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Electrocardiogram Criteria to Diagnose Cardiac Amyloidosis in Men With a Bundle Branch Block

Sunita Sharma1, Sherif B Labib1, Sachin P Shah1

  • 1Division of Cardiovascular Medicine, Lahey Hospital & Medical Center, Burlington, Massachusetts.

The American Journal of Cardiology
|February 2, 2021
PubMed

Insights

Diagnosing cardiac amyloidosis with increased left ventricular wall thickness (LVWT) and bundle branch block (BBB) is challenging. A novel Total QRS Score/LVWT index shows promise as a sensitive and specific screening tool for this condition.

Area of Science:

  • Cardiology
  • Medical Diagnostics

Background:

  • Cardiac amyloidosis diagnosis is difficult, often requiring high suspicion in patients with increased left ventricular wall thickness (LVWT).
  • Low QRS voltage on ECG is a known marker, but its variable presence (20-74%) limits diagnostic accuracy.
  • Existing ECG criteria for cardiac amyloidosis may be unreliable in patients with bundle branch block (BBB) due to conduction system infiltration.

Purpose of the Study:

  • To identify novel ECG criteria for diagnosing cardiac amyloidosis in patients with increased LVWT and BBB.
  • To evaluate the diagnostic accuracy of various QRS voltage/LVWT ratios.

Main Methods:

  • Calculation of several indices including Total QRS Score/LVWT, limb lead QRS score/LVWT, R in lead aVL/LVWT, R in lead I/LVWT, and Sokolow index/LVWT.
  • Comparison of these indices in patients with increased LVWT and BBB, differentiating cardiac amyloidosis from LVH due to pressure overload.

Main Results:

  • The Total QRS Score/LVWT index demonstrated the highest diagnostic accuracy.
  • A cutoff value of 92.5 mV/cm for Total QRS Score/LVWT was 100% sensitive and 83% specific for cardiac amyloidosis.
  • This index effectively distinguishes cardiac amyloidosis from pressure overload-induced LVH in the studied population.

Conclusions:

  • The Total QRS Score/LVWT index is a valuable tool for screening patients with increased LVWT and BBB.
  • This novel index can aid in raising diagnostic suspicion for cardiac amyloidosis, improving early detection.
  • It offers improved diagnostic accuracy compared to traditional QRS voltage criteria in patients with BBB.

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