Equine Cardiology: Arrhythmias and ECG

In a healthy equine patient, the typical order of auscultation of heart sounds, from the onset of diastole to the end of systole, is best represented by which sequence?

A veterinary student is learning equine auscultation. To best assess the mitral valve, where should they position their stethoscope?

A clinician auscultates a regularly irregular rhythm in a resting Standardbred horse with a heart rate of 32 bpm. Which of the following is the MOST likely physiological explanation for this finding?

When auscultating a horse, you identify a 'dropped beat' that disappears upon exercise. Which characteristic of the heart sound pattern is MOST consistent with a physiological 2nd degree AV block in this scenario?

In equine cardiology, atrial fibrillation is considered an important pathogenic arrhythmia. Which of the following statements accurately reflects a key characteristic differentiating atrial fibrillation from other equine arrhythmias?

Differentiating between ventricular tachycardia and supraventricular tachycardia is critical in equine cardiology for prognosis and treatment. What is the MOST reliable ECG characteristic to distinguish ventricular tachycardia from supraventricular tachycardia?

A 15-year-old Warmblood presents with exercise intolerance. Auscultation reveals a grade 3/6 systolic murmur loudest over the left heart base. Which of the following is the MOST likely underlying cause of this murmur in an older athletic horse?

Thoracic radiographs are often part of the diagnostic workup for equine cardiac conditions. However, their utility in directly assessing the heart is limited compared to other modalities. What is the PRIMARY information gained from thoracic radiographs in a horse with suspected cardiac disease?

Echocardiography is a cornerstone diagnostic tool in equine cardiology. Which of the following best describes the optimal probe frequency range used for equine echocardiography and the rationale behind it?

M-mode echocardiography is utilized in equine cardiology to assess specific cardiac parameters. Which of the following BEST describes the primary application of M-mode echocardiography?

Pulsed wave Doppler echocardiography is essential for evaluating blood flow in equine cardiology. What is a key limitation of pulsed wave Doppler compared to continuous wave Doppler?

In color flow Doppler echocardiography, different colors are used to represent blood flow direction and velocity. What does the color 'yellow' typically indicate in the context of equine cardiac blood flow mapping?

Cardiac Troponin I (cTnI) is increasingly used in equine medicine as a biomarker. Which of the following clinical scenarios would BEST justify the use of cTnI measurement in a horse?

A client calls your clinic concerned about their horse. They describe the horse as 'not performing as well' and 'tiring easily'. Which of the following historical details would be MOST critical to elicit from the client to assess for potential cardiac involvement in exercise intolerance?

A horse presents with acute onset of weakness, ataxia, and episodes of collapse. While colic and neurological conditions are considered, what specific historical or clinical finding would STRONGLY suggest a primary cardiac etiology for these neurological-like signs?

A horse diagnosed with third-degree atrioventricular (AV) block is presented for evaluation. What is the IMMEDIATE clinical significance of this arrhythmia in relation to physical examination findings and patient management?

A horse is exhibiting coughing and nasal discharge that appears frothy and blood-tinged. In the context of equine cardiology, what is the MOST concerning interpretation of these respiratory signs?

Sudden death in horses during exercise is a devastating event. In cases of exercise-related sudden death where necropsy reveals no gross lesions, what is the MOST probable underlying cause?

During a routine pre-purchase examination of a sport horse, you palpate the facial artery to assess the pulse. Which of the following pulse characteristics is MOST important to evaluate in the context of a cardiovascular assessment?

During a physical examination, you observe pronounced jugular venous distention extending high up the neck in a horse at rest with its head in a normal position. This finding is MOST suggestive of:

A jugular pulse is normally visible in the distal third of the jugular vein when a horse is standing with its head raised. If the jugular pulse is observed to extend further up the neck, this ABNORMAL finding is MOST likely associated with:

You are evaluating a horse with cyanotic mucous membranes. This bluish discoloration is primarily caused by an increased concentration of:

While assessing mucous membrane color, you note that a horse's mucous membranes are white. This finding is MOST consistent with which underlying physiological derangement?

Ventral edema in horses, characterized by fluid accumulation along the ventral abdomen and limbs, is a frequent clinical sign of:

During cardiac auscultation, which of the following components is MOST crucial for a comprehensive assessment, beyond just heart rate?

S1 heart sound is primarily attributed to the closure of which cardiac valves in the equine heart?

To auscultate the pulmonic valve area effectively in a horse, where should the stethoscope be optimally placed in relation to anatomical landmarks?

Cardiac murmurs are indicative of turbulent blood flow. Which of the following factors is LEAST likely to contribute to the generation of a cardiac murmur in a horse?

When describing a cardiac murmur, timing is a critical characteristic. A systolic murmur is heard during which phase of the cardiac cycle?

A holosystolic murmur is characterized by its duration. Which statement BEST describes the temporal extent of a holosystolic murmur?

You auscultate a cardiac murmur and grade its intensity as a Grade 4/6. According to the grading scale for cardiac murmurs, what is a defining characteristic of a Grade 4 murmur?

