OPD, BLK Super Speciality
Monday - 11:00 am to 2:00 pm
Thursday - 11:00 am to 2:00 pm
Friday - 2:00 pm to 5:00 pm
Room No. 115
OPD 3, 1st Floor
For Appointments Call
8860017412 / 8130698143 / 011 30403040
Sudden Cardiac Arrest (SCA) is the sudden, abrupt cessation of pumping of blood by the heart leading to immediate loss of consciousness and death.
The most common cause of SCA is ventricular tachycardia and ventricular fibrillation. SCA can occur without any warning and if the patient is to have any chance of survival he or she must be treated with a defibrillation shock within about six minutes.
Defibrillation is a technique in which a brief high-energy electric shock is administrated to the heart to treat life-threatening arrhythmias. The therapy can be given externally across the patient's chest using an external defibrillator or internally using an implantable defibrillator. The shock passes through the heart, stops the erratic electrical activity that caused the cardiac arrest and allows the heart to return to a more regular rhythm.
Cardiac arrest is different from a heart attack. During a heart attack, the blood flow to portions of heart muscle is interrupted due to blockages in the arteries that supply blood to the heart muscle. These portions of heart muscle are therefore deprived of oxygen and get damaged or even die. Usually, however, the rest of the heart muscle still functions properly and the patient's heart continues to pump blood, unlike during cardiac arrest.
Which Patients Are At A High-Risk Of Dying From Sudden Cardaic Arrest?
Since the most common cause of SCA is VT or VF, patient's who have already experienced VT or VF or whose heart condition makes them vulnerable to developing VT or VF are at the highest risk of suffering from the SCA.
Various clinical studies that have studied patient risk for VT/VF and SCA suggest that the following groups of people are at highest risk for SCA:
• Patients who have already suffered an episode of SCA due to VF but who managed to survive.
• Patients with low heart pumping efficiency (indicated by a parameter called the ejection fraction) who have episodes of VT, especially when these episodes are associated with symptoms like dizziness and fainting.
Patients who have episodes of VT but do not experience serious symptoms during these episodes could also be at high-risk and need to be further evaluated and suitably treated.
Patients who have suffered a heart attack and who have a poor heart pumping efficiency and whose heart possesses the triggers for causing VT / VF could also be at high risk for SCA. They must be carefully evaluated and suitably treated.
In addition to the above, patients who have dilated hearts (dilated cardiomyopathy) coupled with low heart pumping efficiency or heart failure, patients with abnormally thick ventricular muscle (hypertrophic cardiomyopathy) and some other structural heart problems could also be at high risk for SCA due to VT/VF. These patients too must be closely evaluated and suitably treated.
What Therapies Are Available To Manage Patients At High Risk For Sca?
Until the mid-1980s, ventricular tachycardia was treated mainly with medications. These medications work by reducing the frequency of occurrence of VT/VF and in this way attempt to prevent SCA. While these drugs do reduce the frequency of VT or VF, clinical studies have shown that in very high-risk groups of patient the best drugs available today are only partially effective in preventing SCA. Moreover, some of these drugs can have serious side-effects and studies have shown that up to 40% of patients do not take their medications regularly. All the same drugs continue to play a vital role in the management of patients with ventricular tachycardia. They are often used in conjunction with the other treatment options available for the management of SCA.
Radiofrequency ablation (or burning) is emerging as another treatment option for VT. This involves the insertion of soft, thin tubes called catheters into the heart through a vein. Once inside, these catheters are used to deliver energy to small portions of heart tissue that are responsible for starting or maintaining the VT. The energy heats up and destroys this portion of heart tissue and thereby prevents the VT from recurring. With the currently available technology, radio-frequency ablation has been successful in the treatment of very few types of VTs and is not yet a suitable treatment for the vast majority of VTs encountered.
Another way to treat VT/VF and prevent SCA is with a device called an Implantable Cardioverter Defibrillator (ICD). (Give Link of ICD)