High‐density contact and noninvasive mapping of focal atrial tachycardia: Evidence of dual endocardial exits from an epicardial focus

We report a case of recurrent focal atrial tachycardia (AT) which mechanisms could be resolved by using noninvasive electrocardiographic imaging (ECGI) reconstructing epicardial potentials and rapid high‐density endocardial contact mapping (Rhythmia?, Boston Scientific, Natick, MA, USA). ECGI demonstrated focal activity from the anterior of the left superior pulmonary vein antrum, although Rhythmia? showed focal activity from the high anterior left atrium with the 2^nd focus originating from the site where identical to the focus on the ECGI map with slightly delay (by 8 ms). Elimination of the AT by radiofrequency applications for both of the endocardial focuses indicated the dual endocardial exits from an epicardial focus.     

A Nonfluoroscopic Technique for Coronary Arteries Three‐Dimensional Mapping during Epicardial Ventricular Tachycardia Ablation

When performing epicardial ablation of ventricular tachycardia (VT), caution must be taken not to damage the coronary arteries. We report a case in which a new, nonfluoroscopic technique for incorporating an accurate, real‐time reconstruction of the main coronary vessels into a three‐dimensional electroanatomic map was used for epicardial VT ablation.     

Coexistence of a permanent form of a junctional reciprocating tachycardia and coronary sinus aneurysm: A case report

A 58‐year‐old man with a long R‐P' narrow QRS tachycardia underwent an electrophysiological study. The tachycardia was diagnosed as a permanent form of junctional reciprocating tachycardia (PJRT), and the earliest atrial activation site during tachycardia was coronary sinus (CS) ostium. Radiofrequency ablation at the site was initially not successful because the tip impedance and temperature were unstable. After changing of the ablation catheter to that with contact force sensor, the accessory pathway was immediately ablated and the PJRT was no longer induced. A retrograde CS angiogram revealed a fusiform aneurysm, which was located at the earliest activation site during the tachycardia.     

Contrast‐Enhanced Transrectal Ultrasound for Follow‐up After Focal HIFU Ablation for Prostate Cancer

The optimal strategy for imaging after focal therapy for prostate cancer is evolving. This series is an initial report on the use of contrast‐enhanced transrectal ultrasound (TRUS) in follow‐up of patients after high‐intensity focused ultrasound (HIFU) hemiablation for prostate cancer. In 7 patients who underwent HIFU hemiablation, contrast‐enhanced TRUS findings were as follows: (1) contrast‐enhanced TRUS clearly showed the HIFU ablation defect as a sharply marginated nonenhancing zone in all patients; (2) contrast‐enhanced TRUS identified suspicious foci of recurrent enhancement within the ablation zone in 2 patients, facilitating image‐guided prostate biopsy, which showed prostate cancer; and (3) contrast‐enhanced TRUS findings correlated with multiparametric magnetic resonance imaging and biopsy histologic findings.     

Catheter Ablation of Electrical Storm Due to Monomorphic Ventricular Tachycardia in Patients with Nonischemic Cardiomyopathy: Acute Results and Its Effect on Long‐Term Survival

Background: Electrical storm due to recurrent ventricular tachycardia (VT) in patients with implantable cardioverter defibrillator (ICD) can adversely affect their long‐term survival. This study evaluates the efficiency of the radiofrequency catheter ablation of electrical storm due to monomorphic VT in patients with idiopathic dilated cardiomyopathy (DCM) and assesses its long‐term effects on survival. Methods and Results: Between April 2004 and October 2008, 13 consecutive patients (nine men, mean age 56.8 ± 17.8 years) with DCM and electrical storm due to monomorphic VT who had ICD underwent 17 catheter ablation procedures, including four epicardial, at our center. Acute complete success was defined as the lack of inducibility of any VT at the end of procedure during programmed right ventricular stimulation and was achieved in eight patients (61.5%). During a median follow‐up of 23 months (range 3–63 months) nine patients (69%) were alive and eight patients (61.5%) were free from VT recurrence. Among those with acute complete (n = 8) and partial (n = 5) success, seven patients (87.5%) and one patient (20%) were free from any VT recurrence and ICD therapy, respectively (P = 0.025). Among those with acute complete and partial success, seven patients (87.5%) and two patients (40%) were alive, respectively (Mantel‐Cox test P = 0.082). Among those who had an initially failed endocardial ablation (n = 8), four underwent further epicardial ablation that was completely successful in three patients (75%). Conclusion: Catheter ablation in patients with DCM and electrical storm due to monomorphic VT who had an ICD prevents further VT recurrence in 61.5% of the patients. Complete successful catheter ablation may play a protective role and was associated with reduced mortality during the follow‐up period. More aggressive ablation strategies in patients with initially failed endocardial ablation might improve the long‐term survival of these patients; however, further studies are needed to clarify this issue. (PACE 2010; 33:1504–1509)     

