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The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
The Cardiac Cycle7
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The Cardiac Cycle7


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Review of the Cardiac Cycle

Review of the Cardiac Cycle

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  • Transcript

    • 1. The Cardiac Cycle Mercy Hospital Intern Presentation James Ratliff
    • 2. Presentation Overview
      • Cardiac Anatomy
      • Electrophysiology
        • Pacemaker Action Potential
        • Myocardial Action Potential
      • Cardiac Physiology / Cycle
      • Heart Sounds
      • Murmurs
      • Heart Sound Cases
    • 3. Heart Anatomy
      • The normal size of the heart is approximately the size of a fist
        • Males: 300-350 gm
        • Females: 250-300 gm
      • The 4 cardiac valves and the number of leaflets in each are:
        • Tricuspid: 3
        • Pulmonic: 3
        • Mitral: 2
        • Aortic: 3
    • 4.  
    • 5. Cardiac Cycle
    • 6. SA/ AV Node Action Potential 0 2 4
    • 7. Pacemaker Action Potential
      • Occurs in the SA and AV nodes
      • Major differences vs the ventricular myocardial action potential:
        • Phase 0: upstroke
          • Opening of voltage gated Ca2+ channels; these cells lack fast voltage gated Na+ channels
          • Results in slow conduction velocity that is utilized by the AV node to prolong transmission from the atria to ventricles
        • Phase 2: The plateau is absent
        • Phase 4: slow diastolic depolarization
          • The membrane potential spontaneously depolarizes as Na+ conductance increases
          • Accounts for automaticity of SA and AV nodes
          • The slope of Phase 4 determines the HR
    • 8. Cardiac Cycle
    • 9. Myocardial Action Potential
      • Occurs in the atrial and ventricular myocytes and Purkinje fibers
      • Phase 0: rapid upstroke
        • Voltage gated Na+ channels open
      • Phase 1: initial repolarization
        • Inactivation of voltage gated Na+ channels
        • Voltage gated K+ channels begin to open
      • Phase 2: plateau
        • Ca2+ influx through voltage gated Ca2+ channels balances K+ efflux
        • Ca2+ influx triggers another Ca2+ release and myocyte contraction
      • Phase 3: rapid repolariazation
        • Massive K+ efflux - opening of voltage-gated slow K+channels and closure of voltage-gated Ca2+ channels
      • Phase 4: resting potential
        • High K+ permeability through K+ channels
    • 10. Myocardial Electrical Activity
      • 1) Atrial Depolarization
      • 2) Atrial Depolarization
      • 3) Ventricals Depolarize at apex; Atria Repolarize
      • 4) Ventricles Depolarize
      • 5) Ventricles begin to Repolarize at apex
      • 6) Ventricles Repolarize
    • 11. Cardiac Cycle
    • 12. Cardiac Cycle
      • Phases
        • I: Isovolumetric contraction
          • Period between MV closure / AV opening
          • Period of HIGHEST O2 consumption
        • II: Systolic ejection
          • Period between AV opening and closing
        • III: Isovolumetric relaxation
          • Period between AV closing / MV opening
        • IV: Rapid Filling
          • Period just after MV opening
        • V: Slow Filling
          • Period just before MV closure
    • 13. How to Examine Heart Sounds
    • 14. Who is Your Patient?
    • 15. Are They -
      • Sick/well
      • Comfortable/in distress
      • Cyanosed/plethoric
      • Wet/dry
      • Young/old
      • Male/Female
      • Establish probabilities of disease
    • 16. Common Associations
      • Younger people
        • Functional murmur vs MVP vs bicuspid AV
      • Older people
        • Aortic sclerosis vs aortic stenosis
    • 17. Probabilities
      • Males more commonly have aortic valve disease
        • Young – BAV
        • Elderly - Degenerative
      • Females more commonly have mitral valve disease
      • MVP > rheumatic heart disease
    • 18. Inspect
      • Facies/body habitus
        • Cyanosis
        • Xanthelasma
        • Arcus senilis
        • Conjunctival hemorrhages
      • Syndromes
        • Marfan’s
        • Down’s
    • 19. Heart Sounds vs Cardiac Cycle
      • P wave: Atrial Depolarization
      • PR interval: Atrioventricular conduction time
      • QRS: Ventricular Depolarization
      • T wave: Ventricular Repolarization
      • S1: same time as the QRS
      • S2: just after the T wave
      • S3: before the P wave
      • S4: just before the QRS
    • 20. Heart Sounds
      • S1
        • MV followed by TV closure
      • S2
        • AV and PV closure
      • S3
        • At the end of rapid ventricular filling
        • Ventricular “gallop”
        • Dilated CHF
      • S4
        • High atrial pressure in a stiff ventricle
