Dysrhythmias Management Flashcards
Think of this big picture stuff?
–IDENTIFY AND TREAT ANY PRIMARY CAUSE
–Is the dysrhythmia causing a problem?
•MAY need to manage it
–Antidysrhythmic medication is NOT benign!
•Proarrhythmia – DIGOXIN!
–BE SYSTEMATIC
Consider the causes of dysrhythmias?
Consider
–Structural heart disease
•Supraventricular rhythms – atrial stretch
–Metabolic disease
–Electrolyte disorders
–Trauma
–Drugs and toxins
–Sepsis, neoplasia (esp ventricular)
How can we document dysrhythmia during episodes?
Paper trace ECG – 30 seconds?
Ambulatory (Holter) ECG – 48hours?
5 minute ECG picks up most rhythm disturbances found on Holter
Antidysrhythmic medication is indicated if?
Treatment of the dysrhythmia is likely to improve patient survival or if the patient is showing clinical signs related to the occurrence of a dysrhythmia.
The significance of a dysrhythmia, and therefore any decision to implement therapy, is determined by:
- The heart rate and the frequency of the abnormal event.
- The timing of the abnormal event with respect to the preceding PQRST complex
e. g. long pause and ventricular escape – DON’T SUPPRESS IT!
e. g. Very early VPC lands on top of preceding T wave – VERY BAD!
Antidysrhythmic drugs are?
“…toxins with occasional beneficial side effects!”
Other mechanisms of dysrhythmia control:
•Specialist procedures
–Pacing
–Ablation with catheters.
–Implantable cardiovertors.
Discuss Bradydysrhythmias?
–Variations on sinus arrhythmia – not usually clinically significant
–Sinus arrest, 2nd/3rd degree AV block – usually are clinically significant
Discuss Tachydysrhythmias?
–Supraventricular – arise in or above AVN, USUALLY narrow and upright in lead II
–Ventricular – arise from ventricles – wide and bizarre in lead II
Clinically significant bradydysrhythmias?
- High grade 2nd degree AV block
- 3rd degree AV block
- Sinus arrest
- Sick sinus syndrome
- Atrial standstill
Bradydysrhythmias clinical signs?
Clinical signs:
- weakness
- lethargy
- syncope
- sudden death - rare
Bradydysrhythmias must rule out primary cause?
MUST rule out primary causes
- cardiomyopathy
- digitalis/drug toxicity/effect
- AV node fibrosis
- endocarditis
- electrolyte imbalance
Think about this for bradysysrhythmias?
- Is it vagal?
- Usually sinus pause/block/arrest
- Abolished by atropine/exercise
- Rarely produce clinical signs
- Rule out if exercise intolerant/collapsing
What is this?
Persistent atrial standstill
What is the treatment for bradydysrhythmias?
Treatment
- Primary cause – especially electrolyte disorders
- Pacemaker implantation
- Parasympatholytic drugs (e.g. atropine) – rules out “sinus” rhythms
Discuss Tachydysrhythmias?
•Supraventricular – NARROW COMPLEX
–Unless conduction abnormality
•Ventricular – WIDE COMPLEX
–No P wave
Causes
–Structural heart disease
–Systemic disease
–Sympathetic nervous system activation
–Drugs and toxins
Name Anti-dysrhythmic drug classes?
•Class 1 drugs block sodium channels
–lidocaine, mexiletine
•Class 2 drugs - beta blockers
–propranolol, atenolol
•Class 3 drugs block potassium channels
–amiodarone, sotalol
•Class 4 drugs - calcium channel blockers
–diltiazem, verapamil
•Does not account for DIGOXIN
What is the cardiac action potential?
SupraV tachycardias - summary?
Narrow complex tachycardias
Treat any underlying primary condition, esp CHF
Treat if clinical signs of poor output
- Is patient in heart failure – digoxin +/- diltiazem (CaChBl)
- Calcium channel blocker – diltiazem
- Sotalol
- Beta blocker
Discuss Fast supraventricular tachycardia?
- Frequent in heart failure (big atria) ESP atrial fib!
- Treat the failure – rate may drop
- If out of HF but still fast
–Use diltiazem and/or digoxin
Primary SVT causing clinical signs. Give what?
–diltazem +/- sotalol
VENTRICULAR PREMATURE COMPLEXES (VPCs).
Associated conditions:
There are many!
- Maybe none in some individuals
- Structural cardiac disease - congenital and acquired
- Drugs - digitalis glycosides, anaesthetics etc
- Hypoxia
- Autonomic tone
- Systemic disease
VENTRICULAR DYSRHYTHMIAS
Treatment?
Treatment:
Treat underlying primary condition.
Indications for specific antidysrhythmic therapy:
- Short coupling interval (“R on T” phoenomenon)
- Clinical signs associated with the dysrhythmia
- ideally document occurrence of dysrhythmia during episode
Ventricular dysrhythmias - medical treatment?
- If critical – i/v lignocaine
- If stable/episodic signs
–sotalol
Tachydysrhythmia management?