Successful epicardial catheter ablation of a septal ventricular tachycardia after myocardial infarction

A 55-year-old man underwent catheter ablation of ventricular tachycardia (VT) after anterior myocardial infarction. Although electrophysiological study suggested that the VT originated from the septum, biventricular endocardial irrigated radiofrequency ablation failed to interrupt the VT. Epicardial ablation at the site located halfway between the lesions in the right and left ventricles via a pericardial approach eliminated the VT, suggesting that the VT likely originated from the top of the septum. When VTs originating from the upper septum are refractory to endocardial ablation, epicardial mapping and ablation may be considered because only that site may be accessible with an epicardial approach.     

High‐frequency components in ECG analysed in guinea‐pig Langendorf preparations

High‐frequency components in ECG during global ischaemia were studied in isolated guinea‐pig hearts perfused ad modum Langendorf. Electrocardiograph recordings were carried out from the epicardial surface both in normo‐ and low‐flow perfusion. After bandpass filtering (5–500 Hz), signal‐averaging, was undertaken. The high‐frequency components either increased or decreased after low‐flow perfusion was instituted. Root‐mean‐square voltage (RMS) of the depolarization signal correlated poorly with the signal amplitude, but highly with the first and second derivative, i.e. the velocity and the acceleration of the signal. It is concluded that high‐frequency components are not pathological phenomena per se, but reflect the shape of the original electrocardiographic signal.     

Contrast‐Enhanced Sonographically Guided Thermal Ablation for Treatment of Solid‐Organ Hemorrhage

The purpose of this series was to preliminarily evaluate the use of contrast‐enhanced sonographically guided percutaneous thermal ablation in the evaluation and treatment of solid‐organ bleeding by retrospectively analyzing 6 cases observed in clinical practice. Six patients who underwent contrast‐enhanced sonographically guided thermal ablation for treatment of solid‐organ bleeding (5 in liver and 1 in spleen) from December 2005 to August 2012 were included in this series. Clinical information, contrast‐enhanced sonograms before and after ablation, and the ablation method were retrospectively collected and analyzed. In 5 of the 6 patients, the location of the bleeding lesion was clearly seen. Hemostasis was successfully achieved in 4 of these 5 patients: 1 by radiofrequency ablation and 3 by microwave ablation. Ablation failed to achieve hemostasis in 1 patient who had postbiopsy splenic arterial bleeding because the bleeding vessel was a thick branch of the splenic artery. In the sixth remaining patient, who had bleeding after liver biopsy, hemostasis failed because contrast‐enhanced sonography did not precisely locate the bleeding lesion; hence, the ablation zone did not cover the whole lesion. Contrast‐enhanced sonographically guided ablation can be an alternative choice for treating solid‐organ bleeding because of its effectiveness and minimal invasiveness. However, it should be carefully investigated for those in whom the bleeding lesion cannot be located by contrast‐enhanced sonography and in those who have bleeding in a large vessel.     

Five‐year follow‐up report: Box lesion radiofrequency ablation procedure for atrial fibrillation under video‐assisted thoracoscope

We report the initial 5‐year follow‐up of a novel mini‐invasive procedure for epicardial ablation for the treatment of atrial fibrillation. The initial 5‐year survival rate is acceptable and comparable with that of hybrid ablation. And this shared procedure has the advantages of shorter operation time and less surgical trauma.     

