Manifestation of Novel Social Challenges of the European Unionin the Teaching Material ofMedical Biotechnology Master’s Programmesat the University of Pécs and at the University of DebrecenIdentification number: TÁMOP-4.1.2-08/1/A-2009-0011

CHARACTERISTICS OF THE CARDIOVASCULAR SYSTEM, ABNORMALITIES AND DISEASES PART 2

Miklós Székely and Márta BalaskóMolecular and Clinical Basics of Gerontology – Lecture 9

Manifestation of Novel Social Challenges of the European Unionin the Teaching Material ofMedical Biotechnology Master’s Programmesat the University of Pécs and at the University of DebrecenIdentification number: TÁMOP-4.1.2-08/1/A-2009-0011

TÁMOP-4.1.2-08/1/A-2009-0011

Left ventricular volume (ml)ventricular filling

isovolumic contraction

ejection

isovolumic relaxation

systolic pressure

ventricular diastolic pressure

Volume-pressure diagrams 1

0 50 100

150

200 250

Vent

ricul

ar p

ress

ure

(mm

Hg)

0

50

100

150

200

250

SV

Young

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Left ventricular volume (ml)

Volume-pressure diagrams 2

0 50 100

150

200 250

Vent

ricul

ar p

ress

ure

(mm

Hg)

0

50

100

150

200

250

1st case

systolic pressure

ventricular diastolic pressure

SV

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Left ventricular volume (ml)

ventricular diastolic pressure

Volume-pressure diagrams 3

0 50 100

150

200 250

Vent

ricul

ar p

ress

ure

(mm

Hg)

0

50

100

150

200

250

2nd case

systolic pressure

SV

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Left ventricular volume (ml)

systolic pressure

ventricular diastolic pressure

Volume-pressure diagrams 4

0 50 100

150

200 250

Vent

ricul

ar p

ress

ure

(mm

Hg)

0

50

100

150

200

250

3rd case

SV

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Left ventricular volume (ml)

systolic pressure

ventricular diastolic pressure

Volume-pressure diagrams 5

0 50 100

150

200 250

Vent

ricul

ar p

ress

ure

(mm

Hg)

0

50

100

150

200

250

4th case

SV

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Exercise in the elderly• There is a higher sympathetic tone even

at rest• Diminished contractility• Tachycardia develops sooner and

easier, but its maximum is limited• EDV increases quickly, but here the EDp

also increases significantly• TPR is higher and grows (both the syst.

and diast. pressures increase quickly)• Stagnation develops quite early

(dyspnoe)

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Maximal heart rate vs. age

Heart rate (bpm)

Trained

Non-trained Mean

Age (years)

200

190

180

170

160

150

14020 30 40 50 60 70

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• Impaired coronary perfusion have only a small influence on myocardial function in healthy old people (of course, severe atherosclerosis does have!)

• Ejection fraction of healthy old women and men does not decrease at rest (when the end systolic and end diastolic volumes are comparable to those in young people)

• Stroke volume: SV × heart rate – does not change with age, even in case of a slight (still physiological) increase in the systolic pressure. (The stroke volume would rather increase a little.)

• Heart rate: resting heart rate (horizontal position) in healthy men is not age-dependent. The respiration-induced changes in heart rate decrease though. The increase of the heart-rate is age-dependent: 220-age (The elderly responds to the same stress with smaller increase in heart rate -120-130 frequency is already submaximal tachycardia)

• Intrinsic sinus rhythm (by symp. and parasymp. blockade)-significantly decreased with age: at 20-y it is104/min, at 45-55-y 92/min

Age-related alterations in major cardiac parameters

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4-5

Tim

e (m

inut

es)

Endurance times according to age

Maximal oxygen consumption and endurance times according to age

male

female

Maximal oxygen consumption vs. age

VO2

max

(l/m

in)

6-7 8-910-1214-1516-18 25 35 45 55 65

56789

10111213

0 10 20 30 40 50 60 70Age (years) Age (years)

1.0

2.0

3.0

4.0

0.0

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Atherosclerosis• One of the most significant diseases of

the elderly• Clinical picture includes: pectoral

angina, AMI, TIA, stroke, dementia, arteriosclerosis obliterans

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Risk factors of atherosclerosis 1

Intrinsic risk factors• Age: male 45, female above 55 years• Gender: estrogen provides some

protection (TG, lower LDL cholesterol, higher HDL), after menopausa the protection diappears: by the age of 60 the risks of the females exceed the risks of the male

