Twenty-five years of catheter ablation of ventricular tachycardia: a look back and a look forward

This article will discuss the past, present, and future of ventricular tachycardia ablation and the continuing contribution of the Europace journal as the platform for publication of milestone research papers in this field of ventricular tachycardia ablation.

Focused electric field (FEF) ablation in a left ventricular and infrared thermal imaging model: a proof-of-concept study

BACKGROUND

Currently, RF ablation is limited in its ability to deliver deep lesions, as most of the energy delivered to the tissue is dissipated in the first few millimeters from the catheter tip. Focused electric field (FEF) is a novel technology with the potential to ablate deeper than currently available RF catheters. This work is the first proof of concept of FEF technology.

OBJECTIVE

To introduce FEF technology and demonstrate its feasibility as an ablation tool.

METHODS

We constructed a FEF catheter with a truncated dome-shaped tip, creating a toroidal ablating surface. We performed ablation ex vivo in porcine hearts and examined ablation characteristics using both tissue sectioning and real-time thermal imaging.

RESULTS

RF lesions were 9.1 ± 1.0 mm wide by 6.1 ± 1.1 mm deep with ablation using a conventional irrigated tip catheter (Thermocool SF). In contrast, lesions created using FEF ablation were 12.8 ± 1.6 mm wide and 14.0 ± 1.6 mm deep. Steam pops were less frequent in the FEF group. Thermal imaging demonstrated that in contrast to an irrigated tip RF catheter, the FEF catheter generated a uniform temperature profile down to a maximum depth exceeding 15 mm.

CONCLUSION

This study is the first proof of concept of FEF technology. Using a novel toroidal catheter tip design, the electric field remains confined to a narrow tissue region, thus avoiding the rapid fall off in energy delivery from the tissue surface inherent to current RF catheter designs. FEF ablation may allow delivery of deeper ablations lesions with potentially lower risk of tissue hyperthermia than conventional catheters. Future studies are needed.

Impedance-decline-guide power control long application time bipolar radiofrequency catheter ablation

INTRODUCTION

Bipolar (BIP) radiofrequency (RF) ablation creates deep myocardial lesions but ideal energy application modes to treat ventricular arrhythmias originating from deep inside the thick myocardium have not been well established. An experimental study was performed to clarify whether high power and long application time BIP ablation were performable by impedance-decline-guide power control (PC) and whether it could create transmural lesions in the thick ventricle with a minimum risk of steam-pop.

METHODS AND RESULTS

Perfused porcine ventricle (18.4 ± 2.3 mm) was placed in an experimental bath and BIP ablation (50 W) for 120 s was attempted with catheter contact of 30-g using two protocols; fixed power (FP) and impedance-decline-guide PC. In the latter protocol, BIP ablation was started from 50 W, while the energy was decreased to 40-20 W according to the impedance decline during RF ablation. FP ablation was attempted in 30 applications and the transmural lesion was created in all 30, although steam-pop occurred in 16/30 applications (53%). Low minimum impedance, large total impedance decline (TID), and %-TID were associated with the steam-pop occurrence. PC ablation was attempted in another 21 applications, and the transmural lesion was created in all 21 without steam-pop. PC ablation was superior to FP ablation (21/21 vs. 14/30, p < .001) in the creation of a transmural lesion without resulting in steam-pop.

CONCLUSIONS

High power and long application time BIP ablation seems to be feasible according to the impedance-decline-guide approach, which could create transmural lesions in thick porcine ventricles with minimal risk of steam-pop.

A novel technique of pulmonary artery banding by means of radiofrequency ablation: An experimental study in rabbits

Background

The aim of this study was to evaluate the efficacy and feasibility of a novel method of narrowing pulmonary arteries with catheter angiography using radiofrequency energy in rabbits.

