Thyroid disease and the heart

Posted by e-Medical PPT Thursday, November 15, 2012
AC is 45 yo WM with palpitations, sob, sweating,
and chest pains x 2 weeks
• DOE over past month, worsening x 2 weeks
• Palpitations last a few minutes follow by
diaphoresis, lightheadedness, and chest pain
• Chest pain is substernal chest pressure, radiates
to left arm, 8/10 intensity; exertional in nature
and relieved with rest or leaning forward

Thyroid hormone
T4 prohormone converted to T3 active
• Animal studies demonstrate
– Direct positive inotropic effect
• Increases sodium-calcium-ATPase which increases calcium
influx
– Increase in LV cavity without change in EDP
• Increases rate of depolarization
• Decreases refractory period

Hyperthyroidism
Symptoms
– Palpitations
– Dyspnea
• Signs
– Tachycardia
– Systolic hypertension
– Hyperactive precordium
– Loud S1, accentuated P2, S3
– Occasional systolic click, midsystolic murmur
– Means-Lerman scratch – systolic scratch near LUSB

Hyperthyroidism and Atrial Fibrillation
Previously thought that hyperthyroid patients
have 5-15% incidence of atrial fibrillation
– Studies involved older patients with known structural
heart disease
• 1996 study demonstrates only 1% of new onset
atrial fibrillation is caused by overt
hyperthyroidism
• Treatment involves restoration of euthyroid state

Hyperthyroid Angina & CHF
Previously thought only to occur in presence of
coronary disease
– CHF occurs experimentally in animals by administering T4
– CHF has developed in children with thyrotoxicosis and no
coronary disease
– Angina has been reported in a patient with normal
coronaries, thought to be thyroid mediated coronary arterial
vasospasm
– Abnormal exercise LV function not reversed with b blockade,
but is reversed by treating hyperthyroidism
– Thyroid mediated cardiomyopathy may not be reversible
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