Arrhythmias Flashcards
Name the types of tachyarrhythmia.
Afib, SVPC, VT, VPC
Describe the pathogenesis of Afib
Atrial stretch (eg CHF, endocarditis, MVDV)
What ECG complexes are seen with ventricular disease?
Wide and bizarre QRS
What ECG complexes are seen with supraventricular disease?
Thin QRS with no P waves (superimposed on other complex)
What type of changes on an ECG may be seen with a lesion originating near the AV junction?
Negative P wave or no P wave, normal QRS complex
What changes would be seen on an ECG with a supraventricular tachycardia?
Superimposition of the P wave on the previous complex (t wave, st segment or QRS complex)
What drugs may be used in the treatment of Afib (minus those for primary disease)?
Dignoxin (negative chronotrope, vagomimetic - slows av conduction)
Diltiazem (negative inotrope)
Beta-blockers (negative inotrope)
In what situation would you NOT use beta blockers?
In cases of uncontrolled CHF
What changes on ECG may be seen with sinus arrhythmia?
Alternating periods of fast and slow rhythm (respiration), +/- irregular p wave confirguration
What is a sinus arrhythmia?
Irregular sinus rhythm originating in the SAN
What physiological factors may lead to increased vagal tone?
Vomiting, intubation, brachycephalic, elevated ICP, hypothermia, hypothyroidism
What events may lead to sinus tachycardia?
Stress, exercise, pain
What causes an SVPC?
Ectopic nodal tissue in the atria (other than SAN)
What is wolff-parkinson-white syndrome?
Accessory nervous pathway creation leading to supraventricular tachycardia
What treatment may be involved in an emergency SVT?
Vagal manoeuvres! Ca+ channel blockers - Diltiazem, Vermapil. Negative chronotropes - Digoxin. Beta-blockers - Esmolol
Why do junctional premature complexes generate negative P waves?
Retrograde spread of electrical signal to the atria
What does a fusion complex suggest?
Paroxysmal ventricular tachycardia (none constant VT)
Define ventricular tachycardia.
3 or more VPCs in a row
What underlying causes lead to ventricular ectopic rhythms?
Catecholamine release, CHF, myocardial ischemia, acidosis, hypokalaemia, abdominal disease, thoracic trauma
What is the treatment of choice for ventricular tachycardia?
IV Lidocaine. If persistent use beta blockers such as propranolol, amiodarone, soltalol etc
Describe the emergency treatment of ventricular tachycardia.
IV access and lidocaine bolus, CRI amiodarone if Lido not affective. Within 24 hours oral mexiltine, propranolol, soltalol and amiodarone
MOA amiodarone
Potassium channel blockers
What mineral imbalance may lead to atrial standstill?
Hyperkalaemia
Describe the changes associated with atrial standstill seen on ECG.
Absent P waves, spikey T waves, mildly prolonged QRS
