Aging of Cardiac Muscle and Cardiac Failure

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Aging of Cardiac Muscle and Cardiac Failure

• Dr. Franco Navazio

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Aging Heart in the Elderly
In absence of specific disease the heart adjusts
very well to advancing age.
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Myocardium Cardiac muscle syncytium
(multi-nucleated) Endocardium Internal layer of
heart Pericardium External connective tissue
layer of heart Valves openings between cardiac
chambers (atrial ventricular) or between heart
the arteries (aorta and pulmonary) Conduction
system sinoatrial node (SA) is the pacemaker
also atrial ventricular node (AV), Bundle of His,
Purkinje system

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Aging Heart Physiology

• Decline in the VO2 Max with advancing age
• Minor decline in the cardiac output
• Important Variables
• physical conditions
• dietary habits

Conclusions Physically fit elderly people have
a cardiac physiology similar to younger
individuals
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Physiological Changes with Age
Parameter 20 years 60 years
VO2 Max (mL x kg x min) 39 29
Maximum Heart Rate 194 162
Resting Heart Rate 63 62
Max. Cardiac Output (L x min) 22 16
EJECTION FRACTION 70-80 50-55
Resting BP 120/80 130/80
Total Lung Capacity (L) 6.7 6.5
Vital Capacity (L) 5.1 4.4
Residual Lung Volume (L) 1.5 2.0
Body Fat 20.1 22.3
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Cardiovascular Changes with Age

• Hypertension most common treatable
  cardiovascular change in the elderly
• Definition values above 140/190
• In young, if standing BP but in elderly it may
  to 20 mmHg

Systolic mumur 50 of elderly but of very short
duration EXG (or ECG) only nonspecific changes
due to aging in voltage and nonspecific
RBBB Hypotension diminished baro-reflex response
in the elderly. With age, cerebral blood flow
but autoregulation acts in a compensatory
fashion some patients maybe affected by
symptomatic orthostatic hypotension Orthostatic
hypotension drop of 20 mmHg in the systolic and
10 or more in the diastolic BP on standing
upright MEMO as well as the post-prandial
hypotension
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Pathology of the Aging Heart

• Changes due to
• Normal Aging Processes
• Superimposed Processes
• (i.e. endocarditis)
• Residuals of other conditions
• (i.e. hypertension, bicuspid, aortic valve

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Aging Heart

• Size can atrophy, remain unchanged or develop
  moderate hypertrophy. The normal aging heart
  demonstrates a modest in L ventricular wall
  thickness. Possible enlargement of the L atrium
  and L ventricular cavity.
• Cardiac myocytes in size, not numbers (some
  replaced with fibrous tissue). Cardiac myocytes
  effective in reentering the cell cycle
  proliferating, partly offsetting cell loss due to
  necrosis or apoptosis.
• Amyloid deposition half of those 70 years have
  some amyloid deposits in the heart but mostly in
  small amount confined to the atria. Amyloid is
  not present in all elderly persons, not even in
  centenarians.

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Aging Heart

• Vasculature (atherosclerosis)
• Walls of large arteries thicken, vessels become
  dilated and elongated
• Increase intimal thickness (due to cellular and
  matrix deposition)
• Fragmentation of the internal elastic membrane
• Cardiac output (L x min)
• not decreased in healthy older men
• slightly decreased in older women

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Age Associated Changes in Cardiac Function

1. Overall in systolic BP due to arterial
   stiffening in plus wave velocity. Reflects
   resetting of the baro-receptor reflex to a higher
   level in the elderly
2. Myocardial contractility relaxation is prolonged
   in senescent cardiac muscle due the sarcoplasmic
   reticulum seugesters less Ca2
3. Ejection Fraction (EF) no change in resting EF
4. Heart Rate (HR) supine HR does not change, in
   sitting and standing positions from 10 to 25.

