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Unstable Tachycardia

ACLS Unstable Tachycardia Case

What rhythms might you anticipate in the tachycardia case? A – fib, A flutter, SVT, Monomorphic VT, Polymorphic VT, Wide-complex tachycardia of uncertain type
What are the criteria for identification of Atrial fibrillation on the ECG? p waves are replaced with fibrillatory waves, Heart rate is irregularly irregular
What are the criteria for identification of Atrial flutter on the ECG? Rate: fast, Rhythm: regular (usually), QRS: narrow, P-waves replaced with flutter waves with saw toothed appearance, More Flutter waves then QRS’s
What drugs are used to treat unstable tachycardia? Drugs are generally not used for unstable tachycardia with the exception of sedation drugs for the conscious patient before cardioversion when such administration will not delay treatment for an unstable patient.
Give a broad overview of the management of the patient with tachycardia. Determine the presence of pulses and whether the patient is stable or unstable. Provide treatment based patient condition and rhythm. Find and treat the source of sinus tachycardia.
Explain the pathophysiology of unstable tachycardia. The rapid rate results in ineffective blood filling and pumping resulting reduced cardiac output which can in turn cause pulmonary edema, coronary ischemia, and reduced blood flow to vital organs
What signs and symptoms would result from symptomatic tachycardia? Hypotension, Acutely altered mental status, Signs of shock, Ischemic chest discomfort, Acute heart failure
What are two keys to the management of patients with unstable tachycardia? Rapid recognition that the patient is significantly symptomatic or unstable, Rapid recognition that the signs and symptoms are caused by the tachycardia
What must be quickly determined when a tachycardic patient has signs and symptoms? Whether the signs and symptoms are due to the arrhythmia or whether signs and symptoms are causing the arrhythmia (Pain of an acute MI, for example, could be the root of a fast heart rate.)
Determining whether tachycardia is the cause or result of signs and symptoms can be difficult. What guidelines are suggested by experts to help make that determination? For the most part, heart rates <150/min are unlikely to be the source of signs and symptoms except in ventricular dysfunction. Heart rates >150/min are unlikely to be a response to physiologic stress (fever, dehydration, pain, etc).
Explain why sinus tachycardia will not respond to cardioversion. Sinus tachycardia is a response to physiologic stressors (fever, anemia, dehydration, and hypotension) that require increased cardiac output and triggered by the sympathetic nervous system and neurohormonal factors.
What is the correct course to take if your patient has tachycardia but is stable? Expert consultation
What symptoms would you expect to see in the patient with atrial flutter and a heart <150/min? Atrial flutter at this rate is usually stable in patients without heart or serious systemic disease.
What treatment would you employ for a symptomatic patient with atrial flutter and a rate greater than 150? Cardioversion
How does underlying cardiovascular disease or serious illness tend to affect a patients response to tachycardic rhythms? Symptoms may be present at lower rates
What is step 1 in the “Tachycardia with Pulse” algorithm? assess appropriateness for clinical condition
Define tachycardia. arrhythmia with a rate >100/min
At what rate are symptoms likely to be due to tachycardia rather than physiologic stress? > 150/min
It is unlikely that symptoms are due to heart rates <150/min except under what circumstances? Except when there is impaired ventricular function
What is step 2 in the “Tachycardia with Pulse” algorithm? Identify and treat underlying cause: Maintain patent airway, Assist in breathing as necessary, Look for signs of increased work of breathing, Oxygen (if hypoxemic), Cardiac Monitor to identify rhythm, Monitor BP and pulse ox, IV access
What if the patient continues to have symptoms despite support of adequate oxygenation and ventilation? Step 3 – Decision point - Determine if the arrhythmia is causing symptoms: Hypotension, Acutely altered mental status, signs of shock, ischemic chest discomfort, acute heart failure
What signs and symptoms would cause you to proceed to immediate synchronized cardioversion? rate –related cardiovascular compromise with symptoms such as hypotension, ams, signs of shock, ischemic chest discomfort, acute HF or signs of shock suspected to be due to tachyarrhythmia
At what rate would signs and symptoms be unlikely? <150 unless the patient is seriously ill or has an underlying heart disease
What if the patient has narrow complex tachycardia? try adenosine
What is the dosing for adenosine? 6 mg rapid IV push; follow with NS flush, Second dose 12mg if needed
If your patient has narrow regular rhythm what is the recommended dose for synchronized cardioversion? 50-100 J
If your patient has a narrow irregular rhythm what is the recommended dose for synchronized cardioversion? 120 -200 J biphasic or 200 J monophasic
What is the dose for synchronized cardioversion if the patient has a wide regular rhythm? 100 j
What is the appropriate action for wide irregular rhythm? defibrillation (not cardioversion)
What do you do if the patient is stable (No rate related cardiovascular compromise)? Proceed to step 5 – Determine if the patient has Wide QRS
What is the definition of wide QRS? > 0.12 seconds
What are the next steps if the patient does not have symptomatic tachycardia and does not have wide QRS? box 7 – IV access, 12 lead ECG, Vagal maneuver, Adenosine if regular, Beta blocker or calcium channel blocker, expert consultation
What are the next steps if the patient does not have symptoms but does have wide QRS tachycardia? Box 6 – IV access and 12 lead ECG, consider adenosine only if regular and monomorphic, consider antiarrhythmic infusion, expert consultation
What are the antiarrhythmic drugs used for stable wide QRS tachycardia? Procainamide, Amiodarone, and Sotalol
What is the appropriate dose of Procainamide for stable wide QRS tachycardia? 20-50 mg/min until arrhythmia is suppressed, hypotension ensues, QRS duration increases >50%, or maximum dose of 17mg/kg is given. Maintenance dose is 1-4mg/min.
