Rhythm & Rate 13

This 65 year old man presented with dizziness for investigation. He had a past history of Human Immunodeficiency Virus infection and thyroidectomy. Examination of the nervous system was normal, apart from the observation that he was a vague historian. The following blood tests results from 30 months ago were normal: electrolytes, urea and creatinine concentration; calcium & phosphate concentration; full blood examination; thyroid function tests.
Figure_1 shows the ECG taken on arrival



+ Describe the main ECG findings

The main findings in R-0013 are

  • Sinus rhythm with a heart rate of about 52 beats per minute
  • Prolonged PR interval
  • T wave flattening in the anterolateral leads
  • Q waves in Leads V1 to V3 and I mm of ST elevation in Lead V2 and Lead V3
  • The QRS complexes in Lead I, Lead III, Lead aVL and Lead aVF have a low amplitude (5 mm [0.5 mV] or less). The QRS amplitude in Leads V1, V4 and V6 have a low amplitude (10 mm or less)

Thyroid function tests showed a elevated TSH of 178.2 mIU/L (normal 0.4-4.0 mIU/L) and a low free thyroxine level of < 5.2 pmol/L (normal 10-25 pmol/L). The patient is hypothyroid

Key Points:

Sinus bradycardia due to hypothyroidism

The effects of hypothyroidism on the heart are discussed in "Thyroid Disease and the ECG" in the "Nuts & Bolts" section of the website