Bradycardia & Tachycardia

Lalith Sivanathan 2015

ADVANCED CONCEPTS IN EMERGENCY CARE (EMS

483)

Content• Rhythms for bradycardia• Symptomatic bradycardia

– Signs and symptoms of symptomatic bradycardia– Management of symptomatic bradycardia– Transcutaneous pacing

• Unstable Tachycardia– Rhythms– Signs and symptoms– Management– Synchronized cardioversion

• Stable Tachycardia– Rhythms– Management

Rhythm for bradycardia

• Sinus bradycardia• First degree AV block• Second degree AV block– Type I (Wenckeback / mobitz I)– Type II ( Mobitz II)

• Third degree AV block

Symptomatic bradycardia

• Patient have heart rates in the normal sinus range but these rates are inappropriate or insufficient for them. This is called functional or relative bradycardia (for eg. A heart rate of 70/min is too slow for a patient in cardiogenic shock.

• A symptomatic bradycardia exists clinically when 3 criteria are present– The heart rate is slow– The patient has symptoms– The symptoms are due to the slow heart rate.

Signs and symptoms

• Symptoms– Chest discomfort or pain, shortness of breath– Decreased level of consciousness– weakness, fatigue, light – headedness, dizziness or syncope

• Signs– Hypotension, drop in BP on standing (orthostatic

hypotension)– Diaphoresis, pulmonary congestion, frank congestive heart

failure or pulmonary edema– Bradycardia related frequent premature ventricular

complexes or VT

ManagementA Maintain patent airway

B Assist breathing as needed; give oxygen in case of hypoxemia; monitor oxygen saturation

C Monitor blood pressure and heart rate; obtain and review 12-lead ECG; establish IV access

D Conduct a problem focused history and physical examination; search for and treat possible contributing factors

If patient has poor perfusion secondary to bradycardia

• Give atropine as first line treatment– Atropine 0.5mg IV – may repeat to a total dose of

3 mg• If atropine is ineffective– Transcutaneous pacing

Or– Dopamine 2 to 10 mcg/kg per minute

(chronotropic or heart rate dose)– Epinephrine 2 to 10 mcg/min

TRANSCUTANEOUS PACING

• Indications– Hemodynamically unstable bradycardia– Symptomatic Sinus bradycardia– Mobitz type II Second degree AV block– Third degree AV block

• Precautions– TCP is contraindicated in severe hypothermia and not

recommended for asystole– Conscious patients require analgesia for discomfort– Do not assess the carotid pulse to confirm mechanical capture;

electrical stimulation causes muscular jerking that may mimic the carotid pulse.

Steps to perform TCPStep Action

1 Place pacing electrodes on the chest according to package instructions

2 Turn the pacer ON

3 Set the demand rate to approximately 60/min. This rate can be adjusted up or down (based on patient clinical response) once pacing is established

4 Set the current milliampered output 2 mA above the dose at which consistent capture is observed (safety margin)

Unstable Tachycardia

• Unstable tachycardia exists when the heart rate is too fast for the patient’s clinical condition and the excessive heart rate causes symptoms or an unstable condition because the heart is– Beating so fast that cardiac output is reduced. This

can cause pulmonary edema, coronary ischemia and reduced blood flow to vital organs

– Beating ineffectively so that coordination between atrium and ventricles or the ventricles themselves reduces cardiac output

Rhythms for unstable tachycardia

• Atrial fibrillation• Atrial flutter• Reentry supraventricular tachycardia (SVT)• Monomorphic VT• Polymorphic VT• Wide complex tachycardia or uncertain type

Symptoms and signs

• Hypotension• Altered mental status• Signs of shock• Ischemic chest discomfort• Acute heart failure

Management

• Look for signs of increased work of breathing (tachypnea or intercostal, suprasternal retractions)

• Give oxygen, if indicated and monitor oxygen saturation

• Obtain an ECG to identify the rhythm• Evaluate the blood pressure• Establish IV access• Identify and treat reversible causes.

• If the patient is unstable but has a pulse with regular uniform wide complex VT (monomorphic VT)– Treat with synchronized cardioversion and an

initial shock of 100 J monophasic waveform)– If there is no response to the first shock increasing

the dosage in a step wise pattern is reasonable

• Arrhythmic with a polymorphic QRS appearance (polymorphic VT) such as torsades de pointes will usually not permit synchronization. If patient has polymorphic VT– Treat as VF with high energy unsynchronized

shocks ( defibrillation doses)

When to use synchronized shocks

– Unstable SVT– Unstable atrial fibrillation– Unstable atrial flutter– Unstable regular monomorphic tachycardia with

pulses

When to use unsynchronized shocks

– For a patient who is pulseless– For a patient demonstrating clinical deterioration

(in prearrest) such as those with severe shock or polymorphic VT, when you think a delay in converting the rhythm will result in cardiac arrest

– When you are unsure whether monomorphic or polymorphic VT is present in the unstable patient

Should the unsynchronized shock cause VF (occurring in only a very small minority of patients despite the theoretical risk), immediately attempt defibrillation

Synchronized cardioversion

1. Sedate all conscious patients unless unstable or deteriorating rapidly

2. Turn on the defibrillator (monophasic or biphasic)3. Attach monitor leads to the patient and ensure

proper display of the patient’s rhythm. Position adhesive electrode (conductor) pads on the patient

4. Press the SYNC control button to engage the synchronization mode.

5. Look for markers on the R wave indicating sync mode.

6. Adjust monitor gain if necessary until sync markers occur with each R wave

7. Select the appropriate energy level8. Announce to team members: “charging

defibrillator – stand clear”9. Press the CHARGE button10. Clear patient when the defibrillator is

charged

11. Press the SHOCK button12. Check the monitor. If tachycardia persists,

increase the energy level (joules) Activate the sync mode after delivery of each

synchronized mode after delivery of synchronized shock.

STABLE TACHYCARDIA

• Rhythms for stable tachycardia– Narrow QRS complex (SVT tachycardias)• Sinus tachycardia• Atrial fibrillation• Atrial flutter• AV nodal reentry

– Wide QRS comples tachycardias• Monomorphic VT• Polymorphic VT

– Regular or irregular tachycardia

Narrow QRS with regular rhythm

• Attempt vagal maneuvers– Valsalva maneuver or carotid sinus massage will

terminate about 25% of SVTs• Give adenosine– If SVT does not respond to vagal maneuvers:– Give adenosine 6 mg as a rapid IV push in a large (eg

anticubital) vein over 1 sec. follow with a 20 ml saline flush and elevate the arm immediately

– If SVT does not convert within 1 to 2 mins, give a seond dose of adenosine 12 mg rapid IV push following the same procedure above

Summary• Rhythms for bradycardia• Symptomatic bradycardia

– Signs and symptoms of symptomatic bradycardia– Management of symptomatic bradycardia– Transcutaneous pacing

• Unstable Tachycardia– Rhythms– Signs and symptoms– Management– Synchronized cardioversion

• Stable Tachycardia– Rhythms– Management

Thank you….

Questions?