How does the blood usually flow through the heart?
From right atrium to right ventricle via a tricuspid valve
From the right ventricle to the pulmonary arteries via the semilunar valve
From the pulmonary veins to the left atrium (there are 4)
from the left atrium to the left ventricle via the bicuspid valve
From the left ventricle to the aorta via the smilunar valve
What are the two components of blood pressure?
What is diastole pressure?
relaxation of the ventricle where the ventricle fills.
The aorta is closed
What is systole pressure?
The contraction of the ventricle.
The ejection of blood out of the ventricle
systole pressure reflects stroke volume, rates and force, elasticity of aorta and large arteries.
How to you work out blood pressure?
BP= CO x PR (peripheral resistance)
The following involves the cardiac cycle and BP
What are congentital heart defects?
Cardiac anomalies which are structural defects that develop in the first eight weeks of embryonic life
What are some congenital heart diseases?
1. Valvular defects- interfere with normal blood flow
2. Septal defects- allowing mixing of oxygenated blood from pulmonary circulation with unoxygenated blood fom the systemic circulation
3. Shunts- may be cyanotic or acyanotic depending on direction of shunt
Or a combination of these
What is cyanotic and acyanotic?
Cyanotic not enough oxygen person goes blue
Acyanotic- heaps of oxygen they are pinky colour
Examples ofcongenital heart defects
Note fluid always flows from and area of high pressure to low pressure
What is the etiology of congential heart defects?
Genetic influences- chromosomal abnormalities eg down syndrome
Environmental influences- viral infection such as rubella, maternal alcoholism and diabetes
What are the signs and symptoms of congenital heart defects?
Large defects lead to:
- pallor and cyanosis
- dyspnea on exertion
- squatting position in toddlers and older children
- clubbed fingers
- intolerance for exercise and cold weather
- delayed growth and development
How do you diagnosis congential defects?
Severe defects are often diagnosed at birth (untreated = heart failure)
1. Auscultation- stethoscpoe
2. Diagnostic imaging
3. Echocardiogram (3D)
4. Electrocardiogram (ECG)
5. Cardiac catherisation
How do you treat congenital heart defects?
What is VSD? (Ventricular Septal Defect)
THe most common congenital heart defect- 20-30% "hole in the heart.
Opening in the interventricular septum- vary in size and location. Atrial septum- foramen ovale fails to close
Large openings permit a left to right shunt of blood then may eventually, if untreated, lead to a reveral of the shunt- right to left.
Note in VSD left to right. Blood flows from a high pressue to low pressure. Blood flows from the left ventricle to the right then to the lungs.
What is the result of VSD?
Decreased SV and CO
increase in oxygenated blood entering pulmonary circuit
overloads and irreversibly damages the pulmonary blood vessels = pulmonary hypertension
Acyanotic condition results
What hapens if VSD is untreated. RIGHT TO LEFT SHUNT
Abnormally high pressure in the right ventricle, from conditions such as pulmonary hypertension, leads to a reversal of the shunt. Right to left.
Leading to cyanosis- venous blood mixes with arterial blood resulting in unoygenated hb back into the systemic system
results in a bluish lips and nails etc
What happens to the heart when it is suffering from VSD?
increase force of contraction CO
decrease in coronary perfusion
increase peripheral resistance
increase in respiatory reate
Chronically- increase in RBC production as a result of hypoxia
What are some valvular defects?
- Stenosis- narrowing of the valve, restricts the forward flow of blood
- valvular incompetence- failue of a valve to close completely, flaps back, blood regurgitates or leaks backwards eg mitral valve prolapse, abnormal enlarged, floppy valve leaflets that ballon backwards effect 1-3% pop
Heart valve defects
What are the compensatory effects of VD?
decrease in efficiency of the heart pump
decrease in stroke volume
increase contractility of myocardium
hypertrophy of the chamber with the faulty valve
with lead to heartfailure and pulmonary congestion
What is the main cause of congestive heart failure (CHF)?
What is the main treatment of valve defects?
Surgical replacement- mechanical, animal
What is tetalogy of Fallot?
Most common cyanotic (R to L shunt) congenital heart condition
alt pressure within heart and alt blood flow
includes four abnormalities:
- pulmonary valve stenosis
- Dextropositio of the aorta
- right ventricular hypertrophy
Congenital heart defects:
What is the pathophysiological cascade?
Pulmonary valve stenosis- restricts flow to lungs
increase right ventricle pressure and right ventricle hypertrophies
increase pressure R to L
Unoxygenated lood R to L ventricular flow
Pulmonary circulation decrease of unoxygenated blood
What are some ventricular conduction abnormalities?