Methods

A total of nine New Zealand white rabbits weighing 3.0 to 4.2 kg each were utilized in this experimental study. After the location of pulmonary artery was confirmed by echocardiography and angiography, radiofrequency energy was applied by starting with 5 W energy for the first time and increasing by 5 W, if there was no rupture to a maximum of 20 W. Multiple applications of radiofrequency energy with different durations were performed at different levels of the pulmonary artery. Eight weeks later, surviving rabbits were sacrificed. The pulmonary arteries were removed for histological investigation.

Results

Five rabbits remained alive after the experiment. There was a significant correlation between radiofrequency power and the degree of vessel thickness change in the pulmonary artery. The endothelial integrity of the tunica intima was impaired in all groups and the diameter of vessel was thickened by an average of 3.5 times.

Conclusion

The narrowing of the pulmonary artery using radiofrequency energy was successfully performed in a small sample size of experimental animals in this study.

Increasing Lesion Dimensions of Bipolar Ablation by Modulating the Surface Area of the Return Electrode

OBJECTIVES

This study sought to examine the effect of the return electrode's surface area on bipolar RFA lesion size.

BACKGROUND

Bipolar radiofrequency ablation (RFA) is typically performed between 2 3.5-mm tip catheters serving as active and return electrodes. We hypothesized that increasing the surface area of the return electrode would increase lesion dimensions by reducing the circuit impedance, thus increasing the current into a larger tissue volume enclosed between the electrodes.

METHODS

In step 1, ex vivo bipolar RFA was performed between 3.5-mm and custom-made return electrodes with increasing surface areas (20, 80, 180 mm²). In step 2, ex vivo bipolar RFA was performed between 3.5-mm and 3.5-mm or 8-mm electrode catheters positioned perpendicular or parallel to the tissue. In step 3, in vivo bipolar RFA was performed between 3.5-mm and either 3.5-mm or 8-mm parallel electrode at the: 1) left ventricular summit; 2) interventricular septum; and 3) healed anterior infarction.

RESULTS

In step 1, increasing the surface area of the return electrode resulted in lower circuit impedance (R = -0.65; P < 0.001), higher current (R = +0.80; P < 0.001), and larger lesion volume (R = +0.88; P < 0.001). In step 2, an 8-mm return electrode parallel to tissue produced larger and deeper lesions compared with a 3.5-mm return electrode (P = 0.014 and P = 0.02). Similarly, in step 3, compared with a 3.5-mm, bipolar RFA with an 8-mm return electrode produced larger (volume: 1,525 ± 871 mm³ vs 306 ± 310 mm³, respectively; P < 0.001) and more transmural lesions (88% vs 0%; P < 0.001).

CONCLUSIONS

Bipolar RFA using an 8-mm return electrode positioned parallel to the tissue produces larger lesions in comparison with a 3.5-mm return electrode.

Bipolar radiofrequency ablation of septal ventricular tachycardia in a patient with dilated cardiomyopathy using two 8-mm tip catheters-case report

Septal ventricular tachycardias exhibit high recurrence rates after radiofrequency ablation, which is mainly attributed to the deep intramyocardial circuits and the inability to create transmural lesions with the conventional unipolar ablation. Bipolar radiofrequency ablation is feasible and it has been reported as a valid technique in these cases, leading to deeper lesion formation, high non-inducibility rates, and acceptable recurrence rates during follow-up. Our goal is to report a successful case of bipolar ablation of a septal ventricular tachycardia using a simple bipolar ablation configuration with two 8-mm tip catheters.

Impedance decrement indexes for avoiding steam-pop during bipolar radiofrequency ablation: An experimental study using a dual-bath preparation

INTRODUCTION

This experimental study was conducted to explore impedance monitoring for safely performing bipolar (BIP) radiofrequency (RF) ablation targeted to arrhythmia focus.

