ECG/heart rhythms/treatments/etc Flashcards
What is/are the potential ECG finding(s) for left atrial enlargement and why?
Notched P waves (called P-mitrale). Occur d/t asynchronous depolarization of the atria (takes more time for action potentials to travel through the left atrial myocardium than the right atrium)
What is/are the potential ECG finding(s) for right atrial enlargement and why?
Tall/high amplitude P waves (called P-pulmonale). Occurs d/t the closer proximity of the hypertrophied right atrial myocardium to the SA node).
What is/are the potential ECG finding(s) for left ventricular enlargement?
Hint: there’s a general finding and a way you can differentiate eccentric and concentric hypertrophy from looking at different leads.
In general, taller R waves are indicative of left ventricular enlargement.
A taller R wave in lead 1 only (compared to leads 2 and aVF) can indicate concentric hypertrophy.
Taller R waves in leads 1, 2, and 3 can indicate dilation.
Other things that can indicate LV hypertrophy: prolongation of the QRS duration, shift in MEA to the left, S-T segment sagging/coving
What is/are the potential ECG finding(s) for right ventricular enlargement? (3 things)
Deep S waves
Prolongation of the QRS duration
Shift in the MEA to the right.
What are the potential causes for a prolonged Q-T interval? (5 things)
Hint: electrolyte, electrolyte, temperature, drug, toxin
Hypocalcemia
Hypokalemia
Hypothermia
Quinidine
Ethylene glycol poisoning
What are the potential causes for a shortened Q-T interval? (5 things)
Hint: electrolyte, electrolyte, drug, drug, drug
-Hyperkalemia
-Hypercalcemia
-Digitalis
-Atropine
-Beta blockers/Ca2+ channel antagonists
What are the ECG characteristics of a hyperkalemic patient? (6 things in order of increasing severity of hyperkalemia)
- Progressive bradycardia
- Increased amplitude of the T wave (will appear narrow and spiked)
- Progressive dec. in the amplitude of the R wave
- Progressive dec. in amplitude of the P wave
- Disappearance of the P wave (i.e. atrial standstill)
- Vfib or asystole
Explain the difference between Mobitz type I and II second degree AV blocks.
What are each frequently associated with? Which holds a worse prognosis?
Mobitz type I: progressive prolongation of the P-R interval until a nonconducted P wave occurs. Associated with disorders of the AV node and/or high vagal tone.
Mobitz type II: Uniform P-R intervals preceding the blocked impulse. Associated with disease lower in the AV conduction system (His bundle or major bundle branches).
Mobitz type II holds a worse prognosis.
T/F You can see tall P waves as well as superimposition of the P and T waves in a patient with sinus tachycardia.
T
What drugs are commonly used in dogs with atrial fibrillation to slow their HR?
Diltiazem, atenolol, and/or digoxin
What is the other name for Boxer Cardiomyopathy and what breeds are commonly affected (besides boxers)?
Arrhythmogenic right ventricular cardiomyopathy (AVRC)
Bulldogs & german shepherds
What arrhythmia is most commonly seen in patients with ARVC? Because of this, what is often a clinical sign of this disease?
Vtach, which can degenerative into Vfib
Syncope/collapse (potentially death)
What is the other name for Boxer Cardiomyopathy and what breeds are commonly affected (besides boxers)?
Arrhythmogenic right ventricular cardiomyopathy (AVRC)
Bulldogs & german shepherds (before 24mo/age)
What dog breeds are most commonly affected by sick sinus syndrome?
West highland white terriers, dachshunds, min. schnauzers, boxers, cocker spaniels
What are the most common clinical signs of sick sinus syndrome?
Collapse, exercise intolerance
What is always the treatment for clinical SSS patients?
Pacemaker (normally very good response to treatment)
What is the treatment for atrial standstill (not the myocardial form)?
Treating the cause of hyperkalemia (insulin, bicarb, glucose, calcium carbonate)
What are the common signalments associated with atrial standstill?
Blocked cats, acute renal failure (hyperkalemia)
Older schnauzers and dachshunds (myocardial form)
What disease is characterized by an irregular rhythm with long pauses, with periods of sinus tachycardia and sinus bradycardia?
Hint: Syncope is a common clinical sign during periods of sinus bradycardia
SSS
Describe the P and QRS waves in a patient with vtach.
