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Tachycardias

Quick Diagnosis

Aetiology

Assessment

Management

Practical Points

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Normal heart rate is 60 - 100 beats/minute

Tachycardia refers to any heart rate > 100 beats per minute

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Tachycardias are a common cause of clinical review/MET calls

  • 14 - 24% of MET calls are for tachycardia

  • Commonly stable AF with rapid ventricular response (rapid AF)

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This section aims to:

  • Assist in identification of both common and life-threatening causes of inpatient tachycardias

  • Guide initial and emergency management of tachydysrhythmias

  • Outline appropriate escalation to critical care services

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Key Points:

  • You can ALWAYS call for advice if you are unsure, worried or have reached the limit of your practice

  • Many non-cardiac causes exist, which are non-life-threatening and easily treatable

    • For example, pain, fever, anxiety, smoking​

    • Always check for these causes and treat appropriately BUT you must always consider and rule out more significant causes

  • Assessment of patient and ECG are ESSENTIAL for the diagnosis of any likely cause

  • If adverse features exist and you are trained in ALS, call a code blue, apply pads, prepare sedation and prepared for a SYNCHRONISED DC shock

  • If adverse features exist and you are NOT trained in ALS, call a code blue and apply pads whilst waiting for support to arrive

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Quick Tachyarrhythmia Diagnosis

  1. Narrow complex vs broad complex (QRS > 120 msec/3 small sqares)

  2. Regular vs Irregular

Quick Diagnosis

Aetiology

Life-threatening causes that must be immediately ruled out:

  • Cardiogenic

    • VF/VT​

    • SVT

    • Acute coronary syndrome

    • Cardiac tamponade

  • Non-Cardiogenic

    • PE​

    • Sepsis

    • Haemorrhage/Severe hypovolaemia

    • Hypoxia

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Other common causes

  • Paroxysmal AF with rapid ventricular response

  • Pain

  • Electrolyte disturbance

  • Fever

  • Mild hypovolaemia

  • Anaemia

  • Hyperthyroid

  • Drugs

  • Pacemaker

Aetiology

Assessment

 

1. ABCDE assessment

  • If shocked, consider whether dysrhythmia is cause of shock or secondary to underlying shock state

  • ECG!

2. Identify adverse features that necessitate URGENT DC cardioversion

  • Profound hypotension

  • Syncope​

  • Myocardial ischaemia - eg. acute severe chest pain, dyspnoea

  • New, acute heart failure - eg. acute pulmonary oedema

3. Summon help

  • MET call

  • Code blue if any adverse features (see below) or peri-arrest/arrest

  • Don't forget you can call ICU reg/ICU liaison nurse for back-up at any time​

4. Brief pertinent history

  • Can occur simultaneously with 5.

5. Gain IV access

  • 2x large bore IV in the unstable patient​

6. Bloods

  • FBE

  • UEC

  • Calcium/Mag/Phosphate

  • Coags (If bleeding or coagulopathy suspected)

  • ABG or VBG

  • Consider cardiac enzymes

7. Imaging​

  • Identify either causes or effects

    • For example, CXR, CT abdomen, CTPA, etc.​

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Assessment
Mangement

Management

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Unstable/Shocked

  • Follow tachycardia algorithm above

  • If broad-complex tachycardia without adverse features necessitating immediate DCR:

    • Amiodarone 300mg IV over 20 minutes​

    • Ensure you notify more senior medical support prior to administration

  • DCR without the presence of syncope requires sedation prior to cardioversion

    • Fentanyl 25 - 50 micrograms PLUS midazolam 1 - 2 mg (depending on patient stability)​

    • Ask nursing staff to draw up drugs whilst waiting for support to arrive

    • Commence oxygen administration via hudson mask

  • Identify and treat any underlying causes

    • For example, antibiotics, facilitate transfer to cath lab, therapeutic anticoagulation, etc.​

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Stable Tachycardia

  • Correct electrolytes

    • Target K+ > 4.0​

    • Target Mg > 1.0

  • Optimise volume state

  • Address pain

  • Address fever

  • Identify and treat any underlying causes

    • For example, antibiotics, therapeutic anticoagulation, aspirin, etc.​

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AF

  • Most common stable tachycardia

  • Stable, Rate < 130

    • Investigate and treat any underlying aetiology

    • Optimise electrolytes

    • Metoprolol 12.5 - 25 mg orally if no contraindications​

    • Alter MET criteria and review in 1 hour

      • Can give further 12.5 - 25mg if HR remains > 110 and BP > 100 systolic​

      • Repeat until 75mg administered

  • Rate > 130 or failed beta-blocker therapy

    • Optimise electrolytes

    • Digoxin 750 - 1000 microgram loading dose​ IV

      • Given as 500 microgram dose, following by 250 mcg 6 hours later​

      • Further 250 mcg may be administered 6 hours subsequently

Practical Tips

  • Effective communication is vital

  • Most patients can be managed safely on the ward with altered vital sign criteria and more frequent review

  • Ensure you communicate to the entire care team that the heart rate may remain high, and that repeated review and intervention may be required

  • Ensure you instruct the increased frequency of observation required and the new criteria that should warrant escalation

  • Altering MET criteria without a review plan and without either thorough investigation or a sense of underlying cause of tachycardia is NEVER appropriate!

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Practical Tips

       Author: Fabien Dade, Peer Reviewer: Irma Bilgrami Date: 02/04/20

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