PHTY208 Lecture Notes - Lecture 9: Blunt Trauma, Shortness Of Breath, Asystole
Disorders of cardiac conduction and rhythm:
Lecture overview:
-Cardiac diagnostic techniques
-Cardiac conduction system
-Disorders of cardiac rhythm and conduction
-Some types of arrhythmias
Introduction:
-The heart is a muscle that can spontaneously generate action potentials
-Usually, doctors can tell whether a person has a heart or blood vessel disorder on the basis of
the medical history and the physical examination
-Diagnostic procedures are used to confirm diagnosis
Concept 1: Diagnostic techniques:
Bedside:
-History- obtaining a medical history is always the first “test”
-Heart problems often produce no symptoms until very advanced
-Such as palpitations and sensations of extra or missing heart beats correlate poorly with
relative heart health vs disease
-Auscultation- employs a stethoscope to more easily hear various normal and abnormal sounds
Laboratory:
-Blood tests
-Blood obtained by venipuncture
-Determine the presence of damage to the myocardial
-Tests include
-Lipid levels
-Homocysteine
-C-reative protein
-Blood sugar control
-Myoglobin
-Creatie kinase
-Troponin
-Brain-type natriuretic peptide
ECG/EKG:
-a 12 lead recording, recording the electrical activity in three planes
-The ECG allows observation of the heart electrical activity by visualising waveform
-Observing the PQRST morphology
-Rhythm abnormalities can also be visualised a sin slow heart rate bradycardia, or fast heart rate
tachycardia
-The procedure is totally harmless, painless and inexpensive
Holter monitoring:
Small, portable monitoring device
-Continuous ECG is recorded on a magnetic tape recording while the patient conducts normal
daily living
-Used for suspected frequent rhythm abnormalities, especially ones the wearer may not
recognise by symptoms
-They are more expensive than event monitors
Event monitor:
-Similar to the hotter monitor in that it also records the electrical active city of the heart while
patient goes about usual daily activities
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-Can be used for a longer period of time than a Holter monitor
-Usually a month
-There are several different types with different capabilities
-When the wearer presses a button records for a short additional period
Chest X-ray:
-A CXR involves radiation tot he body though the level is just minimal
-A pregnant woman needs special precaution and shielding of the foetus
-The CXR gives us information about
-It is a routine cardiac investigation procedure with very low radiation exposure
Echocardiography:
-Diagnostic procedure for studying the structure and motion of the heart
-Useful in evaluating structural and functional changes in a variety of heart disorders
-Excellent spatial resolution
-Useful in the diagnosis and grading of the severity of:
-Valular and congenital heart diseases
-Endocarditis
-Heart chamber movement and hypokinesia
-Pericardial effusion
-Cardiac tumours
-Trans-oesophageal
-Ultrasound probe into the oesophagus
-The patient will need to be under light sedation
-Better image of the heart as the ultrasound beam do not need to pass through the skin, fat
and lung heart
-Particularly useful for the imaging valves of the heart, aorta and septal defects
-Intravascular ultrasound
-Catheters attached to computerised ultrasound visualise the lumen and the interior all of
blood vessels
Exercise stress testing:
-The speed and slope of the treadmill will increase gradually in stepwise fashion in order to test
the function of the heart
-Monitoring with ECG, blood pressure and heart rate
-Useful for the diagnosis of:
-coronary artery disease, post myocardial infarction risk stratification and exercise induced
arrhythmia
-Radionuclide can be used to demonstrate areas of perfusion abnormalities
-Maximal stress test
-Level of exercise is increased until the patient heart rate will not increase any higher, despite
increased exercise
Cardiac catheterisation:
-Diagnostic procedure in which a catheter is introduced into a larger vein or artery and to the
heart
-Used to obtain:
-information about the structure and function of the heart chambers, valves and the great
vessels
-Pressure gradients
-Angiography
-X-ray visualisation of internal anatomy of heart and blood vessels after introducing a
radiopaque substance (contrast medium)
-Promotes imaging of internal structures that are otherwise difficult to see on X-ray film
-Substance is injected into an artery or a vein
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Document Summary
The heart is a muscle that can spontaneously generate action potentials. Usually, doctors can tell whether a person has a heart or blood vessel disorder on the basis of the medical history and the physical examination. Diagnostic procedures are used to con rm diagnosis. History- obtaining a medical history is always the rst test . Heart problems often produce no symptoms until very advanced. Such as palpitations and sensations of extra or missing heart beats correlate poorly with relative heart health vs disease. Auscultation- employs a stethoscope to more easily hear various normal and abnormal sounds. Determine the presence of damage to the myocardial. A 12 lead recording, recording the electrical activity in three planes. The ecg allows observation of the heart electrical activity by visualising waveform. Rhythm abnormalities can also be visualised a sin slow heart rate bradycardia, or fast heart rate tachycardia. The procedure is totally harmless, painless and inexpensive.
