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Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

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1. Of pediatrics patients with left axis deviation (LAD) found incidentally on electrocardiogram (ECG), only 15% of patients had heart disease (HD) on further work up.

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2. Features indicating the possibility underlying HD included those patients with a more severe degree of LAD, those with chamber enlargement or hypertrophy, and those with abnormal cardiac physical exam findings.

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Evidence Rating Level: 2 (Good)

Study Rundown:

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Pediatricians order ECGs on children for a multitude of reasons, and the clinical significance of abnormal findings is sometimes difficult to determine. In this study, researchers sought to determine if incidentally-discovered left axis deviation (LAD) was associated with underlying heart disease (HD). Researchers reviewed the charts of children with ECGs revealing LAD but without previously diagnosed HD or other conduction abnormality. Of those patients who received further work up with a transthoracic echocardiogram (TTE), only 15% were found to have underlying heart disease. Those who were found to have HD on TTE were noted to significantly more severe axis deviation than those with LAD but without HD, as well as evidence of cardiac chamber enlargement and abnormal cardiac physical exam findings. Though limited by small sample size, these findings provide more data which warrant further investigation of how best to identify patients who may need further work up for incidentally found LAD.

In-Depth [retrospective cohort]:

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In this study, researchers conducted a retrospective chart review using the Mayo Clinic’s electronic medical record. Participants included patients between the ages of 1-18 years with evidence of LAD on an ECG from January 2002 to December 2014. Those with previously diagnosed HD, left bundle branch block, paced ventricular rhythm, LAD in the setting wide complex tachycardia, and LAD after heart transplant were excluded, leaving 296 patients for evaluation. Of those patients, 158 received further workup with TTE. In this subset who received TTE, 24 (15%) were found to have underlying HD, of which most were either valvular or septal in nature. In comparison to those patients who received TTE and did not have HD, those with HD were more likely to have an average QRS axis ≤−42° (58% vs 26%; P = .003) (sensitivity: 58%; specificity: 74%; positive predictive value [PPV]: 29%; negative predictive value [NPV]: 91%), cardiac chamber enlargement or hypertrophy as noted on ECG (38% vs 5%; P < .0001) (sensitivity: 38%; specificity: 95%; PPV: 56%; NPV: 89%), and abnormal cardiac exam findings (75% vs 8%; P < .0001) (sensitivity: 75%; specificity: 92%; PPV: 62%; NPV: 95%).

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