Bundle branch block
Premature ventricular contractions (PVCs)
What is a bundle branch block?
Interference with conduction in one of the bundle branches. wide QRS, cardiac output is unchanged
What is ventricular tachycardia?
Likely to reduce cardiac output as reduced diastoe occurs
decrease filling time and force of contraction
What is ventricular fibrillation?
muscle fibres contract independently and rapidly
uncoordinated quivering/ ineffective pump
cardiac standstill occurs if not treated immediately
What is premature ventricular contractions? (PVCs)
additional beats from ventricular muscle cells or ectopic pacemaker. May lead to venticular fibrillartion- cardiac arrest
What is the treatment of cardiac dysrhythmias?
Cause needs to be determined and treated:
defective conductive system
electrolyte abnormalities- K and Na
Anti dysrythmic drugs are effective in many cases:iebeta blokers- metoprol,atenolo
calcium channel blockers- verapamil
When is a pacemaker necessary?
SA node problems or a total heart block
defibrillator may be needed to be used/ implanted for conservation of ventricular fibrillation, back to sinus rhythm
What is cardiac arrest? (asystole)
Cessation of heart activity- no conduction of impulses- no cardiac output
FlatECG (O2 deprivation to brain and heart)- loss of consciousness, no respiration- no pulse
What causes cardiac arrest?
Excessive vagal nerve stimulation
blow to heart
what is congestive heart failure?
heart is unable to pump outsufficient blood to meet metabolic demands of the body.
What are the two main effets of congestive heart failure?
What are forward effects ofcongestive heart failure?
Cardiac output/ stroke volume decreases:
- less blood reaches the various organs iekidney
- decreased cell function
- fatigue and lethargy
- mild acidosis develops
WHat are backup effects of congestive heart failure?
backup/ congestion develops
output from ventricle isless than the inflow of blood
congestion in venous circulation draining into the affeced side of the heart.
Notes on congestive heart failure:
usually a complication of another cardio-pulmonary condition
may present as an acute episode, but is usually chronic
Various compesation mechanisms maintain ccardiac output-often some aggravate the condition
What is the etiology of CHF?
from a problem in the heart- infarction, congenital heart defect, valve changes
may be a result of an increase in demand on the heart- hypertension, pulmonary disease, leading to either left orright sided heart failure
coronary artery disease is the leading cause of CHF
1. thichekendleft ventricle wall
2 thickened right ventricle wall
Overview of CHF
to be broken down
what are some of the compensatory mechanisms for those with CHF?
What are some compensatory mechanisms for CHF?
Sympathetic nervous system activity:mainttains perfusion of various body organs, increases in HR and contractility and regulation of vascular tone, increase in peripheral resistance and vasoconstriciton.
But the increase in HR- decreases the efficiency causing increases in workload. Ventricle wall stress- dilation= hypertrophy can = ischemia
decrease CO = reduced renal blod which increases renin- angio which increases aldosteron secretion that increases vasoconstricition and sodium and water retention therefore increases blood volume.
But vasoconstricition increases afterload and increases blood volume increases preload = hard work for heart.
What are the effects of CHF on the left ventricle?
Hypertension/ aortic valve stenosis and LV infarction
Back upof blood into pulmonary vein, high pressure of blood in lungs, decreased CO, left V weak can cant empty, decrease in renal blood flow.
What are the effects of CHF on right ventricle?
Pulmonary disease/ valve stenosis RV infarction:
right ventricle weak and cant empty
dereased renal flow
increase in venous pressure can cause eema in legs etc
backup of blood into systemic circulation
very high venous pressure causes distended neck vein and cerebral edema.
What are the signs and symptoms of CHF forward effects?
similar with failure on either side:
decrease blood supply to tissues, general hypoxia
Fatigue and weakness
Dyspnes and shortness of breath
What are the compenstion mechanisms for those with CHF forward effects?
cutaneous and visceral vasoconstriction
Daytime oliguria (low output of urine)
What are the signs and symptons of CHF, backup effects of left side?
Are related to pulmonary congestion
dyspnea and orthopnea- develops as fluid accumulates in the lungs
cough-fluid irriating the respiratory
Paroxysmal nocturnal dyspnea- indicates the presence of acute pulmonary edema, usually develops during sleep, hemoptysis and rales
excessive fluid in lungs lead to infection
What are the signs and symptons of CHF back up effects of right sided failure?
are related to systemic congestions
dependent edema in feet, leg or but, increase pressure in jugular veins
Hepatomegaly and splenomegaly0 digestive disturbances
Ascites- complcation when fluid accumulates in the peritoneal cavity- abdominal distention