A study published in early 2019 examined the connection between thyroid function and the onset of atrial fibrillation (AF) by analyzing over 37,000 patient medical records. The researchers found that genetic variations resulting in even slightly higher or lower thyroid hormone levels within normal ranges can impact the risk of developing AF. The findings suggest doctors should consider treating subclinical hyperthyroidism with drugs, as that may reduce AF risk.

1. Study Examines Link
between Thyroid
Function and Atrial
Fibrillation
Sanjiv Narayan

2. Introduction
A cardiologist and researcher with decades of experience, Dr. Sanjiv M. Narayan serves as
the director of the Stanford Arrhythmia Center. Formerly a professor of medicine at UC
San Diego, Sanjiv Narayan, MD, PhD, has devoted the majority of his research career to
the study of atrial fibrillation (AF).
In early 2019, a research team at Vanderbilt University Medical Center published results
from a clinical trial that show a connection between thyroid function and the onset of AF.
Researchers conducted a retrospective observational analysis of more than 37,000
medical records in which they examined genetically determined levels of thyroid
hormones and the likelihood of the patient developing AF.
In previous research trials, hyperthyroidism that does not meet the standard for medical
intervention was already defined as a risk factor for AF. This new study goes further,
showing that even small genetic variations in thyroid function that fall within normal
parameters can still contribute to the risk of AF.
Researchers say these findings should be taken into account when doctors determine
whether to treat subclinical hyperthyroidism with drug therapy, as those medications can
also reduce the risk of the patient developing AF.