Point of maximal intensity (PMI) is an important characteristic when describing a cardiac murmur. What does the PMI primarily indicate about the origin of a murmur?

Functional or 'innocent' cardiac murmurs can occur in horses, particularly athletic ones. Which type of functional murmur is MOST commonly auscultated in horses, especially during periods of high cardiac output?

Pathologic cardiac murmurs in horses are most commonly associated with which of the following underlying mechanisms?

Second-degree AV block is considered a common and often physiological arrhythmia in horses. Which of the following statements accurately describes a key characteristic of second-degree AV block in horses?

On an ECG of a horse with Mobitz Type I second-degree AV block (Wenckenbach phenomenon), what is the hallmark ECG finding?

Physiological second-degree AV block in horses is often attributed to high vagal tone. Which of the following clinical scenarios is MOST likely to abolish or diminish physiological second-degree AV block?

Is the following statement true or false? 'All cardiac murmurs in horses indicate abnormal blood flow and underlying cardiac pathology.'

Which of the following statements regarding second-degree AV block in horses is FALSE?

Cardiac arrhythmias are broadly classified based on their origin. Supraventricular arrhythmias originate from which anatomical locations in the heart?

Which of the following is considered a COMMON cause of cardiac arrhythmias in horses, particularly both supraventricular and ventricular types?

Atrial fibrillation (AF) is the most common pathologic arrhythmia in horses. Which of the following statements accurately describes a key etiological factor in equine atrial fibrillation?

What is a HALLMARK clinical feature of 'lone' atrial fibrillation in horses at rest?

On an electrocardiogram of a horse with atrial fibrillation, which of the following ECG findings is MOST characteristic?

Historically, which antiarrhythmic drug was commonly used for chemical conversion of atrial fibrillation to normal sinus rhythm in horses, though its use is now limited due to availability and toxicity concerns?

Transvenous electrical cardioversion (TVE) is now a preferred method for treating atrial fibrillation in horses. What is a significant advantage of TVE over pharmacological conversion using quinidine?

If a horse with atrial fibrillation is not converted to normal sinus rhythm, or owners decline conversion therapy, what is a CRITICAL consideration for the horse's future management, especially if ridden?

In equine cardiology, the S4 heart sound is associated with atrial contraction and increased ventricular filling. Under which of the following clinical scenarios would the presence of an S4 heart sound be considered MOST indicative of underlying cardiac pathology, rather than a normal finding?

When performing equine auscultation to assess cardiac valve function, strategic stethoscope placement is crucial. To optimally evaluate the tricuspid valve, where should the stethoscope be positioned?

A horse presents with exercise intolerance and intermittent episodes of collapse. An ECG reveals a regularly irregular rhythm with a heart rate of 28 bpm. Auscultation identifies 'dropped beats' that disappear with exercise. While physiological 2nd degree AV block is considered, which additional clinical finding would MOST strongly suggest a PATHOLOGICAL, rather than physiological, 2nd degree AV block in this case?

Atrial fibrillation is a significant arrhythmia in horses, often impacting athletic performance. Which of the following statements BEST describes the underlying mechanism that distinguishes atrial fibrillation from other supraventricular tachyarrhythmias, such as atrial flutter?

Differentiating ventricular tachycardia (VT) from supraventricular tachycardia (SVT) with aberrancy is critical for appropriate treatment and prognosis in equine cardiology. Which ECG characteristic is the MOST RELIABLE indicator for distinguishing VT from SVT with aberrant ventricular conduction?

An older equine athlete is diagnosed with a grade 3/6 systolic murmur loudest over the left heart base. Considering the common cardiac conditions in older horses, which of the following is the MOST likely underlying cause of this murmur?

Thoracic radiography has limited direct application in assessing the equine heart itself. However, it remains a valuable diagnostic tool in equine cardiology. What is the PRIMARY clinical utility of thoracic radiographs in horses with suspected cardiac disease?

Echocardiography is a cornerstone of equine cardiac diagnostics. Why is a lower frequency ultrasound probe (2-3 MHz) typically preferred over higher frequencies for equine echocardiography?

M-mode echocardiography is a valuable technique in equine cardiology. What is the MOST specific and primary application of M-mode echocardiography in the equine cardiac evaluation?

Pulsed wave Doppler echocardiography is essential for evaluating blood flow in equine cardiology. What is the fundamental limitation of pulsed wave Doppler compared to continuous wave Doppler when assessing high-velocity blood flow, such as in severe valvular stenosis or regurgitation?

In equine color flow Doppler echocardiography, the color 'yellow' is sometimes observed within blood flow maps. What physiological phenomenon or technical artifact does 'yellow' typically represent in this context?

Cardiac Troponin I (cTnI) is used in equine medicine as a biomarker for myocardial injury. In which of the following clinical scenarios would measuring cTnI levels provide the MOST diagnostically valuable information?

