An electrocardiogram (ECG or EKG) is a test that records the electrical signals of the heart, providing a snapshot of its rate and rhythm to detect cardiac conditions. Anxiety, a state of tension and worry, triggers physiological responses that influence the heart’s activity. This connection between emotional state and ECG results can create uncertainty for individuals undergoing the test.
The Body’s Response to Anxiety
When a person experiences anxiety, the body initiates the “fight-or-flight” response. This reaction is managed by the sympathetic nervous system, a branch of the autonomic nervous system that prepares the body for a perceived threat. The nervous system signals the adrenal glands to release adrenaline and cortisol into the bloodstream.
Adrenaline acts almost immediately, causing a rapid increase in heart rate and the force of the heart’s contractions to boost oxygen delivery. Cortisol sustains the body’s heightened state of arousal. This hormonal surge affects the cardiovascular system by increasing heart rate and elevating blood pressure, which can impact medical measurements.
How Anxiety Can Alter an ECG Reading
The physiological changes from the fight-or-flight response can produce several alterations on an ECG. The most frequent finding is sinus tachycardia, a regular but rapid heart rhythm where the rate exceeds 100 beats per minute. This occurs as the heart’s natural pacemaker, the sinus node, is stimulated.
Anxiety can also cause changes in the ECG waveform that mimic cardiac distress. These include modifications to the ST segment and T wave, which represent ventricular repolarization, the phase when the heart muscle resets after a beat. Intense anxiety can cause ST segment depression or, less commonly, elevation.
The T wave can also appear flattened or inverted. Stress hormones alter how electrical currents move through heart cells during their recovery phase. Because these changes are also patterns that indicate reduced blood flow to the heart, an ECG from an anxious person can be misinterpreted without clinical context.
Distinguishing Anxiety from Cardiac Events
Clinicians interpret ECG findings within a broader clinical picture to differentiate between anxiety-induced changes and a cardiac event. An ECG is a single piece of data, not a complete diagnosis. The patient’s description of their symptoms is important; for example, chest pain from a panic attack often subsides within 30 minutes, while pain from a heart attack may persist.
The characteristics of the ECG changes provide further clues. Anxiety-related ST and T wave changes often appear across multiple, unrelated areas of the heart. In contrast, changes from a coronary artery blockage are localized to the region that the artery supplies. Anxiety also does not cause pathological Q waves, which are markers of heart muscle death.
A clinician will also consider the patient’s age, medical history, and risk factors for heart disease. Comparing the current ECG to any previous recordings is also a practice used to identify new changes.
The Diagnostic Follow-Up Process
When an ECG shows ambiguous results that could be due to anxiety or a cardiac issue, further investigation is needed. The initial step is often repeating the ECG after a period of rest. The transient nature of anxiety-related ECG changes is an indicator; if abnormalities resolve as the patient calms down, it suggests anxiety was the cause.
For intermittent symptoms like palpitations not captured on a standard ECG, a physician may suggest a Holter monitor. This is a portable device that records the heart’s electrical activity continuously for 24 to 48 hours during daily routines. This extended recording increases the chance of capturing rhythm disturbances.
If structural or functional heart problems are suspected, an echocardiogram may be ordered. This test uses ultrasound waves to create detailed images of the heart’s muscle, chambers, and valves. A cardiac stress test might also be used, which monitors the ECG during exercise to see how the heart performs under physical demand.