EX 33 Pre-Lab Lecture

Page 1: Overview of Cardiac Phases

• Cardiovascular Physiology: Understanding the phases of the cardiac cycle.

  • Diastole: 0.4 seconds

  • Atrial Systole: 0.1 seconds

  • Ventricular Systole: 0.3 seconds

  • Valve Status:

    • Semilunar valves open during ventricular systole.

    • AV valves open during diastole.

Page 2: Learning Outcomes

• Definitions:

  • Systole: The phase of contraction of the heart muscle.

  • Diastole: The phase of relaxation of the heart muscle.

  • Cardiac Cycle: The sequence of events in one heartbeat.

• Measurements:

  • Expected length of the cardiac cycle: 0.8 seconds.

  • Pressure changes in the atria and ventricles over the cycle.

  • Timing of valve closures and corresponding volume changes.

• Correlation with ECG:

  • Understanding how ECG readings relate to cardiac cycle events.

Page 3: Heart Sounds and Clinical Significance

• Auscultation Skills:

  • Use of a stethoscope to detect heart sounds.

  • Relates sounds to specific cardiac events.

• Heart Murmurs:

  • Definition and clinical relevance.

• Locations for Heart Sounds:

  • Identifying the best locations to auscultate the 1st and 2nd heart sounds.

Page 4: Key Cardiovascular Terms

• Definitions:

  • Pulse: The rhythmic expansion and contraction of arteries with each heartbeat.

  • Pulse Pressure: The difference between systolic and diastolic blood pressure.

  • Blood Pressure: The pressure of circulating blood against the walls of the arteries.

  • Mean Arterial Pressure (MAP): Average arterial pressure during one cardiac cycle, often calculated as 1/3(SBP - DBP) + DBP.

Page 5: Cardiac Cycle Details

• Key Phases:

  • Systole: Contraction phase of the heart.

  • Diastole: Relaxation phase.

  • Normal Heart Rate: 75 beats per minute (bpm).

  • Cycle Length: 0.8 seconds, with specific durations for systole and diastole.

Page 6: Events of the Cardiac Cycle

• Table Overview:

  • Ventricular Filling (Passive):

    • Atrial pressure > Ventricular pressure = AV valves open, blood fills ventricles.

    • Status: Ventricle relaxed.

  • Atrial Contraction:

    • Atria contract, completing ventricle filling.

    • Status: Atria contracted, ventricles relaxed.

  • Isovolumetric Contraction:

    • Ventricles contract, closing AV valves.

    • Status: Ventricles contracted.

  • Ventricular Ejection:

    • Ventricular pressure exceeds aortic pressure.

    • Blood ejected through open semilunar valves.

    • Status: Ventricles remain contracted, diastole in the atria.

  • Isovolumetric Relaxation:

    • Ventricles relax, SL valves shut (dicrotic notch).

    • Status: Ventricles relaxed.

Page 7: Summary of Cardiac Cycle Events

• Phases Recap:

  • Ventricular Filling Phase: Passive filling and atrial contraction.

  • Ventricular Ejection Phase: Blood leaving the ventricles.

  • Isovolumetric Relaxation Phase: Ventricles relax with no blood flow.

• Phases Illustrated:

  • Events occur throughout the cycle including periods of systole and diastole.

Page 8: Cardiac Cycle Graph Interpretation

• ECG Correlation:

  • Events of the cardiac cycle synchronized with ECG readings (P, QRS, T waves).

• Pressure Changes:

  • Understanding pressure dynamics during various phases, including stroke volume, end-diastolic volume (EDV), and end-systolic volume (ESV).

Page 9: Heart Sounds

• Mechanism:

  • Result from turbulent blood flow during heart contractions.

• Types of Sounds:

  • S1 & S2: 1st sound (closure of AV valves), 2nd sound (closure of SL valves).

  • Often characterized as "lub" (S1) and "dub" (S2).

Page 10: Cardiac Measurements

• Measurements:

  • Pulse: The number of heartbeats per minute.

  • Blood Pressure (BP): Measurement of arterial pressure.

  • Pulse Pressure: Calculated as SBP - DBP.

  • Mean Arterial Pressure (MAP): Average pressure throughout the cardiac cycle.

Page 11: Activity Overview

• Heart Sounds Auscultation:

  • Practical skill to listen to heart sounds correlated with cardiac cycle events.

Page 12: Auscultation Sites for Heart Sounds

• Key Areas:

  • Aortic Valve: 2nd intercostal space (right sternal margin).

  • Pulmonary Valve: 2nd intercostal space (left sternal margin).

  • Mitral Valve: Heart apex (5th intercostal space).

  • Tricuspid Valve: Right sternal margin of the 5th intercostal space.

Page 13: Pulse Measurement Activity

• Palpating Pulses:

  • Index and middle finger used for pulse measurement.

  • Importance of not using the thumb.

Page 14: Sites for Pulse Measurement

• Easily Palpable Pulse Points:

  • Temporal, Facial, Common Carotid, Brachial, Radial, Femoral, Popliteal, Posterior Tibial, Dorsalis Pedis Arteries.

Page 15: Blood Pressure Measurement Overview

• Systolic and Diastolic:

  • Systolic: Pressure when ventricles contract (highest pressure).

  • Diastolic: Pressure when ventricles are relaxed (lowest pressure).

Page 16: Blood Pressure Measurement Procedure

• Procedure Summary:

  • Steps when measuring blood pressure with a sphygmomanometer.

  • Understanding pressure changes in response to cuff inflations and subsequent artery compression.

  • Example Measurement: 120 mm Hg systolic over 70 mm Hg diastolic.