A horse owner reports that their horse is 'not performing as well' and 'tires easily' during exercise. To assess for potential cardiac involvement in this exercise intolerance, which historical detail would be MOST critical to elicit during your initial phone consultation?

A horse presents with acute onset of weakness, ataxia, and collapsing episodes. While neurological and musculoskeletal issues are initially considered, which specific historical or clinical finding would MOST strongly suggest a primary cardiac etiology as the cause of these 'neurological-like' signs?

A horse is diagnosed with third-degree atrioventricular (AV) block. What is the IMMEDIATE clinical significance of this arrhythmia in terms of physical examination findings and patient management?

A horse presents with coughing and nasal discharge described as frothy and blood-tinged. In the context of equine cardiology, what is the MOST concerning interpretation of these respiratory signs?

During a routine pre-purchase examination of a sport horse, you palpate the facial artery to assess the pulse. Which pulse characteristic is MOST important to evaluate in the context of a cardiovascular assessment?

During cardiac auscultation, which component is MOST crucial for a comprehensive assessment beyond simply determining the heart rate?

The S1 heart sound, often described as 'lub,' is primarily attributed to the closure of which cardiac valves in the equine heart?

To effectively auscultate the pulmonic valve area in a horse, where should the stethoscope be optimally placed in relation to anatomical landmarks?

Cardiac murmurs are generated by turbulent blood flow. Which factor is LEAST likely to directly contribute to the generation of a cardiac murmur in a horse?

A holosystolic murmur is defined by its duration. Which statement BEST describes the temporal extent of a holosystolic murmur?

Second-degree AV block is considered a common and often physiological arrhythmia in horses. Which statement accurately describes a key characteristic of physiological second-degree AV block in horses?

Physiological second-degree AV block in horses is often attributed to high vagal tone. Which clinical scenario is MOST likely to abolish or diminish physiological second-degree AV block?

Which statement regarding second-degree AV block in horses is FALSE?

Which is considered a COMMON cause of cardiac arrhythmias in horses, particularly both supraventricular and ventricular types?

Atrial fibrillation (AF) is the most common pathologic arrhythmia in horses. Which statement accurately describes a key etiological factor in equine atrial fibrillation?

On an electrocardiogram of a horse with atrial fibrillation, which ECG finding is MOST characteristic?

In equine cardiology, how does the use of a continuous wave Doppler differ fundamentally from pulsed wave Doppler in echocardiography?

A horse presents with a history of recent antibiotic treatment for a respiratory infection and now exhibits clinical signs of heart failure. Which underlying mechanism should be MOST suspected as a potential cause or contributing factor to the heart failure?

An ECG reveals a supraventricular arrhythmia in a horse with normal QRS complexes. Given the context of the arrhythmia's origin, which of the following best describes the pathway of electrical conduction in comparison to ventricular arrhythmias?

In a horse diagnosed with atrial fibrillation, why is an exercise stress test particularly important if the owner is considering riding the horse without attempting cardioversion?

A horse presents with clinical signs of tachydysrhythmia and elevated cardiac troponin I levels following a recent history of anorexia and diarrhea. Which of the following differentials is MOST likely, considering the horse's history and lab results?

What is the MOST critical therapeutic consideration when treating a horse with ionophore toxicity affecting the myocardium, given the potential complications and contraindications?

A horse presents with acute onset of severe colic, muscle fasciculations, and progresses into cardiovascular collapse. Given the clinical presentation, which of the following toxicities should be HIGHLY suspected?

When evaluating a 3-year-old Thoroughbred racehorse with a Grade 3/6 holosystolic murmur auscultated over the right cardiac window, what is the MOST likely differential diagnosis to consider?

If a horse is exhibiting signs of heart failure, which of the following clinical presentation findings is MOST indicative of progressing RIGHT-sided heart failure?

If a horse presents with a known history of recent caterpillar exposure and now exhibits clinical signs indicative of Pericardial Disease, what is the most likely pathophysiology and what diagnostic test would best support this?

In a horse with a history of cardiac disease, what is the MOST concerning implication of observing frothy, blood-tinged nasal discharge during a physical examination?

What is the MOST appropriate method for diagnosing a Uterine Artery Rupture post-foaling?

In a horse with diagnosed aortic regurgitation that is considered clinically significant, what would be the MOST prudent long-term management recommendation for its athletic use?

In cases of equine sudden death during exercise with no gross lesions, what is the pathophysiologic reasoning that makes fatal arrhythmia considered the most probable cause?

Why may diagnostic blockage when evaluating a lameness complaint lead to additional cardiac work-up?

In the context of equine cardiology, what is the MOST relevant clinical implication of the relatively short half-life of cardiac troponin I (cTnI)?

What mechanism causes second degree AV block to be generally abolished by exercise?

What is now considered to be the common cause of Atrial Fibrillation?

What is the hallmark ECG finding for Atrial Fibrillation?

What specific characteristic is NOT an intended target of treatment when using antiarrhythmic therapy to handle life-threatening ventricular tachycardia?