The cardiologists and cardiovascular program at Saint Francis Hospital South are leaders in the development of heart management techniques, which begin with an accurate evaluation of heart and vascular function.
A number of non-invasive cardiology diagnostic tests are available at Saint Francis Hospital South on both an inpatient and outpatient basis.
The electrocardiogram, or EKG
, tests your heart's electrical conduction system and provides a graphic record of the electrical impulses produced during each heartbeat. The EKG is almost always the first test you will undergo as part of a comprehensive heart evaluation, which is performed routinely in the doctor's office. Its role in diagnosis is first to establish a baseline record for comparison with future EKGs. But, often the EKG serves as the quickest route to a diagnosis when you are experiencing chest pain or blackouts that may be the result of heart disease.
Referred to as a "resting" or "baseline" EKG, the test only requires about 10 to 15 minutes and is performed with the patient lying down on a bed or examination table. A 12-lead EKG is the standard for diagnostic evaluations and requires placement of 10 electrodes. These electrodes are only sensing devices and cannot generate an electrical shock. The procedure is painless and the skin may be prepared beforehand with a jelly-like substance to promote the sending and conveyance of electrical impulses.
The EKG machine translates the electrical signals received from your heart into tracings on graph paper. These tracings, called waveforms, show how well the impulses for contraction and relaxation of the heart muscle are generated and transmitted to reveal the presence or likelihood of certain problems when the waveforms are abnormal. Abnormalities detected with the standard 12-lead electrocardiogram are not always definitive. For example, some individuals with no heart disease may produce an abnormal EKG. Further testing may be required to rule out heart disease. Additionally, a person with significant heart disease may produce a normal EKG.
An EKG is often used to obtain:
- Baseline data for comparisons with future EKGs or with findings from other tests
- Rapid evaluation of chest pain for signs of myocardial ischemia or infarction
- Rapid evaluation of heart rate and rhythm abnormalities
Also referred to as a stress test or exercise tolerance test, the exercise EKG is the same test performed for the resting EKG except you are performing exercise while the heart's electrical activity is recorded. You may be asked to walk on a treadmill or exercise will be simulated using medications while you are lying still. Ultrasound or nuclear images may also be taken of your heart before and after the exercise portion is completed. The exercise EKG allows the doctor to evaluate the performance of your heart and adequacy of coronary circulation under different levels of stress.
Findings may be useful in the following evaluations:
- To evaluate exercise tolerance and capacity
- To distinguish chest pain that is cardiac in origin from pain caused by other problems
- To evaluate heart rhythm at increased heart rates
- To evaluate the effectiveness of medications used to manage chest pain associated with heart disease
In addition to the equipment used to perform the exercise EKG, a blood pressure cuff is placed on your arm for continuous monitoring during the exercise. A baseline EKG and blood pressure reading are taken before exercise begins, then at regular intervals during and after the exercise.
The exercise continues until one of the following endpoints:
• Your target heart rate is achieved.
• You experience chest pain.
• The technician or nurse detects EKG abnormalities.
• There is a significant change, especially a drop, in blood pressure.
• You are exhausted and unable to continue.Nuclear imaging
techniques are usually reserved for cardiology patients whose EKG findings are difficult to interpret or for patients with a normal EKG, whose history is highly suspicious for coronary artery disease. One of several of the following techniques may be used:Myocardial perfusion imaging
is obtained by injection of a small dose of technetium, a harmless radioactive isotope, into the bloodstream. A nuclear camera and computer compile images of your heart based on patterns of concentration of the isotope in the heart muscle tissue. The resting scan offers doctors a non-invasive method to identify the location and extent of damage to heart tissue from a heart attack. Combined with exercise, the scans can be used to evaluate your heart's ability to recover from an ischemic episode.
For the exercise scan, another injection of the isotope is given at peak exercise to record images of your heart muscle during increased work. Areas of your heart not receiving enough blood show up as "perfusion" or blood flow defects. Additional images may be obtained three to four hours later to see if any perfusion defects seen at peak exercise have disappeared or are reduced in size. The technique is also used to detect cardiomyopathies, such as abnormal enlargement of a heart chamber. If you are unable to exercise, medications can be used to generate the same effect.Echocardiography
uses high-frequency sound waves, much like sonar, to create a "picture" of the heart in motion. The technique is used to evaluate your heart's size, interior structures, shape and movements.Transthoracic echocardiography
involves movement of an electronic transducer over your chest wall to transmit the sound waves through your chest wall to your heart and then to sense and convey the returned "echoes" to the ultrasound monitor. While you are lying down on a bed or examination table, a jelly-like substance is applied to your skin to improve the transmission of signals.Stress echocardiography
utilizes the same basic procedure, except that the examination is performed immediately prior to and following an exercise stress test to evaluate the adequacy of circulation to the pumping chambers of the heart. If you are unable to exercise, medications can be used to generate the same effect.Vascular ultrasound
uses high-frequency sound waves to study the flow of blood in the arteries and veins of the body. This technique can look at blood flow to the arms, legs, kidneys and brain, among other areas. Blockages such as plaque or blood clots can be located with this testing. For this test, the patient lies down on a bed or examination table. A jelly-like substance is applied to the skin to improve the transmission of the signal.
