Electrocardiography Flashcards
On 25 mm/s paper, one box is how many seconds?
.04sec
On 50 mm/s paper, one box is how many seconds?
.02sec
What is dromotropy?
Conduction velocity
What lead is used to monitor rhythm in SAM?
Lead II
How is rhythm monitored in LAM?
Base-apex lead
What area does lead I measure?
RA to LA
What area does lead II measure?
RA to LL
What area does lead III measure?
LA to LL
When placing electrodes, what leads SHOULD be positive?
Leads II, III, and AVF
A normal QRS wave in horses is ___ (positive/negative)
Negative
What does the P wave represent?
Depolarization of the atria
What does the PR interval represent?
Time from atrial depolarization to ventricular depolarization (AV node)
What does the QRS wave represent?
Ventricular depolarization (His purkinje)
What does the ST segment represent?
Early ventricular repolarization
What does the T wave represent?
Ventricular repolarization
Where are the leads placed?
White - front right
Green - back right (uncommon)
Black - front left
Red - back left
How is instantaneous heart rate calculated for 25mm/s paper? 50mm/s paper?
1500/ # of boxes between QRS waves
3000/ # of boxes between QRS waves
What is Mean Electrical Axis?
MEA is a tool used to measure the pattern of ventricular depolarization using QRS complexes
How is MEA measured?
Isoelectric method (lead where waves equal out to 0) Tallest R wave
What are some primary cardiac diseases in dogs that cause arrhythmias?
Infectious (Chagas, endocarditis)
Inflammatory
Structural (valvular disease)
Cardiomyopathy (DCM, ARVC)
What metabolic/endocrine disorders can cause arrhythmias in dogs?
Electrolyte imbalance (K, Ca, Mg)
What are some drugs/toxins that cause arrhythmias in dogs?
Digoxin
Amphetamine
Theobromine
What are “the usual suspects” for arrhythmias in dogs?
GDV Sepsis Splenic Dz Hypoxia Hypovolemia Pain Trauma
What autonomic imbalance can cause arrhythmias in dogs?
Pheochromocytoma
What primary cardiac diseases cause arrhythmias in cats?
Cardiomyopathy (HCM, ARVC, restrictive, DCM)
What metabolic/endocrine disorders can cause arrhythmias in cats?
Electrolyte imbalance (K, Ca, Mg) Hyperthyroidism
What drugs and toxins can cause arrhythmias in cats?
Anesthesia
What are “the usual suspects” that cause cat arrhythmias?
Sepsis Hypoxia Hypovolemia Pain Trauma
T/F: arrhythmias in cats are more likely to be due to primary cardiac disease than in dogs
True
What are 5 hemodynamic consequences of arrhythmias?
Decreased cardiac function Drop in blood pressure Reduced tissue perfusion Limited exercise capacity Syncope
What are 3 electrical instabilities arising from arrhythmias?
Myocardial fibrillation
Asystole
Sudden cardiac death
When do you treat an arrhythmia?
If there are clinical signs or an increased risk for sudden death
What breeds are predisposed to arrhythmias?
Boxers, dobermans
What are DADs?
Delayed after depolarizations related to abnormal Ca influx
What are EADs?
Early after depolarizations related to the prolongation of the action potential
