. Although pregnant mice 
      had a higher baseline heart rate (607 +/- 8 bpm, P = .004) and higher T(3) levels 
      (1.9 +/- 0.4 nM, P = .0005) than nonpregnant mice (heart rate: 546 +/- 16 bpm; T(3) 
      levels: 1.2 +/- 0.1 nM), their heart rate responded similarly to T(3) treatment as 
      nonpregnant mice (nonpregnant: Delta130 +/- 22 bpm; pregnant: Delta126 +/- 17 bpm, P = .858). 
      Additionally, the heart rate remained significantly elevated (607 +/- 11 bpm, P = 
      .038) and comparable to untreated pregnant mice, after the use of the antithyroid 
      drug PTU, although T(3) levels (1.3 +/- 0.2 nM, P = .559) returned to nonpregnant 
      values. CONCLUSION: Based on these results, it is unlikely that T(3) contributes 
      significantly to the pregnancy-induced increased heart rate.
CI  - (c) 2021 Heart Rhythm Society. Published by Elsevier Inc.
FAU - Long, Valerie
AU  - Long V
AD  - Research Center, Montreal Heart Institute, Montreal, Canada.
AD  - Faculty of Pharmacy, Universite de Montreal, Montreal, Canada.
FAU - Mathieu, Sophie
AU  - Mathieu S
AD  - Research Center, Montreal Heart Institute, Montreal, Canada.
AD  - Faculty of Pharmacy, Universite de Montreal, Montreal, Canada.
FAU - Fiset, Celine
AU  - Fiset C
AD  - Research Center, Montreal Heart Institute, Montreal, Canada.
AD  - Faculty of Pharmacy, Universite de Montreal, Montreal, Canada.
LA  - eng
PT  - Journal Article
DEP - 20210304
PL  - United States
TA  - Heart Rhythm O2
JT  - Heart rhythm O2
JID - 101768511
PMC - PMC8183852
OTO - NOTNLM
OT  - Heart rate
OT  - Mouse
OT  - Pregnancy
OT  - Propylthiouracil
OT  - Triiodothyronine
EDAT- 2021/06/12 06:00
MHDA- 2021/06/12 06:01
PMCR- 2021/03/04
CRDT- 2021/06/11 06:51
PHST- 2021/06/11 06:51 [entrez]
PHST- 2021/06/12 06:00 [pubmed]
PHST- 2021/06/12 06:01 [medline]
PHST- 2021/03/04 00:00 [pmc-release]
AID - S2666-5018(21)00041-6 [pii]
AID - 10.1016/j.hroo.2021.03.001 [doi]
PST - epublish
SO  - Heart Rhythm O2. 2021 Mar 4;2(2):168-173. doi: 10.1016/j.hroo.2021.03.001. 
      eCollection 2021 Apr.