Dysrhythmias & Their Treatments
how do you treat sinus bradycardia (HR < 60 bpm)? (what is first-line if symptomatic?)
1. treat the underlying cause
2. atropine (first line)
3. transcutaneous or transvenous pacing, dopamine or epinephrine infusion, or permanent pacemaker implantation.
chronic/long-term management of Atrial Fibrillation (AFib)?
what is the pathophysiology of a Complete Heart Block (Third-Degree AV Block)?
complete AV dissociation (atria and ventricles beat independently of each other)
how do we treat stable (with a pulse) patients with Ventricular Tachycardia (VT)?
1. treat the underlying cause
2. drug therapy includes Amiodarone, lidocaine, or procainamide (procainamide can be given in polymorphic VT if the baseline QT interval is normal).
3. polymorphic VT (Torsades de Pointes) with a prolonged QT interval: Treat with Magnesium, isoproterenol, phenytoin, or antitachycardia pacing.
(Immediately stop any drugs known to prolong the QT interval (such as dofetilide))
4. Refractory cases: Cardioversion if drugs are ineffective or if the patient becomes unstable.
what does a p wave represent and what is the duration?
Represents atrial depolarization; normal duration is 0.06 to 0.12 seconds
how do you treat sinus tachycardia (HR > 100 bpm)?
1. treat the underlying cause (treat if fever/pain and provide fluid resuscitation if hypovolemic)
2. beta blockers/ calcium channel blockers
drug therapy needed to treat Atrial Fibrillation (AFib)?
Beta-blockers, Calcium channel blockers, or antidysrhythmics like amiodarone.
what is the treatment for a Complete Heart Block (Third-Degree AV Block) in symptomatic patients?
- Transcutaneous or transvenous pacing.
- Permanent pacemaker.
- Drug therapy: Dopamine or epinephrine infusions
how to treat a patient who has unstable VT? (Patient is PULSELESS)
This is a lethal cardiac arrest rhythm. CPR and ACLS with rapid defibrillation is the first-line, immediate treatment
what does the PR interval represent and what is the duration?
beginning of the P wave to the beginning of the QRS complex (represents time for impulse to spread through conduction pathways to ventricles); normal duration is 0.12 to 0.20 seconds
how do you treat Supraventricular Tachycardia (SVT)? (what maneuver should you instruct the patient and what to do if hemodynamically unstable?)
1. treat the underlying cause
2. have the patient perform vagal maneuvers (coughing/valsalva maneuver)
3. if hemodynamically unstable a cardioversion is indicated
4. adenosine (first-line rapid IV push), beta-blockers, or calcium channel blockers.
what is our goal when treating Atrial Flutter?
slow ventricular response by increasing the AV block
Atropine is used in a third-degree complete heart block, true or false?
FALSE
Atropine is NOT effective in third-degree complete heart block and is typically not administered.
what is the pathophysiology, interventions, and drug therapy of Ventricular Fibrillation (VF)?
what does the QRS complex represent and what is the duration?
Represents ventricular depolarization; normal duration is <0.12 seconds
what is our goal with Atrial Fibrillation (AFib)?
Decrease ventricular response, prevent embolic stroke, and convert the rhythm to Normal Sinus Rhythm (NSR) if possible.
what are the interventions to treat Atrial Flutter?
Elective cardioversion for stable patients; emergent cardioversion for unstable patients. Radiofrequency ablation in the electrophysiology (EP) lab is the treatment of choice. Anticoagulation is required for chronic flutter.
what is the pathophysiology of Premature Ventricular Contractions (PVCs)?
A premature contraction originating from an ectopic focus within the ventricles, causing a premature QRS complex.
what are the interventions and drug therapy used for asystole?
what does the ST segment and T wave represent and what is their durations?
ST segment: Measured from the S wave to the beginning of the T wave (isoelectric/flat line); normal duration is 0.12 seconds.
T wave: Represents ventricular repolarization; normal duration is 0.16 seconds.
how do we treat stable/unstable patients with Atrial Fibrillation (AFib)?
what is the drug therapy used for Atrial Flutter?
what are the interventions and drug therapy associated with Premature Ventricular Contractions (PVCs)?
Treat the underlying cause and determine the patient’s hemodynamic stability.
what are the interventions used for a patient with Pulseless Electrical Activity (PEA)?
1. Organized electrical rhythm on the monitor but no palpable pulse.
2. Requires immediate CPR, ACLS, and identifying/treating the underlying cause. Defibrillation is not used for PEA.
what does the QT interval represent and what is its duration?
Represents total time for depolarization and repolarization of the ventricles; normal duration is 0.34 to 0.43 seconds (must correct for heart rate as cQT).