Arrhythmias Flashcards
(47 cards)
On a 6 lead ECG (3 standard + augmented leads), which one is inverted?
aVR (right arm)
How do Bundle Branch blocks affect the mean electrical axis?
LBBB –> deviates to left and up
RBBB –> deviates right
Name 2 differentials for decreased voltage on ECG
- pericardial effusion
- myocardial damage (infarction or decreased mass)
How does Hypertrophy affect the ECG?
deviates MEA towards the hypertrophy
hypertrophy will require longer time for electrical impulse traveling through and more muscle mass will create greater electrical impulse
longer travel time (prolonged conduction) –> prolonged QRS
How does a bundle branch block affect the T wave?
LBBB - T wave inverted
RBBB - upright
What are the 2 types of 2nd degree AV block?
Mobitz type I (Wenkebach) - PR interval increases with every beat until it finally drops
Mobitz type II - suddenly P without QRS
What is the idioventricular rate?
less than 40
Explain Stokes-Adams Syndrome
total AV block that comes and goes - when AV node is suddenly blocked ventricular escape needs 5-30 seconds to kick in due to overdrive suppression from previous sinus impulse
How does the T wave change after a VPC?
inverted to the polarity of the QRS
What are causes of QT prolongation, what does a prolonged QT interval predispose to?
hypocalcemia, hypokalemia, hypomagnesemia
predisposes to torsades de pointes
Describe the difference between atrial fibrillation and atrial flutter
atrial fibrillation alway have an irregularly irregular beat, impulses travel uncoordinated from different ectopic niduses
atrial flutter - can be irregular or regular, electrical impulse continues to travel through atrium - circus movement
How can you differentiate an ectopic beat of a VPC coming from the right side or the left side of the heart?
L-side - RBBB morphology, deep S wave
R-side - LBBB morphology, upright
What rate is considered VT in cats versus dogs?
over 180 (dogs), over 240 (cats)
Name 3 breed-related heart conditions commonly leading to ventricular arrhythmias
- Dobermann Pincher, DCM
- Boxer, ARVC
- German Shepherd, IVAGSD
What are the beta-1 and beta-2 effect proportions of atenolol, esmolol, and propranolol
atenolol, beta-1 and beta-2 but more beta 1
esmolol, beta-1 selective
propranolol - nonselective beta blockade
Why are class II antiarrhythmics contraindicated in CHF?
because of further suppression of systolic function (negative inotropic), can worsen HF
What class effects does Sotalol have?
II, III
beta-blocking
K-channel blocking (main effect)
What class effects does amiodarone have?
all I, II, III, IV
Why do VPCs have wider QRS complexes than sinus beats?
because they don’t use the normal conduction system - sinus beat ventricular depolarization initiated through Purkinje Fibers which have an extremely fast conduction velocity - will be slower to travel through ventricular myocytes
Describe the physiologic AV block
means that atrial rate is too high and the AV node “purposefully” filters out impulses to slow the ventricular rate, protective
What group of tachyarrhythmias are more responsive to vagal maneuvers?
SVTs - VT almost never repsond to vagal maneuvers
Describe how you would perform a vagal maneuver
carotid massage - between mandibular arch and atlas wings - apply pressure from ventrally to the neck for 5-10 seconds
ocular - apply gentle pressure to the closed eye
What is the recommended ergency treatment for SVTs?
Diltiazem and/or beta-blockers
Name 3 oral treatment options for VTs.
Sotalol, mexiletin, amiodarone