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Orthopedics

April 2009 EKG case

 An 82 year old male presents complaining of palpitations. He has a history of MI, HTN, depression and recently diagnosed hypothyroidism.  His meds include aspirin 81mg daily, Toprol XL 50mg daily, enalapril 5mg daily, nitro S/L prn, celexa 20 mg daily and last week he started levothyroxine 100mcg daily as prescribed by the medical resident he sees in the clinic.

What does the EKG and rhythm strip show?

Rate:      variable

Rhythm:  sinus with atrial bigeminy, a premature p wave occurs after each normal beat

Axis:    left axis deviation

PR:    variable

QRS:     right bundle branch block

ST:    T inversions V1,V2,V3,V4

EKG diagnosis:   Sinus with atrial bigeminy

Clinical diagnosis:  Thyroid hormone overdose

• -100mcg is a very high starting dose.  The usual starting dose is 25 mcg which is gradually titrated over a year to the maintenance dose.

What are some potential causes of this rhythm?

• Anything that can increase the irritability of the atria, often adrenergic substances such as caffeine, amphetamines, cocaine or epinephrine. It can also be caused by hyperthyroidism, ethanol, digoxin and hypoxia.

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