sinus tachycardia

Introduction

Depolarization of the sinus node at a rate >100/min with a normal pattern of atrial & ventricular activation.

Etiology

• increased levels of circulating catecholamines -pheochromocytoma
• pain
• hypovolemia, anemia
• hypoxemia
• myocardial ischemia or myocardial infarction
• pulmonary embolism
• fever
• inflammation
• hyperthyroidism
• anxiety
• exercise

Clinical manifestations

• may lead to decreased cardiac output

Diagnostic procedures

• electrocardiogram:
  • p-wave precedes each QRS complex
  • p-waves have normal configuration & axis
  • PR interval is normal or slightly shortened
  • QRS pattern is usually normal
  • occasionally, bundle-branch block may occur secondary to increased rate

Management

• correct underlying precipitating factors
• fluid replacement in hypovolemic patient
• beta-adrenergic receptor antagonist
  • volume repleted patient
  • myocardial ischemia or myocardial infarction

More general terms

• supraventricular tachycardia (SVT)

More specific terms

• inappropriate sinus tachycardia