EKG Acquisition Study Notes

EKG Acquisition

Chapter 2: EKG Acquisition
Objectives

  • Describe basic anatomy & physiology of the heart: Understand the structure and functioning of the heart.

  • Explain the necessary components of EKG acquisition: Discuss necessary tools and setup for EKG tests.

  • Maintain EKG equipment: Learn how to load paper, replace clips, and disinfect machines and leads.

  • Verify EKG machine settings: Ensure proper speed and gain settings are adjusted for accurate readings.

  • Prepare skin for electrode placement: Understand appropriate skin preparation techniques.

  • Position patient for cardiac testing: Be adept in configuring patients for various EKG tests (e.g., three-lead, five-lead, 12-lead, stress tests, telemetry).

  • Apply electrodes and attach leads: Gain proficiency in placing electrodes for multiple scenarios including standard 12-lead EKG, ambulatory monitoring, and special patients (e.g., pediatric).

  • Verify all leads are recording: Confirm functionality of all connections during EKG recording.

  • Identify and resolve artifacts from the tracing: Address common artifacts that may interfere with the EKG reading (wandering baseline, somatic artifacts, electrical interference).

  • Mount a completed EKG tracing strip for a patient chart: Ensure proper documentation and organization of EKG results.

  • Assist in monitoring patient condition during stress test: Responsibilities in keeping track of patient's health during stress tests.

  • Provide support in responding to complications during a stress test: Know protocols and emergency procedures for potential complications.

Basic Anatomy and Physiology of the Heart

Anatomy Overview

  • The human heart is approximately the size of a human fist, consisting of four chambers: 2 atria (upper chambers) and 2 ventricles (lower chambers).

  • Atria are small, muscular, pouch-like structures that fill ventricles with blood.

  • Ventricles are the chambers that pump blood to the lungs and body.

  • The chambers are divided by the septum:

    • Interatrial septum: divides the atria.

    • Interventricular septum: divides the ventricles.

Heart Layers

  • The heart comprises three layers:

    1. Epicardium: The outer layer made of connective tissue, forming the pericardium (which has two layers: visceral and parietal).

    2. Myocardium: The middle layer made of striated muscle responsible for the heart's contractions.

    3. Endocardium: The inner layer lining the chambers and surface of valves.

Heart Valves

  • The heart has four valves regulating blood flow:

    1. Atrioventricular valves:

    • Tricuspid valve: between the right atrium and right ventricle.

    • Bicuspid (mitral) valve: between the left atrium and left ventricle.

    1. Semilunar valves:

    • Pulmonary valve: between the right ventricle and pulmonary artery, facilitating the flow of deoxygenated blood to the lungs.

    • Aortic valve: between the left ventricle and aorta, directing oxygenated blood to the body.

Blood Flow Through the Heart

  • The heart maintains continuous blood circulation, consisting of two main circuits:

    • Pulmonary Circulation: transports deoxygenated blood to the lungs for oxygenation.

    • Systemic Circulation: distributes oxygenated blood throughout the body.

Blood Flow Process

  1. Deoxygenated blood returns to the right atrium from the body via the superior and inferior vena cava.

  2. Blood flows into the right ventricle through the tricuspid valve, which pumps it to the lungs via the pulmonary valve and pulmonary artery.

  3. Oxygen-rich blood returns to the left atrium from the lungs via pulmonary veins, then moves through the mitral valve into the left ventricle.

  4. The left ventricle pumps oxygenated blood through the aortic valve into the aorta for body distribution.

  5. This cycle repeats with each heartbeat.

Heart Vessels and Blood Supply

  • The right and left coronary arteries arise from the aorta:

    • Right Coronary Artery (RCA): supplies blood to the right side of the heart including the right atrium and ventricle.

    • Left Main Coronary Artery (LMCA): supplies blood to the left side of the heart and splits into:

    • Left Circumflex Artery (LCA): wraps around and supplies the left atrium and lateral wall of the left ventricle.

    • Left Anterior Descending Artery (LAD): supplies blood to the anterior wall of the left ventricle (a blockage here can lead to severe arrhythmias).

Objectives

  • Describe basic anatomy & physiology of the heart: Understand the structure and functioning of the heart which includes four chambers: the two atria (upper chambers) and two ventricles (lower chambers). Atria are responsible for receiving blood, while ventricles pump blood throughout the body.

  • Explain the necessary components of EKG acquisition: Discuss tools such as EKG machines, electrodes, and leads needed for accurate EKG tests.

  • Maintain EKG equipment: Learn how to load paper, replace clips, and disinfect machines and leads to ensure safety and accuracy.

  • Verify EKG machine settings: Adjust speed and gain settings for optimal readings to reflect heart activity accurately.

  • Prepare skin for electrode placement: Understand techniques for proper skin cleaning to enhance electrode adhesion and signal quality

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EKG paper consists of a standardized grid used to record the electrical activity of the heart. Understanding how to read this paper is essential for accurate interpretation of EKG results.