Wide and bizarre QRS (normal rhythm) with no P waves associated (can’t even see P waves)
T/F: Vtach has a regular rhythm.
T
How does prognosis of afib differ depending on signalment/history?
(Afib could have a good, guarded, or poor prognosis depending on sig/hist)
If afib is spontaneous, prog. is good
If in large breeds/large hearts, prog. is guarded
If there’s underlying heart disease, prog. is poor
T/F Afib is characterized by wide, bizarre QRS complexes with several small P waves between each.
F, the QRS complexes are normal during afib. There are no fully formed P waves, only a “saw-toothed” pattern between each QRS.
What abnormalities can be observed on auscultation and pulse palpation in a patient with a first degree AV block?
None lol, gotta use an ecg
What finding on ECG can indicate wandering pacemaker?
Varying P wave morphology (amplitude specifically)
Before using specific antiarrhythmic drugs (which have the potential to be pro-arrhythmic), what two questions should you answer?
- Does the arrhythmia suggest the presence of an underlying disease?
- Is the arrhythmia of primary clinical significance? (i.e. can result in hemodynamic compromise, sudden death, or heart failure)
T/F In general, animals with an arrhythmia but no clinical signs attributed to it should still be treated with an antiarrhythmic drug to prevent future clinical signs from developing.
F, in general there needs to be a sustained reduction in CO to produce clinical signs (which usually means a sustained arrhythmia). Treatment of transient arrhythmias that do not produce clinical signs is unnecessary.
What clinical signs indicate hemodynamic compromise? (4)
Reduced mental status
Weak/poor pulse
Pallor
Cold extremities
More severe: syncope, recumbency, sudden death
What arrhythmias are considered life threatening? (4)
Vtach (=> vfib)
Very frequent/polymorphic ventricular arrhythmias
Sinus arrest (or SSS)
AV block (with an inconsistent ventricular escape rhythm)
What structural change to the heart is most frequently associated with afib? Why?
Dilation of the atria (one or both)
They can no longer sustain the normal depolarization sequence
What is the drug of choice for dogs in afib with myocardial disease?
It’s debatable whether treatment is required for afib for what signalment?
Digoxin (can also use calcium channel antagonists and beta blockers though)
Giant breeds with only afib (no myocardial dz)
What are the most common causes of sinus bradycardia? (6)
Hint: disease, electrolyte, temperature, elevated pressure somewhere, (idk how to give a hint for the last 2 without giving it away)
-Hypothyroidism
-Hyperkalemia
-Hypothermia
-Elevated intracranial pressure
-Systemic disease (e.g. renal failure)
-Drugs (tranquilizers or antiarrhythmic drugs)
Cats can present with sinus bradycardia while in heart failure. Why is this strange?
Tachycardia d/t increased sympathetic tone is often a compensatory response to heart failure
What treatments are indicated for sinus bradycardia?
Resolving the primary cause of the bradycardia.
Vagolytic or beta agonists can be used to increase the HR if they’re symptomatic, but this is rarely necessary.
What signalment can sinus arrest/block be a normal finding in?
Brachycephalic dogs (exaggerated respiratory sinus arrhythmia)
What conditions may be associated with sinus arrest? (some overlap with sinus bradycardia and there’s 7 total)
-Vagal stimulation associated with severe resp. disease or vasovagal response (vomiting, tenesmus)
-Atrial disease such as dilation, fibrosis, cardiomyopathy, neoplasia
-Metabolic/endocrine dz such as electrolyte imbalances or hypothyroidism
-Drugs (either their effects or toxicity)
-Irritation of the vagus nerve by neoplasia in the cervical area (e.g. thyroid carcinoma) or thorax (aortic body tumor)
-Regular/profound can be d/t SSS
What treatments are indicated for sinus arrest/block?
Only for symptomatic cases: pacemaker (sometimes)
Atropine also
Tachycardia in response to the atropine test indicates what?
That a bradyarrhythmia is d/t increased vagal tone
What dose/route of atropine is used for the atropine response test? (it’s the same for dogs and cats)
0.04 mg/kg
IV (repeat ECG in 15 min) or SQ (repeat ECG in 30 min)
Why does temporary atrial standstill most often occur?
