Dysrhythmias Flashcards
List primary causes of dysrhythmias.
- Structural heart disease (supraventricular rhythms)
- Metabolic disease
- Electrolyte disorders
- Trauma
- Drugs and toxins
- Sepsis, neoplasia (esp ventricular)
The significance of a dysrhythmia, and therefore any decision to implement therapy, is determined by what?
- 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!
What specialist procedures can be used for dysrhythmia control?
- Pacing
- Ablation with catheters.
- Implantable cardiovertors.
Which bradydysrhythmias are clinically significant?
- High grade 2nd degree AV block
- 3rd degree AV block
- Sinus arrest
- Sick sinus syndrome
- Atrial standstill
Clinical signs of Bradydysrhythmias?
- Weakness
- Lethargy
- Syncope
- Sudden death - rare
Primary causes of Bradydysrhythmias?
- Cardiomyopathy
- Digitalis/drug toxicity/effect
- AV node fibrosis
- endocarditis
- electrolyte imbalance
What is the most common cause of persistent atrial standstill?
Hyperkalaemia
How are Bradydysrhythmias treated?
- Primary cause – especially electrolyte disorders
- Pacemaker implantation
- Parasympatholytic drugs (e.g. atropine) – rules out “sinus” rhythms
How can we tell if a tachydysrhythmia is ventricular or supraventricular?
- Supraventricular – NARROW COMPLEX
- Unless conduction abnormality
- Ventricular – WIDE COMPLEX
- No P wave
Causes of Tachydysrhythmias?
- Structural heart disease
- Systemic disease
- Sympathetic nervous system activation
- Drugs and toxins
Class 1 anti-dysrhythmic drugs block sodium channels, give examples of these drugs.
lidocaine, mexiletine
Class 2 anti-dysrhythmic drugs are beta blockers, give examples of these drugs.
propranolol, atenolol
Class 3 anti-dysrhythmic drugs block potassium channels, give examples of these drugs.
amiodarone, sotalol
Class 4 anti-dysrhythmic drugs block calcium channels, give examples of these drugs.
diltiazem, verapamil
How should you treat any supraventricular tachycardias?
- Treat any underlying primary condition, esp CHF
- Treat if clinical signs of poor output
- Is patient in heart failure – digoxin +/- diltiazem
- Calcium channel blocker – diltiazem
- Sotalol
- Beta blocker
