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Cardiovascular | EKG's
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Cardiovascular | EKG's

Introduction to EKGs

In this section, the speaker introduces the topic of EKGs (electrocardiograms) and mentions that they will discuss abnormal EKGs in more detail later. They also mention the 12-lead system, which will be covered in future videos.

Basic Components of an EKG

  • The P wave represents atrial depolarization.
  • The QRS wave represents ventricular depolarization.
  • The T wave signifies ventricular repolarization.

Significance of Each Wave

  • The P wave indicates that the atria are depolarizing.
  • The QRS wave represents ventricular depolarization.
  • The T wave signifies ventricular repolarization.

Atrial Repolarization

  • Atrial repolarization is masked within the QRS complex on the EKG.

Ventricular Repolarization

  • Ventricular repolarization occurs during the T wave on the EKG.

Common Abnormalities in EKGs

This section briefly discusses some common abnormalities seen in EKGs and provides a high-level overview. More detailed information will be covered in future videos on pathophysiology.

ST Segment Elevation

  • ST segment elevation can indicate a myocardial infarction or heart attack.
  • It is sometimes referred to as STEMI (ST segment elevation myocardial infarction).

T-Wave Inversion

  • T-wave inversion is when the T waves are flipped or inverted on the EKG.

Understanding Abnormal ECG Patterns

In this section, the speaker discusses abnormal ECG patterns and their significance.

T-Wave Inversion

  • T-wave inversion is observed in myocardial tissue abnormalities.
  • It causes a negative deflection on the ECG.
  • This pattern indicates a potential issue with the heart's electrical conduction system.

PR Interval and Prolonged PR Interval

  • The PR interval represents the time it takes for an electrical impulse to travel from the atria to the ventricles.
  • Normally, the PR interval ranges from 160 to 200 milliseconds.
  • If the PR interval is greater than 200 milliseconds, it is considered prolonged.
  • A consistent prolongation of the PR interval without progressive lengthening is known as first-degree heart block.
  • First-degree heart block is not life-threatening and can be triggered by stress or anxiety.

Second-Degree Heart Block Mobitz I (Wenckebach)

  • Mobitz I is characterized by a progressively lengthening PR interval followed by a dropped QRS complex.
  • The dropped QRS complex indicates that some of the electrical impulses are not reaching the ventricles.
  • Mobitz I typically occurs within or near the AV node and may cause symptoms such as syncope or dizziness.

Second-Degree Heart Block Mobitz II

  • Mobitz II is characterized by a normal PR interval that does not fluctuate but with intermittent dropped QRS complexes.
  • Some P waves fail to reach the ventricles, resulting in missed contractions.
  • Mobitz II can be more dangerous than Mobitz I and may require medical intervention.

Third-Degree Heart Block (Complete Heart Block)

  • Third-degree heart block involves complete dissociation between atrial and ventricular contractions.
  • P waves and QRS complexes occur independently of each other.
  • Third-degree heart block is life-threatening and typically requires an artificial pacemaker.

Summary of Heart Block Types

This section provides a summary of the different types of heart blocks discussed in the previous section.

First-Degree Heart Block

  • Prolonged PR interval without progressive lengthening.
  • Not life-threatening, often triggered by stress or anxiety.

Second-Degree Heart Block Mobitz I (Wenckebach)

  • Progressive lengthening of PR interval followed by a dropped QRS complex.
  • Can cause symptoms such as syncope or dizziness.
  • Typically occurs within or near the AV node.

Second-Degree Heart Block Mobitz II

  • Normal PR interval with intermittent dropped QRS complexes.
  • Some P waves fail to reach the ventricles, resulting in missed contractions.
  • More dangerous than Mobitz I and may require medical intervention.

Third-Degree Heart Block (Complete Heart Block)

  • Complete dissociation between atrial and ventricular contractions.
  • P waves and QRS complexes occur independently of each other.
  • Life-threatening condition requiring an artificial pacemaker.

New Section

This section discusses two cardiac conditions: third-degree heart block and Wolff-Parkinson-White syndrome.

Third-Degree Heart Block

  • In a third-degree heart block, there is no connection between the atria and ventricles, leading to incorrect P and QRS wave alignment.
  • This condition is characterized by the atria and ventricles beating at their own rates.

Wolff-Parkinson-White Syndrome (WPW)

  • WPW syndrome is a congenital condition where individuals have an irregular accessory pathway called the bundle of Kent.
  • The bundle of Kent allows impulses to travel in both directions, creating reentry circuits that can lead to supraventricular tachycardia.
  • Radiofrequency catheter ablation can be used to treat WPW syndrome by creating scar tissue in the bundle of Kent.

New Section

This section provides an overview of Wolff-Parkinson-White syndrome (WPW) and its characteristic EKG findings.

EKG Findings in WPW Syndrome

  • In EKGs of patients with WPW syndrome, there may not be a distinguishable P wave.
  • A distinct wave called a delta wave may be present instead of a typical P wave.
  • Delta waves are indicative of WPW syndrome.

