Evaluation of Tachycardia

Last updated: April 8, 2026, 3:40 PM Pacific Time (PDT)

Symptom-first framework for persistent or clinically significant tachycardia. Start with stability and ECG rhythm, then separate sinus compensation from atrial arrhythmia, SVT, endocrine/toxic drivers, and high-risk causes like PE, sepsis, bleeding, or shock.

All Immediate stabilization Sinus / compensatory Arrhythmia High-risk secondary causes Back to Main Page

Interactive diagnostic assistant

Activate the assistant to re-rank likely tachycardia causes from partial clinical data.
Presentation
Compensatory clues
Arrhythmia clues
High-risk secondary clues
Other drivers

Likely diagnoses from entered data

Recommended next labs, imaging, and diagnostics

Flowchart

First pass
Tachycardia is either compensatory, arrhythmic, or both
The first split is stability plus ECG pattern. Then ask whether the rate is a sinus response to a driver, a primary atrial or supraventricular rhythm problem, or a marker of something dangerous like PE, sepsis, bleeding, or shock.
↓
Immediate stabilization
Instability changes the order of operations
Hypotension, syncope, ischemic chest pain, severe hypoxia, altered mentation, or very wide-complex tachycardia should move ahead of fine-grained rate classification.
Sinus / compensatory
Common inpatient
Sinus tachycardia from pain, fever, volume loss, withdrawal, or anemia
This is often the right answer, but only after checking whether it explains the whole picture.
Other systemic
Endocrine, medication, or toxic-metabolic driver
Thyrotoxicosis, beta-agonists, stimulants, pregnancy, and withdrawal live here.
Arrhythmia
Irregular
AF / flutter with rapid rate
Irregular rhythm plus prior history or trigger context points here quickly.
Regular abrupt
SVT or regular narrow-complex tachycardia
Abrupt onset/offset and very regular rhythm should raise this bucket.
High-risk secondary causes
Hypoxia / pleuritic story
Pulmonary embolism or right-heart strain physiology
Tachycardia may be the first clue when PE, hypoxia, or postop immobility is present.
Hypotension / perfusion issue
Sepsis, hemorrhage, cardiogenic shock, or mixed shock
If the patient is shocky, treat the hemodynamics and source, not just the number.

Topic details