Cardiac resynchronization is a procedure that helps in synchronising heartbeats and saving the life of patients with a risk of heart failure.
Heart failure is a fatal condition that can put a patient’s life at stake. Heart conditions are caused due to the ill-functioning of the heart due to various internal and lifestyle situations. Arrhythmia is another critical issue that is identified as irregular heart rhythms. Age, genetics, high-dose medications, poor lifestyle, damage to the heart, etc. are some of the main reasons behind arrhythmia and heart failure. There are several treatment options available and cardiac resynchronization therapy is one of them. Since this is a technical topic, Onlymyhealth reached out to Dr. Santosh Kumar Dora, Senior Cardiologist, Asian Heart Institute, Mumbai. Continue reading to know how cardiac resynchronised therapy can save the lives of heart patients.
What is Cardiac Resynchronization Therapy?
According to Dr. Dora, “In a certain situation like left bundle branch block, the ventricular myocardium contracts dyssynchronously, the interventricular septum contracts much before the left ventricular lateral wall contraction. It leads to wasted contraction. Cardiac resynchronization therapy is a kind of pacemaker therapy, which leads to simultaneous contraction of all parts of ventricle to generate maximal cardiac output.”
This therapy helps in resynchronising the heart and this is why it is named resynchronised therapy. CRT is also called biventricular pacing. It helps in improving the rhythm of the heart in patients with irregular heart rhythms while improving the symptoms related to arrhythmia.
There are different treatment methods for arrhythmias. Doctors look at the symptoms and severity of irregular heart rhythms to suggest the best treatment. Some common treatment methods include antiarrhythmic drugs, direct antiarrhythmic therapy, cardioversion-defibrillation, catheter ablation, implantable cardioverter-defibrillators (ICDs), pacemakers or cardiac resynchronization therapy and surgery. In some cases, doctors suggest combination treatments.
How is Arrhythmia Caused?
Let us brief you about what leads to arrhythmia. There is a sequential and orderly relationship between cardiac chamber contraction. In some patients, this gets disturbed or in technical terms, becomes dyssynchronous. There are three types:
- Interventricular: dyssynchrony between right and left ventricular contraction
- Intraventricular: dyssynchrony between varied segments of the left ventricular contraction
- Atrioventricular: dyssynchrony between ventricular and atrial contraction
Here is a list of people who are at risk of developing dyssynchrony:
- People with nonischemic or ischemic dilated cardiomyopathy
- People with less than 35% of the fraction of left ventricular ejection in sinus rhythm
- People with greater than 55mm end-diastolic dimension in left ventricular
- People with prolonged QRS interval of more than 130 milliseconds due to left bundle branch block
Dyssynchronisation is identified after checking the parameters of ECG or electrocardiogram and other advanced echocardiography techniques like strain rate, tissue Doppler index, etc.
How is cardiac resynchronised therapy done?
According to Heart Foundation, cardiac resynchronised therapy can reduce the chances of hospitalization in heart failure patients and also lessen the all-cause mortality rate. People with class II, II and IV symptoms shall opt for CRT as the best treatment to save a life. But one important thing to consider here is that patients with permanent atrial fibrillation may or may not get benefited from this therapy. Besides, people with mild prolongation of QRS, non-specific delay in intraventricular conduction and those with right bundle branch block may also not receive any benefit from this therapy.
To resynchronise the heart rhythms or cardiac contractions, Cardiac Resynchronization Therapy uses a pacing system. Generally, CRT includes left ventricular lead, right ventricular lead and right atrial lead. These leads or wires may be placed surgically or transvenously through thoracotomy.
It is a specialized pacemaker where 3 leads are inserted through the subclavian vein. These leads are placed at the right atrial appendage, right ventricular apex and left oblique vein. The leads which are placed at the right ventricular apex and left oblique vein stimulate the interventricular septum and lateral aspect of the left ventricle simultaneously. It leads to synchronised contraction and increases cardiac output.
The devices included in the cardiac resynchronised therapy are:
CRT-P or CRT with a pacemaker: Here, the device used to conduct this therapy has three wires. Two leads are attached to ventricles or the lower chambers and one wire is attached to the right atria or upper right chamber of the heart. These three are then connected to the pacemaker.
CRT-D or CRT with a pacemaker and ICD: People who have experienced heart failure are at greater risk of sudden cardiac death. This device is recommended for them to prevent such mishaps. This device helps in detecting dangerously abnormal heart rhythms and delivering an energy shock to resynchronise your heartbeats. This is better and stronger than a pacemaker.
In which all cases are Cardiac Resynchronised Therapy advised?
Cardiac resynchronization therapy is advised in cases of low left ventricular ejection fraction ( LVEF less than 35%), wide QRS width with left bundle branch block ( QRS width more than 130 ms) and patient symptomatic of heart failure. This is also advised for a patient, who is on standard pacemaker therapy with high dependence on pacing and having low LVEF and is suffering from heart failure. CRT is also advised to patients with atrial fibrillation with fast ventricular rate despite medications and low LVEF with heart failure, who are advised AV node ablation to correct fast heart rate. Cardiac resynchronization therapy is essentially a specialized pacemaker therapy. So all dos and don’ts are the same as that of a standard pacemaker.
What Are The Risks of Cardiac Resynchronization Therapy?
There are risks associated with almost all medical and surgical procedures. CRT therapy also comes with some risks but not all who undergo this therapy are at risk. This is a safe procedure but some complications may arise considering the patient’s overall health and type of implant done. Here are some possible risks with CRT:
- Failure of the inserted device
- Injury to blood vessel
- Cardiac tamponade or fluid buildup in the sac leading to compression of the heart
- Pneumothorax or collapsed lung
- Shifting of parts of the device
Important Points To Note by Dr. Dora
- The patient should avoid going near a strong electromagnetic field area
- Mobile phone should be used at least 15 cm away from pacemaker site
- Request manual check-up rather than checkup by metal detectors at the security check posts etc.
- Patients are usually asked to come for a pacemaker check-up once every 6 months or as and when required if there is any need.
- Nowadays home monitoring systems are also available, which enables patients to send the pacemaker data to concerned doctors through the internet.
Care Tips for Recovery after Cardiac Resynchronization Therapy
If you are wondering about the recovery process and how to take care post-recovery, here is what Dr. Dora has to say- The recovery process is the same as that of standard pacemaker therapy. The patient usually can be ambulated the next day of surgery and discharged to home in a couple of days as per the institutional protocols. The patient is given a timeline when to come for follow up checks at the time of discharge. Patients are advised to avoid taking a head bath for 7 to 10 days till the wound heals completely to avoid infection. Patients are asked to avoid excessive hand movement on the side of the pacemaker for at least 3 months from the date of surgery.
Arrhythmia and heart failure are two chronic ailments that can put your heart health in danger. Heart failure is a progressive condition and cardiac resynchronised therapy is the best way to improve health and help live longer. This therapy is safe if you get it done by an experienced cardiologist. Also, post-recovery care is extremely important to avert the possible risks of CRT.
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