sinustakykardia

Sinus tachycardia, or sinustakykardia, is a heart rhythm characterized by an elevated heart rate with a normal sinus rhythm. In adults, it is defined by a resting heart rate above 100 beats per minute, with regular rhythm and P waves preceding every QRS complex and a normal PR interval.

The condition arises from increased automaticity of the sinoatrial node or reduced vagal tone, usually due to sympathetic stimulation. Common physiological triggers include exercise, fever, heat exposure, pregnancy, anxiety, pain, dehydration, and volume loss. Pathological causes encompass anemia, hypoxemia, hyperthyroidism, heart failure, pulmonary embolism, sepsis, and certain drugs or substances (stimulants, caffeine, beta-agonists, thyroid hormone).

Clinical presentation varies. Many people are asymptomatic and tachycardia is found on examination or ECG. When symptoms occur, they may include palpitations, lightheadedness, shortness of breath, chest discomfort, or faintness, depending on the underlying cause and the heart’s response.

Diagnosis relies on ECG showing a regular rhythm with a rate typically above 100 bpm and normal P waves before each QRS complex. Evaluation also aims to identify underlying causes through history, physical exam, and laboratory tests (eg, complete blood count, thyroid function, oxygenation, hydration status). It is important to distinguish sinus tachycardia from other tachyarrhythmias such as supraventricular tachycardia.

Management focuses on treating the underlying cause and avoiding unnecessary antiarrhythmic therapy. In stable patients, observation and supportive care are common. If symptoms are significant or the condition persists, rate control with medications such as beta-blockers or calcium channel blockers may be used. In unstable patients, standard tachyarrhythmia protocols apply. Sinus tachycardia generally has a favorable prognosis when the underlying issue is addressed.