Cardio Flashcards
What does the ausculation reveal with AF ?
Auscultation reveals an irregularly irregular rhythm with absence of the fourth heart sound due to the lack of active atrial contraction.
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What does the ECG reveal with AF ?
The surface ECG typically shows an irregularly irregular rhythm with normal QRS morphology, the absence of P waves and the presence of coarse or fine undulations of the isoelectric line (fibrillation “f” waves).
The HR at rest is normal in horses in which no underlying cardiac abnormalities are detected.
Atrial fibrillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What does the ECG reveal during exercise with AF ?
- The HR increases disproportionally during exercise or stress, as the HR variability.
- ECG during exercise can detect abnormal QRS complexes or R-on-T-like phenomenon due to aberrant conduction and/or ventricular premature depolarisations
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
Which horses should be treated for cardioversion ?
Aim at cardioversion of the abnormal rhythm to sinus rhythm.
- Especially recommended in competition and racehorses (high intensity exercise)
- Not recommended in horses without clinical signs, performing low intensity exercise and not presenting abnormal ventricular responses (conflicting)
- Not recommended in horses with severe underlying heart disease or congestive HF, as the risk of recurrence is very high
Should be treated :
- racehorses and competition horses,
- > 220 bpm during their regular exercise,
- abnormal QRS complex or R-on-T phenomenon
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
When horses should be treated for cardioversion ?
- Cardioversion should not be performed within the first few days after onset of AF, as the arrhythmia might be paroxysmal.
- After the first few days, treatment should not be delayed since the electrical, contractile and structural remodelling during AF makes the arrhythmia more stable and more difficult to treat.
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
How to realise cardioversion ?
Pharmacological cardioversion :
* quinidine sulphate administered orally, with an overall success rate ∼ 80%
* flecainide, amiodarone or novel atrial specific compounds.
Transvenous electrical cardioversion (TVEC), with a success rate of >95%.
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What are the mechanisms of action of Quinidine sulfate ?
- Quinidine sulphate is a class 1a antiarrhythmic drug, which mainly blocks the sodium channels and to a lesser extent various potassium channels. As a result, the action potential duration is prolonged and the myocardial fibrillation threshold is increased.
- Anticholinergic effects → atrioventricular nodal conduction increases, which results in an increased ventricular response rate during treatment.
- Overall success rate ∼ 80%
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What are the side effects of Quinidine sulfate ?
Reported in ∼ 45% of treated horses with 1% mortality
Cardiac side effects :
* Supraventricular or ventricular tachycardia, which may require cessation of the therapy. Digoxin can slow down the AV nodal conduction.
* Hypotension through a negative inotropic effect and alpha-adrenergic blockade
* Pro-arrhythmic properties → QRS and QT prolongation. Stop TT if QRS > 25%
* Torsade de pointes, collapse, sudden death
Non-cardiac side effects :
* Nasal edema, depression, mild tachycardia (< 120 bpm)
* Colic, diarrhea, weakness, ataxia, laminitis
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What are the clinical efficacy of flecainide for cardioversion ?
Flecainide is a potent sodium channel blocker. Rate of cardioversion ∼ 41% with dangerous ventricular arrhythmias and sudden deaths reported.
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What are the clinical efficacy of amiodarone for cardioversion ?
- Amiodarone is a multichannel blocker affecting sodium, calcium and several potassium channels as well as having a beta-blocking effect.
- Overall success rate for cardioversion ∼ 58%
- Adverse effects such as temporary hindlimb weakness and diarrhea
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What are the clinical efficacy of TVEC for cardioversion ?
Very high success rate (>95%), even in horses with a prior unsuccessful pharmacological treatment attempt.
Successful in horses with focal or macro-re-entrant atrial tachycardia (AT)
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
What are the negative prognostic indicators following the cardioversion ?
During the days after cardioversion → presence of atrial premature depolarisations and short runs atrial tachycardia assoc. with recurrence.
One study found APD ≧ 25 during 24h ECG recording at 5 days post TVEC → sign assoc. with AF recurrence within 1 year.
Also found LA active fractional area change ≦ 9.6% and lower body weight at 5 days post TVEC → sign assoc. with AF recurrence within 1 year.
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
Atrial premature depolarisations five days post electrical cardioversion are related to atrial fibrillation recurrence risk in horses
evj 2020
What are the risk factors for AF recurrence ?
- Longer AF duration
- Larger atrial size +/- fibrosis
- Atrial electrophysiological remodelling
- Previous unsuccessful TT attempt
- Mitral regurgitation
- Shortened AF cycle length (AFCL) or increased AF rate
Atrial brillation in horses Part 2: Diagnosis, treatment and prognosis
Vet J 2021
Which blood parameters are associated with higher grade arrhythmias during peak exercise ?
Both partial pressure of arterial CO2 (PaCO2) and lactate were significantly associated with arrhythmias occurring at peak exercise, but not immediately post-exercise. As PaCO2 and lactate increased, arrhythmia severity increased.
