DIAGNOSTIC PROCEDURESCARDIOVASCULAR SYSTEMA presentation by Rowell Angeles

CARDIAC CATHETERIZATION Cardiac catheterization

(also called cardiac cath or coronary angiogram) is a procedure that allows your doctor to "see" how well your heart is functioning. The test involves inserting a long, narrow tube, called a catheter, into a blood vessel in your arm or leg, and guiding it to your heart with the aid of a special X-ray machine. Contrast dye is injected through the catheter so that X-ray movies of your valves, coronary arteries and heart chambers can be created.

PURPOSE OF CARDIAC CATHETER Evaluate or confirm the presence of heart disease

(such as coronary artery disease, heart valve disease or disease of the aorta).

Evaluate heart muscle function. Determine the need for further treatment (for

example, angioplasty or bypass surgery ) At many medical centers, cardiac catheterization is

used to perform several interventional, or therapeutic, procedures to open blocked

PROCEDURE FOR CARDIAC CATHETERIZATION

Local anaesthetic is injected into the skin to numb the area. A small puncture is then made with a needle in either the femoral artery in the groin or the radial artery in the wrist, before a guidewire is inserted into the arterial puncture. A plastic sheath (with a stiffer plastic introducer inside it) is then threaded over the wire and pushed into the artery (Seldinger technique). The wire is then removed and the side-port of the sheath is aspirated to ensure arterial blood flows back. It is then flushed with saline.

Catheters are inserted using a long guidwire and moved towards the heart. Once in position above the aortic valve the guidewire is then removed. The catheter is then engaged with the origin of the coronary artery (either left main stem or right coronary artery) and x-ray opaque iodine-based dye is injected to make the coronary vessels show up on the x-ray fluoroscopy image.

PROCEDURE FOR CARDIAC CATHETERIZATION

When the necessary procedures are complete, the catheter is removed. Firm pressure is applied to the site to prevent bleeding. This may be done by hand or with a mechanical device. Other closure techniques include an internal suture and plug. If the femoral artery was used, the patient will probably be asked to lie flat for several hours to prevent bleeding or the development of a hematoma. Cardiac interventions such as the insertion of a stent prolong both the procedure itself as well as the post-catheterization time spent in allowing the wound to clot.

A cardiac catheterization is a general term for a group of procedures that are performed using this method, such as coronary angiography, as well as left ventrical angiography. Once the catheter is in place, it can be used to perform a number of procedures including angioplasty, angiography, balloon septostomy, and an Electrophysiology study.

ELECTRICAL ACTIVITY MONITORINGELECTOCARDIOGRAM (ECG) An electrocardiogram

(ECG or EKG) is one of the simplest and fastest procedures used to evaluate the heart. Electrodes (small, plastic patches) are placed at certain locations on the chest, arms, and legs.

When the electrodes are connected to an ECG machine by lead wires, the electrical activity of the heart is measured, interpreted, and printed out for the physician's information and further interpretation.

PURPOSE OF ECG Check the heart's electrical activity. Find the cause of unexplained chest pain, which could be

caused by a heart attack, inflammation of the sac surrounding the heart (pericarditis), or angina.

Find the cause of symptoms of heart disease, such as shortness of breath, dizziness, fainting, or rapid, irregular heartbeats (palpitations).

Find out if the walls of the heart chambers are too thick (hypertrophied).

Check how well medicines are working and whether they are causing side effects that affect the heart.

Check how well mechanical devices that are implanted in the heart, such as pacemakers, are working to control a normal heartbeat.

Check the health of the heart when other diseases or conditions are present, such as high blood pressure, high cholesterol, cigarette smoking, diabetes, or a family history of early heart disease.

UNDERSTANDING ELECTROCARDIOGRAMTHE HEART'S ELECTRICAL CONDUCTION SYSTEM

The heart is, in the simplest terms, a pump made up of muscle tissue. Like all pumps, the heart requires a source of energy in order to function. The heart's pumping energy comes from an inborn electrical conduction system.

An electrical stimulus is generated by the sinus node (also called the sinoatrial node, or SA node), which is a small mass of specialized tissue located in the right atrium (right upper chamber) of the heart.