METHODS AND RESULTS

Using a newly designed dual-bath experimental model, contact-force-controlled (20-g) BIP ablation (50 W, 60 s) was attempted for porcine left ventricle (17.0 ± 2.7 mm thickness). BIP ablation was successfully accomplished for 60 s in 75 of the 89 RF applications (84.3%), whereas audible steam-pop occurred in the other 14 RF applications (15.7%). Receiver operating characteristic analysis demonstrated the optimal predictive values regarding the occurrence of steam-pop as follows; thinner myocardial wall (≤14.8 mm), low minimum impedance (≤89 ohm), greater total impedance decrement (TID) (≤ -25 ohm) and %TID (≤ -22.5%). Greater impedance decrement was not observed immediately preceding the occurrence of steam-pop but appeared around 15 s before. Four steam-pops happened before reaching the optimal predictive values of minimum impedance, whereas all 14 steam-pops developed 11.5 ± 9.2 and 8.1 ± 8.1 s after reaching the optimal predictive values of TID and %TID, respectively. Total lesion depth (endocardial plus epicardial) was 10.7 ± 1.2 mm on average, and was well correlated with TID and %TID. Transmural lesion through the myocardial wall was created in 22 RF applications.

CONCLUSION

Relatively thinner areas of the myocardium are likely to be at greater risk for steam-pop during BIP RF ablation. Lowering the RF application energy to reduce the impedance decrement may help to lessen this risk.

Grid Mapping Catheter for Ventricular Tachycardia Ablation

Background:

A new grid mapping catheter (GMC)—allowing for bipolar recordings of the electrograms in each orthogonal direction—became available. The aim of the current study is to evaluate the utility of the GMC in creating substrate and ventricular tachycardia (VT) activation maps during VT ablation procedures.

Methods:

From December 2017 to July 2018, 41 consecutive patients undergoing a VT ablation procedure using a GMC were studied. During the substrate mapping, 3 different maps were created using the 3 GMC bipolar configurations (along the spline, across the spline, HD wave solution); the low voltage area and late potential areas were compared. In case of inducible VTs, the GMC was used to create the VT activation maps focusing on the diastolic interval. The relation between diastolic activities during VT and substrate abnormality during sinus rhythm was also investigated.

Results:

The median low-voltage area drawn by the HD wave configuration was 28.9 cm 2 , 13% and 15% smaller than the low-voltage areas identified by the along and across configuration, respectively (33.1 and 33.9 cm 2 ; P <0.0001). The late potential areas obtained with the 3 GMC configuration did not differ ( P >0.05). VT activation mappings using the GMC were performed in 40 VTs, visualizing the full diastolic pathway in 22 (55%) of them. While the latest late potential areas were included in VT diastolic pathway in 17 VTs, the other 6 VTs showed mismatching of them. Identifying the full diastolic pathway led to a higher ongoing VT termination rate during the ablation than in case of partial recordings (88% versus 45%; P =0.03); furthermore, in the former situation, the noninducibility of the targeted VTs was achieved in all cases.

Conclusions:

The GMC is a useful tool for performing substrate and VT activation mappings during the VT ablation procedure, precisely identifying the low-voltage areas and quickly visualizing the diastolic pathways.

Radiofrequency catheter ablation of accessory pathways at the site of prior valve surgery

BACKGROUND

Radiofrequency catheter ablation (RFCA) for accessory pathways (APs) at the site of prior valve surgery (VS) remains challenging. We aimed to clarify the factors associated with successful RFCA for such APs.

METHODS

Upon reviewing a RFCA registry and previous case reports, we included nine patients who underwent RFCA of APs at the site of prior VS (total-VS group; age, 34.0 [24.5-45.0] years; men, 4/9) and 196 patients who underwent RFCA of APs with no history of VS (no-VS group; age, 40.5 [23.0-54.0] years; men, 114/196). Electrophysiological features, procedural details, and outcomes were examined.

RESULTS

Accessory pathway exhibited decremental conduction in four of nine patients in the total-VS group. The number of RFCA attempts was significantly higher in the total-VS group than in the no-VS group (10.0 [4.5-14.5] vs 2.0 [1.0-3.0]; P < 0.001). In four patients who underwent mitral VS, successful RFCA was achieved using the transaortic approach, coronary sinus (CS) approach, or bipolar ablation. In three patients who underwent tricuspid VS, successful RFCA was achieved using the above-prosthetics or trans-prosthetics approach. In two patients, RFCA failed. The trans-prosthetics approach and bipolar ablation technique were effective. The transaortic and CS approaches were occasionally effective. The transseptal approach was ineffective.

