Management of Unstable Tachycardia with Hypotension
For a patient becoming unstable with elevated heart rate and low blood pressure, immediate synchronized cardioversion is recommended as the first-line intervention.1
Initial Assessment
- Assess for signs of hemodynamic instability: altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or shock 1, 2
- Check oxygen saturation and provide supplementary oxygen if oxygenation is inadequate 1, 2
- Establish IV access, attach cardiac monitor, and evaluate blood pressure 1, 2
- Obtain a 12-lead ECG if the patient is stable enough to wait, but do not delay treatment if the patient is extremely unstable 1, 2
Immediate Management for Unstable Tachycardia with Hypotension
Electrical Therapy
- Perform immediate synchronized cardioversion for unstable tachycardia causing hypotension 1
- Sedate the patient prior to cardioversion if conscious and time permits 1
- For unstable wide-complex tachycardia, presume ventricular tachycardia and perform immediate cardioversion 2
- Consider precordial thump for witnessed, monitored unstable ventricular tachycardia if a defibrillator is not immediately ready 1
Pharmacological Management
- If cardioversion is unsuccessful or tachycardia recurs, consider antiarrhythmic medications based on the specific rhythm 1
- For persistent hypotension after cardioversion, initiate vasopressor therapy 1, 3
- Norepinephrine is recommended as the first-choice vasopressor for hypotension 1, 3
Specific Management Based on Rhythm Type
For Narrow-Complex Tachycardia
- If the patient is unstable with narrow-complex tachycardia, immediate synchronized cardioversion is recommended 1
- In select cases of regular narrow-complex tachycardia with unstable signs, a trial of adenosine before cardioversion may be considered 1
- Avoid AV nodal blocking agents in patients with pre-excited atrial fibrillation or flutter 2
For Wide-Complex Tachycardia
- For unstable wide-complex tachycardia, immediate synchronized cardioversion is recommended 1
- If cardioversion is unsuccessful, consider amiodarone (150 mg IV over 10 minutes) 2
- Avoid adenosine for irregular or polymorphic wide-complex tachycardias 1
Volume Resuscitation
- Assess for hypovolemia as a potential cause of tachycardia with hypotension 1
- Administer crystalloids initially for volume resuscitation 1
- Norepinephrine should not be given to patients who are hypotensive from blood volume deficits except as an emergency measure to maintain coronary and cerebral artery perfusion until blood volume replacement can be completed 3
- Target systolic blood pressure of 80-100 mmHg until major bleeding has been stopped in trauma patients without brain injury 1
Special Considerations
- Tachycardia is not always a reliable sign of hypotension after trauma; absence of tachycardia should not reassure the clinician about the absence of significant blood loss 4
- Patients who are both hypotensive and tachycardic have an increased mortality and warrant careful evaluation 4
- In some cases, relative bradycardia may occur with hypotension, particularly in severe injuries, and may be associated with better prognosis than tachycardia 5
- Elderly patients may present with orthostatic hypotension and tachycardia due to age-related physiological changes, medications, or comorbidities 6
Common Pitfalls to Avoid
- Delaying cardioversion in unstable patients while waiting for 12-lead ECG 2
- Using AV nodal blocking agents in pre-excited atrial fibrillation/flutter 2
- Administering adenosine for irregular or polymorphic wide-complex tachycardia 1
- Normalizing heart rate in compensatory tachycardias where cardiac output depends on rapid rate 1
- Administering norepinephrine without addressing underlying hypovolemia 3
- Assuming tachycardia will always be present with hypotension 4, 5