An electrocardiogram (EKG) is a quick, non-invasive test that measures the electrical activity of the heart. It provides a snapshot of the heart’s rhythm and overall electrical health, making it a fundamental tool in assessing cardiac function. Receiving an “abnormal” result can cause worry, but this term is broad, encompassing findings from harmless variations to signs of serious disease. Understanding the context of the abnormality helps manage this concern.
Understanding the EKG Test
The EKG works by placing small electrodes on the skin of the chest and limbs to detect the electrical impulses generated by the heart muscle. These impulses trigger the heart’s contraction and relaxation cycle, which the EKG machine translates into a standard tracing of waves and segments known as the PQRST complex. Each deflection represents a specific electrical event.
The P wave reflects the electrical signal causing the atria (the heart’s upper chambers) to contract. The QRS complex marks the rapid depolarization of the ventricles (the lower chambers responsible for pumping blood). The T wave represents ventricular repolarization, the electrical recovery phase as the heart prepares for the next beat. Any deviation in the size, shape, or timing of these waves signals an alteration in the heart’s electrical system that warrants medical review.
How Common Are Abnormal EKG Findings?
Abnormal EKG findings are frequent, especially when the test is used for general screening in older populations. In one large study focusing on individuals aged 40 years or older, approximately 48.8% of participants did not have a completely normal electrocardiogram. This means nearly half of people in this age bracket show some variation from the textbook normal tracing.
The prevalence of EKG changes increases with advancing age, as the heart’s electrical pathways naturally change over time. Many findings are minor, such as slight changes in the electrical axis or certain repolarization patterns. Major EKG abnormalities, which are more likely to indicate underlying heart disease, are less common, affecting about 6.0% of men and 4.3% of women in one broad population study.
A machine-generated report of “abnormal” is a flag for a physician, not a definitive diagnosis of a serious condition. Some findings are common in otherwise healthy individuals, such as athletes who have slower resting heart rates (sinus bradycardia). Therefore, the frequency of an abnormal reading should not be confused with the severity of the finding, which always requires clinical interpretation.
The Spectrum of Abnormal EKG Results
The term “abnormal EKG” covers a wide clinical range, grouped into three main categories of significance.
Benign Variants
This category includes deviations from the norm that are not associated with disease. An example is early repolarization, an often-upward slurring of the ST segment frequently observed in younger, healthy people and athletes. Isolated premature ventricular contractions (PVCs), which feel like a skipped or extra beat, are also common and often harmless in people without structural heart disease.
Technical or Incidental Findings
This category involves findings not directly caused by heart disease itself. Non-cardiac factors like temporary electrolyte imbalances (e.g., low potassium or high calcium) can significantly alter the electrical tracing. Certain medications can also affect the heart’s electrical conduction, causing an abnormal reading. Simple issues like improper electrode placement or patient movement during the test can create artifacts that lead the machine to flag the result as irregular.
Clinically Significant Findings
This is the most concerning category, strongly suggesting underlying cardiac pathology. These include signs of inadequate blood flow to the heart muscle (ischemia), often visible as depression or elevation of the ST segment. Other serious findings are severe arrhythmias, like atrial fibrillation, or patterns suggesting a past heart attack through pathological Q waves. Evidence of heart enlargement, such as left ventricular hypertrophy, can also appear on the tracing, often linked to long-standing high blood pressure.
Next Steps Following an Abnormal Reading
When an EKG result is flagged as abnormal, the next step is a thorough clinical assessment by a physician, often a cardiologist, to provide context. The doctor reviews the specific EKG pattern alongside the patient’s medical history, symptoms, and existing risk factors. For low-risk or asymptomatic patients with minor variants, the physician may recommend watchful waiting without immediate further testing.
For concerning findings or if the patient reports symptoms like dizziness or chest pain, confirmatory testing is typically ordered. This often includes an echocardiogram, which uses ultrasound to visualize the heart’s structure, muscle function, and valves. A Holter monitor may also be used to record the heart’s electrical activity continuously over 24 to 48 hours to capture intermittent rhythm disturbances.
A stress test is often performed to evaluate the heart’s electrical response and blood flow demands during physical exertion. The physician may also review all current medications to see if a change in dosage or type could resolve the EKG changes. This systematic approach ensures the interpretation of the electrical tracing leads to an appropriate and personalized management plan.