A diagnostic procedure is performed in the cath lab to determine the extent of disease present in the vascular system. Left heart catheterization (arterial) is performed to determine blockages in the coronary vascular system. Right heart catheterization (venous) is performed to determine how well the heart valves are functioning and how effective the heart is pumping blood to the lungs.
During left heart catheterization a sheath (small flexible catheter) is inserted into the femoral or brachial artery. A heart catheter is then advanced through the sheath to the aortic arch and engaged in the ostium of the coronary artery to be visualized. There are two main coronary artery systems; the right and the left. Once the catheter is engaged, contrast (iodine based dye) is injected into the artery and visualized under fluoroscopy to detect blockages. During the left heart catheterization additional contrast may be injected to visualize the left ventricle, carotid, renal, and peripheral arteries. Pressure readings are taken at various sites to determine stenosis (narrowing of an artery) and valve function.
During right heart catheterization a sheath is inserted into the femoral or brachial vein. A catheter (usually a swan ganz catheter) is then advanced to the pulmonary artery via the right atrium and ventricle. Pressures readings and blood oxygen saturations are obtained from the different chambers to determine abnormalities. If significant abnormalities are noted a cardiac output study may be performed.
Prostin Studies are performed to diagnose pulmonary hypertension in heart transplant candidates. Due to frequent occurrence of right ventricular failure, after cardiac transplantation caused by pulmonary hypertension, additional assessment is required to separate candidates with fixed increased pulmonary vascular resistance. A diagnostic right heart catheterization (pressure monitoring) with cardiac output measurements is performed prior to prostin infusion. If the pressure readings meet predetermined criteria, the prostin infusion is then started. Following infusion repeat cardiac output measurements and pulmonary pressure readings are obtained to determine response to the prostin infusion.
Ergonovine Testing is a diagnostic test to induce coronary artery spasm. Patients suspected of prinzmetal angina/variant angina are candidates for this test. Prior to injection of ergonovine a left heart catheterization is performed. Incremental doses of ergonovine are given via peripheral IV. After each incremental dose the patient is assessed for nausea, headache, angina, EKG changes and increased blood pressure. Angiography of the coronary artery is preformed after positive results or after five minutes. If the patient experiences a positive result, Nitroglycerine is administered directly into the coronary artery to reduce spasm.
A right heart biopsy is performed either from the internal jugular or femoral vein. A sheath is first introduced in the vein and a swan ganz catheter is advanced to measure right heart pressures prior to obtaining biopsy specimens. After pressure readings are obtained a bioptome (tissue biting forceps) is advanced to the right ventricle and multiple specimens are obtained and sent to the pathology laboratory. During the procedure absolute care is taken not puncture the wall of the ventricle.
Electrophysiology Study (EPS) is the study or detailed analysis of normal and abnormal electrical conduction systems of the heart. The EP study enables the physician to assess the function of the SA node, AV node, and the His-Purkinje system. It can also help to evaluate the electrophysiologic properties such as automaticity, conduction velocity and refractoriness of the cardiac tissue. Conduction intervals are measured within the heart by means of intra-cardiac electrode catheters. From these measurements the doctor is able to identify problem areas of conduction.
In a controlled clinical environment this test permits the electrophysiologist to study cardiac abnormalities and locate the cardiac activation and arrhythmia mechanism that are responsible for these abnormalities. The electrophysiology procedure is an invasive examination, similar to a heart catheterization that is performed by introducing electrode catheters into the right side of the heart via the femoral vein, brachial vein, or jugular vein. The catheters are positioned in the heart and then used to measure and record the activating sequence of the cardiac circuit.
