ECG of diastolic (volume) vs systolic (pressure) overload

Diastolic (volume) overload

Example includes aortic regurgitation and dilated cardiomyopathy

ECG

LVH by voltageS
Sinus rhythm with LVH criteria met

  • Tall R wave with upright T wave is typical of volume overload

Other ECG features

  1. Negative U wave
  2. Septal Q wave
    – Q wave represents end diastolic volume. Therefore a dilated LV will have a deep Q wave.
    – Q wave represents initial left to right septum depolarization. A hypertrophied septum (HOCM) will have a deep Q.

Question: LV is dilated, not thickened. So why is LVH voltage criteria met?

  • Known as Brody effect
  • Blood is a good electricity conductor, and therefore will amplify the transmural current and resulting in high QRS voltage.

Pressure overload

Example includes hypertension and aortic stenosis.

ECG


ECG shows LVH with strain pattern (slurred ST segment).

Comparison of volume vs pressure overload:

LVH by voltageS
Volume overload


Pressure overload

Capture1

References:

  1. http://drsvenkatesan.com/2012/02/05/what-is-the-mechanism-of-deep-q-waves-in-volume-over-load-of-left-venricle/
  2. http://drsvenkatesan.com/2009/09/07/what-is-brody-effect-in-ecg/
  3. http://babymhospital.org/blog/bmh-ecg-library-left-ventricular-hypertrophy-lvh-by-voltage/
  4. http://lifeinthefastlane.com/ecg-library/basics/left-ventricular-hypertrophy/
  5. SRIDHAR VENKATACHALAM, MD, MRCP, CURTIS M. RIMMERMAN, MD, MBA. Electrocardiography in aortic regurgitation: It’s in the details. CCJM 2011 Aug;78(8):505-506.
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