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Questions and Answers
Which of the following symptoms is NOT associated with premature ventricular contraction (PVC)?
Which of the following symptoms is NOT associated with premature ventricular contraction (PVC)?
What is a premature ventricular contraction (PVC)?
What is a premature ventricular contraction (PVC)?
A premature beat arising from the ventricles
What characteristic does PVC display on an ECG?
What characteristic does PVC display on an ECG?
What term describes a run of ≥ 4 PVCs occurring sequentially?
What term describes a run of ≥ 4 PVCs occurring sequentially?
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Ventricular fibrillation is characterized by coordinated activation of ventricular cells.
Ventricular fibrillation is characterized by coordinated activation of ventricular cells.
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Define hyperkalemia.
Define hyperkalemia.
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What ECG abnormality is associated with hypokalemia?
What ECG abnormality is associated with hypokalemia?
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Which heart block is characterized by prolonged delay in conduction of action potentials through the AV node?
Which heart block is characterized by prolonged delay in conduction of action potentials through the AV node?
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In third-degree AV block, the atria and ventricles are electrically separate.
In third-degree AV block, the atria and ventricles are electrically separate.
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List some signs and symptoms that indicate a patient's exertion level is too high.
List some signs and symptoms that indicate a patient's exertion level is too high.
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Which scenario is most likely to be the least concerning in an individual at rest?
Which scenario is most likely to be the least concerning in an individual at rest?
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What is an electrocardiogram (ECG or EKG)?
What is an electrocardiogram (ECG or EKG)?
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What is an echocardiogram (Echo)?
What is an echocardiogram (Echo)?
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What are the electrical and mechanical order of events in the heart?
What are the electrical and mechanical order of events in the heart?
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Electrical activity of the heart controls mechanical activity of the heart.
Electrical activity of the heart controls mechanical activity of the heart.
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What occurs during the P wave?
What occurs during the P wave?
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Atrial systole occurs before the P wave.
Atrial systole occurs before the P wave.
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What is the PR interval?
What is the PR interval?
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What happens during the QRS complex?
What happens during the QRS complex?
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Ventricular systole occurs after the S wave.
Ventricular systole occurs after the S wave.
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What occurs during the T wave?
What occurs during the T wave?
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If the QRS interval is lengthened, then _____________________________________________.
If the QRS interval is lengthened, then _____________________________________________.
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What happens during the ST segment?
What happens during the ST segment?
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What is the QT interval?
What is the QT interval?
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What is an arrhythmia?
What is an arrhythmia?
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How are arrhythmias classified?
How are arrhythmias classified?
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What is normal sinus rhythm?
What is normal sinus rhythm?
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What are sinus arrhythmias?
What are sinus arrhythmias?
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What are some critical questions regarding arrhythmias?
What are some critical questions regarding arrhythmias?
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Study Notes
Electrocardiogram (ECG or EKG)
- Records electrical activity of the heart, generated by impulse conduction.
- Non-invasive tool for diagnosing heart conditions such as conduction pathway abnormalities, heart enlargement, and damaged regions.
Echocardiogram (Echo)
- Utilizes ultrasound to assess heart structure, function, and related vessels.
Electrical and Mechanical Events of the Heart
- Sequence includes: Atrial Depolarization, Atrial Systole, Ventricular Depolarization, Ventricular Systole, Ventricular Repolarization, and Ventricular Diastole.
- Electrical activity regulates mechanical heart functions.
ECG Waves and Segments
- P Wave: Represents atrial depolarization; lasts 0.06-0.1 seconds.
- PR Segment: Indicates atrial systole occurring after the P wave.
- PR Interval: Duration from P-wave start to QRS complex; 0.12-0.2 seconds, showing conduction delay through AV node.
- QRS Complex: Reflects ventricular depolarization; atrial repolarization not visualized.
- T Wave: Indicates ventricular repolarization.
- ST Segment: Flat segment between S wave and T wave, occurs during ventricular systole and atrial diastole.
- QT Interval: Duration from QRS to T wave, signifies ventricular depolarization through repolarization; diluted by drugs or conditions affecting repolarization.
Long QT Syndrome (LQTS)
- Associated with delayed repolarization; can lead to arrhythmias and impaired tissue perfusion.
- Symptoms may include fainting and risk of sudden cardiac death.
- Exercise considerations include possibly avoiding strenuous activities and careful monitoring.
ECG Lead Placements
- Limb Leads: RA, LA, LL, RL provide a 2D picture of heart's electrical activity in the frontal plane.
- Chest Leads (V1-V6): Offer localized information on the heart's electrical activity from a horizontal plane.
Arrhythmias
- Defined as disturbances in heart rate/rhythm due to improper electrical impulse generation or conduction.
- Types include: Supraventricular vs. Ventricular; Fibrillation vs. Flutter; Tachycardia vs. Bradycardia.
- Symptoms can vary; understanding clinical significance is vital for detecting serious conditions.
Specific Arrhythmias
- Sinus Bradycardia: HR < 60 bpm, often seen in trained athletes.
- Sinus Tachycardia: HR > 100 bpm, may result from hyperthyroidism or certain medications.
- Atrial Fibrillation: Characterized by chaotic atrial impulse firing leading to ineffective atrial systole; lacking true P waves on ECG.
- Premature Ventricular Contraction (PVC): Early heartbeat from ventricles, often asymptomatic but can be triggered by stress or caffeine; irregular QRS complex observed.
- Ventricular Tachycardia (V-tach): Series of PVCs leading to compromised cardiac output; can be non-sustained or sustained.
