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Tachycardia
Aka: Tachycardia, Unstable Tachycardia, Unstable Tachyarrhythmia
- See Also
- Cardiopulmonary Resuscitation
- Sinus Tachycardia
- Narrow Complex Tachycardia
- Wide Complex Tachycardia
- Signs: Unstable
- Rapid Heart Rate
- Poor Perfusion
- Altered Level of Consciousness
- Hypotension
- Shock
- Differential Diagnosis
- Pulseless Electrical Activity
- Narrow Complex Tachycardia
- Sinus Tachycardia
- Irregular Supraventicular Tachycardia
- Atrial Fibrillation
- Regular Supraventricular Tachycardia
- Sinus Tachycardia (rarely >150 in adults)
- Atrial Flutter
- Atrial rate: 300 bpm
- Ventricular rate most commonly 2:1 = 150 bpm
- Paroxysmal Supraventricular Tachycardia (PSVT)
- Atrioventricular Nodal Reentry (AVNRT)
- Signal down the slow AV nodal pathway and retrograde up the fast AV nodal pathway
- In 10% of cases, the signal reentry route is reversed
- Atrioventricular Reciprocating Tachycardia (AVRT)
- Includes Wolff-Parkinson-White Syndrome (characterized by delta wave)
- Accessory pathway outside the AV Node
- Orthodromic (narrow complex): Signal down the AV Node and up the accessory path
- Antidromic (wide complex): Signal down the accessory path and up the AV Node
- Atrial Tachycardia (AT)
- Abnormal focus of atrial automaticity (outside the SA Node)
- Unlike AVNRT and AVRT, no accessory pathway is involved
- Junctional Ectopic Tachycardia
- Wide Complex Tachycardia
- Ventricular Tachycardia (VT)
- Torsade De Pointes
- Supraventricular Tachycardia (SVT) with aberrancy (e.g. Bundle Branch Block)
- Mistakenly managing Ventricular Tachycardia as SVT can be lethal (assume VT first)
- Even using established guidelines for wide SVT, will miss 10-40% of cases
- Findings consistent with Ventricular Tachycardia
- Lead V1 with taller R than R' (taller left rabbit ear)
- Lead V6 with R Wave < S Wave (RS upward deflection < downward deflection)
- Atrioventricular Dissociation
- Fusion complexes (Fusion Beats)
- Combined supraventricular and ventricular beats (e.g. QRS Complex merges into P Wave)
- References
- Mattu (2018) Crit Dec Emerg Med 32(5): 29
- Management (Same initial approach for all ages)
- ABC Management
- Mnemonic: IV-O2-Monitor
- Obtain IV Access
- Oxygen Delivery
- Cardiopulmonary monitor
- Additional evaluation
- Vital Signs
- History
- Exam
- Electrocardiogram
- Chest XRay
- If signs of immediate failure present:
- Pulse Present and NOT Sinus Tachycardia
- Prepare for immediate Synchronized Cardioversion
- Brief trial of medications (e.g. Adenosine) if no delay
- Pulse Absent
- Asystole
- Pulseless Electrical Activity
- Ventricular Tachycardia
- Ventricular Fibrillation
- Assess QRS Duration
- If QRS Duration narrow (<0.09 sec in children or <0.12 sec in adults)
- See Narrow Complex Tachycardia
- See Supraventricular Tachycardia Management in the Child
- See Supraventricular Tachycardia Management in the Adult
- If QRS Duration wide (>0.09 sec in children or >0.12 sec in adults)
- See Wide Complex Tachycardia
- See Ventricular Tachycardia Management in the Adult
- See Ventricular Tachycardia Management in the Child
- References
- Cardiopulmonary Resuscitation Guidelines
- http://www.circulationaha.org
- (2010) Guidelines for CPR and ECC [PubMed]
- (2000) Circulation, 102(Suppl I):86-9 [PubMed]