Free Cardiac Subspecialty Questions and Answers — Questions and Answers
Question 1: Which electrolyte condition will reveal shortened QT intervals and cardiac repolarization on an EKG?
- Hypocalcemia
- Hyperkalemia
- Hypokalemia
- Hypercalcemia (Correct answer)
Correct answer: Hypercalcemia
Hypercalcemia, an elevated level of calcium in the blood, causes a characteristic shortening of the QT interval on an EKG. Calcium plays a vital role in myocardial contraction and repolarization. Excess calcium accelerates the repolarization phase of the cardiac action potential, leading to a quicker return to the resting state and thus a shorter QT interval.
Question 2: What is measured by the horizontal component of the EKG?
- Watts
- Waveforms
- Duration (Correct answer)
- Voltage
Correct answer: Duration
On an electrocardiogram (EKG), the horizontal axis represents time. Therefore, the horizontal component of the EKG tracing is used to measure the duration of various cardiac electrical events. This includes intervals such as the PR interval, QRS duration, and QT interval, which reflect the time taken for electrical impulses to travel through different parts of the heart.
Question 3: A patient who has experienced one episode of syncope with reports of feeling lightheaded and dizzy presents. His blood pressure was 90/70 mm Hg, and the nurse noted his pulse rate as 40/minute. His EKG results point to a type II AV block in the second degree. What ought to be the patient's treatment objective?
- Improve blood supply to vital organs
- Increase blood pressure (Correct answer)
- Increase the heart rate
- Restore sinus rhythm and maintain cardiac output
Correct answer: Increase blood pressure
The patient's symptoms of syncope, lightheadedness, and dizziness, coupled with significant bradycardia (HR 40/min) and hypotension (BP 90/70 mm Hg), indicate inadequate cardiac output and poor perfusion to vital organs. While increasing the heart rate is a mechanism to improve cardiac output, the primary and most immediate treatment objective is to increase the blood pressure. Restoring adequate blood pressure ensures sufficient blood flow to the brain and other critical organs, thereby resolving the symptoms and stabilizing the patient's hemodynamic status.
Question 4: Which of the following conditions is treated with alpha-adrenergic antagonists?
- Hypertension, pheochromocytoma (Correct answer)
- Cardiac arrhythmia, carcinoid syndrome
- Cardiogenic shock, postprandial hypertension
- Hypotension, cardiac arrhythmia
Correct answer: Hypertension, pheochromocytoma
Alpha-adrenergic antagonists, also known as alpha-blockers, block the effects of norepinephrine and epinephrine on alpha-adrenergic receptors, primarily causing vasodilation. This property makes them effective in treating hypertension by lowering peripheral vascular resistance. They are also crucial in managing pheochromocytoma, a tumor that secretes excessive catecholamines, as they prevent severe hypertensive crises by blocking the vasoconstrictive actions of these hormones.
Question 5: Which of the following investigations can help distinguish between neurogenic and arterial claudication that is intermittent?
- Doppler flow studies
- Digital subtraction angiography scan
- Real-time Duplex scanning
- All of above (Correct answer)
Correct answer: All of above
Distinguishing between neurogenic and arterial intermittent claudication requires a comprehensive approach, and all the listed investigations play a role. Doppler flow studies (e.g., Ankle-Brachial Index) and Real-time Duplex scanning directly assess arterial blood flow to diagnose or rule out arterial insufficiency. Digital subtraction angiography provides detailed anatomical visualization of arterial blockages. By confirming or excluding arterial causes, these tests indirectly help to identify neurogenic claudication when symptoms persist in the absence of significant arterial disease.
Question 6: Which of the following summaries best fits the pacemaker's five-position code?
- Position one (I) - chambers being paced, Position two (II) - chambers being sensed, Position three (III) - device’s response to sensing, Position four (IV) - for defibrillation function, Position five (V) - only for rate modulation
- Position one (I) - chambers being paced, Position two (II) - chambers being sensed, Position three (III) - device’s response to sensing, Position four (IV) - programmability and rate of modulation function, Position five (V) - for defibrillation functio
- Position one (I) - chambers being paced, Position two (II) - chambers being sensed, Position three (III) - device’s response to sensing, Position four (IV) - programmability and rate of modulation function, Position five (V) - only for tachycardia funct (Correct answer)
- Position one (I) - chambers being sensed, Position two (II) - chambers being paced, Position three (III) - device’s response to sensing, Position four (IV) - programmability and rate of modulation function, Position five (V) - only for tachycardia funct
Correct answer: Position one (I) - chambers being paced, Position two (II) - chambers being sensed, Position three (III) - device’s response to sensing, Position four (IV) - programmability and rate of modulation function, Position five (V) - only for tachycardia funct
The NBG (North American Society of Pacing and Electrophysiology/British Pacing and Electrophysiology Group) code is a standardized five-position system for describing pacemaker functions. Position one (I) indicates the chamber(s) being paced, position two (II) indicates the chamber(s) being sensed, and position three (III) describes the device’s response to sensing. Position four (IV) denotes programmability and rate modulation functions, while position five (V) is used for antitachycardia functions or multisite pacing capabilities.
Question 7: Which of the following drug classes belongs to the vasodilator family?
- Beta agonist, adrenaline, isoproterenol
- Beta-blockers, nitrates, calcium channel blockers (Correct answer)
- Beta-blockers, sympthomimetic drugs, diuretics
- Beta-agonist, cardiac glycoside, steroids
Correct answer: Beta-blockers, nitrates, calcium channel blockers
Nitrates and calcium channel blockers are well-known classes of vasodilator drugs. Nitrates directly relax vascular smooth muscle, primarily in veins, reducing preload. Calcium channel blockers block calcium entry into vascular smooth muscle cells, leading to arterial vasodilation and reduced peripheral resistance. While some beta-blockers (e.g., carvedilol) possess vasodilatory properties due to additional alpha-blocking effects, nitrates and calcium channel blockers are fundamentally classified as vasodilators, making this the most appropriate option among the choices.
Free Cardiac Subspecialty Questions and Answers
Which electrolyte condition will reveal shortened QT intervals and cardiac repolarization on an EKG?