The normal beating
of the heart is maintained by another complex system generally called "conduction pathways". There are portions of the heart
that act as small electrical circuits, producing electrical discharges that will eventually lead to contraction of heart muscle.
can affect the conduction pathways and generally produces two main types of abnormal beating of the heart (the so called "arrhythmia"),
either causing the heart to beat too fast (tachycardia) or too slow (bradycardia). Fast heart beat can cause palpitations
or fluttering sensation in the chest. Slow heart beat may cause giddiness or black-outs.
Some diseases of the heart started prior to birth. Development of the heart and vascular
system is a complex process and there are many possible disruptions which will lead to abnormal structure and function of
For example, heart chambers are separated by wall (called 'septum' in medical terminology). If the wall
was not properly formed, a hole will result. This will affect blood flow within the heart. This is the basis for "hole-in
the heart" diseases such as atrial septal defect and ventricular septal defect.
Coronary arteries supply the heart muscle with oxygen and nutrients for its contraction.
Deposition of cholesterol into the wall of these blood vessels will hinder blood flow. In the extreme situation, total blockage
can occur, leading to "acute myocardial infarction" or "heart attack".
Patients with coronary artery disease may present
with chest pain (angina) or shortness of breath, usually occurring during exertion.
The main action of the heart is to pump blood to the rest of the body. To do this work,
the heart has to be strong. Any disease that causes weakness to the heart muscle will lead to heart failure. The weak heart
is now unable to pump the required amount of blood to the rest of the body. Heart failure is a common terminal event for many
of the mentioned heart diseases, especially coronary artery disease.
Someone with heart failure initially complains
of shortness of breath on exertion. Later on, breathing difficulties may be encountered during sleep. In later stages, generalised
swelling may be a problem.
Valvular Heart Disease
a one-way flow of blood across heart chambers. There are four valves in the human heart. A diseased valve can become leaky
or narrowed. This malfunction will eventually lead to heart failure.
Patients with valvular heart disease can be completely
healthy in the early stages. A murmur (additional, abnormal rumbling sound in the heart) may sometimes be detected during
routine medical examination.
In more severe stage, usual complaints are shortness of breath and forceful beating of
CXR is taken to allow your doctor to see certain structures within the chest. Shape and size of the heart could be assessed
by CXR. CXR is a safe procedure involving minimal radiation exposure. It is produced with an X-ray machine, much like taking
Among the conditions that can be detected on CXR are:
Enlargement of heart shadow (heart failure)
Presence of fluids in the lungs
Disease of the coronary arteries is one of the commonest heart diseases.
These small structures running on the surface of the heart could not be seen by normal X-ray. To study the network of coronary
arteries, a tube need to be passed through the aorta and into the origin of these arteries. The tube (or "cathether") is passed
up through the groin into the leg artery and threaded up to the coronary arteries. Once in place, "contrast material" is then
injected to fill up the coronary vessel, producing a picture of the coronary artery (called "angiogram").
an angiogram, the severity of narrowing or blockages could be assessed and definitive treatment could then be given.
An ECG records electrical activity occurring in the
heart. Normal contraction of heart muscle is achieved by coordinated conduction of electrical impulses. ECG is recorded by
"electrodes" placed on the chest, arms and legs.
By examining the ECG, your doctor can detect; disturbances of heart
rhythm coronary artery disease enlargement of chambers.
using ultrasound waves, information can be gathered from the heart. With sophisticated computer technology, the information
derived are used to generate a two-dimensional image of the heart (with even more computing power, even a 3-dimensional reconstruction
is possible). By scanning different parts of the heart, your doctor can determine the anatomy and structure of the live beating
Information is gathered using a probe called a "transducer". The transducer emits and receives ultrasonic waves.
The computer analyses the data and displays the image on the monitor. Sophisticated measurement and analysis can be performed
on these data.
Among some of the information that can be gathered include:
Leaky or narrowed valves
Hole in the heart
Fluid around the heart
When abnormal rhythm of the heart is suspected, your doctor may request for a continuous
24 hour monitoring of your heart rate. Proper treatment of heart beat abnormalities ("arrhythmias") will require exact diagnosis.
Heart beat abnormalities are usually transient event and hence are not captured during normal ECG test, which lasted for a
By using electrodes, much like ordinary ECG (with lesser number), each heart beat is recorded electronically.
The recorder is usually small (about the size of a Walkman) and worn around the waist with a belt. Patients are instructed
to undertake normal activities and the recorder is left in place for 24 hours.
The recorded signals are then retrieved
from the recorder and the data analysed by computer reconstruction.
By doing Holter monitoring, your doctor can detect
abnormal heart beat formation, which are usually of two common varieties:
tachyarrhythmias (fast heart beat)
bradycardias (slow heart beat)
your doctor needs to assess the functioning capacity of your heart muscle. Heart muscle cells receive its oxygen and nutrients
through coronary arteries. If blood supply to a particular area is impaired, less blood supply will be delivered to the area.
By utilising radioisotopes (Technetium of Thallium, usually), this area of insufficient blood supply can be mapped out.
person undergoing the scan will first have to undergo a form of stress test by either an exercise treadmill or given a medication
to simulate stress. Technetium or thallium will be injected during the stress test. Following this a scan of the heart will
be acquired by a gamma camera which normally takes up between 12-20 min. A resting scan is taken about 4 hours after the first
scan requiring a second injection of radioisotope.
Thus two images will be obtained comparing the stress and rest scans
to determine if the flow down the coronary arteries is adequate. The test is particularly useful in diagnosing coronary heart
disease in situations where interpretation of the stress ECG test is difficult or for those who cannot undergo an exercise
stress test due to physical constraints.
The heart muscle needs blood supply (containing oxygen and nutrients) to function normally.
Blood is supplied to the muscle via blood vessels running on its surface, called coronary arteries.
If these arteries
are narrowed (usually by atherosclerosis), blood supply to heart muscle will be reduced during period of physical exertion.
The "starving" heart muscle will give rise to chest pain and changes will occur to the ECG tracing. Physical exertion is usually
achieved by use of a treadmill.
A resting ECG tracing can be completely normal at rest in a patient with coronary artery
disease as the demand for blood at rest is not that great. By utilising stress test, demand is increased and a narrowed blood
vessel will not be able to supply the required blood, leading to changes on the ECG.
A stress test is usually performed
in the following situations:
Investigation of chest pain
Following a heart attack
Following balloon angioplasty or surgery
Routine screening in healthy individual
BALLOON ANGIOPLASTY (PTCA)
In coronary artery disease, the artery is narrowed due to deposition
of cholesterol in its wall. By using small balloons, these areas of narrowing can usually be opened in up to 80-85% of patients.
The procedure is usually performed through an artery at the wrist or the groin. The balloon is used to open up the narrowing
and will be removed after that.
angioplasty, sometimes the vessel wall can collapse and cause obstruction to blood flow. A wire mesh could be inserted into
the artery and following balloon dilatation, will scaffold the wall of the artery. It is also used where the results from
balloon angioplasty alone is adequate.
CORONARY ARTERY BYPASS SURGERY
angioplasty is not feasible sometimes either because of too many narrowings or blockages or the unfavourable location of the
narrowing. An open heart surgery will then be required. The surgeon will connect "new" blood vessels to bypass the blockages,
this usually is taken from the legs.
Source : Insititut Jantung