ECG changes that may be seen in obese individuals

  Low voltage: due to excessive chest wall fat and/or increased epicardial fat.

 
Increased voltage due to left ventricular hypertrophy (the Cornell voltage and Cornell product appear to be

      the best ECG criteria for diagnosing LVH in obese persons)

 
Left axis deviation

 
PR interval prolongation (controversial)

 
QT interval prolongation

 
Flattening of the T wave in the inferior and lateral leads (49%),

      T wave flattening in the lateral leads in 29% of morbidly obese patients (and 1% of controls).

 
Negative T wave in lead III: (49%)

 
Non-specific ST and T wave abnormalities (11%)

 
ST depression: very rare.

 
Ventricular Premature Contraction (VPC): Prevalence of premature ventricular (but not atrial) contractions

      was reported to be 30 times higher in obese patients with eccentric left ventricular hypertrophy

      compared with lean subjects.

  Increased heart rate (resting tachycardia in 0.5% of obese individuals).




Obesity therapy and the ECG changes

  Sleeve gastrectomy in morbidly obese patients was reported to be associated with a significantly lower

      QTc interval 3 months after surgery.

  T wave abnormalities in obese individuals may return to normal after weight loss.




Comorbidities that may further modify the ECG in obese patients

  Hypertension

  Diabetes Mellitus

  Coronary artery disease (stenosis or
coronary slow flow phenomenon)

  Obstructive Sleep Apnea (OSA)

  Pickwickian syndrome (Obesity hypoventilation syndrome)




References

  J Am Heart Assoc 2014 Mar 4;3(2):e000477. doi: 10.1161/JAHA.113.000477.

  Int J Cardiol 2014 Oct 20;176(3):841-846. doi: 10.1016/j.ijcard.2014.08.008.

  Arterioscler Thromb Vasc Biol 2006;26:968-976.

  Obes Surg 2014;24:167-170.

  Obes Rev 2005;6:275-281.

  J Am Coll Cardiol 1986;7:295-299.

  Arch Intern Med 1987;147:1725-1728.





ECG 1. The ECG above is from a 60 years-old hypertensive, obese woman with coronary artery ectasia and slow flow.
Negative T waves are seen in leads III and aVF.

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ECG 2. The ECG above is from a morbid obese (
171 kg) woman with hypertension and normal coronary arteries.
Precordial leads show negative T waves and ST segment depression.

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ECG 3. The ECG above is from a morbid obese woman with normal coronary arteries and Pickwickian syndrome.
Anterior and lateral leads show negative T waves.





ECG 4. The ECG above is from a 58 years-old, hypertensive obese man with coronary artery ectasia and slow flow.
He has right bundle branch block. Negative T waves are present throughout the chest leads.
However, he does not have obstructive coronary artery disease.





ECG 5. The ECG above is from a 33 years-old morbid obese man with normal coronary arteries.
Negative T waves are seen in leads III and aVF.





ECG 6. The ECG above is from a 50 years-old obese and hypertensive man with coronary artery ectasia and slow flow.
Widespread T wave negativity is seen.

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ECG 7. The ECG above is from a 56 years-old obese and hypertensive man with coronary artery ectasia and slow flow.
Widespread T wave negativity is seen.

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ECG 8. The ECG above is from an old woman with obesity, hypertension and normal coronary arteries.
She is diabetic for the last 12 years.
The ECG shows sinus tachycardia and ST depression despite the presence of normal epicardial coronary arteries.
At the time the above ECG was recorded, her blood glucose level was measured as 552mg/dL.

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ECG 9a. The ECG above is from a 52 years-old obese woman with marked slow flow in the LAD coronary artery.
She has no obstructive epicardial coronary artery disease.
The above ECG was recorded in the morning. Leads III and aVF show negative T waves.

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ECG 9b. Above is her ECG, which was recorded 8 hours after the ECG 9a.
In addition to leads III and aVF, lead V4 to V6 also show negative T waves.

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