CARDIOVASCULAR PATHOPHYSIOLOGY

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CARDIOVASCULAR PATHOPHYSIOLOGY PHARMACOLOGY

• Week 8
• Lecture Outline

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CARDIOVASCULAR PATHOPHYSIOLOGY PHARMACOLOGY

• DISORDERS OF THE CIRCULATION GENERAL SYSTEMIC
  AND CORONARY
• BLOOD PRESSURE DISORDERS hypertension,
  hypotension and circulatory shock
• MYOCARDIAL INFARCTION AND
• HEART FAILURE
• CARDIOVASCULAR DRUGS 1
• antihypertensive drugs
• CARDIOVASCULAR DRUGS 2
• drugs for angina and heart failure

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DISORDERS OF THE CIRCULATION GENERAL SYSTEMIC
AND CORONARY

• Blood flow interruption
• Alterations to arterial blood flow
  (atherosclerosis, aneurysms, acute arterial
  occlusion)
• Alterations to venous blood flow (thrombus
  formation, varicose veins)

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BLOOD PRESSURE DISORDERS HYPERTENSION,
HYPOTENSION, CIRCULATORY SHOCK

• Assessment of hypertension
• Effects of hypertension on body organs
• Orthostatic hypotension
• Definition of circulatory shock, causes
• Signs and symptoms of compensatory mechanisms in
  circulatory shock
• Complications of shock

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MYOCARDIAL INFARCTION AND HEART FAILURE

• Pathophysiology of myocardial infarction
• Acute complications
• Congestive heart failure as a chronic
  complication
• Other causes of CHF (CHD, angina, valvular
  disease, congenital heart defects, increased
  volume work, increased pressure work)
• Definition of CHF
• Consequences of CHF
• right and left-sided consequences

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CARDIOVASCULAR DRUGS 1 antihypertensive drugs

• Objectives of antihypertensive therapy
• Lifestyle modification
• Use of pharmacotherapy
• ?-blockers,
• ACE inhibitors
• Ca2antagonists,
• thiazide diuretics
• ?1-antagonists

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CARDIOVASCULAR DRUGS 2 drugs for angina and
heart failure

• Causes and treatment of angina
• Treatment of CHF treat correctable underlying
  causes
• reduce cardiac workload (vasodilators)
• reduce fluid overload (diuretics)
• increase force of contraction (digoxin)

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ANATOMY PHYSIOLOGY
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CARDIOVASCULAR SYSTEM Brief review

• THE HEART - pulmonary and sytemic circulation
• differentiate atria from ventricles, diastole
  from systole?
• how are heart sounds produced? - valves lub,dub
• describe the electrical activity - (P, QRS,
  T)(SA, AV, Bundle of His, r l bundle branches,
  Purkinje fibres)
• describe the cardiac cycle
• when does blood flow through coronary arteries?
  Peak?
• how is heart rate controlled?
• State Starlings law of the heart and input
  pressure
• define the relationship bet venous return, CO and
  blood pressure
• define stroke volume, cardiac output (HR 70/min,
  SV70 ml, CO4.9 L/min)

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CARDIOVASCULAR SYSTEM Brief review

• Blood vessels
• why are arterioles important? ANS, peripheral
  resistance, autoregulation
• differentiate arteries from veins?
• Walls, lumen, pressure, arteriosclerosis, loss of
  elasticity, valves, blood reservoir
• what is the normal blood pressure range?
• What are the determinants of blood pressure? CO
  and peripheral resistance
• how is BP controlled? baroreceptors

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ACTIVITY 1

• Differentiate between preload afterload.
• How will the following affect BP?
• Adrenaline
• elevating the feet
• hypoxia
• RA A system
• Draw a diagram of the conducting system.

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CV DISORDERS
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DISORDERS OF CARDIOVASCULAR SYSTEM An Overview

• Abnormal valves - Heart murmur (whoosh sound,
  leakage of valve, rheumatic fever, stenosis)
• Abnormal rhythms - AV block (ectopic
  pacemaker),dysrhythmias - fibrillation
• Ischaemic heart disease - diminished blood supply
  to the heart (arteriosclerosis, angina, MI, CAD)

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DISORDERS OF CARDIOVASCULAR SYSTEM An Overview

• CONGENITAL DEFECTS
• coarctation of the aorta
• septal defect
• valvular defects
• Diminished contractility - heart failure -
  hypertension, renal response (angiotensin
  aldosterone)
• Alterations in flow (DVT, shock, haemorrhage,
  blood viscosity, aneurism)

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ALTERATIONS IN ARTERIAL VENOUS FLOW
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DISORDERS OF THE CIRCULATION GENERAL SYSTEMIC
AND CORONARY

• aneurysms
• weakness of arterial wall
• cause - arteriosclerosis, trauma, infections,
  etcbl
• several forms - berry, fusiform, sac, dissecting
• acute arterial occlusion
• thrombus or emboli originating from the heart
• occlusion in extremity
• thrombolytic/anticoagulant

• atherosclerosis
• fibrofatty lesions arteries
• insidious, risk factors
• intra-extracellular lipids, vascular smooth
  muscle cells, scar tissue/connective tissue
  proteins
• occlude vessel, thrombus formation, decreased
  blood flow

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DISORDERS OF THE CIRCULATION GENERAL SYSTEMIC
AND CORONARY

• thrombus formation or thrombophlebitis
• DVT --- PE
• Virchow triad - stasis of blood,
  hypercoagulability, vessel wal injury
• manifestations related to inflammatory response
• diagnosis and treatment

