ObjectivesObjectives
• 1. Discuss heart sounds• 2. Describe the major types of cardiac
valve disorders• 3. Explain how a myocardial infarction
might occur.• 4. Describe the major types of cardiac
dysrhythmia.• 5. List and describe possible causes of
heart failure.
Heart SoundsHeart Sounds
• Two distinct sounds can be heard when listening to the heart – “lub dup”
• “lub” – caused by vibration and abrupt closure of the AV valves as the ventricle contracts
• This sound is of a longer duration and lower pitch than is the second sound.
• “dup” – closing of the semilunar valves
Valve DisordersValve Disorders
• Incompetent valves – leak
• Stenosed valves – narrower than normal
• Rheumatic heart disease – inflammation of cardiac valves and other tissues
• Mitral valve prolapse (MVP) – bicuspid valve flaps extend into left atrium causing incompetence
Heart AttackHeart Attack
• A myocardial infarction may result from occlusion or blockage of the left coronary artery
Cardiac DysrhythmiaCardiac Dysrhythmia
• Heart block – AV node block
• Bradycardia – slow heart rhythm (below 60 beats per minute); slight bradycardia is normal during sleep; abnormal caused from improper autonomic nervous control of the heart or a damaged SA node
• Tachycardia – rapid heart rhythm (over 100 beats per minute); normal during exercise or stress response; abnormal results from improper autonomic control of the heart, blood loss or shock, action of drugs and toxins, fever, et al
• Sinus dysrhythmia – variation in heart rate during breathing cycle
ExtrasystolesExtrasystoles
• Frequent premature contractions
• Can lead to fibrillation – cardiac muscle fibers contract out of step with each other
• Ventricular fibrillation – immediately life-threatening
Heart FailureHeart Failure
• Cardiomyopathy – disease of the myocardial tissue, reduces pumping effectiveness
• Dysrhythmias can impair pumping effectiveness
• Congestive heart failure – left heart failure; decreases pumping pressure in the systemic circulation (portions become congested with fluids)