        • “ atrial kick”; hypertrophic ventricle
    • 21. S1
      • Coincides with the pulse in the Carotid Artery
      • Pulmonary Hypertension, Anemia, Fever, Hyperthyroidism may INCREASE S1
      • Obesity, Muscularity, COPD, B-Blockers, Fibrosis, Calcification, Fluid may REDUCE S1 and S2.
      • Mitral valve Stenosis - PROMINENT S1
    • 22. S2
      • The beginning of diastole - the heart's relaxation phase - when the ventricles fill with blood.
      • S2 more pronounced in children.
      • Right ventricular ejection time is slightly longer than the left resulting in delayed Pulmonic Valve closure A2P2
      • Higher closing pressures result in a Louder A2
        • high blood pressure
        • pulmonary hypertension
        • exercise or excitement
      • Left Bundle Branch Block may cause aortic valve closing (A2) to be slower than pulmonic valve closing (P2).- P2A2
    • 23. Splitting of the Second Sound
    • 24. S3
      • 2 sounds of ventricular filling :
        • The first is from the Atrial walls
        • 2nd is from the Contraction of the Atria
        • Caused by Vibration of the Ventricular walls
          • Caused by Rapid Filling
          • Heard just after S2
      • S3 either physiological or pathological.
    • 25. S3 Continued
      • Normal S3 is common in:
        • children
        • young adults
        • third trimester of pregnancy
      • Abnormal S3:
        • Anyone above 40 is associated with:
          • Decreased Myocardial Contraction
          • Myocardial Failure
          • Volume Overload of a Ventricle
            • Mitral or Tricuspid Regurgitation
    • 26. S4
      • S4 can be normal, but generally pathological. A normal S4 rarely occurs in:
        • trained athletic
        • otherwise healthy older individuals
      • An abnormal S4 is associated with:
        • coronary artery disease (left sided)
        • cardiomyopathies (left sided)
        • hypertensive heart disease (left sided)
        • aortic stenosis (left sided)
        • pulmonary hypertension (right sided)
        • pulmonic stenosis (right sided)
    • 27. Other Heart Sounds
      • Opening Snap
        • Caused by a noncompliant valve
      • Ejection Click
        • Shortly after S1
        • Dilated Pulmonary Artery or Septal Defect
      • Pericardial Friction Rub
        • Waxes and wanes with diastole and systole
      • Murmur
        • Secondary to Turbulent blood flow
          • Increased flow across a normal valve
          • Forward flow across an irregular valve
          • Enlarged heart chamber
          • Back-flow through an insufficient valve
      • Thrill
        • Vibration, high in frequency and sustained
    • 28. Grading Murmurs
      • I - Lowest intensity, difficult to hear even by expert listeners
      • II- Low intensity, but usually audible by all listeners
      • III - Medium intensity, easy to hear even by inexperienced listeners, but without a palpable thrill
      • IV - Medium intensity with a palpable thrill
      • V - Loud intensity with a palpable thrill. Audible even with the stethoscope placed on the chest with the edge of the diaphragm
      • VI - Loudest intensity with a palpable thrill. Audible even with the stethoscope raised above the chest.
    • 29. Murmur Timing & Quality S1 S2 S1
    • 30. Heart Sounds Ejection Click Opening Snap Pansystolic Murmur Diastolic Rumble MVP Mitral Stenosis Normal Split S1 Normal Split S2 S3 S4 !/6 Systolic Murmur PDA
    • 31. Case 1
      • A 73 yo man is hospitalized for SOB, chest heaviness, and weight gain. His medical history is significant for hypertension and recently diagnosed nonischemic cardiomyopathy. His medications include aspirin, lisinopril, HCTZ, and lovastatin. He was recently on vacation, when he ran out of his medications and was not fully compliant with his usual cardiac diet.
      • What cardiac sound would you assume you would hear on ascultation?
      • Which of the following sounds would correspond with what you would expect to hear?
      • A B C D
    • 32. Case 2
      • A 19 yo woman is evaluated for palpitations described as “extra beats” that do not occur with any regularity. She has no history of syncope or pre-syncope, no cardiovascular risk factors, and no familial history of cardiovascular disease. She denies signs any signs or symptoms of congestive heart failure. She is on no medication.
      • On exam, her lungs are clear and a grade 2/6 late systolic murmur is detected. The murmur is heard best at the cardiac apex and radiates to the left axilla. A mid systolic click is heard.
      • What would you expect the diagnosis to be?
      • Which of the following sounds would you associate with the above diagnosis? A B C D
    • 33. References
      • American College of Physicians - MKSAP 14 Cardiovascular Medicine