Cardiac anomalies 2014

Common Cardiovascular Anomalies and
Diseases
Heart Attack:
This is a vascular disease of the heart characterized by inadequate blood supply to heart muscle leading to their damage and ultimate death. Heart Block:
This is a nervous disease of the heart in which the ventricles contract independent of the SA node. In this condition the heart usual y beats at a slower rate most of the time.
Myocardial Infarction (MI):
• This is a vascular disease of the heart
characterized by necrotic myocardial
c h a n g e s f o l l o w i n g i n a d e q u a t e o r
interrupted blood flow to the myocardium.
• It is most commonly caused by coronary
i n s u f f i c i e n c y r e s u l t i n g f r o m
atherosclerosis of the coronary arteries.
• Myocardial infarction could be slowly
progressive or acute (sudden) in nature.
• The necrotic myocardial tissue is usually
replaced by fibrous tissue scar.
Angina Pectoris:
This is severe constricting pain or feeling of
tightness in the chest. It is usually caused by
arterial constriction due to:
1. Stress
2. Strenuous exercise after a heavy meal
3. Sudden exposure to a cold environment
Angina pain is normally relieved by a few
minutes of rest after it occurred
It is also relieved by the administration of a
vasodilator e.g. Sublingual Nitroglycerin which
relaxes the coronary arteries.
Angina pain is often less severe than the pain of
myocardial infarction which is also not relieved
Cardiac Functions and Ions
• Low Potassium and Calcium in blood
depresses the heart while
• Excess of calcium could lead to sustained
cardiac muscle contraction resulting in
death (Death by lethal injection)
SOME CARDIAC PARAMETERS
• Heart rate (HR):
• Female - 72-80/min
• Male – 64-72/min
• Average – 75/min
• Fetal heart rate = 140-160
• Abnormal Heart rate
• Tachycardia = over 100/min
• Bradycardia = below 60/min
• Stroke Volume (SV) – 70ml (Same for right and
left ventricles)
• Cardiac output – HR x SV =70 x 75 = 5252ml =
approximately 5 litres.
• Systemic BP
120/80 mmHg
• Pulmonary BP
25/8 mmHg
• End-Diastolic-Volume
• End-Systolic-Volume
• Therefore, Stroke volume = EDV-ESV=
120-50=70ml
• Venous return is increased by:
1.Slow heart rate
2.Exercise
• Venous return increases EDV
• Afterload = Back pressure exerted by
Arterial Blood. It is the pressure the
ventricles must overcome before they
could eject blood.
• It is equal to the diastolic pressure (80 or 8
mmHg) and impedes the ability of the
ventricles to release blood.
• High afterload leads to high ESV but
reduced SV

Source: http://flat18.co.uk/uni/bio276/CARDIAC%20ANOMALIES%202014.pdf