1. Blood Pressure Disorders

1. Hypertension

• An elevated arterial pressure
• Primary or secondary hypertension
• Caused by factors that change cardiac output or peripheral resistance of blood vessels

1. Primary Hypertension

1. contributing factors

• Increased action of sympathetic nervous system/decreased action of parasympathetic nervous system
• Increased levels of norepinephrine
• Increased levels of renin (angiotensis and aldosterone)
• Increased Prostaglandin E
• Defect in renal excretion of salt and water

1. risk factors

• obesity
• high dietary salt intake
• genetic predisposition ?
• alcohol and smoking
• diabetes mellitus

1. manifestations

• acceleration of atherosclerotic plaques
• coronary heart disease
• congestive heart failure
• nephrosclerosis
• stroke

1. treatment

• diet, weight loss, restriction of dietary sodium
• drug therapy

1. Secondary Hypertension

• Identifiable underlying cause

1. causes

• oral contraceptives
• pregnancy
• renal disease/renal failure
• renin-secreting tumors
• aldosteronism
• cushing’s syndrome

1. Circulatory Failure

• Hypotension
• Circulatory failure = decrease in blood flow that impairs the delivery of oxygen to the cells

1. causes

• volume loss (hypovolemic shock)
• decrease in heart rate/rhythm (cardigenic shock)
• alterations in blood distribution (distributive shock)
• obstruction of blood flow (obstructive shock)

• metabolic acidosis (lactic acidosis)
• increased capillary hydrostatic pressure (loss of intravascular volume)

• hypotension
• hyperventilation
• cyanosis
• cold, clammy, pale skin
• confusion

• provide adequate ventilation
• restore blood volume
• improve cardiac performance

2. Vascular Disorders

1. Atherosclerosis

• Cardiovascular disease in which localized areas of the tunica intima become thickened, with injury to the wall and possible occlusion of the vessel.
• principal cause of disease in adults in Western countries.

1. Pathogenesis

• earliest lesions (fatty streaks) found in infants and children
• fatty streaks develop into more advanced lesions (fibrous or atheromatous plaques)
• response-to-injury hypothesis => endothelial damage
• increased permeability
• secretion of procoagulants
• increased endothelial cell turnover
• secretion of vasoactive substances
• secretion of growth factors
• macrophage damage endothelial cells and secrete growth factors that stimulate proliferation of smooth muscle cells and disrupt tight junctions between cells. Platelets interact and aggregate to form plaques.

1. Risk Factors

• Cigarette smoking
• obesity
• genetic predisposition?
• diabetes
• hypertension
• hypercholesteremia
• gender (females have higher level of HDL and lower level of LDL due to estrogen production)

1. Manifestations

• Atherosclerotic lesions affect medium and liarge-sized arteries
• Abdominal aorta, coronary arteries
• occlusion of vessel (infarction, arteriosclerosis)
• formation of microthrombi (stroke, thromboembolism)
• aneurysm

1. Treatment

• avoid smoking
• lose weight
• control blood pressure
• control blood lipid levels

3. Disorders of the Heart

1. Ischemic Heart Disease (Coronary Heart Disease)

• myocardial infarction => interruption of blood supply to heart and death of cardiac muscle.

1. Myocardial Infarction

1. Causes

• occlusion of coronary vessels
• atherosclerosis
• complication of surgery or result of excess exertion

1. Manifestations

• severe chest pain
• may have slight elevation in temperature
• dyspnea, sweating and nausea
• hypotension and bradycardia

1. Consequences

• ventricular tachycardia and or fibrillation
• abnormalities in conduction through AV nodes
• cardiogenic shock and circulatory failure

1. Management

• alleviate pain
• administer oxygen and/or anticoagulant therapy
• control blood pressure
• surgery or angioplasty

1. Congestive Heart Failure

• excessive filling of heart which results in increased volume in pulmonary vessels or increased volume on venous side of systemic circulation.

1. Causes

• high or low cardiac output
• right or left-sided failure of the ventricles

1. left-sided failure

• most commonly due to hypertension (increased peripheral resistance) => this can result in a back-up of blood in the left atrium and congestion of the pulmonary vascular system.
• Caused by Aortic Stenosis or Coarctation of the Aorta
• Caused by mitral regurgitation.

1. right-sided failure

• Pulmonary stenosis or Pulmonary hypertension
• Cor Pulmonale
• Atrial septal defect => blood flow from left to right atria

1. Physiological Responses

1. Dilation or enlargement of a heart chamber

• need more tension to contract & increased oxygen needs

1. Hypertrophy of muscle wall

• decreased contractile force
• ischemia

1. Hormonal effects

• increase norepinephrine and epinephrine
• increase renin, aldosterone and angiotensin and ADH

1. Improved oxygenation

1. Manifestations

• Initially cay involve one side of heart but as progresses involves both sides of heart.

1. Left-sided

• pulmonary edema, nonproductive cough, pleural effusion, rales and wheezing
• Cardiac asthma, Cardiomagaly, Cardiac arrhythmias
• Dyspnea

1. Right-sided

• Jugular vein distension
• Peripheral edema
• Nocturia
• Hepatomegaly
• Cardiac arrhythmias

1. Management

• Treatment of contributing or aggravating factors
• Drug therapy
• Dietary Restrictions

4. Congenital Heart Defects

1. Patent Ductus Arteriosus

• Ductus Arteriosis carries blood from the bifurcation of the pulmonary artery directly to the aorta just distal to the left subclavian artery (bypass lungs because blood is oxygenated in placenta)
• Vessel normally closes within 24 hours of birth

1. Occurrence

• more common in females
• maternal rubella
• premature hypoxia or birth at high altitudes

1. Physiological effects

• consequences depend on size of defect and extent of pulmonary vascular resistance

1. left-to-right shunt

• blood flow from aorta to lungs
• pulmonary vascular engorgement
• increased volume returned to left heart

1. right-to-left shunt

• blood flow from pulmonary artery to aorta
• lower body cyanosis
• aorta somewhat enlarged in older patients

1. Manifestations

• pulmonary hypertension
• clubbing

1. Ventricular Septal Defect

• opening in the septum that separates the right and left ventricles

1. Occurrence

• most common congenital heart abnormality seen in children

2) Physiological effects

• If pulmonary vascular resistance in normal => left-to-right shunt that increases right ventricular pressure
• As pulmonary resistance falls => increased right ventricular pressure and left ventricular volume overload => left and right ventricular hypertrophy and cardiac failure

3) Manifestations

• Large defects => frequent pulmonary infections, growth retardation and cardiac failure in infancy.
• Moderate shunts => exercise intolerance and fatigue and pulmonary hypertension develops over time.