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Johns Hopkins Bayview Medical Center

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Specialty Cardiology Services

Our experts specialize in treating the root causes of cardiovascular problems, not just symptoms. Learn more about some of the services we offer at Johns Hopkins Bayview.

MaryJo's Story: Women's Cardiovascular Health Center

Cardiac care centered on MaryJo's unique needs as a woman at the Women's Cardiovascular Health Center helped her avoid unnecessary heart surgery.

Arrythmia Ablation

Ablation is used to treat a variety of abnormal heart rhythms (also called arrhythmias), including atrial flutter, AV nodal re-entry, ventricular and atrial tachycardia and atrial fibrillation. Ablation can help patients normalize or control their heart rhythm and prevent blood clots and stroke by disconnecting or blocking the pathway of the abnormal rhythm.

Ablation procedures are performed surgically and non-surgically, depending on the type of arrhythmia and other medical factors. For patients who need surgery, traditional “open” procedures, as well as minimally invasive procedures, are available. Ablation also may be combined with other procedures, such as bypass surgery or valve repair or replacement. Non-surgical ablation is performed in an electrophysiology laboratory. During the procedure, a catheter is used to direct energy to areas of the heart that are causing the abnormal rhythm.

Cardiac Catheterization

Cardiac catheterization is an invasive imaging procedure commonly performed on patients who have coronary artery disease, valvular heart disease, heart failure or angina. During the procedure, a long, narrow tube, or catheter, is inserted into a blood vessel in the patient’s arm or leg and guided to the heart with the assistance of a specialized X-ray machine. Dye is injected through the tube so physicians can see how the heart is functioning.

Cardiac catheterization can diagnose or confirm the presence of heart disease, evaluate heart muscle function or determine the need for further treatment. If the arteries are blocked, physicians can open them by using the catheter in conjunction with a balloon and other tools to perform angioplasty, stenting or atherectomy.

Cardiac CT

Computed tomography, commonly known as a CT scan, allows physicians to see cross-sectional X-ray images of the heart on a computer screen. Cardiac CT can be performed with or without intravenous dye to visualize the heart’s anatomy, circulation and vessels.

Cardiac MRI

Magnetic resonance imaging (MRI) is another tool cardiologists can use to diagnose a range of heart conditions, such as coronary artery disease, pericardial disease, cardiac tumors, heart valve disease, cardiomyopathy and congenital heart disease. Using large magnets and radio-frequency waves, MRI produces images of the heart throughout its pumping cycle to allow doctors to obtain information about the heart as it is beating.

Cardiologists use MRI to evaluate the anatomy and function of the structures of the chest, including the heart, lungs, major vessels and outside lining of the heart.


Cardioversion is a treatment for fast or irregular heart rhythms, especially atrial flutter and fibrillation. During the procedure, a special machine sends electrical energy to the heart muscle to restore normal heart rate and rhythm, allowing the heart to pump more effectively.

While a patient’s heart and blood pressure are monitored, doctors administer a short-acting sedative, then deliver an electrical shock to the chest wall through paddles or patches that stops the irregular heartbeat and restores a normal rhythm.

Cardioversion and defibrillation procedures are similar. Both use a device to deliver an electrical shock to the heart. Cardioversion, however, uses significantly lower levels of electricity. Defibrillation is more appropriate for severe arrhythmias that are difficult to regulate.

Cholesterol Testing

The American Heart Association recommends that adults as young as age 20 have a fasting lipoprotein analysis every two years. This test, which measures total cholesterol, HDL cholesterol LDL cholesterol and triglyceride levels, can help doctors determine a patient’s risk for cardiovascular disease and make decisions about preventive treatment.

A fasting lipoprotein analysis measures the amount of fatty substances in the blood. High levels of these substances can increase your risk for heart disease and stroke. Too much cholesterol in the blood can cause plaque to build up in the artery walls, decreasing the amount of blood flow to the heart.

HDL cholesterol, sometimes referred to as “good cholesterol,” helps remove fat from the body. Higher levels of HDL cholesterol may decrease your risk. LDL cholesterol, on the other hand, carries fat to other parts of the body and can contribute to higher cardiovascular disease risk. Triglycerides are a type of fat the body uses to store energy. A high triglyceride level combined with high LDL cholesterol further increases your risk.

The symptoms of high cholesterol are difficult to detect. That’s why it’s important to have your cholesterol checked regularly, especially if you are at risk.


Patients who go into cardiac arrest or have potentially life-threatening irregular heartbeats are treated with defibrillation. During this process, an electric shock is delivered to the heart to help reestablish a normal rhythm.

In emergency situations, external defibrillators are used. The defibrillator is an electronic device with electrocardiogram leads and paddles. During defibrillation, the paddles are placed on the patient's chest and the electric shock is delivered.

Another type of defibrillator, an implantable cardioverter-defibrillator, can help prevent cardiac arrest by detecting and stopping dangerous arrhythmias in patients with ventricular tachycardia (an extremely fast heartbeat), ventricular fibrillation (a fast, chaotic heartbeat) or other risk factors and conditions. The pager-sized device, implanted in the patient’s chest, continuously monitors the heartbeat and delivers electrical shocks to restore normal rhythm when needed.


An echocardiogram is a type of ultrasound test that uses sound waves to produce images of the heart. During the procedure, doctors can view real-time video of your heart in motion. An echocardiogram may be recommended when a doctor suspects problems with the heart valves or chambers that affect its ability to pump.

A transesophageal echocardiogram may be recommend if it is difficult to obtain a clear picture of the heart through a traditional echocardiogram. During this procedure, the tube is guided down a patient’s throat and into the esophagus to obtain detailed images of the heart. A trans-esophageal echocardiogram can provide clearer images because the probe is located closer to the heart, and the bones of the chest wall do not block the sound waves produced by the probe.


A pacemaker is often used to correct a heartbeat that’s become too slow or too fast, or to treat congestive heart failure, hypertrophic cardiomyopathy or fainting spells. It is a small device—about the size of a watch—that sends electrical impulses to the heart to maintain a normal heart rate and rhythm.

During a minor surgical procedure that typically lasts less than three hours, a pacemaker is implanted just under the skin of the chest. The device includes leads and a pulse generator that help maintain a healthy heartbeat. A doctor programs the device with the minimum heart rate. When the rate drops below this number, the pacemaker fires an electrical impulse that passes through the lead to the heart muscle, causing it to contract and create a heartbeat.

There are several types of pacemakers. Your doctor will decide which one is best for your condition and special needs.

Stress Testing

A stress test allows a doctor check for changes in your heart during exercise. The test shows how well your heart handles work. A physician may recommend a stress test to diagnose coronary artery disease, find the cause of unexplained symptoms of possible heart-related conditions or monitor the effectiveness of a previous cardiovascular procedure.

During an exercise stress test, commonly called exercise electrocardiography, a patient either walks on a treadmill or pedals a stationary bike. The person taking the test is hooked up to electronic equipment that monitors heart rate, breathing, blood pressure and fatigue.

Exercise stress testing may not be appropriate for certain patients. In these cases, pharmacologic stress testing is available. During these tests, certain medications are used to stimulate the heart and mimic the effects of exercise.

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