Secondary to a reversible condition (hyperkalemia, diabetic ketoacidosis, oliguric renal failure, iatrogenic from potassium administration or K+ sparing diuretics)
Potentially digitalis toxicity
Persistent atrial standstill is one of 3 subsets of atrial standstill. What breeds are most commonly affected and what clinical signs are normally associated with this subtype?
What most commonly follows this
English springer spaniels, old english sheep dogs, mixed breed dogs, and CKCSs
Weakness, lethargy, syncope, inability to inc. HR during activity
Insidious onset of heart failure
T/F Atrial standstill most often will not respond to the atropine test
T
What things can cause a first degree AV block?
Can occur normally in an animal with slow HR or aging animals d/t degenerative changes in the AV node
Drugs (digitalis toxicity or propranolol)
Abnormal K+ level
What, on auscultation of the heart, can indicate a second degree AV block?
Intermittent pauses in the cardiac rhythm (need an ECG to confirm this, though)
What clinical signs are associated with a second degree AV block?
Weakness, lethargy, syncope
Hereditary stenosis of the bundle of His, which can cause a second degree AV block, is associated with which breed?
the pug :(
Mobitz type I second degree AV blocks are sometimes seen in dogs with _________ _________, particularly ______cephalic breeds.
Mobitz type I second degree AV blocks are sometimes seen in dogs with sinus arrhythmias, particularly brachycephalic breeds.
What drugs can cause a second degree AV block?
Digoxin, xylazine, detomidine, atropine, dexmedetomidine, and quinidine (and potentially more that aren’t listed)
What are some potential causes of a third degree AV block? (7)
Cardiomyopathy (general)
Cardiac neoplasia
Digitalis toxicity
AV node fibrosis
Endocarditis
Electrolyte imbalance
Lyme disease
What finding on thoracic rads is common in animals with a chronic third degree AV block?
Generalized cardiomegaly (with or without evidence of of congestive heart failure).
What medications can be used in patients with a third degree AV block?
Parasympatholytic drugs (e.g. atropine)
Sympathomimetic drugs (clenbuterol, terbutaline)
Millophyline in cats, Theophylline in dogs
Pimobendan can be tried
Which bundle branch (left or right) is more commonly damaged and why?
The right, as it’s long and slender (more vulnerable to damage) compared to the left, which is thicker and requires a larger lesion to be disrupted.
What dose of atropine can be used in patients with third degree AV blocks?
0.02-0.06 mL/kg q6-8h PO
Is the left or right bundle branch more susceptible to damage?
The right (it’s long and slender whereas the left is thick)
T/F A right bundle branch block alone does not cause significant hemodynamic problems. However, in combination with a left bundle branch block, a complete heart block would result.
T
What are potential causes of a left bundle branch block? (5)
Congenital abnormalities (e.g. subaortic stenosis)
Acquired heart dz (hypertrophic/dilated cardiomyopathy)
Myocardial ischemia
Cardiac neoplasia
Trauma
T/F: Vtach has a regular rhythm.
T
Of the left and right bundle branches, which being blocked (alone) would cause significant hemodynamic problems?
Neither, the only way significant hemodynamic problems would result from a bundle branch block is if both sides were affected.
What drugs can induce VPCs? (4 with one being general)
Digitalis, some anesthetics, atropine, and isoprenaline
T/F Often, parasympathomimetic/sympatholytic drugs are used in patients with CHF and persistent sinus tachycardia, to allow for more efficient filling during diastole.
F, sinus tachycardia is often a necessary compensatory response in animals with CHF in an attempt to maintain cardiac output.
There are six indications for antiarrhythmic drug treatment of ventricular arrhythmias. What are they?
(ECG findings)
- Frequent, polymorphic VPCs
- VPCs with a very short coupling interval (i.e. R on T)
- VPCs frequently in pairs/triplets
- Rapid sustained VT (>200/min)
- Frequent VPCs or VT in boxers and dobermans (with cardiomyopathy)
- VT with inherited ventricular arrhythmias of GSDs (<18mo/age)
What is always the treatment for clinical SSS patients?
Pacemaker (normally very good response to treatment)
What drugs can cause a second degree AV block?
Digoxin, xylazine, detomidine, atropine, dexmedetomidine, and quinidine (and potentially more that aren’t listed)
What is treatment of atrial standstill most often geared towards?