When should procainamide be avoided? Prolonged QT or Congestive Heart Failure
What is the appropriate dose of Amiodarone for stable wide QRS tachycardia? First dose 150mg over 10 minutes. Repeat as needed if VT recurs. Follow with maintenance infusion of 1mg/min for the first 6 hours.
What is the appropriate dose of Sotalol for stable wide QRS tachycardia? 100mg (1.5mg/Kg) over 5 minutes.
When should Sotalol be avoided? Prolonged QT
What do you do if your patient is unstable, has a pulse with regular uniform wide complex VT (monomorphic)? Treat with synchronized cardioversion and an initial shock of 100 j (monophasic), increase dose in stepwise fashion if no response
What do you do if your patient has polymorphic VT such as torsades des pointes? Treat as VF –defibrillation dose
What if you are not sure if your patient has monomorphic or polymorphic VT? Don’t waste time trying to figure it out. Provide high energy unsynchronized shock.
Discuss time concerns vs patient comfort in situations requiring immediate cardioversion. If possible establish IV access before cardioversion and administer sedation if the patient is conscious. Do not delay cardioversion if the patient is extremely unstable.
What can you do while preparing for cardioversion if your patient has regular narrow complex SVT or a monomorphic wide complex tachycardia not resulting in hypotension? Administer Adenosine
What is the proper dosing of adenosine? 6mg rapid IV push, NS flush, Second dose 12mg if needed
What are the two types of shocks that can be delivered by modern defibrillators/cardioverters? Synchronized and unsynchronized
What is an unsynchronized shock? A higher energy shock than synchronized that is delivered anywhere in the cardiac cycle based on when the operator pushes the “shock” button
What is a synchronized shock? A lower energy shock that is timed by the cardioverter to land on the highest part of the QRS complex (the R wave) and miss the T wave (repolarization) so as not to precipitate VF.
Why is it important that low energy shocks be delivered as synchronized shocks? to avoid precipitation VF
What are some potential problems with synchronization? R-wave peaks, if they of low amplitude or difficult to distinguish may not be recognized by the cardioverter. Many cardioverters cannot synchronize through handheld quick look paddles. These problems and placing electrodes can cause delays.
Name four rhythms/conditions for which synchronized shocks are recommended. Unstable SVT, Unstable atrial fib, Unstable atrial flutter, Unstable regular monomorphic tachycardia with pulses
Name three clinical conditions that would require unsynchronized shocks. Pulselessness, clinical deterioration (pre-arrest) such as severe shock or polymorphic VT in which delays for synchronized cardioversion may result in arrest, unable to distinguish monomorphic from polymorphic VT in unstable patient
Although rare, what is the course of action of unsynchronized shock causes VF? Immediately attempt defibrillation
Describe the appropriate dosing of synchronized shocks for unstable atrial fibrillation. Monophasic = 200 joules, Biphasic=120-200 joules – Increase in stepwise fashion in both cases
Describe the appropriate dosing for SVT and Atrial Flutter. 50 – 100 joules biphasic waveform initially and increase in stepwise fashion
Describe the appropriate dosing for monomorphic VT regular form and rate with a pulse. 100 joules biphasic or monophasic, increase in stepwise fashion
What are the steps to perform synchronized cardioversion? sedate conscious patients if stable, defibrillator on, attach leads, press SYNC , look for R markers, adjust gain if needed, select energy level, “Charging – Stand Clear!”, press charge, press shock, Check rhythm, increase energy if persistent, Press sync
What is the purpose of adjusting the monitor gain in synchronized cardioversion? There should be markers on each R wave. If not, adjust gain.
What are the appropriate beginning energy levels for synchronized cardioversion? Unstable Afib = 200j, Unstable monomorphic VT 100j, Other unstable SVT or Aflutter 200j, Polymorphic VT =defibrillation
Why is it necessary to press the SYNC button after delivering a synchronized shock? Most defibrillators default back to unsynchronized mode after delivery of a synchronized shock to allow for immediate defibrillation if cardioversion produces VF.