Hypercapnia and hyperlactatemia were positively associated with higher-grade arrhythmias during peak exercise in horses during poor performance evaluation on a high-speed treadmill
Vet J 2020
Is a horse with paroxysmal AF at greater risk of recurrence?
Thoroughbreds are at increased risk of recurrent AF after both paroxysmal and persistent episodes compared to horses with no previous episode, but the duration of time between episodes varies widely.
Median duration between episodes was 343 days (range, 34-1065).
Recurrence was seen in 64% of horses previously treated for persistent AF, which was higher than recurrence in horses with paroxysmal AF (23%).
Incidence, recurrence, and outcome of postrace atrial fibrillation in Thoroughbred horses
JVIM 2021
What are the most prevalent arrhythmias during the race : APC or VPC ?
When arrhythmias are the most prevalent : during or after the race ?
During the race, 92% of horses had arrhythmias (81% APC ; 33% VPC).
During active-recovery, 58% of horses had arrhythmias (56% APC ; 15% VPC)
Prevalence of cardiac arrhythmias and R-R interval variation in healthy
Thoroughbred horses during of cial Chuckwagon races and recovery
Vet J 2021
What is the maximal R-R variation reported during the race ?
* 15 %
* 25 %
* 35 %
* 45 %
What is the maximal R-R variation reported during the race ?
* 15 %
* 25 %
* 35 %
45 %
And 40% during the active recovery
Prevalence of cardiac arrhythmias and R-R interval variation in healthy
Thoroughbred horses during of cial Chuckwagon races and recovery
Vet J 2021
What is the goal of Implantable loop recorders ? In which anatomical location ?
This study indicates that ILRs can be used for detection of PAF episodes and could be a useful ECG tool for horses presenting with poor performance.
During submaximal exercise only the sixth left intercostal space position was able to record ECG signals of diagnostic quality. No position yielded diagnostic signals at maximum exercise due to artefacts.
Implantable loop recorders can detect paroxysmal atrial
fibrillation in Standardbred racehorses with intermittent poor
performance
evj 2021
Detection of atrial fibrillation with implantable loop recorders in horses
Technical notes - evj 2021
What is the impact of URT obstructions on the cardiac rythm of racehorses ?
Exercise-associated upper respiratory tract obstructions increase the risk of rhythm disturbances.
Exercise-associated rhythm disturbances in poorly performing Thoroughbreds: risk factors and association with racing performance
evj 2021
What factor could be used to predict complex ventricular arrhythmias during recovery ?
The maximum average HR during peak exercise was an excellent predicter for complex ventricular arrhythmias during recovery.
Cardiac arrhythmias in poorly performing Standardbred and Norwegian–Swedish Coldblooded trotters undergoing high-speed treadmill testing
Vet J 2021
Which procedural factors should be considered for TVEC ?
Catheter type, previous AF episode, tricuspid regurgitation, and body weight were significantly correlated with cumulative amount of energy delivered.
Both horse and procedural factors should be considered when assessing treatment options and prognosis in horses with AF.
Transvenous electrical cardioversion of atrial fibrillation in horses: Horse and procedural factors correlated with success and recurrence
JVIM 2022
Which sex seems to be predisposed to reccurrence after TVEC ?
Stallions (RR 3.05)
Transvenous electrical cardioversion of atrial fibrillation in horses: Horse and procedural factors correlated with success and recurrence
JVIM 2022
What is the most appropriate definition of accelerated idioventricular rhythms in horses?
A. Persistent or intermittent tachycardia with HR ranging from 50 to 100 beats/min, often abates at exercise or with sympathetic stimulation.
B. Persistent tachycardia with HR > 100 beats/min, often abates at exercise or with sympathetic stimulation.
C. Irregular rhythm with HR > 100 beats/min, often it doesn’t disappear at exercise or with sympathetic stimulation.
D. Regular rhythm with HR < 100 beats/min, often abates at exercise or with sympathetic stimulation.
A. Persistent or intermittent tachycardia with HR ranging from 50 to 100 beats/min, often abates at exercise or with sympathetic stimulation.
Diagnosis and management of accelerated idioventricular rhythms in horses Elizabeth Williams Louie1 | Katharyn J. Mitchell, EquinE Veterinary Journal, 2023
Which of these factors may predispose horses with atrial fibrillation to develop EIPH during exercise?
A. Increased left atrial pressure
B. Decrease in myocardial contractility
C. Increased circulating volume
D. Increased cardiac output
Which of these factors may predispose horses with atrial fibrillation to develop EIPH during exercise?