Congestive heart failure if present. They rarely respond to medication or pacemakers
What treatment is indicated in most cases of third degree AV block?
Pacemaker (reduces symptoms and risk of sudden death)
What type of arrhythmias is use of IV lidocaine indicated?
For treatment of acute ventricular arrhythmias and those induced by digitalis intoxication
T/F Unlike lidocaine, procainamide can be used for both supraventricular and ventricular arrhythmias.
T
How/when is procainamide most often used in treatment of arrhythmias?
In combination with lidocaine to treat life-threatening ventricular arrhythmias
How/when is mexiletine most often used in treatment of arrhythmias?
Most often as an adjunctive treatment (severe, chronic ventricular arrhythmias not well controlled by beta blockers alone)
Or in dogs with chronic ventricular arrhythmias that do not tolerate beta blockers.
The function of which organ should be monitored when treating arrhythmias with mexiletine?
How often should it be monitored?
The liver (hepatotoxicity is a common adverse effect of mexiletine administration)
Once before treatment and q6mo. during treatment
What are the 6 most common uses of beta blockers in veterinary medicine?
- Inappropriate sinus tachycardia
- Ventricular and supraventricular arrhythmias
- Chronic hypertension
- Palliation of uncontrolled hyperthyroidism in cats
- Pheochromocytoma in dogs
- Dec. aqueous humor production in glaucoma (timolol)
What is wandering pacemaker thought to be associated with?
High vagal tone
What sound on auscultation of the heart can indicate a second or third degree AV block?
A very faint S4 (may need to use the bell of the stethoscope) (only at a faster rate with third degree)
Which oral medication is used in dogs for control of ventricular arrhythmias is reported to have significant side effects and is often used as a last resort?
Amiodarone (need to monitor liver and thyroid function regularly)
Supraventricular premature complexes can occur due to structural changes of the atria. What are some potential causes of this?
Dilation secondary to AV valve regurgitation, cardiomyopathy, congenital cardiac shunts
Right atrial hemangiosarcoma
What metabolic disease can cause supraventricular premature complexes in cats?
Hyperthyroidism
What maneuvers can terminate or slow down a SVT for identification of the type of arrhythmia?
When might these be ineffective?
Carotid sinus massage (up and down moving pressure applied behind the angle of the jaw for 10s) - may work better after admin. of beta blockers or Ca2+ channel antagonists
Precordial thump to the left apex beat (may produce a VPC and break the SVT)
May be ineffective in animals with high sympathetic tone (nervous or in heart failure)
T/F Afib can sometimes result following rapid drainage of pericardial effusion.
T
What are the 3 contraindications for pacemaker implantation?
- Active infection
- DCM
- Cardiac neoplasia
What are the 8 situations (bradyarrhythmias) in which pacemaker implantation is indicated?
3rd degree AV block
2nd degree AV block (mobitz type II - persistent or intermittent)
2nd degree AV block (mobitz type I - symptomatic)
Profound sinus bradycardia (symptomatic)
Sinus arrest
Tachy-brady SSS (when anti-tachyarrhythmic drugs cause symptoms)
Afib or flutter w/ an AV block and symptoms
Persistent atrial standstill
What is the drug of choice for the cardioversion of acute, life-threatening vtach?
Lidocaine
Which beta blocker’s use is contraindicated in animals with asthma or primary respiratory disease?
Propranolol (causes bronchoconstriction as it blocks both beta 1 and 2 receptors)
Which beta blocker should be used with caution in animals with CHF and DCM?
Atenolol (titrate up when starting, titrate down when stopping)
(Pretty sure I have a question/saw somewhere not to give beta blockers to patients in CHF d/t the compensatory and necessary tachycardic response to keep them alive if anyone finds some more info on this let a girl know)
Sally sue is an 80 year old chihuahua who has been your patient for the past 82 years. Her owner rolls her around in a stroller and while they’re out shopping has a tendency to scream at sales associates for just doing their job. She has been on atenolol for the past 85 years, as she felt bad for the sales associates and from then on was persistently in ventricular tachycardia (but she’s still kicking somehow). Today, you attend Sally sues 81st birthday. You notice her softly coughing and breathing rapidly following her pole dancing routine, that unfortunately only lasted 12 seconds. As her veterinarian, what do you plan to do in terms of her medication?
