Question | Answer |
Define stable tachycardia. | heart rate >100/min, no significant signs or symptoms |
What questions do you ask yourself to determine the tachycardic patient’s classification? | symptoms present or absent? Due to tachycardia? Stable or unstable? QRS wide or narrow? Rhythm regular or irregular? QRS monomorphic or polymorphic? Sinus tachycardia? |
What are some things that can help you distinguish sinus tachycardia from SVT. | Sinus tachycardia does not exceed 220/min, usually does not even exceed 120-130/min and has a gradual onset and termination. SVT has an abrupt onset/termination. |
What causes sinus tachycardia? | External influences on the heart such as fever, anemia, hypotension, blood loss, pain, or exercise |
What is the treatment for sinus tachycardia? | Fix the cause. Vagal maneuvers may work. No cardioversion! |
Describe how and why beta blockers could cause clinical deterioration in the patient with sinus tachycardia. | A condition that impairs stroke volume such as large MI requires beta receptor mediated HR to compensate. |
Broadly define the steps to managing a patient with tachycardia. What do you need to figure out? | First determine if pulses are present (not present = Cardiac arrest algorithm). If pulses are present manage the patient according to tachycardia algorithm. Next determine if the patient is stable are unstable. Provide treatment accordingly. |
What is the first step in the adult tachycardia with a pulse algorithm? | Assess appropriateness for clinical condition = Assess condition, typically heart rate >150 is due to tachyarrhythmia and not sinus rhythm |
What is the second step in the adult tachycardia with a pulse algorithm? | identify and treat underlying cause, Maintain patent airway, assist with breathing as necessary, oxygen if hypoxemic, monitor to identify rhythm, monitor BP and pulse ox |
What is the third step in the adult tachycardia with a pulse algorithm? | determine if the patient is experiencing symptoms from the tachyarrhythmia (hypotension, AMS, signs of shock, ischemic chest discomfort, acute heart failure) |
What is the course of action if the patient does not have symptoms and does not have wide QRS? | IV access, 12 lead ECG, Vagal maneuvers, Adenosine if regular,BB or CCB, Expert consultaion |
What is the course of action if the patient is asymptomatic and has wide QRS? | IV access, 12 lead ECG, Adenosine for regular and monomorphic rhythm, Antiarrhythmic infusion, expert consultation |
What is the course of action if the patient is stable and has monomorphic wide complex tachycardia? | Expert consultation |
What is the course of action if the patient is unstable and has polymorphic wide complex tachycardia? | immediate cardioversion |
What is the course of action if the patient is stable and has wide complex tachycardia? | Transport and monitor, expert consultation because treatment has potential for harm |
What two rhythms could be represented by regular wide complex tachycardia? | VT or SVT with aberrancy |
It can be difficult at times to distinguish ventricular wide complex rhythms from SVT with abberancy. Which rhythm is most likely? | Most wide complex rhythms are ventricular in origin. |
Which common forms of wide complex tachycardias are likely to deteriorate to VF? | monomorphic VT and polymorphic VT |
What rhythms could be represented by irregular wide complex tachycardias? | A fib with aberrancy, pre-excited atrial fibrillation (using accessory pathway for antegrade conduction), Polymorphic VT/torsades des pointes |
What is the treatment for likely VT or SVT in an stable patient even if the rhythm cannot be determined for sure, but it is regular and monomorphic? | IV adenosine is relatively safe for both treatment and diagnosis. IV antiarrhythmics, procainamide, amiodarone, or sotalol may also be effective |
What is the course of action for irregular wide complex tachycardia? | Control the rate, convert hemodynamically unstable afib to sinus rhythm or both – Expert consultation. |
What drugs should be avoided when patients have irregular wide complex tachycardia? | AV nodal blocking agents such as adenosine, CCBs, Digoxin, and possibly BB, because if the rhythm is pre-excitation A fib these drugs can cause paradoxical increase in ventricular response. |
What is the treatment for narrow QRS with regular rhythm? | vagal maneuvers, adenosine |
Describe administration of adenosine when SVT does not respond to vagal maneuvers. | Give adenosine 6 mg rapid IV push, 20 mL saline flush, elevate arm, If SVT does not convert in 1-2 minutes follow with adenosine 12 mg rapid IV push |
How can adenosine be diagnostic? What does adenosine do to A fib and A flutter? | It won’t stop it but it will slow AV conduction so that fibrillation or flutter waves can be identified |
Is adenosine safe for pregnant women and their babies? | yes |
What drugs if present at significant levels in the patient’s blood would require larger doses of adenosine for effectiveness? | Theophylline, caffeine, or theobromine |
What cases would require a 3mg dose of adenosine? | Patient’s taking dipyridamole or carbamazepine, or patients with transplanted heart |
Why shouldn’t adenosine be used if the patient has asthma? | May cause bronchospasm |
Treatment with adenosine has resolved a narrow complex tachycardia causing you to believe the rhythm was likely SVT. After resolution the rhythm recurs. What is your next action? | administer adenosine or longer acting AV nodal blocking agents such as Verapamil and Diltiazem or Beta blockers. Typically, you should obtain expert consultation if the rhythm recurs. |
If you treat a regular narrow complex tachycardia with vagal and adenosine unsuccessfully, what is your next action? | Transport and seek expert consultation because stable tachycardia can wait and treatment can cause harm. |