Diagnostic and Prognostic Value of Abnormal Electrocardiogram Results

Diagnostic Value of Abnormal ECG Findings

The American College of Cardiology recommends that ECG abnormalities can identify specific cardiovascular pathologies including arrhythmias, conduction disorders, ischemia, cardiomyopathies, and channelopathies 2
Specific ECG patterns may suggest underlying conditions such as T-wave inversion patterns, which may indicate cardiomyopathy, ST-segment depression ≥0.5 mm in two or more contiguous leads, which suggests myocardial ischemia, pathologic Q waves, which may indicate previous myocardial infarction, ventricular pre-excitation, which suggests Wolff-Parkinson-White syndrome, prolonged QT interval, which may indicate congenital or acquired long QT syndrome, and epsilon waves, which may suggest arrhythmogenic right ventricular cardiomyopathy 3
In athletes, abnormal ECG findings require careful interpretation, as some patterns represent normal physiological adaptation, while others indicate pathology, according to the American College of Cardiology 1, 3
In patients with syncope, an ECG is a crucial diagnostic tool, although it provides a definitive diagnosis in only approximately 5% of cases, as stated by the American Heart Association and the American College of Cardiology 4, 5

Abnormal ECG findings are associated with increased risk of all-cause mortality at 1 year in patients presenting with syncope, according to the American Heart Association 4, 5
Specific ECG abnormalities carrying prognostic significance include atrial fibrillation, intraventricular conduction disturbances, voltage criteria for left ventricular hypertrophy, and ventricular pacing, which are associated with increased risk of death, as reported by the American College of Cardiology 4
P-wave amplitude in lead II of ≥0.25 mV is associated with a 2.8-fold greater risk of death over a 6-year follow-up period in patients with pulmonary arterial hypertension, according to the American Thoracic Society 6

The American College of Cardiology recommends that ventricular arrhythmias or high-grade AV block require immediate intervention 2
Asymptomatic competitive athletes with substantial ECG abnormalities but normal initial clinical evaluation should be followed with longitudinal clinical surveillance, including imaging, as stated by the American College of Cardiology 1

The ECG lacks sufficient sensitivity to serve as a screening tool for certain conditions like pulmonary arterial hypertension, with sensitivities of right-axis deviation and right ventricular hypertrophy being only 73% and 55%, respectively, according to the American Thoracic Society 6
The positive predictive value of ECG is poor when the population prevalence of the disorder being tested is low, as reported by the American Heart Association 7

A resting 12-lead ECG is an essential component of the initial evaluation of patients with known or suspected bradycardia or conduction disorder, according to the American College of Cardiology 5
ECG interpretation in athletes should follow current consensus recommendations, with clinical evaluation tailored to address the specific cardiovascular pathology suggested by the ECG abnormality, as stated by the American College of Cardiology 1, 3