Sally sue likely has developed CHF (to be confirmed). The use of atenolol in patients with CHF is contraindicated (will reduce the necessary compensatory tachycardic response) - so you should reduce the dosage and eventually discontinue it.
(Abrupt cessation should be avoided unless the CHF is life threatening)
What 3 adverse effects are associated with the use of beta blockers?
Bradyarrhythmias
Hypotension
Heart failure (in patients already diagnosed with CHF, will make it worse)
What two categories of antiarrhythmics does sotalol belong to?
Beta blockers & potassium channel blockers
What is the clinical use of sotalol?
What drug can it be combined with for this purpose?
Long-term treatment for hemodynamically significant ventricular arrhythmias
Can be combined with mexiletine (but needs to be at a lower dose)
T/F Sotalol is safe for use in patients concurrently on ace inhibitors. furosemide, spironolactone, and pimobendan.
T
What drugs are unsafe to use in combination with sotalol?
Other beta blockers and amiodarone
Which class 4 antiarrhythmic is most useful for treatment of supraventricular arrhythmias in dogs and cats?
What is the dosage and route? (in dogs and cats, they’re different. There’s also a standard and sustained release formulation)
Diltiazem
Dogs: 0.05-0.2mg/kg IV over 5 min (can be repeated for a cumulative dose of 0.3mg/kg) to stabilize, then 0.5-2mg/kg PO q8h (standard) or 1-4mg/kg PO q12h (sustained release)
Cats: 7.5mg/cat PO q8h (standard) or 30-60mg/cat PO q12-24h (sustained release)
What is the clinical use of amiodarone as it relates to the treatment of arrhythmias in dogs?
Used to treat life-threatening ventricular arrhythmias and severe afib (but is rarely first-line treatment).
What are the adverse effects associated with diltiazem use? (4)
Systemic hypotension
Negative inotropy and bradycardia (sinus or AV blocks)
Exacerbation of CHF
GI signs (more common in cats)
Which classes of antiarrhythmics can cause systolic dysfunction (dec. contractility)?
(there are 2)
Class II (beta blockers) & class 4 (calcium channel blockers)
Seeing this again i’m not sure if class I and III are also negative inotropes (i feel like they are but its not listed under adverse effects in Dr. Davis’ lecture like the otehrs) so lmk if you find that out
T/F Class 4 antiarrhythmics (calcium channel blockers) can be used to treat both supraventricular and ventricular tachyarrhythmias.
F, only supraventricular tachyarrhythmias
Class I antiarrhythmics (sodium channel blockers) are further subdivided based on what types of tachyarrhythmias they treat.
Quinidine and procainamide can be used to treat:
A. Supraventricular tachyarrhythmias only
B. Ventricular tachyarrhythmias only
C. Both supraventricular and ventricular tachyarrhythmias
C
Class I antiarrhythmics (sodium channel blockers) are further subdivided based on what types of tachyarrhythmias they treat.
Lidocaine and mexiletine can be used to treat:
A. Supraventricular tachyarrhythmias only
B. Ventricular tachyarrhythmias only
C. Both supraventricular and ventricular tachyarrhythmias
B
Class II antiarrhythmics (beta blockers) can be used to treat:
A. Supraventricular tachyarrhythmias only
B. Ventricular tachyarrhythmias only
C. Both supraventricular and ventricular tachyarrhythmias
C
Class III antiarrhythmics (potassium channel blockers) can be used to treat:
A. Supraventricular tachyarrhythmias only
B. Ventricular tachyarrhythmias only
C. Both supraventricular and ventricular tachyarrhythmias
C
What effects does digoxin have on the AV node and contractility?
Digoxin slows the conduction of the AV node, and increases contractility
What situation warrants the use of digoxin as an antiarrhythmic?
(there’s an arrhythmia and condition)
Afib, particularly in patients with DCM
What antiarrhythmic is the only drug that both slows the AV node and doesn’t impair contractility?
Digoxin
You have a tachycardic patient hooked up to an ecg. Their rhythm is regular and you notice their QRS complexes are wide and bizarre with no identifiable P waves.
What is your rhythm diagnosis until proven otherwise?
What rare cardiac pathology can also cause this rhythm?