Structure of EKG Paper

  • Grid Layout: The paper is printed with small squares, typically measuring 1mm x 1mm. Each 1mm square represents a specific time interval.

  • Vertical Axis: The vertical lines indicate voltage (measured in millivolts), which reflects the amplitude of the heart's electrical signals.

  • Horizontal Axis: Each 5 small squares (or 1 large square) on the horizontal axis represents 0.2 seconds, allowing for time measurement of electrical events in the heart.

Key Components in Reading EKG Paper

  1. P Wave: Represents atrial depolarization. It's small and round, occurring before the QRS complex.

  2. QRS Complex: Represents ventricular depolarization, characterized by a sharp spike representing electrical activity moving through the ventricles. It is typically narrower than the T wave.

  3. T Wave: Represents ventricular repolarization. It follows the QRS complex and is usually a bit wider and rounded.

  4. U Wave: Occasionally seen after the T wave, its origin is often unclear, but it may represent further repolarization of the ventricles.

Measuring Time Intervals

  • To measure the duration of the P wave, QRS complex, and T wave, count the small squares for each segment. For example, a normal QRS duration is usually 2-3 small squares (or 0.08 to 0.12 seconds).

Heart Rate Calculation

  • The heart rate can be calculated by measuring the distance between R waves (the peaks of the QRS complex). Count the number of large squares between two R waves and divide 300 by that number. For example, if there are 4 large squares, the heart rate would be approximately 75 beats per minute (300/4 = 75).

Understanding these elements allows health professionals to assess heart rhythms, identify abnormalities, and make informed decisions regarding patient care.

The EKG (electrocardiogram) acquisition encompasses key tasks and knowledge areas necessary for obtaining accurate heart readings. Here’s a breakdown:

Objectives of EKG Acquisition

  • Understand Heart Anatomy: The heart has four chambers: two atria (upper) and two ventricles (lower). Atria receive blood, while ventricles pump blood out.

  • Components of EKG Acquisition: Tools such as EKG machines, electrodes, and leads are essential for tests.

  • Equipment Maintenance: Learn how to load paper and disinfect machines to ensure they work properly.

  • Machine Settings: Adjust the speed and gain settings for accurate readings.

  • Skin Preparation for Electrodes: Proper cleaning techniques are important for good signal quality.

  • Patient Positioning: Understand how to position patients for different EKG types (like 3-lead, 12-lead, stress tests).

  • Electrodes and Leads: Master the placement of electrodes for various scenarios.

  • Lead Functionality: Confirm that all leads are connected properly during a record.

  • Identifying Artifacts: Learn to recognize and solve issues like wandering baseline or electrical interference.

  • Documenting EKG Results: Know how to properly mount an EKG tracing for the patient’s record.

  • Monitoring During Stress Tests: Be aware of how to observe patients’ conditions while conducting stress tests.

  • Responding to Complications: Familiarize yourself with protocols for dealing with problems that arise during testing.

Basic Anatomy and Physiology of the Heart

  • Structure: About the size of a fist, the heart includes the atria and ventricles which work together to circulate blood.

  • Chambers:

    • Atria: Act as receiving chambers for blood.

    • Ventricles: Pump blood to the lungs and body.

  • Septum: Separates the left and right sides of the heart (interatrial and interventricular septa).

Heart Layers

  1. Epicardium: The outer protective layer.

  2. Myocardium: The muscle layer responsible for contractions.

  3. Endocardium: The inner lining of the heart chambers and valves.

Heart Valves and Blood Flow

  • The heart has four valves that control blood flow:

    • Tricuspid Valve: Between right atrium and ventricle.

    • Mitral Valve: Between left atrium and ventricle.

    • Pulmonary Valve: Between the right ventricle and pulmonary artery.

    • Aortic Valve: Between the left ventricle and aorta.

  • Blood Circulation: The heart operates two circuits:

    • Pulmonary Circulation: Sends deoxygenated blood to the lungs.

    • Systemic Circulation: Delivers oxygenated blood to the body.

Understanding EKG Paper

  • Grid Layout: EKG paper is marked to record electrical heart activity, with small squares indicating time and voltage.

  • Key Components of EKG Reading:

    • P Wave: Atrial depolarization.

    • QRS Complex: Ventricular depolarization, represented by a sharp spike.

    • T Wave: Ventricular repolarization.

    • U Wave: Occasionally seen after T wave.

Measuring Time Intervals

  • Count small squares to determine durations of waves and intervals, which helps with heart rhythm assessment. For instance, a normal QRS duration ranges from 2 to 3 small squares.

Heart Rate Calculation

  • To find the heart rate, measure large squares between R waves; the formula is 300 divided by the number of large squares.

By understanding these concepts, learners can accurately interpret EKG readings and ascertain patient heart health and conditions.