CONCLUSIONS

Successful RFCA of APs at the site of prior VS can be achieved by detailed mapping of the areas both above and below the prosthetic valve, as well as by ensuring effective radiofrequency energy delivery using various catheter approaches and RFCA techniques.

Role of catheter ablation in patients with ischemic ventricular tachycardia: From basic to clinical practice

Catheter ablation provides a therapeutic option for decreasing episodes of ventricular tachycardia in patients with coronary artery disease. Clinical studies show improvement with catheter ablation in reducing arrhythmia recurrence and therapy from implantable defibrillators, but not in decreasing mortality. Ablation can be an important tool for patients with electrical storm. Overall, complication rates of catheter ablation are acceptable, but recurrence rates are still significant. Advances in mapping and ablation technologies could be expected to improve the success rates and reduce the mortality.

Use of Bipolar Radiofrequency Catheter Ablation in the Treatment of Cardiac Arrhythmias

Background:

Arrhythmia management is a complex process involving both pharmacological and non-pharmacological approaches. Radiofrequency ablation is the pillar of non-pharmacological arrhythmia treatment. Unipolar ablation is considered to be the gold standard in the treatment of the majority of arrhythmias; however, its efficacy is limited to specific cases. In particular, the creation of deep or transmural lesions to eliminate intramurally originating arrhythmias remains inadequate. Bipolar ablation is proposed as an alternative to overcome unipolar ablation boundaries.

Results:

Despite promising results gained from in vitro and animal studies showing that bipolar ablation is superior in creating transmural lesions, the use of bipolar ablation in daily clinical practice is limited. Several studies have been published showing that bipolar ablation is effective in the treatment of clinical arrhythmias after failed unipolar ablation, however, there is inconsistency regarding the safety of bipolar ablation within the available research papers. According to research evidence, the most common indications for bipolar ablation use are ventricular originating rhythmic disorders in patients with structural heart disease resistant to standard radiofrequency ablation.

Conclusion:

To allow wider clinical application the efficiency and safety of bipolar ablation need to be verified in future studies.

Catheter ablation of ventricular tachycardia in nonischemic cardiomyopathy

The number of patients with nonischemic cardiomyopathy (NICM) undergoing catheter ablation of ventricular tachycardia (VT) has increased by the years, however, there are no randomized studies of VT ablation in this population. Many studies have reported more mixed or inferior outcome after the ablation in patients with NICM as compared to in those with ischemic cardiomyopathy (ICM)-likely because of the heterogeneous VT substrates in each etiology. While, various ablation strategies for substrate modification in the setting of ICM, including low voltage area ablation, late potential abolition, and local abnormal ventricular activity elimination, have been well established, it is still unknown which ablation strategy is effective for prevention of recurrence VTs in NICM patients. Therefore, this review will highlight the recent progress made in VT ablation in patients with NICM.

Role of contact force in ischemic scar-related ventricular tachycardia ablation; optimal force required and impact of left ventricular access route

BACKGROUND

Contact force-sensing technology has become a widely used addition to catheter ablation procedures. Neither the optimal contact force required to achieve adequate lesion formation in the ventricle, nor the impact of left ventricular access route on contact force has been fully clarified.

PATIENTS AND METHODS

Consecutive patients (n = 24) with ischemic cardiomyopathy who underwent ablation for scar-related ventricular tachycardia were included in the study. All ablations (n = 25) were performed using irrigated contact force-sensing catheters (Smart Touch, Biosense Webster). Effective lesion formation was defined as electrical unexcitability post ablation at sites which were electrically excitable prior to ablation (unipolar pacing at 10 mA, 2 ms pulse width). We explored the contact force which achieved effective lesion formation and the impact of left ventricular access route (retrograde aortic or transseptal) on the contact force achieved in various segments of the left ventricle. Scar zone was defined as bipolar signal amplitude < 0.5 mV.