Cardiac Catheterization Lab
In the past, hospitals used cardiac catheterization
labs for a very limited number of procedures, primarily studies of blood flow and pressure in the heart; visualization of the coronary arteries; and balloon angioplasty. Today, the modern cardiac "cath" lab is home to a wide variety of diagnostic and treatment techniques that allow the doctor to tailor care for the very specific needs of individual patients. Saint Francis doctors have contributed to this rapid development in interventional cardiology. Patients at Saint Francis Hospital South benefit from the complete range of state-of-the-art care. The procedures done in the cath lab are sometimes referred to as catheter-based modalities because they all employ the basic techniques of cardiac catheterization.
Cardiac catheterization is when a narrow tube, called a catheter, is inserted into an artery or vein of your leg or arm and passed through the blood vessel to your heart or the heart's circulation. Passage of the catheter is monitored by a special X-ray camera called a fluoroscope. The fluoroscope can also be used to record the flow of a radiopaque dye through your heart, coronary vessels and large vessels that supply blood to your heart and circulation.
Artificial Cardiac Pacemaker
Treatment with an artificial cardiac pacemaker
has made great strides in becoming safer and applicable to a larger group of patients. An electrical device, the pacemaker, is surgically implanted to override or supplement your heart's own pacemaker and electrical conduction system. The treatment may be used for temporary assistance or for long-term therapy of abnormal heart rhythms.
The pacemaker weighs about 1.5 ounces and is powered by a lithium battery, which can last up to 10 years. The pacemaker is placed beneath your skin, just below your collarbone on the right side of the chest. One type is connected to an insulated wire lead that is passed through a large vein into the right side of your heart. Most often, this type of pacemaker is required in treatment of bradycardia (abnormally slow heartbeat). The pacemaker is programmed to sense when your heart's rate drops below a pre-set limit and to discharge an electrical impulse to the heart wall. These limits can be set and re-set by your physician after the pacemaker is implanted. A two-wire model may be used to correct sequence problems by making sure the atria contract before the ventricles in every cardiac cycle.
Pacemakers used today are very different from models used 10 and 20 years ago. Today, most patients no longer have to worry about electrical interference from such appliances as microwave ovens. However, caution is still important when you may be exposed to high voltage transmission lines and sub-stations, arc welding and magnetic resonance imaging technology. It is also important to protect the pacemaker and insertion site from injury due to a hard blow to your chest or sustained, extreme pressure against the chest.
Implantable Cardioverter Defibrillator
The implantable defibrillator
is another device that is designed for electrical stimulation of your heart tissue. It is different from a pacemaker in that it is used to treat patients at risk of recurrent, sustained ventricular tachycardia (abnormally fast heartbeat) or fibrillation (ineffective "quivering" of the heart which can result in cardiac arrest). The defibrillation device is connected to leads positioned either inside your heart or on the heart surface. These leads sense the normal heart rhythm, detect abnormalities and deliver shocks to your heart as needed to return it to a normal rhythm. The internal device is connected to an implanted pulse generator at a separate site. Some models can also be used to supplement heart rate in the event of a slower than normal beat.
In years past, a relatively larger device was implanted during open chest surgery with electrode leads placed directly on the heart surface. The leads were then connected to a wallet-sized generator placed under the skin in the abdomen. About half of all patients who could have benefitted from the treatment were considered poor risks for such major surgery. Today, a non-surgical approach has increased the number of patients who can be considered for implantation. This technique involves insertion of the electrode wires into the heart by passage through veins leading to the heart with an electrode patch placed just under the skin.
Cardiology of Tulsa at Saint Francis Hospital South
Warren Clinic Cardiology of Tulsa physicians and staff are available at Saint Francis Hospital South every Monday through Friday from 8 a.m. to 4:30 p.m.
Committed to providing the highest quality of patient care by utilizing leading edge technology, Cardiology of Tulsa’s services include:
• Heart disease prevention
• Diagnostic testing
• Interventional cardiology
In addition to Warren Clinic Cardiology of Tulsa physicians, cardiologist Bryan A. Lucenta, M.D.
also practices at Saint Francis Hospital South.