INVASIVE STUDIES: DIAGNOSTIC AND THERAPEUTIC

Cardiac Catheterization

Coronary

Coronary Angioplasty and Coronary Stents

Cardiac Electro-phisiology

Heart Stimulus

There are three main types of treatment for people with angina (chest pain) caused by coronary disease:

  1. Medical The patient takes medicines to control the disease or the risk factors.

  2. Interventionist which opens or clears the coronary blockage, caused by one or more plaques of atherosclerosis with a balloon catheter or angioplasty.

  3. Surgical utilizes grafts or bypasses to clear the coronary obstruction. These may be venous or arterial and the procedure is known as open heart surgery or coronary bypass.

The objective of the different types of treatment are to relieve symptoms such as angina, or fatigue and improve quality of life. In some individuals, these interventions may prolong life, delaying or halting the progression of the disease or decreasing the chance of complications.

 I. Cardiac Catheterization

Specialized invasive procedure to insert a thin flexible tube (catheter) through a blood vessel (vein or artery), it is carried to different areas of the circulatory system, most often to the heart chambers where the physician obtains information on the circulation and on the seriousness of the ailment in the different cardiovascular diseases (stroke, angina, valvular lesions, vascular lesions, biopsies).

 II. Coronary

Invasive procedure through which a catheter is inserted into the orifice of the coronary and a special liquid (contrast medium) is injected. Through X-Rays (Fluoroscopy) the physician is able to determine the severity of lesions of these arteries.

Is performed only in hospitals that have the necessary facilities for hemodynamics and to perform cardiovascular surgery if necessary.

What is required for coronary angiography?

It is better if the patient fasts for 6 to 8 hours before the procedure, although is not necessary, especially in an emergency. Your doctor will advise you on what drugs you can take on the day of the procedure.

Doses of drugs used as anticoagulants such as warfarin will be reduced, and sometimes temporarily suspended before the study, depending on the reason for anticoagulation. Intake of other medications such as aspirin, clopidogrel and drugs for the treatment of high blood pressure or cholesterol will continue as usual.

The instructions should be followed accurately, otherwise the procedure may have to be canceled or delayed.

What is the procedure of the study?

This study is usually performed under local anesthesia. It is virtually painless and during the procedure the patient is alert and cooperating with the doctor such as taking more deep breaths, coughing or stop breathing at the request of the physician. If necessary or requested by the patient, a mild sedative might be considered, thus many patients do not remember the details of the procedure.

A small catheter is inserted into an artery in the leg (femoral artery) or arm (radial artery). And through the blood vessels leading to coronary arteries, where a contrast solution is injected . This facilitates the diagnosis.

Based on the results of this test, the doctor may immediately proceed to perform an angioplasty, a procedure in which an obstructed artery is cleared.

 III. Coronary Angioplasty and Coronary Stents

Angioplasty is a therapeutic procedure where a catheter with a balloon in the tip is introduced in the obstruction and then inflated. With the pressure from inflating the balloon the artery is cleared and the flow of blood increases. The procedure often includes a metallic stent, a mesh, which is placed internally, to reduce the possibility of a blockage This is how angioplasty restores the blood flow to the heart muscle.

Why angioplasty is needed and by whom?

Chest pain caused by a heart problem is called angina. It is a sign that the heart muscle is not receiving enough blood especially oxygen. This is called ischemia. Blood flow is reduced when coronary arteries are blocked. The narrowing of these, or other arteries of the body occurs as a result of fatty and calcium deposits in atherosclerotic plaques that we call simply plaques.

Someone with narrow coronary arteries may develop angina during exercise, because it increases the need for oxygen in the blood or in other body muscles.

A person with narrow coronaries can develop angina if there is a change in the usual pattern, not only by physical activity or exercise but is also at rest or during sleep. Depending on a change in the intensity or duration of the discomfort, or increased frequency of episodes, it is known as unstable angina.

Unstable angina may be associated with damage to the heart muscle (myocardial infarction) when the episode of angina lasts more than 20 minutes. The term acute coronary syndrome refers to people with unstable angina or myocardial infarction and these conditions require immediate evaluation by your doctor in a hospital. In severe cases, acute coronary syndromes can lead to heart failure or sudden death.

This procedure is applicable to:

  • People who experience intolerable or persistent symptoms despite optimal medical treatment.

  • Those with coronary blockages that present high risk of a complete obstruction or acute myocardial infarction or sudden death.