New Section

This section explains the mechanism behind Wolff-Parkinson-White syndrome (WPW) and its potential complications.

Mechanism and Complications of WPW Syndrome

  • In WPW syndrome, the accessory pathway known as the bundle of Kent allows impulses to travel bidirectionally.
  • Reentry through this pathway can cause supraventricular tachycardia.
  • Treatment options for WPW syndrome include radiofrequency catheter ablation to create scar tissue in the bundle of Kent.

New Section

This section focuses on the EKG findings associated with Wolff-Parkinson-White syndrome (WPW).

EKG Findings in WPW Syndrome

  • In EKGs of patients with WPW syndrome, a delta wave may be present instead of a distinguishable P wave.
  • Delta waves are characteristic of WPW syndrome and can be seen in multiple leads.

New Section

This section discusses the significance of delta waves in diagnosing Wolff-Parkinson-White syndrome (WPW).

Delta Waves and WPW Syndrome

  • The presence of delta waves in an EKG is highly indicative of WPW syndrome.
  • Delta waves can be observed in multiple leads and are an important diagnostic feature for identifying WPW syndrome.

New Section

This section provides an overview of atrial flutter and atrial fibrillation, two common cardiac arrhythmias.

Atrial Flutter

  • Atrial flutter is characterized by sawtooth-like structures on the EKG, known as F waves.
  • It is not life-threatening but can progress into more serious conditions if left untreated.
  • Causes of atrial flutter include myocardial infarctions, thyrotoxicosis, and mitral valve prolapse.

Atrial Fibrillation

  • Atrial fibrillation is characterized by irregular baseline activity without distinct P waves.
  • F waves are present but are lowercase compared to uppercase F waves seen in atrial flutter.
  • Atrial fibrillation can be caused by metabolic syndrome, thyrotoxicosis, obesity, among other factors.

New Section

This section explains the mechanism behind atrial flutter and its progression to atrial fibrillation.

Mechanism and Progression of Atrial Flutter

  • Atrial flutter is caused by reentry circuits in the atria, resulting in sawtooth-like F waves on the EKG.
  • If left untreated, atrial flutter can progress into atrial fibrillation, characterized by irregular baseline activity without distinct P waves.

New Section

This section highlights the differences between atrial flutter and atrial fibrillation on an EKG.

EKG Findings in Atrial Flutter and Atrial Fibrillation

  • In atrial flutter, F waves are present and have a sawtooth-like appearance.
  • In atrial fibrillation, there are no distinct P waves, and the rhythm appears irregular with squiggly baseline activity.

New Section

This section discusses the potential complications of atrial fibrillation.

Complications of Atrial Fibrillation

  • In atrial fibrillation, functional contractions of the atria are compromised, leading to blood pooling inside them.
  • Stagnant blood flow increases the risk of thrombus formation and subsequent embolism.
  • Mitral valve vegetations can form due to stagnant blood flow in atrial fibrillation.

New Section

This section explains a specific EKG finding associated with drug overdoses.

EKG Findings in Drug Overdoses

  • In individuals using drugs or experiencing drug overdoses, P wave morphology may change.
  • The shape of P waves can vary between triangular-shaped, normal-looking, or abnormal forms.

New Section

This section discusses different types of cardiac arrhythmias and their causes.

Types of Cardiac Arrhythmias

  • Pacemaker malfunction: Commonly seen in drug overdoses, characterized by three distinguishable P waves. Can be caused by nicotine or caffeine consumption.
  • Premature Ventricular Contraction (PVC): Triggered by an ectopic focus within the ventricles, causing a premature contraction before the P wave. Can be caused by certain drugs, nicotine, caffeine, or exercise.
  • Absent P wave with PVC: The premature ventricular contraction bypasses the P wave, indicating PVCs.
  • Torsades de Pointes: Life-threatening arrhythmia characterized by twisting of the points around the isoelectric line. Requires immediate medical attention. Often associated with prolonged QT syndrome.
  • Prolonged QT Syndrome: Commonly caused by metabolic reasons such as low magnesium levels or hypokalemia. Certain medications can also contribute to this condition.

Timestamps are provided for each bullet point to help locate specific information in the transcript.