Vtach
Can happen rarely with supraventricular tachycardia with a bundle branch block, though)
You have a tachycardic patient hooked up to an ecg. Their rhythm is irregular, and you notice their QRS complexes are wide & bizarre with no identifiable P waves.
What is your rhythm diagnosis until proven otherwise?
(this one is kinda weird bc it’s two different things)
Atrial fibrillation with cardiac enlargement or BBB
You have a tachycardic patient hooked up to an ecg. Their rhythm is regular and their QRS complexes are narrow. There is a P for every QRS and a QRS for every P.
What is your rhythm diagnosis? (there are 2 possible answers)
Atrial tachycardia
Sinus tachycardia
You have a tachycardic patient hooked up to an ecg. Their rhythm is irregular, and you notice their QRS complexes are narrow, but there are no recognizable P waves (just a sawtooth pattern between each QRS).
What is your rhythm diagnosis until proven otherwise?
Afib
You’re working in an emergency clinic and a Doberman comes in for collapse. The owner claims he was previously diagnosed with DCM and “some sort of liver disease” but doesn’t know any additional details. You hook the ECG up and the dog is in vtach. You administer lidocaine IV, and hope for the best.
Unfortunately, the vtach doesn’t resolve after 5 minutes following administration. What should you do?
A. Discharge the patient with an oral prescription of mexiletine.
B. Administer procainamide IV
C. Suggest the owner change the dogs diet to Royal Canin Early Cardiac⟨™⟩ and discharge the patient
D. Administer esmolol IV
E. Administer atropine IV
F. Begin mouth to mouth resuscitation via the ear canal
Correct answer is B (patient not responding to lidocaine => cover supraventricular tachyarrhythmias (SVT) as well, could be SVT w/ a BBB)
A. No, if the vtach didn’t resolve with lidocaine it won’t with mexiletine. This is also an emergency, so discharging the patient would be stupid. Mexiletine can be potentially hepatotoxic, so using it in a patient with a hx of liver disease is not recommended.
B. Yes! you can also use amiodarone IV (preservative free) or esmolol IV (in a healthy patient, more on that later).
C. lol
D. While esmolol can be used, it’s contraindicated in patients with significant systolic dysfunction. Since you don’t have any details about the DCM and this is an emergency situation, I would avoid using it.
E. if you picked this drop out
F. lol
You make a rhythm diagnosis of atrial tachycardia, what drugs can you use for acute management of this rhythm?
Procainamide !!
Amiodarone
Esmolol (as long as the P doesn’t have significant systolic dysfunction)
You make a rhythm diagnosis of atrial fibrillation. What drugs can you use for acute management of this rhythm?
(hint, PO)
Digoxin and diltiazem
Your patient has a history of chronic vtach that doesn’t respond to lidocaine. What are your options in terms of drugs?
Sotalol (remember that higher doses cause systolic dysfunction)
Atenolol
Amiodarone
NOT mexiletine (if it doesn’t respond to lidocaine it won’t respond to this).
T/F In a patient with a hx of chronic ventricular tachycardia, mexiletine is contraindicated for use in combination with sotalol and atenolol.
F, combining mexiletine with either of these beta blockers may actually be better at controlling the vtach than mexiletine alone.
Besides diltiazem and esmolol, what else can be done to acutely manage supraventricular tachycardia?
Vagal maneuvers (ocular pressure or massage of the carotid sinuses per Menciotti)
T/F Esmolol can be used to treat supraventricular tachycardia.
T
What is the dose of diltiazem administered IV for acute mgmt of supraventricular tachycardia?
0.15-0.35 mg/kg IV
Why shouldn’t you combined diltiazem and atenolol for chronic management of afib in dogs?
What can you combine diltiazem with for this purpose?
They’re both negative inotropes.
You can combine it with digoxin, as digoxin is a positive inotrope.
What beta blocker can you combine with diltiazem for the chronic management of atrial tachycardia in dogs?
Trick question, none. You shouldn’t combine diltiazem with any beta blocker, as they’re both negative inotropes.
You can use diltiazem or atenolol as monotherapy for this purpose, though
You recently prescribed digoxin (0.003mg/kg) as a monotherapy for chronic management of atrial fibrillation in your canine patient with no history of renal disease. You scheduled a follow-up appointment to assess the levels of circulating digoxin 8 days from the start of treatment, and 8 hours after the last pill was administered. During this appointment, O reported that P was missing some meals and had soft stool but this isn’t too out of the ordinary for P. You receive the results and it’s found the level of circulating digoxin to be 1.6 ng/mL.