A. Increased left atrial pressure
B. Decrease in myocardial contractility
C. Increased circulating volume
D. Increased cardiac output
Associations between postrace atrial fibrillation and measures of performance, racing history and airway disease in horses | Nath, Laura C. Elliott, Adrian Gerche, Andre La Weir, Joe Forbes, Grace, | JOURNAL OF VETERINARY INTERNAL MEDICINE 2023
Horses with AF can have :
A. Increased frequency and severity of EIPH and low prevalence of clinically important tracheal mucus accumulation (TMA)
B. Increased severity of EIPH and high prevalence of clinically important TMA
C. Decreased severity of EIPH and high prevalence of clinically important TMA
D. Decreased severity of EIPH and low prevalence of clinically important TMA
Horses with AF can have :
A. Increased frequency and severity of EIPH and low prevalence of clinically important tracheal mucus accumulation (TMA)
B. Increased severity of EIPH and high prevalence of clinically important TMA
C. Decreased severity of EIPH and high prevalence of clinically important TMA
D. Decreased severity of EIPH and low prevalence of clinically important TMA
Associations between postrace atrial fibrillation and measures of performance, racing history and airway disease in horses | Nath, Laura C. Elliott, Adrian Gerche, Andre La Weir, Joe Forbes, Grace, | JOURNAL OF VETERINARY INTERNAL MEDICINE 2023
Based on a study examining atrial fibrillation (AF) in racehorses, which of the following statements is correct?
A) Horses with AF had lower career earnings before the event compared to horses performing as expected (TE).
B) The volume of exercise was a significant factor contributing to AF in racehorses.
C) Horses with AF were more likely to have a higher grade of exercise-induced pulmonary hemorrhage (EIPH) compared to horses with poor performance but without AF (PP).
D) Age was not a significant factor when comparing horses with AF to those performing to expectation (TE).
Based on a study examining atrial fibrillation (AF) in racehorses, which of the following statements is correct?
A) Horses with AF had lower career earnings before the event compared to horses performing as expected (TE).
B) The volume of exercise was a significant factor contributing to AF in racehorses.
C) Horses with AF were more likely to have a higher grade of exercise-induced pulmonary hemorrhage (EIPH) compared to horses with poor performance but without AF (PP).
D) Age was not a significant factor when comparing horses with AF to those performing to expectation (TE).
Associations between postrace atrial fibrillation and measures of performance, racing history and airway disease in horses | Nath, Laura C. Elliott, Adrian Gerche, Andre La Weir, Joe Forbes, Grace, | JOURNAL OF VETERINARY INTERNAL MEDICINE 2023
Which of these pathological arrhythmias have been found during swimming and active recovery?
A. AF and supraventricular premature depolarization
B. Supraventricular premature depolarization and ventricular premature depolarisation
C. Ventricular tachycardia and supraventricular premature depolarization
D. Ventricular tachycardia and ventricular premature depolarisation
B. Supraventricular premature depolarization and ventricular premature depolarisation
Frequency of cardiac arrhythmias in horses during straight and untethered swimming Emma Santosuosso | Florent David | Shannon Massie | Silvio A. Filho |Persephone McCrae | Sarah Johnson | Renaud Leguillette, EQUINE VET EDUC, 2022
Which of these are considered proarrhythmogenic factors during swimming?
A. Apneic breathing, facial immersion, hypotension
B. Apneic breathing, facial immersion, diving exercise
C. Tachypnea, facial immersion, hypertension
D. Tachypnea, hypertension, stress
B. Apneic breathing, facial immersion, diving exercise
Frequency of cardiac arrhythmias in horses during straight and untethered swimming Emma Santosuosso | Florent David | Shannon Massie | Silvio A. Filho |Persephone McCrae | Sarah Johnson | Renaud Leguillette, EQUINE VET EDUC, 2022
Which of the following statements is correct regarding the breathing strategy and upper respiratory tract (URT) behavior in swimming horses, as observed in a prospective study?
A) Horses showed URT collapse both during swimming and overground exercise.
B) Horses exhibited a complete collapse of the URT, including the external nares, nasopharynx, and rima glottidis, during apnoea while swimming.
C) Locomotor-respiratory coupling was observed during both swimming and overground exercise.
D) Post-swim plasma lactate levels were lower than pre-swim levels, indicating minimal exertion during swimming.
B) Horses exhibited a complete collapse of the URT, including the external nares, nasopharynx, and rima glottidis, during apnoea while swimming.
Frequency of cardiac arrhythmias in horses during straight and untethered swimming Emma Santosuosso | Florent David | Shannon Massie | Silvio A. Filho |Persephone McCrae | Sarah Johnson | Renaud Leguillette, EQUINE VET EDUC, 2022
Which of the following could be an adequate treatment in the case of accelerated idioventricular rhythms that does not resolve spontaneously?
A. Sodium and calcium channel blockers (lidocaine/lignocainehydrochloride) and beta blocker
B. Sodium and calcium channel blockers (lidocaine/lignocainehydrochloride) and magnesium sulphate.
C. Potassium channel blocker (amiodarone) and magnesium sulfate.
D. Calcium channel blocker (diltiazemil) and magnesium sulfate.
B. Sodium and calcium channel blockers (lidocaine/lignocainehydrochloride) and magnesium sulphate.
Diagnosis and management of accelerated idioventricular rhythms in horses Elizabeth Williams Louie1 | Katharyn J. Mitchell, EquinE Veterinary Journal, 2023
Where is located the focal source of AT in most horses, using electro-anatomical mapping ?
In 8 out of 9 horses, AT originated from a localized macro-reentrant circuit (n= 5) or a focal source (n= 3) located at the transition between the right atrium and the caudal vena cava.