Electroanatomic Mapping to Identify Breakthrough Sites in Recurrent Typical Human Flutter

SRA, J., et al. : Electroanatomic Mapping to Identify Breakthrough Sites in Recurrent Typical Human Flutter. The accuracy of conventional techniques in localizing previous radiofrequency (RF) ablation sites and thus breakthrough sites of recurrent atrial flutter is somewhat limited. We investigated the role of electroanatomic mapping for identifying breakthrough sites or "gaps" at the tricuspid annulus and inferior vena cava (IVC)/eustachian ridge isthmus to help RF ablation in patients with recurrent typical flutter. Twelve patients (  8 men, 4 women, age 63 ± 10 years  ) with recurrent typical atrial flutter were included in the study. An electroanatomic mapping system (CARTO) was used to create a voltage map and activation and propagation patterns in the right atrium. Detailed voltage, activation, and propagation mapping of the tricuspid annulus and IVC/eustachian ridge isthmus allowed precise identification of gaps in all 12 patients at the tricuspid annulus (eight sites), IVC ridges (two sites), mid-isthmus region (one site), and tricuspid annulus and IVC ridges (one site). Radiofrequency energy directed at these sites eliminated atrial flutter in all 12 patients, confirmed by noninducibility of atrial flutter and demonstration of conduction block during atrial pacing on either side of the lesion lines. During a mean follow-up of  14.8 ± 3.5 months  (  range 8–19 months  ), paroxysmal atrial flutter recurred in only one patient and was subsequently treated with amiodarone, although this had been ineffective prior to ablation. Electroanatomic mapping can precisely identify gaps in the lesion line responsible for breakthrough of recurrent typical atrial flutter at the tricuspid annulus and at the IVC/eustachian ridge isthmus. These sites can be targeted with RF ablation with a high degree of success.     

Ablation of ventricular fibrillation in an orthotopic heart lung transplant

Arrhythmia is well described following cardiac transplantation. We report a case of recurrent ventricular fibrillation (VF) originating from an orthotopic cardiac allograft. VF was consistently initiated on each occasion by a relatively early-coupled monomorphic ventricular ectopic. Antiarrhythmic agents failed to suppress the arrhythmia. Electrophysiological testing with noncontact mapping showed a high-frequency potential at the earliest activation site. Radiofrequency ablation resulted in abolition of ventricular ectopy with no further VF recurrence. Although there is substantial experience with ablation of atrial tachycardias in this setting, experience with ablation for ventricular arrhythmias is limited and ablation of VF not described.     

Epicardial ablation utilizing remote magnetic navigation in a patient with Brugada syndrome and inferior early repolarization

We report a case of epicardial ablation in a combined Brugada and inferior early repolarization syndrome patient with recurrent defibrillator therapy for spontaneous ventricular fibrillation. Electroanatomic mapping and ablation were achieved with remote magnetic navigation. Highly fractionated electrograms were seen epicardially in the anterior right ventricular outflow tract (RVOT) and at the anterior‐inferior right ventricle. Ablation of the RVOT region resulted in resolution Brugada pattern electrocardiogram. The inferior early repolarization persisted despite ablation of the inferior right ventricular epicardium. Our patient remained event free at 12‐months follow‐up.     

Site‐specific tissue inhibitor of metalloproteinase‐1 governs the matrix metalloproteinases‐dependent degradation of crosslinked collagen scaffolds and is correlated with interleukin‐10

