Congenital Heart Disease Care Model: Heart Rhythm
This is the fourth entry in our blogpost series that describe the different aspects of the Congenital Heart Disease Center's multi-disciplinary model of care. In this post, the role of Heart Rhythm study in care of CHD patients is examined and explained by Mayo Clinic Rochester electrophysiologist Malini Madhavan, M.B.B.S.
The heart’s rhythm is defined as the electrical activity of the heart that makes the heart muscles squeeze and pump blood. Observing the heart’s rhythm is an integral part of the well-rounded care of a congenital heart disease patient.
A patient is aware of a heart rhythm problem when they start experiencing symptoms, after a chamber of the heart starts beating too fast or slow, generally above 100 beats per minute or below 60 beats per minute. Malini Madhavan, M.B.B.S, an electrophysiologist at Mayo Clinic says that congenital heart disease patients have a higher risk of these abnormalities.
“Patients with adult congenital heart disease are more prone to heart rhythm abnormalities. In fact, it's the second most common cause for illness and hospital admissions in patients with adult congenital heart disease.”
Symptoms of heart rhythm problems are: heart palpitations, which is a sensation of the heart racing; lightheadedness or fainting spells; and increased tiredness or difficulty breathing with activities. Heart rhythm monitoring is recommended when patients experience these symptoms.
Where an irregular heart rhythm occurs, whether it occurs in the top chambers of the heart (atrium), or in the bottom chambers of the heart (ventricle) depends on the specific congenital heart disease diagnosis and the type of procedures performed in the past. The prognosis and treatment for the different arrhythmias will vary based on the type of arrhythmia and the underlying congenital heart disease. If left untreated for a significant period of time, heart rhythm abnormalities can lead to heart failure, stroke, or sudden death. Hence prompt diagnosis and treatment is key.
When a patient has symptoms, a doctor will first listen to the patient’s symptoms and heart sounds and then obtain an electrocardiogram to determine if an arrhythmia (abnormal heart rhythm) is present. If more monitoring is necessary a heart rhythm monitor is given to the patient for 24 hours to a month for the patient to wear continuously to detect problems with the heart rhythm. For patients who have infrequent symptoms that cannot be recorded on a month long monitor, small implanted heart rhythm monitoring devices can provide answers. An improvement in mobile technology gives physicians another tool to potentially use:
“Another advancement in the last five years are smartphone apps that patients can use to record their ECGs. The ECG quality from the smartphone is not the same as what is recorded by medical devices that we give out to patients, but it is of reasonable quality.” She added, “These mobile apps provide an additional diagnostic tool for patients who experience symptoms suspicious for heart rhythm abnormalities.”
The speed and location of the rhythm determines what treatment is appropriate, with treatment tailored to the particular patient and rhythm. Treatment can include medications (anti-arrhythmic drugs) with monitoring from an electrophysiologist. A catheter ablation is another treatment option, which is especially helpful for a particular subset of congenital heart disease patients.
“Patients with congenital heart disease are more prone to arrhythmias due to a combination of their heart disease and scars from prior surgical procedures. The presence of surgical scars can increase the chance of electrical movement around scarred regions leading to arrhythmia” Dr. Madhavan said.
According to Dr. Madhavan, an ablation procedure is a minimally invasive procedure. During this procedure, the physician passes catheters through the veins and arteries of the groin to the heart. The physician then identifies where the previous surgical scars are located and they proceed with an ablation procedure. During the ablation procedure, energy similar to electrocautery heat is used to target the area of the scar that is causing the irregular heartbeat. Success rates of up to 80 percent are noted for some rhythms.
Another important treatment option, is the implantation of devices called pacemakers and defibrillators. Pacemakers are used to treat slow heart rhythms and defibrillators are specifically for ventricular arrhythmias. Ventricular arrhythmias are fast rhythms from the lower chamber (ventricles), that put a patient at high risk for sudden death. A defibrillator can be life-saving for these patients. Dr. Madhavan elaborated,
“Ventricular arrhythmias are frequently stopped using a shock to the heart. A defibrillator is able to diagnose a ventricular arrhythmia and provide a lifesaving shock in a timely fashion. So for patients who need it, having a defibrillator is like having an EMT with them all the time. The device is able to avoid the delays that occur when emergency medical services are activated and provides timely treatment that preserves the function of vital organs such as the brain. Defibrillators are devices that are most often implanted through minimally invasive procedures, less often they need to be surgically implanted. But these devices pick up on life threatening rhythms within a few seconds and either pace or shock the heart. Once the rhythm is back to normal, a patient’s consciousness is quickly restored within a few minutes.”
Dr. Madhavan concluded by stating the importance of having a team approach: “I take care of the heart rhythm problem, but work very closely with a team of specialists from adult congenital cardiology and cardiovascular surgery. It has to be a team approach.”