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Aerobic Capacity Cardiovascular Function During
Exercise in the Elderly

• With age, peak exercise capacity peak oxygen
  consumption slightly but inter-individual
  variation is substantial
• Aerobic capacity 50 between 20 years to 80
  years
• Maximal Cardiac Output (CO) 25
• Peripheral O2 utilization 25 (due to in
  muscle mass strength)
• Although the stroke volume in older persons is
  maintained, age apparently blunts the
  Frank-Starling mechanism

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Heart Failure Cardiac Output (CO) insufficient
to meet physiologic demands

• In the elderly, heart failure due to
• Mostly systemic arterial hypertension
• Coronary artery valvular diseases (due to
  impaired cardiac filling chronic volume
  overload)
• Combined right left cardiac failure most
  common, but isolated occurrence of left or right
  also probable

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Heart Failure in the Elderly

• Symptoms dyspnea, orthopnea, fatigue on exertion
  and dependent edema
• Severity classified according to the NY Heart
  Association Scale

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The CardiomyopathiesMyocardial disorders
without a known underlying cause BUT where
other heart diseases may coexistDilated
CardiomyopathyHyperthrophic CardiomyopathyRestri
ctive Cardiomyopathy
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Dilated Cardiomyopathy
Normal Heart



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Hypertrophic Cardiomyopathy
Normal Heart



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Restrictive Cardiomyopathy The classic example
is the senile cardiac amyloidosis of the elderly,
especially over 95 years old.
Normal Heart



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Cardiomyopathy Any heart muscle disorder not
caused by coronary artery disease, hypertension
or congenital valvular or pericardial diseases.

• Prevalence of heart failure
• 25-54 yrs 1
• 55-65 yrs 3
• 65-74 yrs 4.5
• 75 yrs 10

• gt 75 of patients with heart failure 60 years
  of age
• Primary reason is Coronary Heart Disease (CHD)
• Secondary reason is Hypertension
• Third reason is cardiomyopathy

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Sudden Death

• In young athletes (also in middle aged men),
  SUDDEN DEATH can occur in patients with
  congenital hypertrophic cardiomyopathy
• Usually due to severe arrythmia (ventricular
  fibrillation)
• If diagnosis is made a cardiac defibrillator
  should be implanted.
• The SUDDEN DEATH of runners are usually limited
  to 1 case per 15,000 runners per year-- hence,
  very rare.
• MEMO There is still the possibility of
  ANAPHYLACTIC SHOCK in runners or walkers, if
  stung by a bee.

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Syncope in Elderly

• Definition temporary suspension of conciousness
  due to cerebral ischemia
• Causes
• Orthostatic Hypotension
• Vaso-Vagal Reflex (?)
• Arrhythmias (brady- tachyarrhythmias)
• Drugs
• Antihypertensives (vasodilators/diuretics)
• Cardiac drugs beta-blockers, digitalis, anti-
  arrhythmias, Ca2 channel blockers, nitrates.
• Recreational alcohol, marijuana and cocaine.
• Psychiatric Antidepressants and phenothiazines

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Contributory Causes to Heart Failure in the
Elderly

• Hypertension (poor elasticity of arterial system)
• Alcohol, but only if in excess
• Viral infections
• Autoimmunity
• Heredity (specially for the cardiomyopathies)
• Senile amyloid
• Diabetes (due to the microvascular disease)
• Arrhythmias and especially the TACHYCARDIAS

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Conduction System in Aged Heart

• Sinoatrial Node Increased fibrous tissue
  seldom origin for arrythmias
• Atrio-Ventricular Node Slight increase in
  collagen fibers
• Bundle of His Increased fibrous tissue with
  higher frequency of First or Second degree heart
  block (the mobitz)
• Also the possibility of L or R BBB (Bundle
  Branch Block) -this is seldom a complete heart
  block.
• In the conduction system fibrosis occurs 40
• Coronary Artery Disease 20
• Calcification 10

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Normal ECG
Ventricular Fibrillation
Atrial Fibrillation
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Aortic StenosisNarrowing of the aortic orifice
of the heart or of the aorta itself

• A common condition due to
• Fatty alteration of collagen
• Calcification
• Rigidity and various degrees of aortic stenosis
• Amyloid infiltration of the valves

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Age Specific Lesion The Valves

• Fibrous thickening at sites of closure
• Valvular sclerosis caused by collagen and elastic
  tissue, this is a true wear and tear phenomenon
• Calcification of the mitral ring where fatty
  degeneration invites deposition of calcium
• Calcifications is detected in 17 to 45 of
  patients over 90 years of age
• Complications include heart blocks, infections,
  embolic