The source of right atrial AT in horses was safely treated by radiofrequency catheter ablation.
Detection of the origin of atrial tachycardia by 3D electro-anatomical mapping and treatment by radiofrequency catheter ablation in horses
jvim 2022
What is the difference between the atrial fibrillatory cycle length and atrial fibrillatory rate ?
Atrial remodelling → shortening of the atrial effective refractory period (aERP) and thus shortening of atrial fibrillatory cycle length (AFCL). Can be measured invasively with a catheter placed in the atrium.
The atrial fibrillatory rate (AFR) measures the number of fibrillations (f waves) per minute (fpm) and is inversely correlated with AFCL. The AFR can be measured noninvasively from surface ECG recordings.
Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion
jvim 2022
How atrial fibrillatory rate can be useful for AF horses ?
High AFR is associated with failure of quinidine cardioversion and AF recurrence after successful TVEC.
Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion
jvim 2022
What changes in cardiorespiratory parameters are observed during peak exercise in AF horse?
- Lower maximum velocity
- Higher HR
- More abnormal QRS complexes
- EIPH (horses with AF had increased frequency and severity of EIPH)
Atrial fibrillation as a risk factor for exercise-induced pulmonary haemorrhage following a standardised exercise test
evj 2023
Associations between postrace atrial fibrillation and measures
of performance, racing history and airway disease in horses
jvim 2023
What is the impact of arrhythmias on HR variability parameters during exercise ?
The presence of arrhythmia increased HRV in submaximal and strenous exercise, and recovery (RMSSD and SDRR).
Lameness decreased HRV during submaximal exercise.
Heart rate variability during high-speed treadmill exercise and recovery in Thoroughbred racehorses presented for poor performance
evj 2023
What are the differences in type and frequency of arrhythmias recorded during training vs racing ?
None.
The total number of arrhythmias was repeatable between training and racing, but the reliability of arrhythmia type was poor to moderate.
Race-simulated training elicits the same physiological response as competition in Chuckwagon horses.
Training vs. racing: A comparison of arrhythmias and the repeatability of
findings in Thoroughbred Chuckwagon racehorses
Vet J 2023
Why pulmonary veins can play a role in AF of horses (and humans) ?
Conductive tissue with gap junctions and adrenergic and non-adrenergic nerve fibres is present within the entire myocardial sleeve in all pulmonary vein ostia.
Morphological and histological investigation of the conduction system in the equine atrial muscle sleeve of pulmonary veins
evj 2024
During the cross-country phase of eventing, what is related with premature depolarisations nb and complexity ?
A- The duration of exercise
B- Upper levels of eventing and respiratory rate
C- The amount of time the HR > 199 bpm and upper levels of eventing
D- Event duration and history of collapse
C- The amount of time the HR > 199 bpm and upper levels of eventing
Premature depolarisations in horses competing in United States Eventing Association and Fédération Equestre Internationale-sanctioned 3-day events
evj 2024
Which structures have myocardial sleeves that could be a potential trigger for initiation and perpetuation of AT and AF?
Caudal vena cava and pulmonary veins
Isolation of these myocardial sleeves by radiofrequency catheter ablation may be an effective treatment for these arrhythmias.
Successful caudal vena cava and pulmonary vein isolation in healthy horses using 3D electro-anatomical mapping and a contact force-guided ablation system
evj 2024
Which drugs have been used before and during TVEC to prevent recurrence ?
- Sotalol : prolonged QT interval, which entails potential risks combined with anesthesic drugs. No longer used in Ghent.
- Amiodarone : should only be used before or during TVEC in case of unsuccessful cardioversion or high risk of recurrence, and preferably in the absence of sotalol co-treatment. Hypotension.
Anti-arrhythmic drugs before, during and after transvenous electrical cardioversion of atrial fibrillation in horses: Weighing the benefits and risks (Clinical commentary)
eve 2024
Which drugs have been used after TVEC to prevent recurrence ?
- Sotalol
- Amiodarone
- Propafenone
- Phenytoin
Anti-arrhythmic drugs before, during and after transvenous electrical cardioversion of atrial fibrillation in horses: Weighing the benefits and risks (Clinical commentary)
eve 2024
What was the primary method used to accurately locate the accessory pathway (AP) in the horse treated for ventricular pre-excitation?
A) 12-lead electrocardiogram (ECG) only
B) Echocardiography
C) Three-dimensional electro-anatomical mapping (3D EAM)
D) Continuous 24-hour ECG monitoring
Correct Answer: C) Three-dimensional electro-anatomical mapping (3D EAM)
Justification:
The correct answer is C) Three-dimensional electro-anatomical mapping (3D EAM), as it was the primary tool that enabled precise localization of the AP by identifying the earliest site of ventricular activation, which is essential for targeting the correct location during ablation. The text states, “3-dimensional electro-anatomical mapping (3D EAM) and RFCA, using the CARTO 3 System…were used to identify and treat the AP” and “This procedure identified an AP at the right cranial free wall between the right atrium and right ventricle”
Three-dimensional electro-anatomical mappingand radiofrequency ablation as a novel treatment foratrioventricular accessory pathway in a horse: A case report
2022
In the first successful high-density 3D electroanatomical mapping of the right atrium in standing horses, which of the following was used as a positional reference during the procedure?