  • The usefulness of angioplasty depends on the degree of arterial narrowing and is often recommended when arterial narrowing is moderate to severe, up 75%. The number of arteries affected and which are affected will be assessed by the cardiologist to make the decision to perform this procedure.

  • People who have extensive coronary artery disease or trunk of the left coronary artery should be individualized and is the doctor who performed the study to decide whether it is more convenient to perform this procedure or recommend open-heart surgery.

What are the benefits?

Angioplasty relieves angina and improves a person's ability to exercise. However, several individual factors that influence its effectiveness may be considered for long-term treatment It is important to analyze each patient's realistic expectations with the doctor.

Risks of angioplasty?

It is an invasive procedure and is associated with risks that should be discussed with your doctor.

Regularly it is required for the patient or a close relative, to sign a consent for the procedure, which will describe the likely risks and complications. Feel free to ask any questions you may have.

What preparation is needed for angioplasty?

Blood tests, including coagulation and renal function tests, and hemoglobin and sugar count before the study. If necessary, a chest radiograph and an electrocardiogram shoulw be taken. Your doctor along with the cardiologist who performed the procedure, will tell you if it needs further study.

 IV. Cardiac Electro-phisiology

Is the science that studies transmission mechanisms to improve cardiac impulses using one or several catheters from the femoral veins and arteries to the heart. Then through specialized procedures an electric simulus is sent to several areas of the heart to diagnose arrhythmias.

There are different arrhythimas which can be cured after this diagnosis. This is done by applying controlled heat to the internal part of the heart with a catheter This process is called ABLATION.

It is very important to know that most of the arrhythmias which may be subject to ablation have shown a high rate of recovery, especially those of the supra-ventricular type, either chronic or paroxistic, with a rate of success of over 95% and a low relapse rate of between 3% and 8%.

Ventricular arrhythmias may alter hemodynamics and compromise the life of the patient.Ventricular arrhythmias may alter hemodynamics and compromise the life of the patient.

Arrhythmias such as auricular fibrilation are under continuous research to improve the success of ablation and minimize relapses because at the present time this is one of the most frequent arrhythmias associated to dilated miocardiopathy of different origins.

In addition to the arrhythmias, electrophisiology studies cardiac stimulus either partial or permanent. This type of stimulus may be achieved through 3 types of devices: pacemaker, defibrilaors and re-synchronizers.

These are eletronic devices which analyze the heart rhythm and treat arrhythmias through eletronic stimulus. Pacemakers and automatic defibrilators are the most common.

The Electrophisiologic Study is the procedure used to determine the electric activity of the heart.

Through these studies we can:

- Determine the normal rhythm of the heart

- Recognize simple and complex arrhythmias

- Evaluate abnormalities found in surface electrocardiograms

- Evaluate the possibility of sudden death when anomalies are detected in the electrocardiogram

- Determine the effectiveness of specific treatments

The elecrophisoiologic study is indicated in patients with symptoms of arrhythmic situations and which are manifested through loss of consciousness, palpitations or alterations of the vital signs which may compromise the life of the patient.

There are two tpes of studies:

1. For Diagnosis: investigates the electric activity of the heart and identifies the origin of the arrhythmias, blockings and their types, as well as determines the likelihood of developing arrhythmias, or of cardiac death in the future.

2. Therapeutic: once the origin of the arrhythmia is determined, it can be estabished if it is susceptible to treatment. If so, it is done by applying heat directly to the heart tissue through special catheters which stop the electric activity of the cells which originate, contribute to or maintain the arrhythmia. This procedure is called ablation.

The rate of success is 95%.

 V. Heart Stimulus

Heart stimulus refers to placing, controlling and programming of

- Pacemakers

- Defibrilators

- Re-synchronizers

Pacemakers: Devices that are placed when the heart beats are slow or in the case of pauses or blockings that may compromise the life of the patient. These may have one or two cables.

Defibrilators: Devices that perform the functions of the pacemaker and recognize potentially malignant arrhythmias. They send an electric stimulus directly to the heart and stabilize the rhythm. These are prescribed to patients that have experienced malignant arrhythmias (secondary prevention) or who due to an illness are susceptible to generate arrhythmias that may compromise their life (primary prevention). These devices may have one or two cables and should always be placed on the left side of the thorax.

Re-synchronizers: Devices that perform the functions of a peacemaker and defibrilator and impove the movement of the heart muscle, that results in a stronger contraction and therefore, a better health. It has 3 cables.

It is imortant to mention that an adequate and periodic control of all these devices improves their operation, and in most cases, extend the life of the battery.