Quick guide
Diagnostic approach
- ABCDE survey
- Targeted clinical evaluation
- 12-lead ECG
- POC glucose
- CBC
- BMP
- Blood gas analysis
- Thyroid function tests
Red flag features
- Signs of unstable tachycardia
- Hypotension
- Hypoxemia
- Altered mental status
- Chest pain
- Signs of sepsis
Life-threatening causes
- Hemorrhagic shock
- Sepsis
- Pulmonary embolism
- Cardiac tamponade
- Drug toxicity (e.g., severe stimulant intoxication)
- Thyroid storm
- Hypoglycemia
Management checklist
- Assess for signs of unstable tachycardia.
- IV access
- Continuous cardiac monitoring and pulse oximetry
- Hypoxemia: supplemental oxygen
- Shock: IV fluid resuscitation
- Identify and treat the underlying cause.
- Pulseless: treat as PEA.
- Unstable tachycardia: Follow unstable tachycardia algorithm.
- Stable and uncertain diagnosis of sinus tachycardia: Follow stable, regular narrow-complex tachycardia algorithm.
Summary
Sinus tachycardia is a heart rate exceeding 100/minute that originates from the sinus node, and it can be physiological or inappropriate. It commonly results from sympathetic activation or vagal withdrawal triggered by a myriad of factors (e.g., exercise, hypovolemia, hyperthyroidism, drug toxicity). Patients may be asymptomatic or report dizziness, palpitations, fatigue, and/or chest pain, in addition to symptoms of the underlying cause. Diagnosis is based on characteristic ECG findings, including a regular P wave followed by a narrow QRS complex, regular ventricular rhythm, and equal atrial and ventricular rates. Diagnosis and management are focused on identifying and treating the underlying cause. Physiological sinus tachycardia typically resolves with treatment of the underlying condition and requires no specific intervention. Inappropriate sinus tachycardia warrants referral to cardiology for advanced testing and specialized treatment.
Definitions
- Sinus tachycardia: a heart rate exceeding 100/minute that originates from the sinus node; can be physiological or inappropriate [1]
- Physiological sinus tachycardia: sinus tachycardia that is a physiological response to a stressor (see "Etiology") [1]
- Pathological sinus tachycardia: sinus tachycardia due to an underlying disorder (see "Etiology") [1]
- Inappropriate sinus tachycardia: symptomatic, pathological, and unexplained sinus tachycardia (i.e., known triggers have been ruled out) [1][2]
- Reflex tachycardia: sinus tachycardia that is a baroreceptor-mediated sympathetic nervous system response to hypotension
- Postural orthostatic tachycardia syndrome (POTS): a subtype of sinus tachycardia triggered by orthostatic changes that typically manifests with presyncope in addition to tachycardia
Etiology
Generally, sinus tachycardia is caused by sympathetic activation or vagal withdrawal on the SA node due to the following underlying conditions:
Physiological sinus tachycardia [1][3]
- Exercise
- Deconditioning
- Anxiety
- Pregnancy
Pathological sinus tachycardia [1][3]
- Fever
- Hypoxemia
- Hypovolemia and/or hemorrhage
- Hypotension (e.g, orthostatic hypotension, distributive shock, obstructive shock)
- Anemia
- Hyperthyroidism
- Hypoglycemia
- Inflammation (e.g., SIRS)
- Conditions associated with catecholamine release (e.g., pheochromocytoma)
- Drugs that have sympathomimetic, vagolytic, and/or vasodilatory effects, e.g.:
Clinical features
- Rapid heart rate
- Dizziness, lightheadedness, and/or weakness
- Palpitations
- Pallor
- Fatigue
- Anxiety
- Chest pain
- Clinical features of the underlying cause, e.g.:
Diagnosis
Initial diagnosis of sinus tachycardia is based on characteristic ECG findings. Further diagnostics are typically obtained to assess for the underlying cause.
ECG [1][3]
-
Regular sinus P wave
- Normal P wave axis and morphology
- Each P wave is followed by a narrow QRS complex.
- Ventricular rhythm: regular
- Atrial rate = ventricular rate
- Beat-to-beat variability is typical.
- Typical maximum heart rate
- Adults: 130–140/minute; rarely exceeds 170/minute [4]
- Children: < 180/minute [5]
- Infants: < 220/minute [5]
The likelihood of supraventricular tachycardia increases when heart rate exceeds maximal ranges; use clinical judgment and consider specialist consultation when interpreting ECGs, as P waves may be subtle or invisible due to concurrent atrial and ventricular impulses. [4]
Common diagnostics [1][3]
Workup in patients with sinus tachycardia focuses on assessing the underlying cause to guide treatment and may include:
-
Laboratory testing
- CBC
- BMP
- Blood gas analysis
- Blood glucose
- Thyroid function tests
- Toxicology screening (rarely helpful for acute management) [3][6]
- Diagnostics for sepsis
- Diagnostics for heart failure
- Advanced studies
Differential diagnoses
The following are mimics of sinus tachycardia; see "Etiology for underlying causes."
The differential diagnoses listed here are not exhaustive.
Management
Initial management
If the diagnosis of sinus tachycardia is uncertain, follow ACLS algorithms for management of tachycardia.
- Undifferentiated tachycardia: See "Approach to tachycardia."
- Pulseless patient with sinus tachycardia: Treat as pulseless electrical activity and begin ACLS for nonshockable rhythms.
- Patient with pulse and signs of unstable tachycardia: See "Management of unstable tachycardia with pulse."
- Stable patients with a regular narrow-complex tachycardia (NCT): See "Management of stable regular NCT.
Definitive management [1]
Once the diagnosis of sinus tachycardia is established:
- Identify and treat the underlying cause (see "Etiology").
- Physiological sinus tachycardia: No specific treatment required.
- Idiopathic and/or inappropriate sinus tachycardia: Refer to cardiology for advanced testing (e.g., Holter monitor, tilt table test, serology, metanephrines) and treatment.
- Suspected POTS: See "POTS" in "Noncardiac syncope."
Disposition
- Patients with physiological sinus tachycardia without underlying disease may be discharged with reassurance and encouraged to avoid potential triggers. [1]
- Consider emergency department referral and/or admission as indicated by the underlying cause (e.g., sepsis, acute heart failure, pulmonary embolism, cardiac tamponade).