A. The left atrium
B. A 10-pole catheter in the caudal vena cava
C. The P-wave on the surface ECG
D. The sinoatrial node
Correct Answer: B. A 10-pole catheter in the caudal vena cava
Justification:
Option A is incorrect: The study focused on mapping the right atrium, not the left atrium.
Option B is correct: A 10-pole catheter was placed in the caudal vena cava to serve as a positional reference during the mapping procedure.
Option C is incorrect: The P-wave on the surface ECG was used as a timing reference, not a positional reference.
Option D is incorrect: The sinoatrial node was one of the areas mapped, but it was not used as a positional reference.
First catheter-based high-density endocardial 3D electroanatomical mapping of the right atrium in standing horses
2020
In the study of ultra-high-density 3D electro-anatomical mapping in horses, which chamber required additional tools, such as a deflectable sheath, to successfully complete mapping?
A. Right atrium
B. Left atrium
C. Right ventricle
D. Left ventricle
Correct Answer: B. Left atrium
Justification:
Option A is incorrect: There was no mention of the right atrium requiring additional tools for mapping.
Option B is correct: The study noted that the left atrium was the most challenging chamber to map, requiring the use of a deflectable sheath.
Option C is incorrect: The right ventricle did not require additional tools according to the study.
Option D is incorrect: The left ventricle was mapped successfully, but there was no mention of extra tools needed for it.
More info :Mild elevations in cardiac troponin I were observed post-procedure, indicating some myocardial stress.
Three dimensional ultra-high-density electro-anatomical cardiac mapping in horses: methodology 2020
What are the characteristics of congestive heart failure ? (3)
CHF = vasocontriction
‘+ renal sodium retention
‘+ abnormal tissue growth (hypertrophy and fibrosis)
CHF is a clinical syndrome, not a specific disease. It is the consequence of cardiac dysfunction and compensations chronically activated to maintain systemic BP.
VetClinics Cardio 2019
What is the common clinical sign associated with endocarditis ?
Synovial distention is common and often of minimal significance in older horses, but in tandem with intermittent pyrexia of unknown origin and the sudden appearance of a cardiac murmur, this finding may be consistent with the synovitis frequently noted in endocarditis cases.
VetClinics Cardio 2019
How to calculate ejection fraction (EF), fractional shortening (FS), stoke volume (SV) and cardiac output (CO) ?
LV volume at peak-systole (LVIVs), LV volume at end-diastole (LVIVd)
Ejection fraction (EF) → %EF = [LVIVd - LVIVs] / LVIVd x 100
Stroke volume (SV) → SV = LVIVd - LVIVs
Cardiac output (CO) → CO = SV x HR
LV internal diameter (LVID)
Fractional shortening (FS)
→ %FS = [LVIDd - LVIDs] / LVIDd x 100
VetClinics Cardio 2019
Which biomarkers could be measured in jumping horses with valvular regurgitation ?
ANP, BNP, and endothelin-1
According to the study results, it can be assumed that the measurement of these cardiac biomarkers can be helpful in the diagnosis of the jumping horse with cardiac valvular disorders (especially pulmonic valve regurgitation) and changes in the dimensions of the heart ventricle.
Measurement of ANP, BNP and endothelin-1 concentrations in jumping horses with heart valvular regurgitation and their correlation with the dimensions of heart structures
eve 23
What heart disease are Friesians predisposed to?
Friesians are predisposed to aortic rupture near the ligamentum arteriosum (the remnant of the ductus arteriosus) in conjunction with aortopulmonary fistulation.
The condition can occur as an acute event of sudden death, or can be more chronic with aneurysm, with less specific clinical signs, making the diagnosis challenging.
Presenting signs are recurrent colic, increased rectal temperature, tachycardia, and respiratory signs.
Reference values for 2-dimensional and M-mode echocardiography in Friesian and Warmblood horses
jvim 20
Which conditions are true ?
Compared to WB, Friesians have :
- lower or higher blood pressure ?
- smaller or higher LV and RV ?
- lower or higher FS and EF ?
- Friesians have higher systemic blood pressure and higher arterial wall stiffness than WB.
- Several left ventricular measurements were significantly smaller in Friesians compared to Warmbloods. Also the right ventricular end-diastolic and peak-systolic internal diameter were smaller in Friesians.
- Fractional shortening and ejection fraction were significantly larger.
In general, the left ventricular dimensions in Friesians were significantly smaller compared to
Warmbloods, emphasizing the need for breed-specific reference intervals.
Reference values for 2-dimensional and M-mode echocardiography in Friesian and Warmblood horses
jvim 20
What is the consequence on cardiac function of mild physiological stress (associated with hospital for ex) ?
Moderate stress ?
Physiological stress at mildly increased heart rates (40-45 bpm) significantly enhanced atrial pump function.
