1 / 18

Cardiac Pathophysiology Part B

Cardiac Pathophysiology Part B. Heart Failure. The heart as a pump is insufficient to meet the metabolic requirements of tissues. Can be due to: dysfunction of the left ventricle dysfunction of the right ventricle or due to inadequate perfusion despite normal or elevated cardiac output.

hhightower
Download Presentation

Cardiac Pathophysiology Part B

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cardiac PathophysiologyPart B

  2. Heart Failure • The heart as a pump is insufficient to meet the metabolic requirements of tissues. • Can be due to: • dysfunction of the left ventricle • dysfunction of the right ventricle • or due to inadequate perfusion despite normal or elevated cardiac output

  3. Classification of Heart Failure • Acute –develops quickly • Chronic – conditions gradually increase demands on the heart; when the heart and circulatory system can no longer adapt the result is heart failure • Can lead to acute failure with excessive cardiac demand

  4. Four broad consequences of heart failure • Congestion – blood backs up • Activation of circulatory compensations • Cardiac output declines • Death

  5. Types of Heart Failure • High output vs. Low output • High output • Anemia • Septicemia • Hyperthroidism (thyrotoxicosis) • Beriberi • Low output • Decreased pumping ability and cardiac output

  6. Right-sided vs. Left sided Heart Failure • Right-sided HF • Most common cause is left heart failure • Can occur independently in primary lung disease conditions • COPD, ARDS, cystic fibrosis • Cor pulmonale • Left-sided HF • Decreased output to body • Blood backs up

  7. Systolic vs. Diastolic HF • Systolic – decreased contraction leads to decreased output and poor perfusion of tissues

  8. Contractility is reduced by diseases that disrupt myocyte activity • Most common cause is myocardial infarction • Myocarditis • Myocardopathies • When contractility decreases, stroke volume decreases, and left ventricular end-diastolic volume (LVEDV) increases. • This causes dilation of the heart and increased preload

  9. Preload can also increase with excess plasma volume • I.V. Fluid administration • Renal failure • Mitral valve disease • Increased LVEDV at first increases C.O., but over time can cause dysfunction of sarcomeres (stretched too far) and decreased contractility

  10. Increased afterload is usually due to increased peripheral resistance • Hypertension • Left ventricle works harder to overcome resistance, and hypertrophies. • Hypertrophy causes changes in the myocytes. • Also see deposition of collagen between myocyctes which can disrupt contractility and make ventricle more likely to dilate and fail.

  11. Leads to increased blood pressure and pulmonary congestion → • Dyspnea • Orthopnea – difficulty breathing in any position other than upright • Coughing up frothy sputum • Chest pain –due to hypoxia at heart • Fatigue/confusion • Skin is pale, cold, sweaty • Pulse and lung sounds abnormal • Decreased urine output • Edema

  12. Treatment is aimed at breaking the cycle of decreasing contractility and increasing preload and afterload. • Oxygen, nitrates and morphine – improve myocardial oxygenation, help relieve coronary spasm while lowering preload through systemic vasodilation. • I.V. inotropic drugs such as dopamine or dobutamine – increase contractility of the heart and can raise B.P. in hypotensive individuals.

  13. Diuretics – reduce preload • ACE inhibitors – reduce preload and afterload by decreasing aldosterone levels and reducing peripheral venous resistance • Beta-blockers have been helpful in some people • Coronary by-pass • Salt restriction • Heart transplant

  14. Diastolic Heart Failure • See symptoms and signs of heart failure, a preserved ejection fraction, and abnormal diastolic function • Accounts for 25 -40% of all cases of heart failure

  15. Diastolic H.F. Results from: • Decreased compliance of left ventricle and abnormal diastolic relaxation- results in increased pressure in ventricle at the end of diastole • Pressure is reflected back into the atrium and pulmonary circulation

  16. Major causes: • Hypertension – induced myocardial hypertrophy and myocardial ischemia with ventricular remodeling • Aortic valvular disease • Mitral valvular disease • Cardiomyopathies

  17. Signs and symptoms are similar to systolic heart failure • Diagnosis made by echocardiography and heart cateterization

  18. Management • Improve ventricular relaxation and prolong diastolic filling times to reduce diastolic pressure • Calcium channel blockers, beta-blockers, and ACE inhibitors have been used with success

More Related