What is wrong with this scenario?
Everything is correct in this scenario in terms of dosage, indication for tx, and when the circulating digoxin was assessed.
However, P is showing signs of digoxin toxicity (GI upset, inappetence. Other signs include syncope, seizure, and death).
The normal range for circulating digoxin can be up to 1.5-2 ng/mL, but 90% of these dogs will show signs of toxicity. Dr. Menciotti says 0.8ng/mL is what the circulating digoxin level should be.
While these signs of toxicity could be caused by something else as they’re fairly nonspecific, it would be wise to interrupt the treatment to avoid more serious consequences
Four years ago, you diagnosed a west highland white terrier (Bud Light) with sick sinus syndrome, and referred to a cardiologist for pacemaker implantation. Today, Bud Light is back as he’s drinking a ton of water and peeing all over O’s novelty wig collection. After listening to the owner speak for what feels like hours about how Bud Light is an ungrateful piece of crap for taking up half the bed with his beer belly, you decide it’s time to do some bloodwork. What are you going to tell your tech?
No jugs!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Bud Light, the west highland white terrier who you diagnosed with sick sinus syndrome oh so many years ago is back again as he’s 26 years old and decomposing. His owner is not ready to have him stuffed to be placed on the mantle just yet. Him and his pacemaker are still kickin, and you have your assistant get a heart rate on intake. You pull up his 384180471 page record, and see his heart rate when the pacemaker was implanted was 87. During his visits to your clinic since then, his heart rates were: 149, 146, and 91 and today, it’s 85.
What’s the issue with this scenario?
Heart rate should NEVER be lower than what was set at implantation.
This indicates the battery life of the pacemaker is getting too low.
You’re seeing a patient who has a dental procedure scheduled in a month. On PE, you hear and abnormal heart rhythm on auscultation. You decide to hook up an ECG, on 25mm/s paper you count 10 beats in 150mm. You see that each QRS follows a P, and each P precedes a QRS, with the morphology of each being WNL. However, the rhythm is abnormal. 3 equally spaced QRS complexes are followed by a long pause, and the pattern repeats itself.
What’s your rhythm diagnosis? Is this patient safe to be anesthetized?
Sinus arrhythmia
Yes, it’s safe to anesthetize the patient.
You’re in your anesthesia rotation monitoring a 3 y/o golden in surgery for a prophylactic gastropexy following rads that revealed a concerning gas pattern in the duodenum. On ECG, you note an occasional wide/bizarre QRS complex without an associated P wave, all appearing to be the same morphology. Everything else appears normal.
What should you do?
Occasional monomorphic VPCs are most likely secondary to anesthesia, GI pathology, and/or surgery.
You likely wouldn’t need to intervene, but you can pull up a dose of lidocaine just to be safe.
It’s your first day in your anesthesia rotation, and you’ve been assigned to monitor a patient during a 7 hour long procedure with Dr. Lanz as the surgeon (yay..)
After your third stroke of the day, you look up at the ECG and see that your patient is asystolic. You have a fourth stroke, then see a wide, bizarre QRS appear out of nowhere. What would you call that?
A ventricular escape beat
On ECG of a bradycardic patient, you see the heart has a regular rhythm, there is not a QRS for every P, and the QRS complexes you do see are wide, bizarre, and negative.
What is your rhythm diagnosis?
Third degree AV block
On ECG of a tachycardic patient, you see the heart has an irregular rhythm, there is a QRS for every P and a P for every QRS, and the QRS complexes you see are narrow.
What is your rhythm diagnosis?
Atrial (supraventricular) tachycardia
On ECG of a bradycardic patient, you see the heart has an irregular rhythm, there is a p for every QRS, but not a QRS for every P. The QRS complexes are normal in morphology, as are the P waves.
What is your rhythm diagnosis?
Second degree AV block
It’s your first day during your anesthesia rotation, and your patient goes into vfib out of nowhere. What will your response be?
A. Scream for help
B. Administer 0.2mg/kg lidocaine IV
C. Die with the patient
D. Defibrillate
D but all answers except B are acceptable
