Heart Rhythm Treatment
If you have been diagnosed with certain types of arrhythmia, your doctor may refer you to have a more detailed study of the cause of the arrhythmia, this test is called an electrophysiology study. The electrophysiology study is done in a special cath lab called an electrophysiology lab. The aim of the test is to internally map out the electrical pathways in the heart with an aim of finding any abnormal pathways or “short circuits” that may be causing the arrhythmia.
Similar to an angiogram an electrophysiology study uses thin plastic tubes called catheters inserted through a small puncture site in the skin into a blood vessel in the arm or leg and then guided by X-ray images up to the heart. Once in place, special electrodes are passed up through the catheter to record ECG signals directly from the heart. In this way a detailed electrical mapping of the heart can be done. The electrodes can also be used to send small electrical impulses to the heart to see if the doctor can trigger the same pathways that cause the arrhythmia and therefore precisely determine the cause of the irregular heart beat.
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3D Electroanatomic Mapping
ACI is the first country in the English speaking Caribbean to have a new advanced electrophysiology technology called 3D electroanatomic mapping. This technology allows the doctor to view the electrical signals in the heart in a three dimensional view in relation to the anatomy of the heart chambers. This allows the doctor to precisely pinpoint the exact origins of abnormal rhythms.
The doctor can also see the location of the catheters in relation to the mapped electrical anatomy of the heart and therefore can target treatments more precisely and also can do treatment without x-ray fluoroscopy therefore reducing radiation to the patient. 3D Mapping is especially useful for a type of treatment called Pulmonary Vein Isolation which is used in the treatment of certain types of Atrial Fibrillation. It is also very useful in complex arrhythmia treatments.
Catheter ablation is a modern technique for permanently eliminating abnormal electrical signal pathways in the heart and thereby potentially provide a cure for certain types of abnormal heartbeats. It is usually used to treat symptomatic fast heart rates (tachycardia) especially those that occur frequently and which would otherwise require long-term drug therapy to keep the condition under control.
Catheter ablation is usually done in conjunction with an Electrophysiology Study (EP Study). The EP study, as described above, is used to pinpoint the area in the heart which is causing the arrhythmia. Once this has been identified, then in the catheter ablation procedure, a special catheter is directed to that precise location and radiofrequency energy is applied thereby eliminating the area of tissue which is causing the “short circuits” of the electrical impulses. In this way the abnormal heart beat can be eliminated.
ACI was the first centre in Trinidad and Tobago to perform
Cardiac Pacemakers are devices used to treat patients who have an abnormally slow heart beat or bradycardia. As outlined before, the cause of the slow heart beat could be either that there is a problem with heart’s natural starting point for the electrical signals (sinus node) or the conduction pathway from the sinus node is blocked.
A pacemaker is used to either replace the function of the sinus node or to bypass blockages in the conduction pathway and thereby restore a more nominal rhythm to the heart beat.
The pacemaker consists of two parts, one part, called the pulse generator, is external to the body and creates the electrical signals. The other part is the leads that carry the tiny electrical impulses into the body and to the heart.
The implantation procedure is relatively simple and is carried out using local anaesthetic and mild seduction usually in a Cath lab. During the procedure the leads are inserted through a tiny puncture in the skin into a vein and guided using X-rays to the heart where it is carefully implanted into the required chamber of the heart. The pulse generator is then placed in a pouch just under the skin and the leads are connected to the pulse generator. The doctor then uses a programmer to turn the pacemaker on.
In some patients who have developed a condition called heart failure the conduction of electrical signals from the right side of the heart to the left side of the heart becomes disturbed. This can result in a very disorganized and inefficient beating of the heart where both sides of the heart beat independently. Studies have shown that these patients can greatly benefit from a special type of pacemaker device called a biventricular pacemaker.
This device is similar in makeup to the pacemaker devices described above. The leads however are implanted in both the left and right ventricles. The device’s role is to restore the coordination of the heart beat in the left and right sides of the heart.
Implantable Cardioverter Defibrillator (ICD)
As described in FAQ section, the irregular heart beat called ventricular fibrillation is a potentially fatal arrhythmia if it is not treated within minutes of its onset. The main treatment is defibrillation or cardioversion and is usually performed by applying a large electrical voltage to the patient’s chest. This large external electrical impulse has the effect of overwhelming the electrical pathways in the heart and thereby resets the normal electrical rhythm of the heart. This effectively stops the chaotic electrical short circuit that resulted in the ventricular fibrillation.
The problem is however that the underlying condition of the heart is still the same and therefore the ventricular fibrillation may recur.
In such patients who are at risk for recurrent ventricular fibrillation there is now an implantable device called an implantable cardioverter defibrillator (ICD) which can save the patient’s life. The implanted ICD senses the fibrillation event and automatically providing an electrical voltage directly to the patient’s heart thereby restoring a more normal heart beat.
The ICD device is slightly larger than a pacemaker though modern versions are almost the same size. It is implanted in a Cath lab in a similar procedure to that described for the pacemaker above.