- Ventricular Fibrillation (V-fib): Erratic electrical activity, preventing effective heartbeat; requires immediate medical intervention.
Clinical Monitoring and Management
- Importance of recognizing signs of too high exertion levels during exercise: arrhythmias, BP spikes, confusion, and weakness.
- AV blocks signify impaired electrical signal transfer; possibly caused by congenital issues or medications.
ECG Interpretation
- ECG rhythms to identify include Normal Sinus Rhythm, Atrial Fibrillation, V-tach, and others; crucial for assessing cardiac health and exercise safety.### First Degree AV Block
- Characterized by a prolonged delay in conduction of action potentials through the AV node.
- Marked by a PR interval exceeding 0.2 seconds.
- All atrial excitations eventually reach the ventricles.
- Typically asymptomatic; treatment is often unnecessary.
- Addressing electrolyte imbalances and evaluating medications are key steps in management.
First Degree Heart Block on ECG
- Identified by a PR interval longer than 0.2 seconds, indicating a conduction delay.
Second-Degree AV Blocks
- Involves partial blockage of conduction through the AV node, Bundle of His, or bundle branches.
- Only some of the atrial excitations are transmitted to the ventricles.
Second-Degree Heart Block on ECG
- Displays various ECG abnormalities, including:
- Progressive elongation of the PR interval.
- Dropped QRS complexes.
- Widened QRS intervals with shape abnormalities.
Second-Degree Heart Block Symptoms Variation
- Symptoms can range from asymptomatic to:
- Lightheadedness, dizziness, and syncope.
- Chest pain and irregular heart rate.
- Bradycardia and hypotension.
Second-Degree Heart Block and Cardiac Output
- Slowed ventricular rate leads to decreased cardiac output.
- May require pacemaker intervention if symptoms are present.
Third-Degree (Complete) AV Block
- Represents complete loss of electrical communication between atria and ventricles.
- Atria and ventricles function independently; the AV node serves as the pacemaker for the ventricles.
- The resulting heart rate is slow, often dictated by the AV node.
Third-Degree Heart Block on ECG
- Shows P waves, QRS complexes, and T waves that are present but disassociated.
Major Symptoms of Third-Degree Heart Block
- Common symptoms include:
- Bradycardia and hypotension.
- Shortness of breath and angina.
- Lightheadedness, weakness, dizziness, and syncope.
- Fatigue and exercise intolerance.
Third-Degree Heart Block and Cardiac Output
- Cardiac output is compromised.
- Treatment involves medications (e.g., atropine) and possibly a pacemaker.
Comparison: Marathon Runner vs. Third Degree Heart Block Individual
-
Marathon Runner:
- Exhibits left ventricular hypertrophy due to endurance training.
- SA node is the primary pacemaker, allowing a healthy heart with normal hemodynamics and absence of symptoms.
-
Individual with Third-Degree AV Block:
- AV node takes over as pacemaker, leading to significantly reduced heart rate.
- Lacks the ability to increase stroke volume, resulting in compromised hemodynamics and symptoms.
Hyperkalemia
- Defined as elevated potassium levels in the serum (> 5.5 mEq/L).
- Increased attention is needed for trending upwards over time.
Conditions Associated with Hyperkalemia
- Includes renal failure, metabolic acidosis, diabetic ketoacidosis, Addison's disease, excessive potassium intake, and blood transfusions.
Major Signs and Symptoms of Hyperkalemia
- Symptoms manifest as muscle weakness, bradycardia, heart block, and risk of ventricular fibrillation or cardiac arrest.
ECG Abnormalities Associated with Hyperkalemia
- Includes tall T waves, flattened P waves, wide QRS complexes, and potential for a sine wave pattern.
Hypokalemia
- Defined as decreased potassium levels in serum (< 3.5 mEq/L).
Conditions Associated with Hypokalemia
- Related to diarrhea, GI impairments, diuretics, Cushing's syndrome, malnutrition, and alcohol abuse.
Major Signs and Symptoms Associated with Hypokalemia
- Symptoms include muscle weakness, leg cramps, hypotension, and risk of cardiac arrest.
ECG Abnormalities Associated with Hypokalemia
- Notable for flattened T waves, ST segment depression, and prolonged QT intervals.
Hypercalcemia
- Described as elevated serum calcium levels (> 10.3 mg/dL).
Conditions Associated with Hypercalcemia
- Common causes: excessive calcium or vitamin D intake, bone destruction or tumors, immobilization, and renal failure.
Major Signs and Symptoms of Hypercalcemia
- Symptoms include muscle weakness, lethargy, nausea, heart block, and potential for coma or dysrhythmias.
ECG Abnormalities Associated with Hypercalcemia
- Features widened QRS complexes and shortened QT intervals due to rapid ventricular repolarization.
Hypocalcemia
- Characterized by low serum calcium levels (< 8.6 mg/dL).
Conditions Associated with Hypocalcemia
- Related to alcohol abuse, poor dietary intake, limited absorption, pancreatitis, and laxative use.
Major Signs and Symptoms of Hypocalcemia
- Symptoms include anxiety, confusion, seizures, fatigue, and increased reflexes.
ECG Abnormalities Associated with Hypocalcemia
- Notable for prolonged QT interval due to delayed ventricular repolarization.
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Description
Explore the fundamentals of electrocardiograms (ECG or EKG) with these flashcards. Learn about impulse conduction, their role in diagnosing heart conditions, and the electrical changes during a cardiac cycle. Perfect for students looking to enhance their understanding of this non-invasive diagnostic tool.
