Radiofrequency ablation

Radiofrequency ablation (RFA) is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternating current (in the range of 350–500 kHz). RFA is generally conducted in the outpatient setting, using either local anesthetics or conscious sedation anesthesia. When it is delivered via catheter, it is called radiofrequency catheter ablation. Radiofrequency ablation (RFA) is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternating current (in the range of 350–500 kHz). RFA is generally conducted in the outpatient setting, using either local anesthetics or conscious sedation anesthesia. When it is delivered via catheter, it is called radiofrequency catheter ablation. Two important advantages of radio frequency current (over previously used low frequency AC or pulses of DC) are that it does not directly stimulate nerves or heart muscle and therefore can often be used without the need for general anesthetic, and that it is very specific for treating the desired tissue without significant collateral damage. Documented benefits have led to RFA becoming widely used during the 21st century. RFA procedures are performed under image guidance (such as X-ray screening, CT scan or ultrasound) by an interventional pain specialist (such as an anesthesiologist), interventional radiologist, otolaryngologists, a gastrointestinal or surgical endoscopist, or a cardiac electrophysiologist, a subspecialty of cardiologists. RFA may be performed to treat tumors in the lung, liver, kidney, and bone, as well as other body organs less commonly. Once the diagnosis of tumor is confirmed, a needle-like RFA probe is placed inside the tumor. The radiofrequency waves passing through the probe increase the temperature within tumor tissue and results in destruction of the tumor. RFA can be used with small tumors, whether these arose within the organ (primary tumors) or spread to the organ (metastases). The suitability of RFA for a particular tumor depends on multiple factors. RFA can usually be administered as an outpatient procedure, though may at times require a brief hospital stay. RFA may be combined with locally delivered chemotherapy to treat hepatocellular carcinoma (primary liver cancer). A method currently in phase III trials uses the low-level heat (hyperthermia) created by the RFA probe to trigger release of concentrated chemotherapeutic drugs from heat-sensitive liposomes in the margins around the ablated tissue as a treatment for Hepatocellular carcinoma (HCC).Radiofrequency ablation is also used in pancreatic cancer and bile duct cancer. RFA has become increasingly important in the care of benign bone tumors, most notably osteoid osteomas. Since the procedure was first introduced for the treatment of osteoid osteomas in the 1990s, it has been shown in numerous studies to be less invasive and expensive, to result in less bone destruction and to have equivalent safety and efficacy to surgical techniques, with 66 to 95% of people reporting freedom from symptoms. While initial success rates with RFA are high, symptom recurrence after RFA treatment has been reported, with some studies demonstrating a recurrence rate similar to that of surgical treatment. RFA is also increasingly used in the palliative treatment of painful metastatic bone disease in people who are not eligible or do not respond to traditional therapies ( i.e. radiation therapy, chemotherapy, palliative surgery, bisphosphonates or analgesic medications). Radiofrequency energy is used in heart tissue or normal parts to destroy abnormal electrical pathways that are contributing to a cardiac arrhythmia. It is used in recurrent atrial flutter (Afl), atrial fibrillation (AF), supraventricular tachycardia (SVT), atrial tachycardia, Multifocal Atrial Tachycardia (MAT) and some types of ventricular arrhythmia. The energy-emitting probe (electrode) is at the tip of a catheter which is placed into the heart, usually through a vein. This catheter is called the ablator. The practitioner first 'maps' an area of the heart to locate the abnormal electrical activity (electrophysiology study) before the responsible tissue is eliminated. Ablation is now the standard treatment for SVT and typical atrial flutter and the technique can also be used in AF, either to block the atrioventricular node after implantation of a pacemaker or to block conduction within the left atrium, especially around the pulmonary veins. In some conditions, especially forms of intra-nodal re-entry (the most common type of SVT), also called atrioventricular nodal reentrant tachycardia or AVNRT, ablation can also be accomplished by cryoablation (tissue freezing using a coolant which flows through the catheter) which avoids the risk of complete heart block – a potential complication of radiofrequency ablation in this condition. Recurrence rates with cryoablation are higher, though. Microwave ablation, where tissue is ablated by the microwave energy 'cooking' the adjacent tissue, and ultrasonic ablation, creating a heating effect by mechanical vibration, or laser ablation have also been developed but are not in widespread use. A new and promising indication for the use of radiofrequency technology has made news in the last few years. Hypertension is a very common condition, with about 1 billion people over the world, nearly 75 million in the US alone. Complications of inadequately controlled hypertension are many and have both individual and global impact. Treatment options include medications, diet, exercise, weight reduction and meditation. Inhibition of the neural impulses that are believed to cause or worsen hypertension has been tried for a few decades. Surgical sympathectomy has helped but not without significant side effects. Therefore, the introduction of non-surgical means of renal denervation with radiofrequency ablation catheter was enthusiastically welcomed. Although, the initial use of radiofrequency-generated heat to ablate nerve endings in the renal arteries to aid in management of 'resistant hypertension' were encouraging, the most recent phase 3 studying looking at catheter-based renal denervation for the treatment of resistant hypertension failed to show any significant reduction in systolic blood pressure. Radiofrequency ablation is a dermatosurgical procedure by using various forms of alternating current. Types of radiofrequency are electrosection, electrocoagulation, electrodessication and fulguration. The use of radiofrequency ablation has obtained importance as it can be used to treat most of the skin lesions with minimal side effects and complications.