Larger heart rate and blood pressure increases during pharmacological challenge resulted in altered cardiac dimensions (decreased LA, LV, and increased Ao, PA). This should be taken into account when evaluating echocardiographic measurements at increased heart rates.
Effect of physiological and pharmacological stress on heart rate, blood pressure, and echocardiographic measurements in healthy WB horses
jvim 24
What are the physiological arrhythmias in horses ?
Sinus pause, sinus arrhythmia, first- and second-degree atrioventricular [AV] blocks
Consensus Cardio
Which ions are responsible of depolarisation of a ventricular cardiomyocyte ?
Phase 0 : depolarization, Na+ in
Phase 1 : rapid repolarization, K+ out
Phase 2 : plateau, Ca2+ in
Phase 3 : repolarization, K+ out
Phase 4 : resting potential, K+ out (Na+/K+ -ATPase pump)
VetClinics Cardio 2019
Which drugs can be used for quinidine toxicity ? Digoxin toxicity ?
Quinidine sulfate toxicity (class Ia) → sodium bicarbonate (QRS prolongation > 25%) and propanolol (β-blocker, due to vagolytic effect of QS)
Digoxin toxicity → diltiazem (class IV) and phenytoin (class Ib)
VetClinics Cardio 2019
Which drugs are used for the first line TT of atrial tachycardia ? Refractory cases ?
Rate control :
- Digoxin, esmolol
- Refractory cases : diltiazem, propanolol
Rythm control :
- Procainamide (class Ia)
- Sotalol (β-blocker), QS (class Ia)
Treat cases when HR > 100 bpm or evidence of poor perfusion using rate control
VetClinics Cardio 2019
Which drugs are used for the first line TT of ventricular tachycardia ? Refractory cases ?
First line TT : lidocaine (class Ib), magnesium sulfate +/- procainamide (class Ia)
Refractory cases : phenytoin (class Ib, in case of digoxin toxicity), propanolol (class II, in case of QS toxicity), sotalol, propafenone (class Ic)
Treat if evidence of poor perfusion or malignant arrhythmias
VetClinics Cardio 2019
Which drugs are used for the first line TT of atrial fibrillation ? Refractory cases ?
First line TT : QS, TVEC (subacute / chronic)
Refractory cases : amiodarone (class III), procainamide (class Ia)
Treat if causing clinical signs of poor performance / epistaxis, or associated with tachyarrhythmias or ventricular complexes.
VetClinics Cardio 2019
Which drugs are used for the first line TT of ventricular fibrillation ? Refractory cases ?
Not amenable for pharmacologic manipulation
VetClinics Cardio 2019
Which drugs are used for the first line TT of atrial premature complexes ? Refractory cases ?
Consider primary cause (electrolytes, myocardial disease, toxins, SIRS)
First line TT : rarely indicated
If persistent : sotalol
VetClinics Cardio 2019
Which drugs are used for the first line TT of ventricular premature complexes ? Refractory cases ?
Consider and address primary cause (electrolytes, myocardial disease, toxins, SIRS) before TT
First line TT : sotalol (class II)
Refractory cases : Phenytoin (class Ib)
VetClinics Cardio 2019
How to manage an asymptomatic horse with CHF ?
Stroke volume = cardiac contractility x preload x afterload
First line TT : ACEi (benazepril) (↘︎ afterload and ⊖RAAS)
Second line : spironolactone (↘︎ preload and ⊖ RAAS → ⊖ aldosterone)
Third line : inodilator (pimobendan) and β-blockers (↗︎ cardiac contractility)
VetClinics Cardio 2019
How to manage a symptomatic horse with CHF ?
Stroke volume = cardiac contractility x preload x afterload
First line TT : diuretics (furosemide) (↘︎ preload)
Second line : ACEi (benazepril) (↘︎ afterload and ⊖RAAS)
.+ inotrope (digoxin or pimobendan)
. + vasodilator (ACP or hydralazine (arteriodilator))
Third line : spironolactone or β-blockers
VetClinics Cardio 2019
Which VSD are likely to result in hemodynamic derangement ?
Unfavorable prognosis if :
VSD > 2.5 cm in a 500 kg horse
or VSD > 40% of aortic annular diameter
or Doppler velocity < 4.5 m/s
The grade of heart murmur is not discriminatory as small defects may result in loud murmurs and concurrent congenital HD may accentuate abnormal auscultatory findings.
Small VSD may be tolerable even in performance horses and spontaneous closure is possible.
Reexamine annually
VetClinics Cardio 2019
What are the risk factors for aortic regurgitation ?
Male sex and increasing age. Typical condition of the older horse.
Small ponies are less likely to have AR compared with other horse types.
VetClinics Cardio 2019
Consensus Cardio
What is the risk factor for mitral regurgitation ?
Horses older than 15 years were more likely to suffer from MR in a survey of a general horse population in United Kingdom.
MR is the most common form of valvular disease associated with congestive heart failure.
Consensus Cardio
Which clinical characteristics have been associated with poor prognosis of aortic regurgitation ?
