Sinus tachycardia – colloquially known as tachycardia – (synonyms: accelerated heart rate; sinus tachycardia; ICD-10 R00.0: tachycardia, unspecified) is a condition in which the normal physiologic heart rate for the age group is exceeded. In this case, the heart rate is increased to more than 100 beats per minute.
Sinus tachycardia is a cardiac arrhythmia that belongs to the group of excitation disorders. In this case, the excitation formation originates from the sinus node and passes through the excitation conduction system of the heart in a regular manner (= orthotopic tachycardia)
The sinus node (nodus sinuatrialis; synonyms: sinuatrial node (SA node) or Keith-Flack node) is the primary pacemaker center of the heart (= sinus rhythm). It is located in the area of the right ear of the heart near the suclus terminalis (depression that runs between the insertion of the superior and inferior vena cava).
Sinus tachycardia is considered physiological (without disease value) in infants, young children, physical and mental stress, emotional reactions, and pain.
On ECG (electrocardiogram), sinus tachycardia has a narrow ventricular complex (QRS width ≤ 120 ms) and is therefore referred to as narrow complex tachycardia.
Pathologically (pathologically), sinus tachycardia is seen in:
- Extracardiac genesis (origin is independent of the heart) / demand tachycardia – e.g., fever (per 1 °C increase in frequency of about 10 beats/minute), anemia (anemia), hypoxia (reduced supply of oxygen to the body), hyperthyroidism (hyperthyroidism), hypovolemia (reduction in the amount of blood circulating, i.e., in the bloodstream), hypotension (low blood pressure), infection, pulmonary embolism, shock.
- Cardiac genesis – for example, in heart failure (heart failure), myocardial infarction (heart attack).
To assess the tachycardia, the capacity of the heart and age must also be taken into account. One speaks of a critical limit when the heart rate corresponds to a value of 220 minus age.
Sinus tachycardia can be a symptom of many diseases (see under “Differential diagnoses”).
Course and prognosis: The primary focus is treatment of the underlying disease.