• varicose veins
• prolonged dilatation and stretching of vessel
  wall as a result of increased venous pressure
• incompetent valves, deformed venous structures

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BLOOD PRESSURE
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BLOOD PRESSURE DISORDERS HYPERTENSION

• Sustained elevation of systemic arterial
  pressure, asymptomatic
• Control of BP (sympathetic and renin-angiotensin
  system) BPCOxPR COHRxSV
• Causes - adrenocortical disease, tumours JG cells
  / pheocromocytomas, narrowing of renal arteries /
  aorta, renal diseases, severe polycythemia, oral
  contraceptives, toxaemia of pregnancy, unknown
• Primary (Essential) or Secondary types
• Assessment of hypertension
• Effects of hypertension on body organs - heart
  hypertrophies, increased O2 consumption,
  increased incidence of atherosclerosis, heart
  disease, thromboses of cerebral vessels
  haemorrhage, renal disease / failure, blindness

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BLOOD PRESSURE DISORDERS HYPOTENSION,
CIRCULATORY SHOCK

• Orthostatic hypotension
• abnormal drop of BP on standing
• absence of normal circulatory reflexes or blood
  volume
• dizziness/syncope
• causes - fluid, meds, aging, bedrest
• diagnosis treatment

• CIRCULATORY SHOCK
• Definition- failure of CV to adequately perfuse
  vital organs - anaerobic metabolism -
  irreversible cell damage ( low CO,low BP)
• Causes - insufficient cardiac filling, impaired
  ejection of blood, inadequate heart rate,
  increased demand for blood flow, blood loss
• 3 stages - compensated ( negative feedback),
  uncompensated (positive feedback), irrev
• Signs and symptoms - thirst, cool, moist, pale
  skin, increase HR, weak/tready pulse, decreased
  urine, restlessness to apathy
• Complications of shock - shock lung, renal
  failure, GI ulceration, DIC, multiple-organ
  failure

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OTHER DISORDERS
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MYOCARDIAL INFARCTION

• Irreversible muscular changes following severe
  prolonged myocardial ischaemia
• Cause - obstruction of at least 75 of the
  coronary artery lumen by a thrombus in a region
  narrowed by plaques other events precipitating a
  thrombosis
• Pathophysiology of myocardial infarction - heart
  muscle receives inadequate blood because of
  interruption with supply, fatty plaques obstruct
  flow or cause thrombus or embolus
• Signs symptoms - squeezing central pain gt10-15
  mins, radiating to shoulders, neck or arms,
  associated with sweating, SOB and a sick feeling
  in the stomach
• Diagnosis - history, ECG changes and enzyme
  changes
• Acute complications - sudden death, heart
  failure, pericarditis, thromboemboli, heart
  rupture and ventricular aneurysms
• Treatment - coronary angioplasty, streptokinase,
  rehabilitation, reduce risk

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HEART FAILURE

• Congestive heart failure - CO is insufficient for
  the needs of the body, inability to pump
  sufficiently to meet tissue requirements
• Manifestations - tachycardia, cardiac
  enlargement, weakness, fatigue, oedema, wt gain,
  hepatic enlargement, SOB suffocation,
  distension of jugular veins, dysnnoea,
  orthopnoea, pulmonary / peripheral oedema
• PATHOLOGY - homeostatic response (sympathetic NS
  and RA system) compensatory mechanisms
• Consequences of CHF
• right and left-sided consequences

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MEDICATIONS
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CARDIOVASCULAR DRUGS 1 antihypertensive drugs

• Objectives of antihypertensive therapy
• Lifestyle modification
• weight reduction
• sodium restriction
• alcohol restriction
• cease tobacco use
• relaxation / stress therapies
• Pharmacotherapy -
• thiazide diuretics

• ?-blockers - decrease HR, contraction renin
  bradycardia, increased lipids, (bronchoconstrictio
  n)
• ACE inhibitors - suppress formation of
  angiotensin II, vasodilation cough, dysguesia,
  depress renal function
• Ca2antagonists - block Ca channels of the heart,
  dilate arterioles veins modestly odema
  constipation
• ?1-antagonists - vasodilation ortho hypotension,
  syncope, tachycardia, syncope, LOC

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CARDIOVASCULAR DRUGS 2 drugs for angina

• Treatment of angina
• treat pathology
• avoid trigger factors
• implications on diet, weight, smoking exercise
• organic nitrates (vasodilators)
• beta-blockers (decrease HR and force of
  contractions)
• calcium channel blockers (coronary and peripheral
  vasodilators)

• Chest pain from ischaemia of myocardium
• Causes - classic (CAD, atherosclerosis) and
  variant (coronary artery spasm)
• Pathophysiology

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CARDIOVASCULAR DRUGS 2 drugs for heart failure

• vasodilators - decrease peripheral resistance
  against which the heart must pump arteriolar,
  veno-, combined acting vasodilators, diuretic
  (ACE inhibitors)
• diuretics - removal of retained salt water,
  reduce blood volume, diminished venous congestion
  (thiazides loop), rapid relief, K-sparing to
  protect against digitalis-induced arrhythmias
• inotropic agents (digoxin) - increase
  contractility of failing heart (without elevating
  oxygen requirement), reverses all CHF
  manifestations, inhibition of Na-K activated ATP
  pump, increase intracellular calcium increase
  force of contraction, electrical effects,
  aglyconesugars, from foxglove, nursing
  implications