Clinical characteristics that have been shown to be associated with the onset of exercise intolerance or death within 2 years of identification of AR included:
- diastolic murmur ≧ 4/6
- abnormal pulse quality (hyperkinetic),
- pulse pressure > 60 mm Hg measured at the coccygeal artery,
- VPC or APC > 1 per hour
Consensus Cardio
How to assess the severity of aortic regurgitation ?
1- Subjective assessment of the regurgitant jet : mild (< 1/3 of LV outflow tract in diastole), moderate (< 2/3 of LVOT), severe (> 2/3 LVOT)
2- Subjective assessment of left ventricular size in the four-chamber view (1-5 points)
3- M mode measurement of left ventricular internal diameter in diastole
Combined score → mild, moderate, severe AR
Reexamine twice yearly when moderate to severe, annually if stable or mild.
Consensus Cardio
What are the clinical signs associated with severe MR ?
Clinical signs associated with severe MR include:
- murmurs of grade ≧ 3/6,
- loud S3,
- exercise intolerance or respiratory signs,
- congestive heart failure
- +/- ventricular arrhythmias
Consensus Cardio
How to assess the severity of mitral regurgitation ?
Mild : when there is no LA enlargement, and CFM demonstrates 1 or 2 thin regurgitant jets, whose height is subjectively < 1/3 of the height of the LA.
Moderate : ↗︎ in pulmonary wedge pressure at exercise, which may be associated with exercise intolerance.
Severe MR : leads to LA, LV, and pulmonary artery dilation, which can lead to PA rupture, and affected horses will often show signs of congestive heart failure at rest. Compare Ao vs PA.
Reexamine at least annually or every other year if mild.
Consensus Cardio
What are the most prevalent physiologic regurgitations in mature TB racehorses ?
Physiologic valvular regurgitation is extremely common in equine athletes.
In a large echocardiography study including 526 British racehorses, TR was reported in 80% to 90% of mature Thoroughbred racehorses and MR has a prevalence of 40% to 60% in mature Thoroughbred racehorses.
Furthermore, physiologic regurgitation in the athlete increases with cardiac adaptation to exercise.
What are the risk factors for tricuspid regurgitation ?
TR are common in equine athletes, increasing with age and training
Consensus Cardio
How to assess the severity of tricuspid regurgitation ?
Severe TR if grade murmur ≧ 4/6 with poor performance
TR > 3.5 m/s → suspicion of pulmonary hypertension with left-sided heart disease or severe pulmonary disease.
Reexamine annualy if moderate to severe.
Consensus Cardio
What are the most common site of infective endocarditis ?
The most common site of infection is the mitral valve, closely followed by the aortic valve.
The tricuspid valve most frequently occurs in horses with septic jugular vein thrombophlebitis.
Horses of all ages can be affected, but the condition is more common in younger animals and has been reported in males more than females.
Pasteurella / Actinobacillus, Pseudomonas, Rhodococcus equi
Bacteremia is common with equine dental procedures.
Consensus Cardio
What are the clinical signs of endocarditis ?
Presenting signs frequently include fever, shifting leg lameness, and synovial distension, with valvular regurgitation +/- rupture of associated chordae tendineae.
There may also be concurrent myocarditis with arrhythmias.
Ideally, 3 serial blood cultures at 1-hour intervals should be obtained before treatment with antimicrobials. Assay of cardiac troponin I can be helpful to identify myocardial involvement.
Typically, there is neutrophilic leukocytosis with hyperfibrinogenemia, hyperglobulinemia, and anemia of chronic disease.
Azotemia may be detected in horses with renal emboli or may be prerenal in horses with low cardiac output.
What is the best treatment for endocarditis ?
Cases with involvement of the mitral valve have a particularly grave prognosis. Even when bacteriologic cure is achieved, severe valvular regurgitation can ultimately lead to heart failure.
Selection of antimicrobials should be broad-spectrum or whenever possible based on culture and sensitivity results. Antibiotics with good tissue penetration should be chosen. This is a life-threatening condition and therefore, despite concerns regarding antimicrobial resistance, treatment with the critically important antimicrobials, fluoroquinolones, macrolides, or cephalosporins (bof) is often warranted.
Equine Cardiology said : TMPS, macrolides, tetracyclines, fluoroquinolones
Nonsteroidal antiinflammatory drugs are also indicated.
What is the etiology of rupture of chordae tendineae ?
Rupture of one or more chordae tendineae can occur spontaneously or be associated with preexisting degenerative disease or infective endocarditis. The mitral valve is the most common site.
Because of the rapid change in hemodynamics, horses with ruptured chordae tendineae will often develop signs of acute left-sided heart failure, including coughing, foamy nasal discharge, and moist crackles on auscultation of the lung fields. Sudden death is also possible.
How often should valvular regurgitation be assessed?
Recommendations for both MR and AR include regular monitoring of heart rate and rhythm.
MR : annual cardiological reassessment (or if mild, every other year).
AR : biannual reassessment until it is established the condition is stable.