RESULTS

Among 427 ablation points, effective lesion formation was achieved at 201 points (47.1%). Contact force did not predict effective lesion formation in the overall group. However, within the scar zone, mean contact force ≥ 10 g was significantly associated with effective lesion formation [OR 3.21 (1.43, 7.19) P = 0.005]. In the 12-segment model of the left ventricle, the retrograde approach was associated with higher median contact force in the apical anterior segment (31 vs 19 g; P = 0.045) while transseptal approach had higher median force in the basal inferior segment (25 vs 15 g; P = 0.021). In the 4-segment model, the retrograde approach had higher force in the anterior wall (28 vs 16 g; P = 0.004) while the transseptal approach had higher force in the lateral wall (21 vs 18 g; P = 0.032). There was a trend towards higher force in the inferior wall with the transseptal approach, but this was not statistically significant (20 vs 15 g; P = 0.063).

CONCLUSIONS

In patients with ischemic cardiomyopathy, a mean contact force of 10 g or more within the scar zone had the best correlation with electrical unexcitability post ablation in our study. The retrograde aortic approach was associated with better contact force over the anterior wall while use of a transseptal approach had better contact force over the lateral wall.

RF-energised intracoronary guidewire to enhance bipolar ablation of the interventricular septum: in-silico feasibility study

PURPOSE

Although bipolar radiofrequency (RF) ablation (RFA) is broadly used to eliminate ventricular tachycardias in the interventricular septum wall, it can fail to create transmural lesions in thick ventricular walls. To solve this problem, we explored whether an RF-energised guidewire inserted into the ventricular wall would enhance bipolar RFA in the creation of transmural lesions through the ventricular wall.

METHODS

We built three-dimensional computational models including two irrigated electrodes placed on opposing sides of the interventricular septum and a metal guidewire inserted into the septum. Computer simulations were conducted to compare the temperature distributions obtained with two ablation modes: bipolar mode (RF power delivered between both irrigated electrode) and time-division multiplexing (TDM) technique, which consists of activating the bipolar mode for 90% of the time and applying RF power between the guidewire and both irrigated electrodes during the remaining time.

RESULTS

The TDM technique was the most suitable in terms of creating wider lesions through the entire ventricular wall, avoiding the hour-glass shape of thermal lesions associated with the bipolar mode. This was especially apparent in the case of thick walls (15 mm). Furthermore, the TDM technique was able to create transmural lesions even when the guidewire was displaced from the midplane of the wall.

CONCLUSIONS

An RF-energised guidewire could enhance bipolar RFA by allowing transmural lesions to be made through thick ventricular walls. However, the safety of this new approach must be assessed in future pre-clinical studies, especially in terms of the risk of stenosis and its clinical impact.

Treatment of Ventricular Arrhythmias and Use of Implantable Cardioverter-Defibrillators to Improve Survival in Older Adult Patients with Cardiac Disease

Ventricular arrhythmia (VA) and sudden cardiac death (SCD) are well-recognized problems in the overall heart failure population, but treatment decisions can be more complex and nuanced in older patients. Sustained VA does not always lead to SCD, but identifies a higher risk population and may cause significant symptoms. Antiarrhythmic drugs (AAD) and catheter ablation are the mainstays for prevention of VA, but have not been shown to improve mortality. The value of implantable cardiac defibrillators (ICDs) may be influenced by patient age. This article discusses long-term treatment of VA and the use of ICDs in the elderly.

Radiofrequency Ablation Using an Open Irrigated Electrode Cooled With Half-Normal Saline

OBJECTIVES

This study evaluated the use of half-normal saline (HNS) as the radiofrequency ablation (RFA) cooling irrigant.

