Hypothyroidism & thyroid disease

Slow heart, stiff heart, pericardial effusion — or high output, AF and heart failure in thyrotoxicosis.

Echo approach, step by step

Thyroid hormone affects contractility, relaxation, heart rate and vascular resistance. Hypothyroidism causes bradycardia, impaired relaxation, raised SVR, diastolic hypertension, reduced output and pericardial effusion. Hyperthyroidism causes a high-output state with tachycardia, AF, PH and heart failure [201].

  1. PericardiumEffusion, often large and slowly accumulated [201].
  2. LVLVEF (reversible dysfunction), wall thickness, relaxation (E/A, e′) [2,201].
  3. OutputLVOT VTI and CO: low in hypothyroidism, high in thyrotoxicosis [201].
  4. RV and PASPPulmonary hypertension in hyperthyroidism [201].
  5. AtriaLA size (AF) [182].

Causes & echo clues

StateEcho patternManagement
HypothyroidismEffusion, impaired relaxation, low output, bradycardiaLevothyroxine (start low in coronary disease) [201]
Myxoedema with effusionLarge effusion without collapseTreat thyroid; drain only if tamponade [201]
ThyrotoxicosisHyperdynamic LV, high CO, AF, high PASPBeta-blocker, antithyroid therapy [201]
Thyrotoxic cardiomyopathyLow EF with tachycardiaRecovers with euthyroid state [201]

Clinical pathway to the diagnosis

  1. TSH and free T4in any unexplained effusion, AF, bradycardia, or HF with high output [182,201].
  2. EchoEffusion size and haemodynamics; LV function [201].
  3. Repeat echo after 3–6 months of euthyroid stateto document recovery [201].

Clinical pearls & pitfalls

Practical tipA large effusion with no tamponade in a bradycardic, puffy patient → check TSH before pericardiocentesis [201].

Red flags