Exercising ECG with moderate or severe MR and AR, rapidly progressive regurgitation, and in cases in which atrial fibrillation, ventricular ectopy, or other arrhythmias are suspected.
TR is common in athletes. Annual reassessment of moderate and severe TR.
ACVIM Consensus
What are the 3 main cause of toxic cardiomyopathies in horses?
- Ionophores (monensin, lasalocid, salinomycin)
- Plants containing cardiac glycosides (Digitalis spp…)
- Atypical myopathy (hypoglycin-A)
Which horses are predisposed to aortic root rupture ?
Aortic root rupture with or without aneurysmal dilation is commonly reported in older horses of all breeds, predominantly stallions.
Presenting signs in horses with aortocardiac fistulas are acute-onset poor performance, exercise intolerance, sustained tachycardia, and pain or distress that often resembles colic.
Continuous murmur loudest on right side with bounding arterial pulse.
VetClinics Cardio
Consensus Cardio
During an annual vaccination consultation, you detect a heart murmur. What are the criteria for echocardiography? (9)
Echocardiography is indicated when:
1- Previously diagnosed functional murmurs that are louder on serial exam
2- Grade ≧ 3/6 left-sided murmurs compatible with MR and AR
3- Grade ≧ 4/6 right-sided murmurs compatible with TR
4- Suspected VSD or other congenital heart lesion
5- Continuous or combined systolic-diastolic murmurs
6- Murmurs associated with poor performance
7- Clinically important arrhythmias
8- Suspected myocardial injury
9- Suspected CHF
Consensus cardio 2014
What are the clinical utility of Tissue Doppler Imaging (TDI) and 2D Speckle Tracking (2DST) ?
TDI : detection of LV diastolic dysfunction
2D-ST : detection of LA stunning after TT of AF and LV systolic dysfunction in horses with myocardial disease
During an echocardiographic examination, the horse is agitated. What are the consequences of sedation with ⍺2-agonist or ACP on the examination?
⍺2-agonist : ↗︎ afterload and myocardial depression → ↘︎ LV systolic performance and worsen regurgitation
ACP : ↘︎ afterload → may improve LV systolic performance and ↘︎ regurgitation
Does smartphone ECG a reliable tool for arrhythmias screening in horses ?
It is important to obtain SpECG tracings from both sides of the thorax in horses. Significantly more P waves were of diagnostic quality from the right side and significantly more QRS and QT intervals were of diagnostic quality from the left side.
The SpECG is a useful stall-side arrhythmia-screening tool for some common arrhythmias in horses.
Stall-side screening potential of a smartphone electrocardiogram recorded over both sides of the thorax in horses
jvim 20
What impact does training have on the ECG?
We identified decreased HR at rest and increased frequency of 2AVB in trained horses vs untrained horses.
Electrocardiographic characteristics of trained and untrained standardbred racehorses
jvim 22
What are the cardiovascular differences between Friesians and WB ?
Systolic, diastolic, and mean arterial blood pressure and pulse pressure were significantly higher in Friesians compared to Warmbloods.
Friesians seem to have a stiffer aorta (plus rigide), but not cranial and caudal common carotid artery and external iliac artery, which might be related to the higher incidence of aortic rupture in Friesians.
Differences in ultrasound-derived arterial wall stiffness parameters and noninvasive blood pressure between Friesian horses and Warmblood horses
jvim 20
Is there any vascular modification in ageing horses ?
In horses, arteries stiffen with age (se rigidifient), in combination with luminal enlargement and arterial wall thickening.
This might, at least partially, explain the increased incidence of arterial rupture in older horses.
Age-related differences in blood pressure, ultrasound-derived arterial diameters and arterial wall stiffness parameters in horses
evj 20
Is there any increase of cardiac troponin after the race ?
Is there an effect of the racing speed on cardiac troponin ?
Horses experience a postexercise increase in cTnI and cTnT with peaks occurring 2 to 6 hours postexercise and values returning to normal at 24 hours.
Racing speed and placings had no effect on serum cTnT concentrations post-race.
Pre- and post-race serum cardiac troponin T concentrations in Standardbred racehorses
Vet J 20
VetClinics 19
Question:
What were the key cardiovascular changes observed in Shetland pony mares fed a high-energy (HE) diet for 2 consecutive years, according to the study?
A) Increased systolic, diastolic, and mean arterial blood pressure, along with left-sided cardiac hypertrophy.
B) Decreased blood pressure and no changes in cardiac structure.
C) Pathological arrhythmias and significant changes in autonomic tone.
D) Increased splenic volume and reduced packed cell volume (PCV).
Correct Answer:
A) Increased systolic, diastolic, and mean arterial blood pressure, along with left-sided cardiac hypertrophy.
Ingesting a High-Energy diet first induced minor changes in Blood Pressure (first year),
and progressed to left-sided cardiac hypertrophy (increased mean left ventricular wall thickness) (second year) in Shetland pony mares.
These findings are of interest given the increasing incidence of obesity in horses.
Effect of a long-term high-energy diet on cardiovascular parameters in Shetland pony mares
jvim 21