BACKGROUND

Some instances of ventricular arrhythmia may originate deep within myocardium and can be refractory to standard ablation using open irrigated RFA. Recent data suggest that deeper ablation lesions can be created by decreasing the irrigant ionic concentration delivered through open irrigated RFA than by using normal saline (NS).

METHODS

Bovine myocardium was placed in a circulating saline bath. Two RFA catheters were oriented across from each other, with myocardium in between. Sequential unipolar HNS-irrigated RFA was performed and compared to bipolar ablation by using NS or HNS. Unipolar HNS ablation of the ventricles in a porcine model was performed and compared to ablation using NS.

RESULTS

Sequential ex vivo unipolar RFA with HNS produced larger lesions than sequential unipolar RFA with NS and produced lesions of similar size to those created with bipolar RFA using NS. Ex vivo bipolar RFA using HNS created the largest lesions. In vivo unipolar HNS ablation in porcine endocardium created larger lesion volumes, 152.9 ± 29.2 μl, compared to 94.7 ± 33.4 μl for unipolar ablation using NS.

CONCLUSIONS

By decreasing ionic concentration and charge density in RFA using HNS instead of NS irrigant, larger ablation lesions can be created and are similar in size to lesions created using bipolar ablation. This may be a useful ablation strategy for deep myocardial circuits refractory to standard ablation. Further studies are needed to evaluate this novel RFA strategy.

Alternative Approaches for Ablation of Resistant Ventricular Tachycardia

Ventricular tachycardia (VT) ablation is usually performed with an ablation catheter that delivers unipolar radiofrequency (RF) energy to eliminate the re-entry circuit responsible for VT. However, there are some instances when unipolar RF ablation fails, notably in VTs with a deep intramural origin, or cases in which epicardial access is not attainable due to prior cardiac surgery. To overcome these limitations, several alternative approaches have been used in clinical practice, including alcohol ablation or coil embolization, simultaneous unipolar or bipolar RF ablation, surgical ablation, or noninvasive ablation with stereotactic radiosurgery. This review article describes some of these alternative techniques.

Catheter Ablation for Ventricular Tachycardia in Patients with Nonischemic Cardiomyopathy

Although catheter ablation has been successful in reducing the recurrence of ventricular tachycardia in patients with ischemic disease, outcomes in patients with nonischemic cardiomyopathy (NICM) have not met with the same results. Success is predicated on a methodical approach to diagnosis of disease type and identification of critical substrate, and the ablation strategies used. Cardiac MRI with delayed enhancement is able to identify areas of substrate involvement, particularly in situations when conventional catheter mapping is not able to do so. Radiofrequency needle, irrigated bipolar radiofrequency, and transcoronary alcohol ablation are effective and alternative techniques to endocardial and epicardial ablation.

Electrode Contact Force-Controlled Bipolar Radiofrequency Ablation: Different Effects on Lesion Size between Dual- and Single-Bath Preparations

BACKGROUND

During bipolar (BIP) radiofrequency (RF) ablation using two catheters in humans, each catheter is placed in separate cardiac chambers or spaces. We developed a contact force-controlled experimental preparation, and compared measurements made with two catheters placed in a single bath (SB), versus each catheter placed in separate baths, in order to assess the preparation-dependent differences in the results of BIP-RF ablation.

METHODS

In the SB experiments, a porcine heart was placed in the center of the bath, while in the dual-bath (DB) experiments, it was placed between two half baths communicating through windows.

RESULTS

The initial impedance was greatest (110.5 ± 7.2 Ω) with the BIP-DB, followed by the BIP-SB (92.0 ± 5.6 Ω) and the unipolar (UNIP) DB (84.9 ± 4.7 Ω) configurations. During 50-W ablation for 60 seconds at a 20-g contact force, the root mean square voltage was 75.7 ± 2.5 V in the BIP-DB, 68.0 ± 2.1 V in the BIP-SB, and 66.8 ± 2.0 V in the UNIP-DB. The mean surface lesion diameters were similar among the three configurations. However, the endocardial lesion depth was 5.60 ± 0.56 mm with the BIP-DB, 4.71 ± 0.64 mm with the BIP-SB, and 4.24 ± 0.58 mm with the UNIP-DB configuration. On average, the endocardial lesions were significantly deeper than the epicardial ones.

