Cardiology Pharmacology Quiz

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Questions and Answers

What is the term for the rate or speed of the heart?

Dromotropic

Inotropic

Chronotropic (correct)

Lusitropic

Which of the following is NOT a characteristic of pacemaker cells?

Conductivity

Rhythmicity

Automaticity

Contractility (correct)

What is the term for the period during repolarization where the cell can be depolarized if the stimulus is strong enough?

Absolute refractory period

Vulnerable period

Relative refractory period (correct)

Supernormal period

Which of the following is responsible for rapid impulse conduction within the heart?

Purkinje cells (B) Signup and view all the answers

Which phase of the action potential is characterized by rapid repolarization?

Phase 3 (C) Signup and view all the answers

What is the process called when calcium release from the sarcoplasmic reticulum is triggered by calcium entering the cell?

Calcium-induced calcium release (A) Signup and view all the answers

Which of the following is NOT a factor that contributes to myocyte relaxation?

Calcium entering the cell (A) Signup and view all the answers

Which of the following is the most accurate definition of automaticity?

The ability of a cell to generate its own electrical impulse (A) Signup and view all the answers

Which of these is a property of propranolol?

Noncardioselective (C) Signup and view all the answers

What is the preferred route of administration for propranolol?

Intravenous (B) Signup and view all the answers

Which of these is a potential side effect of propranolol?

Hypotension (D) Signup and view all the answers

What is the maximum intravenous bolus dose of propranolol?

10 mg (D) Signup and view all the answers

Which of these conditions is propranolol commonly used to treat?

Hypertension (B) Signup and view all the answers

What drug is no longer available due to a high risk of death or cardiac arrest within the first 14 days of therapy?

Moricizine (C) Signup and view all the answers

Which drug has a synergistic effect with 𝛽-blockers or antiarrhythmics like quinidine or procainamide, allowing for decreased dosages of these components?

Mexiletine (B) Signup and view all the answers

Which drug is indicated for the control of heart rate and blood pressure?

Esmolol (B) Signup and view all the answers

What is the therapeutic blood level for phenytoin?

10-18 mcg/ml (A) Signup and view all the answers

Which drug has a negative ionotropic activity?

Flecainide (B) Signup and view all the answers

What is the elimination half-life of propafenone?

6-12h (C) Signup and view all the answers

Which drug is a fluorinated local anesthetic analog of procainamide?

Flecainide (B) Signup and view all the answers

Which drug is indicated for the suppression of chronic ventricular tachycardia?

Mexiletine (A), Tocainide (B) Signup and view all the answers

What is the mechanism of action of esmolol?

Blocking beta-1 adrenergic receptors (C) Signup and view all the answers

Which drug may widen the QRS complex and potentially cause second-degree or third-degree AV blocks?

Propafenone (A) Signup and view all the answers

What is the primary route of administration for tocainide?

Oral (C) Signup and view all the answers

Which drug is effective in suppressing ventricular arrhythmias associated with digitalis toxicity?

Phenytoin (C) Signup and view all the answers

Which drug is considered a Class IC antiarrhythmic?

Flecainide (A) Signup and view all the answers

Which drug has a shorter elimination half-life compared to others mentioned in the content?

Esmolol (A) Signup and view all the answers

Which drug is known to be effective in atrial fibrillation?

Propafenone (A), Flecainide (C) Signup and view all the answers

What is the primary mechanism of action of dofetilide?

Blockade of rapid potassium channels (A) Signup and view all the answers

What percentage of dofetilide is eliminated unchanged in urine?

80% (B) Signup and view all the answers

Which of the following conditions increases the risk of developing torsades de pointes VT when using dofetilide?

Prolonged QTc (C) Signup and view all the answers

Which of the following is true regarding bretylium?

It was recently reintroduced after a long discontinuation. (C) Signup and view all the answers

What adverse effect can result from the use of verapamil?

Severe bradycardia (B) Signup and view all the answers

What is the key property of verapamil's pharmacokinetics?

Extensive hepatic metabolism (A) Signup and view all the answers

What effect does bretylium have on catecholamines?

Increases catecholamine release initially (D) Signup and view all the answers

For which condition is dofetilide indicated?

Chemical cardioversion of atrial fibrillation (A) Signup and view all the answers

What serious complication is associated with dronedarone due to its effect on cardiac action potentials?

Torsades de pointes (C) Signup and view all the answers

Which statement is true regarding sotalol's mechanism of action?

It predominantly acts as a beta-blocker at low doses. (C) Signup and view all the answers

Before initiating long-term therapy for a patient exposed to pulmonary toxicity, which test is recommended?

Baseline chest X-ray (D) Signup and view all the answers

What is ibutilide predominantly indicated for?

Conversion of recent onset atrial fibrillation (B) Signup and view all the answers

What is a common adverse effect associated with long-term treatment of certain antiarrhythmic agents?

Thyroid dysfunction (D) Signup and view all the answers

For patients receiving dronedarone, what is a significant risk concerning liver health?

Hepatotoxicity (A) Signup and view all the answers

Which of the following antiarrhythmic agents is a pure class III drug?

Ibutilide (C) Signup and view all the answers

What characteristic is true about the disposition of sotalol?

Renally excreted (A) Signup and view all the answers

In the management of atrial flutter or fibrillation, what is the primary role of dronedarone?

Restoring normal sinus rhythm (B) Signup and view all the answers

What safety measure should be taken regarding oxygen in patients under chronic treatment for possible pulmonary toxicity?

Restrict FiO2 in general anesthetics (B) Signup and view all the answers

Which of the following are Class 1A antiarrhythmics?

quinidine (C) Signup and view all the answers

How does the mechanism of action of Class I antiarrhythmics relate to their effect on the heart?

