CRITICAL CARE 240 / NUR 240 COMPLETE STUDY GUIDE ON CARDIOVASCULAR SYSTEM (LATEST 2025/2026 UPDATE) TERMS & COMPLETE DEFINITIONS- COMMUNITY COLLEGE OF ALLEGHENY COUNTY

CRITICAL CARE 240 / NUR 240 COMPLETE STUDY GUIDE ON CARDIOVASCULAR SYSTEM (LATEST 2025/2026 UPDATE) TERMS & COMPLETE DEFINITIONS- COMMUNITY COLLEGE OF ALLEGHENY COUNTY Cardiovascular System Standard 12 Lead electrocardiogram- records electrical impulses as they travel though the heart. Uses of the 12-lead electrode placement - Detect dysrhythmias - Determine electrical axis - Enlargement patterns - Ventricular hypertrophy - Atrial enlargement - Ischemia injury and infarction patterns - Identification of prolonged QT intervals TYPES OF CARDIAC MONITORING SYSTEMS. - There are 2 types. 1. Continuous Hard wire monitoring systems - The pt is linked directly to the cardiac monitor through the ECG cable. - Used in ICU- used with pts confined in bed - The information is displayed at bedside and the central monitor - Hard wire monitors operate on electricity but are well isolated so that h20, blood, and other fluids do not pose an electrical hazard if the machine is maintained properly. 2. Telemetry monitoring system - Connected to a small battery operated transmitter - Displayed at the central monitoring station Dysthymias and the 12-lead electrocardiogram Evaluation of a rhythm strip - Must note too fast, slow or deadly The paper consists of Vertical and Horizontal lines each 1mm apart. Dark lines Thin lines Large square lines- (large boxes)- Each large box consists of 5 small boxes across and 5 small boxes down. The Vertical lines (up and down)- the height measures the voltage- how much electricity is there. Each Small square measured vertically is 1 Millimeter and the large square is 5mm. Height- measured by counting the lines vertically. - amplitude Horizontal lines. - time measurement (pay close attention to this) - each small squares measured horizontally = 0.04 seconds For example, If there are 5 small boxes= 0.04*5 = 0.20 seconds (this makes 1 big box) If there are 5 big boxes= 5*0.20 = 1 second. ECG paper • Small boxes = 0.04 seconds • Large box = 0.20 seconds Conductivity- Ability of cardiac cells to transmit impulses. The electrical conduction system causes the heart to contract and relax in order to pump blood. Polarization = resting - At cardiac cell membrane at rest (resting heart cells) =Vev no electrical activity - Inside the cell is more negative than the outside= polarized - K+ ions leak out Resting Heart Cell - - At rest, the heart cell is negatively charged on the inside due to a difference in ion concentrations - - This is known as the cell being polarized Depolarization= contraction - occurs when the cell membrane becomes more permeable to sodium, causing the cell to contract - Reversal of electrical charge. - Rapid influx of sodium ions. When the cell receives an electrical signal, the cell membrane becomes more permeable to sodium - Sodium enters the cell, causing the cell to become less negative or more positive. This is known as depolarization