Sinus Tachycardia ECG Characteristics

On an electrocardiogram (ECG), sinus tachycardia is identified by a regular and consistent rhythm originating from the sinoatrial node. This means that the P waves are upright in leads II, III, and aVF, while being inverted in lead aVR. The PR interval typically remains within the normal range of 0.12 to 0.20 seconds.

Heart Rate Criteria

One of the defining features of sinus tachycardia is a heart rate exceeding 100 beats per minute in adults. This elevated heart rate is usually a physiological response to various internal or external stimuli rather than a primary cardiac abnormality.

Common Causes and Triggers

Sinus tachycardia is among the most common types of arrhythmia and can be triggered by numerous factors. These include emotional stress, physical exertion, consumption of stimulants such as caffeine from coffee or tea, fever, dehydration, or even certain medical conditions like hyperthyroidism or anemia.

When Medical Intervention is Needed

While sinus tachycardia often resolves on its own once the underlying cause is addressed, some individuals may experience persistent or severe symptoms. In such cases, medical treatment may be necessary to control the heart rate and alleviate discomfort.

Treatment Options

For patients requiring pharmacological management, beta-blockers such as metoprolol (Lopressor), atenolol (Tenormin), or bisoprolol (Zebeta) are commonly prescribed. These medications help reduce heart rate and decrease the workload on the heart, providing symptomatic relief and improving overall cardiac function.