The ECG Rhythms content is currently under development and is being updated by medical professionals.
Sinus tachycardia is characterized by a sinus rhythm where the heart rate exceeds 100 beats per minute in adults. This increase in heart rate is a result of the sinoatrial (SA) node discharging electrical impulses at a faster rate than normal.
Analogy: “The heart’s tempo has increased, like a song played at a faster speed.”
The ECG of sinus tachycardia displays a regular rhythm with a heart rate greater than 100 bpm. A P wave is present before each QRS complex, and its morphology is typically normal and upright in lead II, indicating that the impulse still originates from the SA node. The PR interval and the duration of the QRS complex usually remain within normal limits. The key characteristic is the accelerated rate of the rhythm, while all other features of a normal sinus rhythm are preserved. The atrial rate, as indicated by the frequency of the P waves, is also greater than 100 bpm.
Individuals experiencing sinus tachycardia may report symptoms such as palpitations, a sensation of a rapid heartbeat, shortness of breath, lightheadedness, and chest pain. Sinus tachycardia is often a physiological response to various conditions, including physical exercise, emotional stress, fever, and dehydration. It can also be a symptom of underlying medical conditions.
“Similar to a runner’s heart rate during a sprint, the heart is working harder and faster to meet increased demands.”