CONCLUSIONS

BIP ablation created much deeper lesions as compared to UNIP ablation. Lesion depth could be different depending on experimental preparation, and contact force-controlled DB preparation may be a much more appropriate model for studying the effects of BIP ablation.

Bipolar irrigated radiofrequency ablation of resistant ventricular tachycardia with a septal intramural origin: the initial experience and a description of the method

Bipolar radiofrequency (RF) ablation is effective in treatment of ventricular tachycardia originating from thick interventricular septum. The RF generator and CARTO system can be used to precisely and safely perform ablation. Standard ablation catheter can be used with indifferent ablation electrode connected to the electrode receptacle in RF generator with custom-made cable.

Ablation of ischemic ventricular tachycardia: evidence, techniques, results, and future directions

PURPOSE OF REVIEW

This article summarizes current understanding of the arrhythmia substrate and effect of catheter ablation for infarct-related ventricular tachycardia, focusing on recent findings.

RECENT FINDINGS

Clinical studies support the use of catheter ablation earlier in the course of ischemic disease with moderate success in reducing arrhythmia recurrence and shocks from implantable defibrillators, although mortality remains unchanged. Ablation can be lifesaving for patients presenting with electrical storm. Advanced mapping systems with image integration facilitate identification of potential substrate, and several different approaches to manage hemodynamically unstable ventricular tachycardia have emerged. Novel ablation techniques that allow deeper lesion formation are in development.

SUMMARY

Catheter ablation is an important therapeutic option for preventing or reducing episodes of ventricular tachycardia in patients with ischemic cardiomyopathy. Present technologies allow successful ablation in the majority of patients, even when the arrhythmia is hemodynamically unstable. Failure of the procedure is often because of anatomic challenges that will hopefully be addressed with technological progress.

Better Lesion Creation And Assessment During Catheter Ablation

Permanent destruction of abnormal cardiac tissue responsible for cardiac arrhythmogenesis whilst avoiding collateral tissue injury forms the cornerstone of catheter ablation therapy. As the acceptance and performance of catheter ablation increases worldwide, limitations in current technology are becoming increasingly apparent in the treatment of complex arrhythmias such as atrial fibrillation. This review will discuss the role of new technologies aimed to improve lesion formation with the ultimate goal of improving arrhythmia-free survival of patients undergoing catheter ablation of atrial arrhythmias.

Management of ventricular arrhythmias in structural heart disease

Ventricular arrhythmias (VA) are a source of significant morbidity and mortality in patients with structural heart disease (SHD). The advent of the implantable cardiac defibrillator (ICD) has had a positive effect on mortality, but the associated morbidity remains a significant problem. Modern treatment of VA has advanced far beyond medical therapy and includes strategies as simple as intelligent ICD programming and as complex as catheter ablation (CA). In these pages, the spectrum of management strategies will be discussed; from anti-arrhythmic drugs and ICD implantation and programming to CA and autonomic modulation. The focus of this review will be on strategies for secondary prevention of VA in patients with SHD, supported by clinical evidence for their utilization.

New Ablation Technologies and Techniques

Catheter ablation is an established treatment strategy for a range of different cardiac arrhythmias. Over the past decade two major areas of expansion have been ablation of atrial fibrillation (AF) and ventricular tachycardia (VT) in the context of structurally abnormal hearts. In parallel with the expanding role of catheter ablation for AF and VT, multiple novel technologies have been developed which aim to increase safety and procedural success. Areas of development include novel catheter designs, novel navigation technologies and higher resolution imaging techniques. The aim of the present review is to provide an overview of novel developments in AF ablation and VT ablation in patients with of structural cardiac diseases.