Please confirm topic selection

Are you sure you want to trigger topic in your Anconeus AI algorithm?

Please confirm action

You are done for today with this topic.

Would you like to start learning session with this topic items scheduled for future?

Updated: Feb 6 2024

Cardiac Cycle

  • Snapshot
    • A 15-year-old boy presents to the emergency room after collapsing on the basketball court. His mom reports that he has been pushing himself physically to do well in basketball. She states that he has had several episodes of syncope while playing basketball. There is also a family history of sudden cardiac death in several relatives. On physical exam, the boy has an S4 heart sound and a systolic murmur. (Hypertrophic cardiomyopathy)
  • Introduction
    • The cardiac cycle is divided into 7 components
    • Atrial systole (1)
      • atria contract
        • this is the final phase of ventricular filling
        • electrocardiogram (ECG) finding
          • P wave
      • final phase of ventricular filling
        • ECG finding
          • PR interval
    • Isovolumetric contraction (2)
      • period from between mitral valve closure to aortic valve opening
      • ventricles contract and pressure increases
        • ECG finding
          • QRS complex
      • volume is constant, as all the valves are closed
      • period of highest O2 consumption
    • Systolic ejection
      • period from aortic valve opening to aortic valve closing
      • two phases
        • rapid ejection (3)
          • ventricles contracts and pumps blood into arteries
          • ventricular pressure reaches maximum
          • ECG finding
            • ST segment
        • reduced ejection (4)
          • ventricles pump blood at a slower rate
          • ventricular volume is at its minimum
          • ECG finding
            • T wave
    • Isovolumetric relaxation (5)
      • period from aortic valve closure to mitral valve opening
      • ventricles relax with no filling
    • Rapid ventricular filling (6)
      • period right after mitral valve opens
    • Reduced ventricular filling, or diastasis (7)
      • period right before mitral valve closes
  • Heart Sounds
    • S1
      • closure of the mitral and tricuspid valves
      • loudest at mitral area
    • S2
      • closure of aortic and pulmonary valves
      • loudest at left upper sternal border
    • S3
      • early diastole
      • associated with ↑ filling pressures
        • mitral regurgitation
        • congestive heart failure
        • dilated ventricles
      • normal in children and pregnancy
    • S4
      • late diastole
      • also referred to as “atrial kick”
      • loudest at apex with the patient in left lateral decubitus position
      • associated with ↑ atrial pressure and ventricular hypertrophy
        • left atrium pushes against a stiff and noncompliant left ventricular wall
      • always abnormal
  • Jugular Venous Pulse (JVP)
    • a wave
      • atrial contraction
      • absent in
        • atrial fibrillation
    • c wave
      • right ventricular contraction
      • tricuspid valve is closed and bulges into atrium
    • x descent
      • tricuspid valve is closed and is displaced downward during rapid ejection phase
      • reduced or absent in
        • tricuspid regurgitation
        • right heart failure
    • v wave
      • ↑ right atrial filling pressures against closed tricuspid valve
    • y descent
      • right atrium empties into right ventricle
      • increased in
        • constrictive pericarditis
      • absent in
        • cardiac tamponade
  • Exercise Physiology
    • Increased inotropy
      • Due to cardiac sympathetic activation
    • Increased end-diastolic volume
      • From increased venous return
        • Skeletal muscle pump
        • Increased respiration -> more negative intrapleural pressure
    • Decreased end-systolic volume
      • From increased stroke volume / ejection fraction
1 of 0
1 of 6
Private Note

Attach Treatment Poll
Treatment poll is required to gain more useful feedback from members.
Please enter Question Text
Please enter at least 2 unique options
Please enter at least 2 unique options
Please enter at least 2 unique options