By blocking sodium channels, they reduce the rate of depolarization. (B) Signup and view all the answers

What is the primary mechanism of action of quinidine?

Blockade of sodium channels (A) Signup and view all the answers

Which of the following best describes the effect of Class 1A antiarrhythmics on repolarization?

They prolong the repolarization duration. (C) Signup and view all the answers

Which of the following is NOT a characteristic effect of quinidine?

Increased heart rate (D) Signup and view all the answers

What is the significance of quinidine's effect on the refractory period?

It decreases the risk of arrhythmias. (C) Signup and view all the answers

How is quinidine metabolized in the body?

Primarily by the liver, with some renal excretion. (D) Signup and view all the answers

What is the primary reason for quinidine's relatively narrow therapeutic index?

It can cause significant cardiovascular effects, including hypotension and heart block. (A) Signup and view all the answers

Which of the following conditions is quinidine most effective in treating?

Atrial fibrillation (B) Signup and view all the answers

What is the primary mechanism by which volatile anesthetics can contribute to arrhythmias?

By inhibiting ion channels in the heart. (A) Signup and view all the answers

Which class of antiarrhythmic drug is commonly used in treating supraventricular tachycardia (SVT)?

Class I (B) Signup and view all the answers

What is the primary mechanism by which triggered activity contributes to arrhythmias?

Abnormal electrical activity in response to changes in membrane potential. (D) Signup and view all the answers

How does inhibition of sodium channels by volatile anesthetics affect the refractory period of cardiac cells?

It prolongs the refractory period. (C) Signup and view all the answers

Which of the following is a common adverse effect associated with Class IA antiarrhythmics?

Cardiovascular complications such as hypotension and heart block. (B) Signup and view all the answers

What is the primary mechanism by which Class III antiarrhythmics work to treat arrhythmias?

They block potassium channels. (D) Signup and view all the answers

Which of the following drugs is classified as a Class III antiarrhythmic?

Amiodarone (C) Signup and view all the answers

Study Notes

Myocardial Cells-Electricity

Properties include automaticity, conductivity, rhythmicity, and excitability
Pacemaker cells generate electrical impulses, transitional cells conduct impulses slowly, and Purkinje cells conduct impulses rapidly.

Cardiac Conduction System

Sino-atrial (SA) node initiates the heartbeat
Internodal and interatrial pathways connect the SA node to the AV node
Atrioventricular (AV) node delays the impulse
Bundle of His transmits the impulse to the ventricles
Right and left bundle branches distribute the impulse throughout the ventricles
Purkinje fibers rapidly conduct the impulse throughout the ventricles

Neural Modulation of Contractility

Chronotropic relates to heart rate
Dromotropic refers to impulse conduction
Inotropic relates to contraction strength
Lusitropic relates to relaxation

Cardiac Transplantation

The diagrams show different approaches to cardiac transplantation

Fluid & Electrolyte Balance

Nernst Equation calculates the electrical potential for ions
Goldman Hodgkin-Katz Equation calculates potential for multiple permeable ions

SA Node Pacemaker Cells

Pacemaker action potential has phases (0-4) with specific ion channel involvement (HCN, T-type Calcium, L-type Calcium, and Voltage-gated Potassium)
HRmax = 220 - age

Electrophysiology

Resting membrane potential, threshold potential, depolarization, and repolarization are part of the electrophysiological process
Action potentials of cardiac muscles have specific phases (0-4) involving ion fluxes

Electrophysiology-Phase Repolarization

Phase 0: Depolarization
Phase 1: Early repolarization
Phase 2: Plateau phase
Phase 3: Rapid repolarization
Phase 4: Repolarization

Refractory Periods of Repolarization

Absolute or effective refractory period: The cell cannot be re-stimulated.
Relative refractory period: The cell can be re-stimulated with a strong stimulus.
Supernormal or vulnerable period: The cell can be re-stimulated with a week stimulus.

Action Potentials

Atrial and ventricular myocytes, Purkinje fibers, and pacemaker cells each have unique action potentials

Cardiac Channelopathies

Information on various diseases related to cardiac ion channels

Calcium-Induced Calcium Release

Calcium release from the sarcoplasmic reticulum is triggered by intracellular calcium and these steps in cardiac contraction
SERCA calcium channel is mentioned as important to returning intracellular calcium to the SR

Cardiomyocyte Contractile Cycle

The steps of the cardiomyocyte contractile cycle

Myocyte Relaxation

Repolarization occurs and calcium detaches from troponin and returns to sarcoplasmic reticulum
T-T complex reattaches to binding sites on actin to cause muscle relaxation

Why Arrhythmias Occur?

Enhanced automaticity, triggered automaticity, and reentrant (circus movement) are causes of arrhythmias

Electrolytes & EKG Changes

Information covering electrolytes and EKG changes.

Arrhythmias & Volatile Anesthetics

Volatile anesthetics interact with ion channels, potentially causing arrhythmias

Antiarrhythmic/Arrhythmic Classes

Different antiarrhythmic drugs and their mechanisms of action (including classes I-IV) are discussed

Drugs (and their Classes)

These notes cover various drugs and their classifications, mechanisms of action.
Class IA, IB, IC, II, III, and IV drugs are discussed.

Other Antiarrhythmic Drugs

Digoxin. Adenosine. Ranolanizine. and more specifics regarding the class I-IV antiarrythmic drugs
There is a focus on pharmacokinetics, dosages, indication, and contraindications

Electrophysiology: Phase Re-polarization;

Specific phases and periods.

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Description

Test your knowledge on cardiology pharmacology, including the characteristics of pacemaker cells and the effects of propranolol. This quiz covers essential concepts such as action potentials, impulse conduction, and drug administration routes. Perfect for students of medical courses focused on cardiovascular physiology.