Cardiovascular System Heart Failure Pulmonary Heart Disease Pulmonary Hypertension lecture from Physiology and Pathophysiology II 14. 3. 2023 M. Chalupová Cardiovascular System • closed system of the heart and blood vessels – heart pumps blood – blood vessels allow blood to circulate to all parts of the body • function is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products Heart Heart Valves • allow blood to flow in only one direction • atrioventricular valves – between atria and ventricles – bicuspid valve (left) – tricuspid valve (right) • semilunar valves between ventricle and artery – pulmonary semilunar valve – aortic semilunar valve Heart Heart Valves Operations Blood Circulation Conduction System of the Heart • specialized muscular tissue sets the pace • sinoatrial node (right atrium) – pacemaker • atrioventricular node (junction of r&l atria and ventricles) • Atrioventricular bundle (Bundle of His) • Bundle branches (right and left) • Purkinje fibers Conduction System of the Heart Heart Failure • results from any structural or functional abnormality that impairs the ability of the ventricle to eject blood (Systolic Heart Failure) or to fill with blood (Diastolic Heart Failure) • caused by: – coronary artery disease – heart attack – high blood pressure – infections – heart valve abnormalities – hyperthyroidism Heart Failure • heart failure can involve the left or right side of the heart or both (the left side is rather affected first) • usually a chronic disease • the heart tries to compensate for the loss in pumping function by: – developing more muscle mass (ventricular hypertrophy) – enlarging – pumping faster (tachycardia) Heart Failure LEFT HEART FAILURE • involves the left ventricle of the heart – Systolic failure • the heart loses its ability to contract or pump blood into the circulation – Diastolic failure • the heart loses its ability to relax because it becomes stiff • it cannot be filled properly between each beat Heart Failure RIGHT HEART FAILURE • usually occurs as a result of left heart failure • the right ventricle pumps blood to the lungs for oxygen • occasionally isolated right heart failure can occur due to lung disease or pulmonary embolism Heart Failure Pathophysiology Heart Failure Vicious Cycle Decreased Blood Pressure and Decreased Renal perfusion Stimulates the Release of renin, Which allows conversion of Angiotensin to Angiotensin II. Angiotensin II stimulates Aldosterone secretion which causes retention of Na+ and Water, increasing filling pressure LV Dysfunction causes Decreased cardiac output Causes of Heart Failure CORONARY ARTERY DISEASE • cholesterol and fatty deposits build up in the heart’s arteries • less blood and oxygen reach the heart muscle • this causes the heart to work harder and occasionally damages the heart muscle HEART ATTACK (MYOCARDIAL INFARCTION) • coronary artery being blocked leading to cardiomyocyte necrosis • remaining heart muscle must pump harder to keep up Causes of Heart Failure HIGH BLOOD PRESSURE (HYPERTENSION) • uncontrolled high blood pressure doubles a person´s risk of developing heart failure • heart must pump harder to keep blood circulating • chamber first thickens, then gets larger and weaker Symptoms of Heart Failure • shortness of breath (dyspnoea) – dyspnea on exertion or at rest – difficulty breathing when lying flat – waking up short of breath • persistent cough or wheezing • edemas – swelling in feet, ankles and legs – ascites – weight gain • confusion, impaired thinking Symptoms of Left Heart Failure Symptoms of Right Heart Failure NYHA Heart Failure Classification Class % of patients Symptoms I 35 % No symptoms or limitations in ordinary physical activity II 35 % Mild symptoms and slight limitation during ordinary activity III 25 % Marked limitation in activity even during minimal activity. Comfortable only at rest IV 5 % Severe limitation. Experiences symptoms even at rest Pulmonary Heart Disease • pulmonary heart disease (cor pulmonale) • dilation/hypertrophy of right heart ventricle and heart failure due to increased vascular resistance or high blood pressure in the lungs – acute dilation – chronic hypertrophy Pulmonary Heart Disease • arises in the pulmonary circulation • symptoms – dyspnoea, wheezing, liquid in the abdominal cavity (ascites), cyanosis, enlarged liver, edemas • causes – pulmonary embolism, ARDS, COPD, primary pulmonary hypertension, interstitial lung diseases Pulmonary Hypertension • mean pulmonary artery pressure – 20–25 mmHg – determined by pulmonary vascular resistance, cardiac output and left arterial pressure • pulmonary hypertension – over 25 mmHg • acute – pulmonary embolism with acute cor pulmonale (right ventricle dilation) and acute right heart failure • chronic – lung diseases – chronic thromboembolism – chronic altitude hypoxia – consequence is right ventricular hypertrophy (chronic cor pulmonale) Pulmonary Hypertension • primary • idiopathic damage of small arteries • bad prognosis • secondary • lung diseases • hypoxia (high altitude) • left heart failure, mitral valve disease • thromboembolism