Questions and Answers
What is the electrical conduction of the heart?
SA node = automatic depolarization; initiator of the whole conduction system of the heart
_____________ occurs when blood flow to the myocardium is obstructed by a partial or complete blockage of a coronary artery.
Myocardial ischemia
Describe the biological (ions) mechanism behind cardiac muscle cell depolarization.
Na+ enters the cell causing depolarization; Ca2+ enters the cell & contraction begins; K+ exits the cell causing repolarization.
EKG records the _____________ of electrical activity of the heart via skin electrodes.
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What is the purpose of an EKG?
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What are the limb leads in an EKG?
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What are the chest leads?
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What does the P wave represent?
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What are the 3 methods of rate calculation for EKG?
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List questions to ask yourself when looking at rhythm.
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What are the classes of arrhythmias?
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What is Chester's mnemonic?
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What is a wandering pacemaker?
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What is Multifocal Atrial Tachycardia?
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What is Atrial Fibrillation (AFib)?
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What is an escape rhythm?
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What is a Premature Atrial Contraction (PAC)?
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What is a Premature Ventricular Contraction (PVC)?
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What is the R on T phenomenon?
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What are the types of PVC patterns?
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What is Atrial Flutter?
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What is Atrial Fibrillation (AFib)?
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What constitutes ventricular tachycardia?
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Study Notes
Electrical Conduction of the Heart
- SA node initiates heart's electrical conduction through automatic depolarization.
Myocardial Ischemia
- A condition where blood flow to the heart muscle is obstructed by coronary artery blockage.
Cardiac Muscle Cell Depolarization
- Sodium ions (Na+) enter cells, leading to depolarization.
- Calcium ions (Ca2+) influx initiates contraction.
- Potassium ions (K+) exit, causing repolarization.
EKG Recording
- EKG records the summation of electrical activity in the heart via surface electrodes.
Purpose of EKG
- Provides a visual representation of electrical events in the heart.
- Assesses conduction pathways.
- Highlights potential blood supply issues.
- Evaluates the integrity of heart muscle.
Limb Leads
- Bipolar leads: I, II, III
- Unipolar leads: aVF, aVL, aVR
Chest Leads
- Consist of leads V1 through V6.
P Wave Representation
- Indicates electrical activity resulting from atrial depolarization.
Methods of Rate Calculation
- Quick Method: Count big boxes (300, 150, 100, 75, 60, 50) for regular rhythms.
- Calculator Method for Regular Rhythm: Divide 1500 by number of squares between P or R waves.
- Calculator Method for Irregular Rhythm: Count mm from first to last R in strip and apply formula.
Rhythm Analysis Questions
- Compare rates of P and R waves for consistency.
- Ensure each P wave corresponds with a QRS complex.
- Check for uniformity in wave morphology.
- Measure P-R interval (normal range: 0.12-0.20 sec).
- Assess QRS interval (normal range: 0.08-0.12 sec; >0.12 sec indicates potential bundle branch block).
Classes of Arrhythmias
- Includes irregular rhythms, escapes, premature beats, tachyarrhythmias, and heart blocks.
Chester's Pneumonic
- Aids in remembering types of arrhythmias based on initials.
- W, M, A: Wandering pacemaker, MAT, AFib.
- E, P, A: Escapes, PACs & PVCs, various arrhythmias.
- B: Heart blocks and bundle branch blocks.
Wandering Pacemaker
- Characterized by irregular rhythm within normal rate range with distinct P waves.
Multifocal Atrial Tachycardia
- Rapid irregular rhythm (atrial rate over 100 bpm) with varying P waves, often seen in COPD patients.
Atrial Fibrillation (AFib)
- Continuous chaotic atrial spikes with no identifiable P waves, irregular ventricular response.
Escape Rhythm
- Occurs when an automaticity focus resumes pacing at its inherent rate after overdrive suppression.
Premature Atrial Contraction (PAC)
- Irregular P rhythm with distinct morphology; the automaticity center resets after one cycle.
Premature Ventricular Contraction (PVC)
- Exhibits widened QRS complexes with compensatory pauses; can be uni-focal or multi-focal.
R on T Phenomenon
- A PVC occurring on the vulnerable phase of the T wave, increasing the risk of dangerous rhythms.
Atrial Flutter
- Characterized by "saw-tooth" P waves at a rate of 250-350 bpm, often leads to insufficient ventricular response.
Atrial Fibrillation (AFib)
- Erratic rhythm with no identifiable P waves, typically ranging from 350-450 bpm with irregular RR intervals.
Ventricular Tachycardia
- Defined as three or more consecutive PVCs with a rapid heart rate between 150-250 bpm, originating from an irritable ventricular focus.
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Description
This quiz features flashcards that cover essential concepts related to EKG and the electrical conduction system of the heart. It includes definitions of key terms, such as myocardial ischemia and the role of the SA node in heart function. Perfect for beginners looking to enhance their understanding of cardiac physiology.
