Relationship between atrial fibrillation and primary hypothyroidism in the dog

Gerritsen, Ron; Brom, W. E. van den; Stokhof, Arnold A.

doi:10.1080/01652176.1996.9694614

Cited by 22 publications

(19 citation statements)

References 26 publications

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“…The frequencies of primary hypothyroidism in AF dogs were significantly higher than in the control animals, suggesting hypothyroidism may contribute to AF. 27 Nevertheless, there are no prior experiments specifically designed to examine the effects of hypothyroidism on AF arrhythmogenesis.…”

Section: Discussionmentioning

confidence: 99%

Both Hypothyroidism and Hyperthyroidism Increase Atrial Fibrillation Inducibility in Rats

Zhang

Dedkov

Teplitsky

et al. 2013

Circ: Arrhythmia and Electrophysiology

100

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Background Evidence indicates that cardiac hypothyroidism may contribute to heart failure (HF) progression. It is also known that HF is associated with an increased risk of atrial fibrillation (AF). While it is established that hyperthyroidism increases AF incidence, the effect of hypothyroidism on AF is unclear. This study investigated the effects of different thyroid hormone levels, ranging from hypothyroidism to hyperthyroidism on AF inducibility in thyroidectomized rats. Methods and Results Thyroidectomized rats with serum confirmed hypothyroidism 1 month after surgery were randomized into hypothyroid (n=9), euthyroid (n=9) and hyperthyroid (n=9) groups. Rats received placebo, 3.3mg L-thyroxine (T4), or 20 mg T4 pellets (60 day release form) for 2 months, respectively. At the end of treatment, hypothyroid, euthyroid and hyperthyroid status was confirmed. Hypothyroid animals showed cardiac atrophy and reduced cardiac systolic and diastolic function, while hyperthyroid rats exhibited cardiac hypertrophy and increased cardiac function. Hypothyroidism and hyperthyroidism produced opposite electrophysiological changes in heart rates and atrial effective refractory period, but both significantly increased AF susceptibility. AF incidence was 78% in hypothyroid, 67% in hyperthyroid, and the duration of induced AF was also longer, compared with 11% in the euthyroid group (all p<0.05). Hypothyroidism increased atrial interstitial fibrosis, but connexin 43 was not affected. Conclusions Both hypothyroidism and hyperthyroidism lead to increased AF vulnerability in a rat thyroidectomy model. Our results stress that normal thyroid hormone levels are required to maintain normal cardiac electrophysiology and prevent cardiac arrhythmias and AF.

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Section: Discussionmentioning

confidence: 99%

Both Hypothyroidism and Hyperthyroidism Increase Atrial Fibrillation Inducibility in Rats

Zhang

Dedkov

Teplitsky

et al. 2013

Circ: Arrhythmia and Electrophysiology

100

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“…25 Atrial fibrillation also has been associated with spontaneous canine hypothyroidism. 1,26 One of these studies suggested that atrial fibrillation might be associated with coronary atherosclerosis, 1 but the pathophysiology of cardiac dysfunction in canine hypothyroidism is likely multifactorial and is not well understood. 25 In the present study, 20 of 30 dogs with atherosclerosis had atherosclerosis of the coronary arteries.…”

Section: Discussionmentioning

confidence: 99%

Association between Diabetes Mellitus, Hypothyroidism or Hyperadrenocorticism, and Atherosclerosis in Dogs

Hess

Kass

Winkle

2003

Journal of Veterinary Internal Medicine

124

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The objective of this study was to determine whether dogs with atherosclerosis are more likely to have concurrent diabetes mellitus, hypothyroidism, or hyperadrenocorticism than dogs that do not have atherosclerosis. A retrospective mortality prevalence casecontrol study was performed. The study group included 30 dogs with histopathological evidence of atherosclerosis. The control group included 142 dogs with results of a complete postmortem examination, a final postmortem examination diagnosis of neoplasia, and no histopathological evidence of atherosclerosis. Control dogs were frequency matched for age and year in which the postmortem examination was performed. Proportionate changes in the prevalence of diabetes mellitus, hypothyroidism, and hyperadrenocorticism were calculated by exact prevalence odds ratios (POR), 95% confidence intervals (95% CI), and P values. Multiple logistic regression analysis was used to examine the combined effects of prevalence determinants while controlling for age and year of postmortem examination. Dogs with atherosclerosis were over 53 times more likely to have concurrent diabetes mellitus than dogs without atherosclerosis (POR ϭ 53.6; 95% CI, 4.6-627.5; P ϭ .002) and over 51 times more likely to have concurrent hypothyroidism than dogs without atherosclerosis (POR ϭ 51.1; 95% CI, 14.5-180.1; P Ͻ .001). Dogs with atherosclerosis were not found to be more likely to have concurrent hyperadrenocorticism than dogs that did not have atherosclerosis (POR ϭ 1.8; 95% CI, 0.2-17.6; P ϭ .59). Diabetes mellitus and hypothyroidism, but not hyperadrenocorticism, are more prevalent in dogs with atherosclerosis compared to dogs without atherosclerosis on postmortem examination.

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“…Atrial fibrillation has been suggested to be associated with hypothyroidism in dogs (Gerritsen et al, 1996), but this appears to be rare based on findings in other studies (Panciera, 2001). Abnormalities identified on physical examination may include bradycardia and a weak apex beat.…”

Section: Cardiovascular Signsmentioning

confidence: 97%

Hypothyroidism

Scott‐Moncrieff¹

2015

Canine and Feline Endocrinology

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Relationship between atrial fibrillation and primary hypothyroidism in the dog

Cited by 22 publications

References 26 publications

Both Hypothyroidism and Hyperthyroidism Increase Atrial Fibrillation Inducibility in Rats

Both Hypothyroidism and Hyperthyroidism Increase Atrial Fibrillation Inducibility in Rats

Association between Diabetes Mellitus, Hypothyroidism or Hyperadrenocorticism, and Atherosclerosis in Dogs

Hypothyroidism

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