Sinus tachycardia is a physiological response to sympathetic activation and/or parasympathetic withdrawal. The most common causes include physical activity, fever, anemia, and dehydration.

Electrocardiographic Criteria

  • Sinus rhythm with a rate > 100 bpm
  • 1:1 atrioventricular relationship (P wave followed by QRS and T)

ECG in Sinus Tachycardia

Electrocardiogram showing sinus tachycardia

Sinus tachycardia. ECG showing a HR of 105 bpm.

References

  1. Scheffer MK, De Marchi MFN, de Alencar Neto JN, Felicioni SP. Eletrocardiograma de A a Z. São Paulo: Manole, 2024.