Playlists: Cardiovascular Physiology
Video description

Official Ninja Nerd Website: https://ninjanerd.org Ninja Nerds, Join us in this video where we have a discussion on the fundamentals of EKG's (electrocardiograms) along with a description and diagram of what abnormal rhythms look like. We hope you enjoy this lecture and be sure to check out all of our social media pages and ways to support us below! References: ● Cardiología / [coordinador y autor] Guillermo Saturno Chiu. – 1a edición. – Ciudad de México: Editorial El Manual Moderno, 2017. ● ECG & Echo Waves. (2019, 12 octubre). ECG in myocardial ischemia: ischemic changes in the ST segment & T-wave –. ECG & ECHO. https://ecgwaves.com/topic/ecg-myocardial-ischemia-ischemic-changes-st-segment-t-wave/ ● Sajjan, M. (2013). Learn ECG in a Day: A Systematic Approach (English Edition) (1.a ed.). Jaypee Brothers Medical Publishers (p) Ltd. ● Hearth Block: Types, Diagnosis, Treatment, Follow-up. (2021, 28 may). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/17056-heart-block ● Ibanez, B., James, S., Agewall, S., Antunes, M. J., Bucciarelli-Ducci, C., Bueno, H., Caforio, A. L. P., Crea, F., Goudevenos, J. A., Halvorsen, S., Hindricks, G., Kastrati, A., Lenzen, M. J., Prescott, E., Roffi, M., Valgimigli, M., Varenhorst, C., Vranckx, P., Widimský, P., . . . Gale, C. P. (2017). 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. European Heart Journal, 39(2), 119–177. https://doi.org/10.1093/eurheartj/ehx393 ● Burns, E. (2021, 11 marzo). T wave. Life in the Fast Lane • LITFL. https://litfl.com/t-wave-ecg-library/ ● Hindricks, G., Potpara, T., Dagres, N., Arbelo, E., Bax, J. J., Blomström-Lundqvist, C., Boriani, G., Castella, M., Dan, G. A., Dilaveris, P. E., Fauchier, L., Filippatos, G., Kalman, J. M., La Meir, M., Lane, D. A., Lebeau, J. P., Lettino, M., Lip, G. Y. H., Pinto, F. J., . . . Zakirov, N. U. (2020). 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS). European Heart Journal, 42(5), 373–498. https://doi.org/10.1093/eurheartj/ehaa612 ● Whyte, G., Whyte, G., & Sharma, S. (2010). Practical ECG for Exercise Science and Sports Medicine. Human Kinetics ● Le T, Bhushan V, Sochat M, Chavda Y, Zureick A. First Aid for the USMLE Step 1 2018. New York, NY: McGraw-Hill Medical; 2017 ● Mancini MC. Heart Anatomy. In: Berger S Heart Anatomy. New York, NY: WebMD.https://emedicine.medscape.com/article/905502-overview. ● Hill M. Cardiovascular System - Heart Histology. https://embryology.med.unsw.edu.au/embryology/index.php/Cardiovascular_System_-_Heart_Histology. ● Rosen IM and Manaker S. Oxygen delivery and consumption. In: Post TW, ed. UpToDate .Waltham, MA: UpToDate.https://www.uptodate.com/contents/oxygen-delivery-and-consumption#H4. ● McCorry LK. Physiology of the Autonomic Nervous System. Am J Pharm Educ .2007; 71(4): p.78. doi: 10.5688/aj710478. Standring S. Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier Health Sciences; 2016 ● Leslie P. Gartner, James L. Hiatt. Color Textbook of Histology. New York (NY): Grune & Stratton Inc.; 2006 ● U. S. National Institutes of Health, National Cancer Institute. NIH SEER Training Modules - Classification & Structure of Blood Vessels. https://training.seer.cancer.gov/anatomy/cardiovascular/blood/classification.html. ● Ostenfeld E, Flachskampf FA. Assessment of right ventricular volumes and ejection fraction by echocardiography: from geometric approximations to realistic shapes.. Echo research and practice. 2015; 2(1): p.R1-R11. doi: 10.1530/ERP-14-0077. ● Maceira AM, Prasad SK, Khan M, Pennell DJ. Reference right ventricular systolic and diastolic function normalized to age, gender and body surface area from steady-state free precession cardiovascular magnetic resonance.. Eur Heart J .2006; 27(23): p.2879-88. doi: 10.1093/eurheartj/ehl336. ● Klabunde RE. Hemorrhagic Shock. http://www.cvphysiology.com/Blood%20Pressure/BP031. ● Drucker WR, Chadwick CD, Gann DS. Transcapillary refill in hemorrhage and shock.. Arch Surg .1981; 116(10): p.1344-53. pmid: 7283706. ● Kaur P, Basu S, Kaur G, Kaur R. Transfusion protocol in trauma. J Emerg Trauma Shock .2011; 4(1): p.103. doi: 10.4103/0974-2700.76844. ● Campbell RL, Li JTC, Nicklas RA, Sadosty AT. Emergency department diagnosis and treatment of anaphylaxis: a practice parameter. Ann Allergy Asthma Immunol .2014; 113(6): p.599-608. doi: 10.1016/j.anai.2014.10.007 ● Consortium for Spinal Cord Medicine.. Early acute management in adults with spinal cord injury: A clinical practice guideline for health-care professionals.. J Spinal Cord Med .2008; 31(4): p.403-79. pmid: 18959359. ● Marieb EN, Hoehn K. Anatomy & Physiology. Hoboken, NJ: Pearson; 2020. ● Boron WF, Boulpaep EL. Medical Physiology.; 2017. #ninjanerd #EKGs #electrocardiogram