• Genetic factors: familial appearance, inherited disorders of the lipid metabolism

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Risk factors of atherosclerosis 2Extrinsic risk factors• Smoking (a pack a day increases the

risk 2×)• Hypertension• Dyslipoproteinemia• Hyperglycemia, diabetes mellitus• Obesity• Homocystinuria• Hyperuricemia

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Regulation• The sensitivity of the baroreceptor reflex decreases

(hypertension or orthostatic hypotension)• The serum levels of the catecholamines increase

(increased release, diminished elimination)• The efficacy of the sympathetic tone decreases• The carotids are more rigid (cardiovagal reflex

decreases)• Vestibulosympathic reflex efficacy also decreases

(adaptation to gravitational forces) – orthostatic hypotension (upon standing up a blood pressure fall greater than 20 mmHg)

• The venes are more rigid – decreased CVP (decreased venous stagnation)

• The activity of the plasma renin decreases

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Pectoral angina

• Above 70 years the prevalence of coronary heart disease reaches 70%

• The prevalence of “silent ischemia” increases, especially in females and in diabetics (autonomic neuropathy)

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Arrhythmias• Atrial fibrillation – with heart failure• AV-nodal re-entry tachycardia• Multifocal ventricular premature beats

(polymorphic)

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Hypertension 1• Age-related hypertension is mostly isolated

systolic hypertension (18-24 years 2.6%, above 75 70.3%, 50% undetected, above 80 the BP decreases)

• Due to the loss of elasticity in the aorta the pulse wave returns too early, disturbing the systole and increasing the systolic blood pressure too much

• The pulse-pressure increases, the diastolic pressure decreases.

• This increased pulse-amplitude is one of the main cardiovascular risk factors in the elderly

TÁMOP-4.1.2-08/1/A-2009-0011Mean aortic pressure andaortic pulse wave velocity vs. age

100

95

90

85

80

20 40 60 80Age (years)

Mea

n ao

rtic

pres

sure

(mm

Hg) ▲

, ∆

105

110

800

600

1,000

1,200

UrbanRural

Aorti

c pu

lse w

ave

velo

city

(cm

/sec

) ●, ○

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Hypertension 2• With age not only the amount of collagen increases

but also the rigidity of the collagen – progressive fibrosis

• The vascular diameter decreases relative to the vessel wall + endothelial damage decreases the vasodilatory activity

• RAAS activity decreases (decreased sympathetic tone, decreased responsiveness).

• Plasma norepinephrine increases, but the β-receptor responsiveness and sensitivity is down

• There is, on average, a 1% annual decrease in the cardiac output.

• The proportional increase in total peripheral resistance counteracts this decrease, but the adaptation capacity is impaired.

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Hypertension 3• Age-related hypertension is salt-sensitive –

the nephron number decreases from the original 800,000 to 400,000 by the age of 80. The salt excretion is also decreased.

• This is explained partly through the decreased glomerular function, partly by a decreased production of natriuretic substances (PGE2, bradykinin)

• The impaired activity of the Na-K ATP-ase pump may contribute to hypertension – IC Na – Na+/Ca++ exchange – higher IC Ca – higher vascular tone

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Hypotension• Decreased baroreceptor reflex + more rigid

carotid leads to a tendency for orthostatic hypotension and an excessive HR increase upon standing up

• The BP of the elderly must be measured when sitting and after standing up (BP fall > 20 mmHg)

• Tendency to develop hypovolemia (decreased thirst, lower ECV, decreased responsiveness of regulatory hormones) may promote hypotension and increase mortality

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Hypertension and therapy• Decreased filtration surface (decreased endogenous

creatinine clearance) Na retention and the need to apply thiazide diuretics.

• The renal and hepatic clearance of drugs decrease – drug doses have to be adjusted

• The side effects are less tolerated by the elderly – therapeutic compliance is decreased (ACE inhibitors – 30% cough, Ca-channel blockers – 25% swelling of the legs, combined – dizziness)

TherapyACE inhibitors (Angiotensin II type 1 receptor blockers) and channel blockers (in the elderly appropriate therapy may increase the well-being of the patient more effectively)ACE inhibitors and β-blockers (-25% new DM)General outcome: -19 – -26% stroke, -25% coronary

incident