Carto Ablation For Complex Arrhythmias

What is carto ablation ?

It is a technique to treat patients with different arrhythmias. Catheter ablation is assuming a pivotal role in the management abd treatment of Cardiac arrhythmias. Conventional fluoroscopic catheter mapping has restricted spatial resolution and involves prolonged fluoroscopy. The non fluoroscopic electro anatomic mapping technique or procedure CARTO has been developed to overcome these hitches.

Some electro physiologists use electro anatomic mapping systems like NaVx and CARTO(biosense Webster) which provide colourful 3D images that show variations in a patients anatomy. These systems may help doctors in making sure that lesions are no gaps and in reducing complications, such as perforation of the heart or oesophagus. In addition the use of an electro mapping system may lesser the time, that doctors and patients are exposed to radiation. The CARTO system advances understanding of arrhythmias, and increases the safety, efficacy of radiofrequency of ablation.

How it works ?

Mapping of the heart is one of the basic technology parameter in diagnosing and Treatment of Cardiac Arrhythmias. The principles and clinical experience with anelectroanatomic mapping system that allow 3-dimensional reconstruction of cardiac cavities using aggregate information of the position of the mapping catheter in the electromagnetic field and local activation time. Advantages of the system, as compared to the conventional endocardial mapping with fluoroscopy are discussed, especially detailed and accurate visualization of the activation pattern of arrhythmias and easy catheter navigation to the desired arrhythmic substrate during radiofrequency ablation.

Cardiac mapping, broadly speaking includes various techniques. Electrical activity in the heart can recorded from the body surface (ECG mapping), from the surface of the heart epicardial mapping or from endocardium. Signals can be acquired simultaneously from various sites or sequentially, point by point, and theses data can be visualized parameters encoded. Examples of sequence of activation, map of area with equal potentials or map of propagation of activation wave. Due to recent technological development there have appeared new mapping systems that can be used for extensive endocardial mapping of cardiac arrhythmias. One of these mapping system is called CARTO and was developed in the middle of 90s.

Electro anatomical mapping :

During conventional electrophysiologic mapping the activation time of endocardial signals is compared to referential signal. Limitation of such a technique is the need of fluoroscopic control of the catheter’s position. Besides the risk associated with the use of Xrays, fluoroscopy does not provide accurate information on orientation and position of the catheter tip in three-dimensional heart chamber. This is important e when repeated catheter navigation to desired location is needed during radiofrequency ablation.

In parallel the CARTO system uses electromagnetic fields for localization of the catheter. During the procedure there are magnetic coils placed under the patient that generate low energetic electromagnetic fields and non homogenic electromagnetic fields around patient chest. The mapping catheter contains magnetic sensor that is localized near distal 4mm electrode that allows precious localization of catheter position inside the mapped cavity.

In a CARTO procedure the table where the patients lies has an electromagnetic pad that tracks movement of the catheter, whereas in an EnSite NaVx procedure patches on the patients skin track the catheter. Both systems use algorithms to translate data on the catheter’s location into a 3Dimage. It usually takes about 20mins to complete this procedure.

Electro magnetic mapping systems are also knownas called multi modality mapping or image integration systems because they can show pictures or data from other source options. For instance patient’s CT or MRI scans take a few days or weeks before the procedure may be loaded onto NaVx or CARTO and matched with the real time 3Dimage of the heart. The doctorsdoes this by moving the catheter verifying its location in the heart, and taking note of large structures like the pulmonary veins. After several common areas or location points on the two images are gauged the system merges the real time view and pre procedure scan into one 3D picture. However this positioning of anatomy can even change without just a week so pre procedure scan doesn’t easily match with the real time view of the heart, it can take much longer. Electro magnetic mapping system also provide real time data on electrical activity within the heart, which means that electrophysiologists can see whether conduction block has provide other real time of information, such as atrial easily monitor the patient during the procedure.

Uses of the system :

Three dimensional anatomical mapping is an established method facilitating ablation of cardiac arrhythmias or irregular heart beat. It is a widely used method especially for complex arrhythmias such as atrial fibrillation and ventricular tachycardia.

These mapping systems have helped to decrease procedural complexities. The EnSite NavX system uses impendence measurements between the individual catheter electrodes and the patches placed on the patient's chest and abdomen locations. The CARTO system utilizes magnetic location technology to provide precise visualization of the magnet sensor-equipped catheter tip.

These two systems were compared in only a few set of circumstances. Varied results have been found in simple ablations versus more complex ablation of atrial fibrillation. Advances resulted in the development of new versions of both systems. Carto Express version allows faster mapping and reconstruction of heart cavities and great vessels geometry more precisely as compared to previous versions of Carto XP. EnSite Velocity system incorporates more precise and accurate catheter visualization, and allows quicker and better mapping as compared to previous version of EnSite.

Radio Frequency treatment has taken a decisive and important place in the treatment of complex arrhythmias and, particularly, in the treatment of atrial fibrillation. Radiofrequency treatment is the first-choice treatment for arrhythmias, including complex arrhythmias and also atrial fibrillation, due to the greater benefit/risk ratio compared with anti-arrhythmic drugs. Arrhythmias such as atrial fibrillation require cumbersome procedures with associated risks such as X-ray exposure or complications such as tamponade. Robotic magnetic navigation is a technique well suited to the treatment of arrhythmias, on account of its reliability, the sig reduction in X-ray exposure for both patient and operator, and the v low risk of perforation. Advancement will likely improve results and procedure.

How it is better than other systems :

Cardiac electrophysiology has moved a GREAT way forward during recent decades in the line and treatment of complex cardiac arrhythmias. Contemporary electro-anatomical mapping systems, along with state-of-the-art technology in the manufacture of electrophysiology catheters and cardiac imaging modalities, have enriched our medical armamentarium, enabling the implementation of various mapping techniques in electrophysiology procedures. Beyond conventional mapping strategies, ablation of complex fractionated electro-grams and rotor ablation in atrial fibrillation ablation procedures, the identification and modification of the underlying arrhythmogenic substrate has emerged as a strategy that leads to improved results. Arrhythmogenic substrate modification also has a major role in ventricular tachycardia ablation procedures. Optimisation of contact between tissue and catheter and image integration are a further step forward to augment our precision and effectiveness.

Since the introduction of electroanatomical mapping (EAM) into clinical practice in 1997, remarkable leap has been made in catheter infrastructure, signal recording and processing, catheter guidance and visualisation and simultaneous real-time depiction and processing of different types of critical information during an ablation procedure.

Contemporary three-dimensional (3D) EAM systems (EAMS) have reduced the need for fluoroscopic visualisation of catheters. They have also created a precise ‘virtual environment system’ capable of guiding complex mapping and ablation procedures. The latter is enhanced by integrating data from other imaging modalities, such as computed tomography (CT) and cardiac magnetic resonance (CMR). Contact-based EAM remains the standard of care in most cases.

Conclusion :

Electroanatomic mapping system CARTO is modern electrophysiological mapping system that allows superposition of electrophysiologic data and cardiac anatomy. This results in three dimensional reconstruction of selected heart chamber together with color code activation sequence and /or voltage. Analysis of these three dimensional maps or outputs help to understand more precisely the mechanism of arrhythmia. The system allows precise orientation within mapped cavity and design of ablation lines between two anatomical barriers. In comparison with conventional mapping technique the success rate of catheter ablations are good sans Radiation.

Finally electro-anatomic mapping allows precise depiction of scar extent after myocardial infarction and RF ablation arrhythmogenic substrate during sinus rhythm.



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