The Claim
In patients with hyperthyroidism, higher serum free thyroxine (fT4) levels are strongly correlated with greater severity and extent of myocardial ischemia as measured by Summed Stress Score and number of ischemic segments on 99mTc-Sestamibi scintigraphy.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
In people with hyperthyroidism, higher levels of free thyroxine in the blood are associated with more extensive and severe reductions in blood flow to the heart muscle, as detected by cardiac imaging.
See the scientific wording
In patients with hyperthyroidism, higher serum free thyroxine (fT4) levels are strongly correlated with greater severity and extent of myocardial ischemia as measured by Summed Stress Score and number of ischemic segments on 99mTc-Sestamibi scintigraphy, suggesting a dose-response relationship between thyroid hormone excess and cardiac stress.
Too much thyroid hormone makes the heart beat faster and harder, which uses more oxygen, while also narrowing the blood vessels that supply the heart muscle, so the heart doesn't get enough oxygen when it needs it most.
What the research says
1 studyIn people with an overactive thyroid, the higher their thyroid hormone levels, the more areas of their heart showed reduced blood flow during a stress test — meaning their hearts were working harder under strain. This suggests the excess hormone is directly stressing the heart.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.