A: CARDIAC ARRHYTHMIA Flashcards
Deviation from the normal heartbeat pattern
Cardiac Arrhythmia
Cardiac Arrhythmia includes abnormalities of
- Impulse formation
- Heart rate
- Rhythm
- Site of impulse origin
- Conduction disturbances
- These disrupts the normal sequence of atrial and ventricular activation
This refers to a slow heartbeat
Bradyarrhythmia
A resting heart rate below 60 beats per minute
Bradycardia
This refers to a fast heartbeat
Tachyarrhythmia
A resting heart rate greater than 100 beats a minute
Tachycardia
A transient voltage change (membrane potential) across the membranes of the heart
Myocardial Action Potential
Myocardial Action Potential Phases
a.)Phase 0 (rapid depolarization)
b.) Phase 1 (early rapid depolarization)
c.) Phase 2 ( Plateau)
d.) Phase 3 (final rapid repolarization)
e.) Phase 4 (Slow depolarization)
Two electrical sequences that cause heart chambers to fill with blood and contract are initiated by __ of the heart
Conduction System
1st sequence, takes place when an electrical impulse is generated automatically
Impulse Formation
2nd sequence, occurs once the impulse has been generated, signaling the heart to contract
Impulse Transmission
It serves as the heart’s natural pacemaker, regulating the heartbeat by generating electrical impulses that coordinate the heart’s contractions
Sinoatrial Node
Sinoatrial Node is initiated in
60-100 BPM (Beats Per Minute)
Impulses are delayed briefly to permit completion of atrial contraction
Atrioventricular Node
Atrioventricular Node
Atrioventricular Node
Transmission of impulses along left to right
Bundle of His
Composed of bundle of his and Purkinje fibers
Latent Pacemakers
They contain cells capable of generating impulses
Latent Pacemakers
Depolarization
P Wave
Represents the spread of impulse from atria to the Purkinje fibers
PR Interval
Ventricular Depolarization
QRS Complex
Represents phase 2
ST Segment
Ventricular Repolarization
T Wave
An irregularly fast or erratic heartbeat (arrhythmia) that affects the heart’s upper chambers
Supraventricular Arrhythmias
From enhances automaticity of the SA node or another pacemaker region
Supraventricular Arrhythmias
Occurs below bundle of his, when a ectopic (abnormal) pacemaker triggers a ventricular contraction
Ventricular Arrhythmias
What is the French word for twisting of points
Torsades de pointes
Prolonged QT interval
Torsades de pointes
Precipitating Causes
*Heart Disease
*Myocardial Infarction
*Systemic Hypertension
*Hyperkalemia/Hypokalemia
*COPD
*Thyroid Disorders
*Drug Therapy
*Toxic Doses of Cardioactive Drugs
*Increase Sympathetic Tone
*Decrease Parasympathetic Tone
*Vagal Stimulation
*Increase Oxygen
*Metabolic Disturbances
*Cor Pulmonale
COPD stands for
Chronic Obstructive Pulmonary Disease
COPD compose of
Emphysema and Bronchitis
escape beats and bradycardia
Depressed Automaticity
Premature beats, tachycardia and extrasystole
Increased Automaticity
The only LAB test that can definitely identify arrhythmia
Electrocardiogram (ECG)
Determines the location of the ectopic foci
Electrophysiological Testing
Can locate reentry of heart block or reentry pattern
His bundle study
Electrolytes Laboratory Findings
a.) serum potassium: >5meg/L
b.) serum calcium : >4.5meq/L
c.) serum magnesium: <2.5 meq/L
Moderate depression on conduction, prolongation of repolarization, which results in an increase in the QRS interval and an increase in the QT interval
Class 1A
Class 1A interfere with
Sodium Channel Ion
Drugs of Class 1A
Disopyramide
Procainamide
Quinidine
Suppression and prevention of atrial and premature ventricular complexes
Disopyramide
Frequently given than quinidine because it can be administered in IV and in Sustained release oral preparation
Procainamide
Conversion & prevention of of relapse into atrial fibrillation and/or flutter and the suppression of ventricular arrhythmia
Quinidine
Modest depression of conduction, shortening of repolarization, which results in a decrease in the QT interval
Class 1B
Class 1B interfere with
Sodium Channel Ion
Class 1C interfere with
Sodium Channel Ion
Drugs of Class 1B
Lidocaine
Mexiletine
Phenytoin
Used therapeutically for ventricular arrhythmia that result from acute MI and open - heart surgery
Lidocaine
Reduced first pass liver metabolism, oral dose available
Mexiletine
Used in patients with severe ventricular arrhythmias
Mexiletine
Treatment for digitalis induced ventricular arrhythmias
Phenytoin
Strong depression of conduction w/ mild or no effect on repolarization which results in a very large increase in the QRS interval
Class 1C
Drugs of Class 1C
Flecainide
Propafenone
Treatment for life threatening ventricular arrhythmias
Flecainide
Propafenone
Slow sinus as well as AV nodal conduction, which results in decrease in heart rate and prolongation in the PR interval (atrial depolarization)
Class 2: Beta Blocker
Drugs of Class 2: Beta Blocker
Propranolol
Esmolol
Acebutolol
Control supraventricular arrhythmias
Propranolol
Suppress severe ventricular arrhythmias in prolonged QT interval
Propranolol
Treatment for digitalis induced
Propranolol
Shortest t1/2
Esmolol
Given to patients with atrial fibrillation
Acebutolol
Prolongation of repolarization, which results to prolongation of QT interval
Class 3 Inh. (-) Potassium
Class 3 inhibits
(-) Potassium
Drugs of Class 3 Inh. (-) Potassium
Amiodarone
Sotalol
Ibutilide
Dofetilide
Given to malignant ventricular arrhythmias
Amiodarone
Treatment for supraventricular and ventricular tachyarrhythmias
Sotalol
Used in the conversion of atrial fibrillation
Ibutilide
Restricted access in USA in the treatment of atrial fibrillation
Dofetilide
Calcium channel blockade in calcium-dependent channels, which result in reduced heart rate and an increase in the PR interval
Class 4: Calcium Channel Blockers
Treatment for supraventricular arrhythmias
Verapamil
First line agents for the suppression of PSVT (Paroxysmal Supraventricular Tachycardia) stemming
Diltiazem
Drugs of Class 4: Calcium Channel Blockers
Verapamil
Diltiazem
Blocks vagal effects on SA node
Atropine
Indication of Atropine
Bradycardia and junctional rhythm
Slow conduction through the AV node
Adenosine
Indication of Adenosine
Acute supraventricular tachycardia
Interrupts reentry pathway through the AV node
Adenosine
Slowing the rate of Impulse formation in myocardium
Magnesium Sulfate
Restore normal sinus rhythm in patients with PSVT
Adenosine
Indication of Magnesium Sulfate
Treatment for Drug induced long QT syndrome
Positive inotropic effect
Digoxin
Indication of Digoxin
Stable, narrow complex regular tachycardia
MOA similar to amiodarone
Dronedarone
Indication of Dronedarone
Treatment for atrial fibrillation