ECG as a screening tool

A recent study among asymptomatic post-menopausal women found an adjusted hazard ratios for CHD events of 1.55 (95% CI, 1.14-2.11) for minor, 3.01 (95% CI, 2.03-4.46) for major ECG abnormalities.[1] This study used a well defined list of major and minor ECG abnormalities that can be used to get a feel for major and minor ECG abnormalities:

Major ECG abnormalities[1][2]:

1. atrial fibrillation or atrial flutter
2. high-degree atrioventricular dissociation
3. left bundle-branch block
4. right bundle-branch block
5. indeterminate conduction delay
6. Q-wave MI
7. isolated ischemic abnormalities
8. left ventricular hypertrophy with ST-T abnormalities
9. supraventricular tachycardia
10. ventricular preexcitation
11. ventricular tachycardia

Minor ECG abnormalities[1][2]:

1. first- and second-degree atrioventricular block
2. borderline prolonged ventricular excitation
3. prolonged ventricular repolarization
4. isolated minor Q and ST-T abnormalities
5. left ventricular hypertrophy without ST-T abnormalities
6. left atrial enlargement
7. frequent atrial or ventricular premature beats
8. fascicular blocks

ECG markers of increased risk of ventricular arrhythmias in ICD patients

In a recent study several ECG risk markers were found to be associated with appropiate therapy in ICD patients[3]:

• depressed heart rate variability (HRV) [HR 2.7]
• BBB with large QRS dispersion of > 39 msec (difference between maximal and minimum QRS across 12 leads) [HR 2.9]
• Reduced maximal T wave amplitude (<0.4 msec in patients without BBB) [HR 3.8]
• History of atrial arrhythmias [HR 2.3]

References

1. Denes P, Larson JC, Lloyd-Jones DM, Prineas RJ, and Greenland P. Major and minor ECG abnormalities in asymptomatic women and risk of cardiovascular events and mortality. JAMA. 2007 Mar 7;297(9):978-85. DOI:10.1001/jama.297.9.978 |
2. Rautaharju PM, Park LP, Chaitman BR, Rautaharju F, and Zhang ZM. The Novacode criteria for classification of ECG abnormalities and their clinically significant progression and regression. J Electrocardiol. 1998 Jul;31(3):157-87.
3. Shi B, Harding SA, Jimenez A, and Larsen PD. Standard 12-lead electrocardiography measures predictive of increased appropriate therapy in implantable cardioverter defibrillator recipients. Europace. 2013 Jun;15(6):892-8. DOI:10.1093/europace/eus360 |