FISDAP CARDIOLOGY Q&A
PRACTICE EXAMINATION 2026
QUESTIONS WITH ANSWERS GRADED
A+
SECTION 1: CARDIAC ANATOMY & PHYSIOLOGY
1. Which node is located at the junction of the superior vena cava and
the right atrium, is typically supplied by the Right Coronary artery, and
fires at a rate of 60-100 bpm?
• A) AV node
• B) Bundle of His
• C) Purkinje fibers
• D) SA Node ✓
Rationale: The sinoatrial (SA) node is the natural pacemaker of the heart,
located at the junction of the superior vena cava and right atrium. It
normally fires at 60-100 bpm and receives its blood supply from the right
coronary artery in approximately 60% of the population .
2. What does stimulation of Beta-1 receptors result in?
• A) Vasoconstriction only
, • B) Bronchodilation
• C) Increased inotropy, chronotropy, and dromotropy ✓
• D) Decreased heart rate
Rationale: Beta-1 receptor stimulation increases heart rate
(chronotropy), contractility (inotropy), and conduction velocity
(dromotropy). Beta-1 receptors are also located in the kidneys where they
activate the renin-angiotensin-aldosterone system, leading to
vasoconstriction and increased blood pressure .
3. Which electrolyte flows into cardiac cells to initiate depolarization?
• A) Potassium (K+)
• B) Sodium (Na+) ✓
• C) Calcium (Ca++)
• D) Magnesium (Mg++)
Rationale: Sodium influx through fast sodium channels initiates rapid
depolarization of cardiac muscle cells. This inward sodium current
causes the rapid upstroke of the action potential in working myocardial
cells .
4. Which electrolyte flows out of cardiac cells to initiate repolarization?
• A) Potassium (K+) ✓
• B) Sodium (Na+)
• C) Calcium (Ca++)
• D) Magnesium (Mg++)
,Rationale: Potassium efflux (movement out of the cell) is primarily
responsible for repolarization of cardiac cells. This restores the negative
resting membrane potential after depolarization .
5. Which electrolyte plays a major role in depolarization of pacemaker
cells, maintains depolarization, and myocardial contractility?
• A) Potassium (K+)
• B) Sodium (Na+)
• C) Calcium (Ca++) ✓
• D) Magnesium (Mg++)
Rationale: Calcium influx through slow calcium channels is essential for
depolarization of pacemaker cells (phase 0 of SA/AV node action
potentials) and for myocardial contractility (excitation-contraction
coupling) .
6. Which electrolyte stabilizes the cell membrane and acts in concert
with K+ while opposing the actions of Ca++?
• A) Potassium (K+)
• B) Sodium (Na+)
• C) Calcium (Ca++)
• D) Magnesium (Mg++) ✓
Rationale: Magnesium stabilizes cardiac cell membranes and works
synergistically with potassium. Magnesium opposes calcium actions,
, making it important in preventing dysrhythmias and treating conditions
like torsades de pointes .
7. Hypokalemia results in:
• A) Increased myocardial irritability ✓
• B) Decreased automaticity and conduction
• C) Decreased contractility
• D) Increased conduction
Rationale: Hypokalemia (low potassium) increases myocardial irritability,
predisposing patients to dysrhythmias including premature ventricular
contractions (PVCs), ventricular tachycardia, and torsades de pointes.
Hypokalemia also potentiates digoxin toxicity .
8. Hyperkalemia results in:
• A) Increased myocardial irritability
• B) Decreased automaticity and conduction ✓
• C) Increased contractility
• D) Decreased QT interval
Rationale: Hyperkalemia decreases automaticity and slows conduction
through the heart. ECG changes include peaked T waves, widened QRS
complex, prolonged PR interval, and eventually sinusoidal waveform and
asystole .
PRACTICE EXAMINATION 2026
QUESTIONS WITH ANSWERS GRADED
A+
SECTION 1: CARDIAC ANATOMY & PHYSIOLOGY
1. Which node is located at the junction of the superior vena cava and
the right atrium, is typically supplied by the Right Coronary artery, and
fires at a rate of 60-100 bpm?
• A) AV node
• B) Bundle of His
• C) Purkinje fibers
• D) SA Node ✓
Rationale: The sinoatrial (SA) node is the natural pacemaker of the heart,
located at the junction of the superior vena cava and right atrium. It
normally fires at 60-100 bpm and receives its blood supply from the right
coronary artery in approximately 60% of the population .
2. What does stimulation of Beta-1 receptors result in?
• A) Vasoconstriction only
, • B) Bronchodilation
• C) Increased inotropy, chronotropy, and dromotropy ✓
• D) Decreased heart rate
Rationale: Beta-1 receptor stimulation increases heart rate
(chronotropy), contractility (inotropy), and conduction velocity
(dromotropy). Beta-1 receptors are also located in the kidneys where they
activate the renin-angiotensin-aldosterone system, leading to
vasoconstriction and increased blood pressure .
3. Which electrolyte flows into cardiac cells to initiate depolarization?
• A) Potassium (K+)
• B) Sodium (Na+) ✓
• C) Calcium (Ca++)
• D) Magnesium (Mg++)
Rationale: Sodium influx through fast sodium channels initiates rapid
depolarization of cardiac muscle cells. This inward sodium current
causes the rapid upstroke of the action potential in working myocardial
cells .
4. Which electrolyte flows out of cardiac cells to initiate repolarization?
• A) Potassium (K+) ✓
• B) Sodium (Na+)
• C) Calcium (Ca++)
• D) Magnesium (Mg++)
,Rationale: Potassium efflux (movement out of the cell) is primarily
responsible for repolarization of cardiac cells. This restores the negative
resting membrane potential after depolarization .
5. Which electrolyte plays a major role in depolarization of pacemaker
cells, maintains depolarization, and myocardial contractility?
• A) Potassium (K+)
• B) Sodium (Na+)
• C) Calcium (Ca++) ✓
• D) Magnesium (Mg++)
Rationale: Calcium influx through slow calcium channels is essential for
depolarization of pacemaker cells (phase 0 of SA/AV node action
potentials) and for myocardial contractility (excitation-contraction
coupling) .
6. Which electrolyte stabilizes the cell membrane and acts in concert
with K+ while opposing the actions of Ca++?
• A) Potassium (K+)
• B) Sodium (Na+)
• C) Calcium (Ca++)
• D) Magnesium (Mg++) ✓
Rationale: Magnesium stabilizes cardiac cell membranes and works
synergistically with potassium. Magnesium opposes calcium actions,
, making it important in preventing dysrhythmias and treating conditions
like torsades de pointes .
7. Hypokalemia results in:
• A) Increased myocardial irritability ✓
• B) Decreased automaticity and conduction
• C) Decreased contractility
• D) Increased conduction
Rationale: Hypokalemia (low potassium) increases myocardial irritability,
predisposing patients to dysrhythmias including premature ventricular
contractions (PVCs), ventricular tachycardia, and torsades de pointes.
Hypokalemia also potentiates digoxin toxicity .
8. Hyperkalemia results in:
• A) Increased myocardial irritability
• B) Decreased automaticity and conduction ✓
• C) Increased contractility
• D) Decreased QT interval
Rationale: Hyperkalemia decreases automaticity and slows conduction
through the heart. ECG changes include peaked T waves, widened QRS
complex, prolonged PR interval, and eventually sinusoidal waveform and
asystole .
