Primary Assessment
Identify and treat underlying cause:
- Cardiac monitor to identify rhythm
-Consider causes (Differential Diagnosis-see PEA for Hs and Ts for
some possibilities and treatments)
Ask these questions, does the patient have:
1. Hypotension? (decreased blood pressure SBP < 90
mmHg)
2. Altered mental status?
3. Signs of shock?
4. Ischemic chest discomfort?
5. Acute heart failure?
If the answer is NO to all of the these:
Assess Rapid Heart Rate as Narrow or Wide Complex Tachycardia?
Narrow if QRS complex is < 0.12 seconds or < 3 small boxes on the ECG srip:
Determine tachycardia rhythm: Atrial Fibrillation, Atrial Flutter, Supraventricular Tachycardia (SVT), Paroxysmal SVT (where it comes and goes) are types of narrow complex tachycardias.
*Note:
Is Wolfe Parkinson White (WPW) present? Is yes, then have a defibrillator available if giving Adensine.
Is the duration of the A. fib./A. flutter < 48 hrs or > 48 hrs?
*NOTE: If A.fib/A.flutter > 48hrs, use agents to convert rhythm with extreme caution due to embolic complications
If Narrow, then:
- Consider expert consultation
Treatment:
*Vagal Manuevers - Valsalva maneuver or carotid sinus massage - (vagal manuevers may be done with SVT, first; Do not do carotid massage without auscultation of absence of a bruit, and do not do both carotid arteries at the same time due to cutting off the circulation to the brain or increasing risk of stroke).
*Adenosine - 6 mg IV push in 1-2 minutes if no conversion give
*Adenosine - 12 mg IV push - Adenosine's half life is about 6-10
seconds and needs to be administered in an antebutical
vein or highter and administered through a three way
stopcock with the Normal Saline flush. This will many
times produce asystole for a few seconds and either the
normal SA node will take over or it will resume to the
SVT.
Note: "Adenosine is safe and effective in pregnancy.However,
adenosine does have several important drug interactions.
Larger doses may be required for patients with a significant
blood level of theophylline, caffeine, or theobromine. The
initial dose should be reduced to 3 mg in patients taking
dipyridamole or carbamazepine, those with transplanted
hearts, or if given by central venous access . . . . Adenosine should not be given to patients with asthma". Reference: Neumar RW, Otto CW, Link MS, et al. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;122(8 Suppl 3):S729-S767.
Beta Blockers -
*metoprolol, atenolol, propranolol, esmolol, and labetolol can be used.
With the decrease in cardiac output and longer half-lives, use
cautiously in heart failure patients. Seek expert consultation.
Calcium Channel Blockers -
*Verapamil - 2.5 mg to 5 mg IV bolus over 2 minutes
(over 3 minutes in older patients). It should NOT be given to wide
complex tachyarrythmias or heart failure patients. If no response in
15-30 minute intervals, then give 5 to 10 mg to a maximum dose
of 20 mg.
*Diltiazem - 15 mg to 20 mg (0.25 mg/kg) IV over 2 minutes; if
needed, in 15 minutes give an additional IV dose of 20 mg to 25
mg (0.35 mg/kg). The maintenance infusion dose is 5 mg/hour to
15 mg/hour, titrated to heart rate. Drug of choice for rate control in
Atrial fibrillation.
Amiodarone can be used especially in Atrial fibrillation/Atrial flutter, 150 mg over 10 min, followed by 1 mg/min for first 6 hours, then to 0.5 mg/min but seek expert consultation.
The below time frame has been eliminated from the algorithm, but the caution remains: If a patient is in A. fib/A. flutter, there is an increase risk of a stroke. Be cautious in cardioverting these patients. Seek expert consultation to see if the patient needs to receive anticoagulation precautions. Unless emergent, most times now a Transesophageal Echocardiogram (TEE) will be done to rule out clots on the valves that could be thrown during cardioversion.
If not converted, then:
< 48 hrs - Cardioversion
> 48 hrs - No Cardioversion, then delayed cardioversion, anticoagulation is recommended, to reduce the chance of the patient throwing clots.
