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)