UNDERSTANDING ELECTROCARDIOGRAMTHE HEART'S ELECTRICAL CONDUCTION SYSTEM

The sinus node generates an electrical stimulus regularly at 60 to 100 times per minute under normal conditions. This electrical stimulus travels down through the conduction pathways (similar to the way electricity flows through power lines from the power plant to your house) and causes the heart's chambers to contract and pump out blood.

The right and left atria (the two upper chambers of the heart) are stimulated first and contract a short period of time before the right and left ventricles (the two lower chambers of the heart).

The electrical impulse travels from the sinus node to the atrioventricular (AV) node, where it stops for a very short period, then continues down the conduction pathways via the AV bundle of His" into the ventricles. The "bundle of His" divides into right and left pathways to provide electrical stimulation to both ventricles.

This electrical activity of the heart is measured by an electrocardiogram. By placing electrodes at specific locations on the body (chest, arms, and legs), a graphic representation, or tracing, of the electrical activity can be obtained. Changes in an ECG from the normal tracing may indicate one or more of several heart-related conditions.

UNDERSTANDING ELECTROCARDIOGRAMUNDERSTANDING ECG TRACINGS

The first short upward notch of the ECG tracing is called the "P wave." The P wave indicates that the atria (the two upper chambers of the heart) are contracting to pump out blood.

The next part of the tracing is a short downward section connected to a tall upward section. This next part is called the "QRS complex." This part indicates that the ventricles (the two lower chambers of the heart) are contracting to pump out blood.

UNDERSTANDING ELECTROCARDIOGRAMUNDERSTANDING ECG TRACINGS

The next short upward segment is called the "ST segment." The ST segment indicates the amount of time from the end of the contraction of the ventricles to the beginning of the rest period before the ventricles begin to contract for the next beat.

The next upward curve is called the "T wave." The T wave indicates the resting period of the ventricles.

When the physician views an ECG, he/she studies the size and length of each part of the ECG. Variations in size and length of the different parts of the tracing may be significant.

The tracing for each lead of a 12-lead ECG will look different, but will have the same basic components as described above. Each lead of the 12-lead ECG is "looking" at a specific part of the heart, so variations in a lead may indicate a problem with the part of the heart associated with a particular lead.

IMAGING PROCEDURESCOMPUTED TOMOGRAPHY (CT OR CAT) SCAN

Cardiac computed tomography (to-MOG-rah-fee), or cardiac CT, is a painless test that uses an x-ray machine to take clear, detailed pictures of your heart. It's a common test for showing problems of the heart. During a cardiac CT scan, the x-ray machine will move around your body in a circle and take a picture of each part of your heart.

Because an x-ray machine is used, cardiac CT scans involve radiation. However, the amount of radiation used is small. This test gives out a radiation dose similar to the amount of radiation you’re naturally exposed to over 3 years. There is a very small chance that cardiac CT will cause cancer.

PURPOSE OF COMPUTED TOMOGRAPHY to assess the chest and its organs for tumors and

other lesions, injuries, intra-thoracic bleeding, infections, unexplained chest pain, obstructions, or other conditions, particularly when another type of examination, such as x-rays or physical examination, is not conclusive

to evaluate the effects of treatment of thoracic tumors. Another use of chest CT is to provide guidance for biopsies and/or aspiration of tissue from the chest

PROCEDURES FOR COMPUTED TOMOGRAPHY In computed tomography, the x-ray beam moves in a circle

around the body. This allows many different views of the same organ or structure. The x-ray information is sent to a computer that interprets the x-ray data and displays it in a two-dimensional (2D) form on a monitor.

While many images are taken during a CT scan, in some cases the patient receives the same or less radiation exposure than with a single standard x-ray.

CT scans may be done with or without "contrast." Contrast refers to a substance taken by mouth or injected into an intravenous (IV) line that causes the particular organ or tissue under study to be seen more clearly. Contrast examinations may require you to fast for a certain period of time before the procedure. Your physician will notify you of this prior to the procedure.

PROCEDURES FOR COMPUTED TOMOGRAPHY CT scans of the chest can provide more detailed information

about organs and structures inside the chest than standard x-rays of the chest, thus providing more information related to injuries and/or diseases of the chest (thoracic) organs.

CT scans of the chest may also be used to visualize placement of needles during biopsies of thoracic organs or tumors, or during aspiration (withdrawal) of fluid from the chest. CT scans of the chest are useful in monitoring tumors and other conditions of the chest before and after treatment.