We have previously shown that the foreign body reaction (FBR) against crosslinked collagen type I (Col‐I) differs between subcutaneous and epicardial implantation sites; Col‐I was quickly degraded epicardially, whereas degradation was attenuated subcutaneously. The current study set out to dissect the nature and regulation of the MMP‐based degradation of implanted Col‐I in mice during the FBR. Immunohistochemistry showed that MMP‐2, MMP‐8 and MMP‐13 were present in subcutaneous and epicardial implants, whereas only MMP‐9 was also present epicardially. Western blotting showed that MMP‐8 and MMP‐9 were mainly present in their inactive proform. In contrast, collagenase MMP‐13 and gelatinase MMP‐2 were the predominant active MMPs at both sites. Interestingly, the major MMP inhibitor TIMP‐1 was solely observed in subcutaneous implants, which is why MMP‐13 and MMP‐2 are not able to degrade the collagen scaffold at the subcutaneous implantation site. Interleukin 10 (IL‐10), a potent inducer of TIMP‐1 expression, was also mainly detected subcutaneously; giant cells were the main source. Therefore, we surmise that IL‐10, through regulation of the balance between MMPs and TIMP‐1, suppresses the FBR against implanted biomaterials. Together, our findings would provide cues and clues to improve future therapies in regenerative medicine that are based on the tuned regulation of the degradation of biomaterial scaffolds. Copyright © 2010 John Wiley & Sons, Ltd.     

Atrial Tachycardia as a Proarrhythmic Effect of Radiofrequency Catheter Ablation for Atrioventricular Nodal Reentrant Tachycardia

Radiofrequency catheter ablation is now the first line treatment for atrioventricular nodal reentrant tachycardia. The success rate is high with a low incidence of complications. However, a possible proarrhythmic effect of radiofrequency energy has been rarely reported and no study has demonstrated a direct correlation between the anatomic site of the radiofrequency application and the origin of a new post‐ablation arrhythmia. We present a case of a focal atrial tachycardia that occurred after slow pathway radiofrequency catheter ablation for atrial nodal reentrant tachycardia and originating close to the previous ablation site. This tachycardia was successfully treated with a second ablation session. (PACE 2011; 34:e33–e37)     

Extracardiac ice formation during CoolLoop cryoablation of atrial fibrillation

A 75‐year‐old male patient was referred for longstanding atrial fibrillation ablation. We performed this procedure combining an epicardial and endocardial approach. Under general anesthesia and via a left‐sided thoracoscopic approach, we isolated the pulmonary veins (PVs) and the roofline and inferior line were created using a radiofrequency tool. To isolate the endocardial PVs, a transseptal puncture was performed via the groin, and a cryoablation CoolLoop catheter (AFreeze GmbH, Innsbruck, Austria) was advanced into the left atrium. Ice crystals started to appear on the epicardial surface of the left inferior PV antrum after 121 seconds later, those crystals had formed an ice plaque. For the first time in humans, we were able to visualize the transmural effects of cryothermal energy ablation via a CoolLoop catheter on the epicardial surface of the ostium of the PV.     

High‐Intensity Focused Ultrasonography and Radiofrequency Ablation of Renal Cell Carcinoma Arisen in Transplanted Kidneys: Single‐Center Experience With Long‐Term Follow‐Up and Review of Literature

The purpose of this article is to retrospectively evaluate the long‐term outcome of patients treated with percutaneous thermoablation for renal cell carcinomas that have arisen in kidney grafts. Between April 2008 and February 2011, we treated 3 patients with renal cell carcinoma on a transplanted kidney: 2 cases were treated with high‐intensity focused ultrasonography and 1 patient with radio frequency ablation. Postprocedural ultrasonography did not reveal any complications, and contrast‐enhanced ultrasonography showed an avascular area in the treated nodules. None of the patients had recurrent tumors during a long‐term clinical and radiologic follow‐up (81, 73, and 43 months, respectively).     

Linear Ablation Following Pulmonary Vein Isolation in Patients with Atrial Fibrillation: A Meta‐Analysis

Previous studies have given conflicting data regarding the long‐term adjunctive efficacy of linear lesions (LLs) on top of pulmonary vein isolation (PVI) as an ablation strategy in patients with atrial fibrillation (AF). The aim of this meta‐analysis was to provide a detailed analysis of the available randomized controlled trials (RCTs) regarding the efficacy of LL following PVI in AF patients. Current databases were searched until October 2015. The primary outcome end point of the meta‐analysis was recurrence of any symptomatic or documented episode of AF or atrial tachycardia after a single ablation procedure with or without the use of antiarrhythmic drugs. Ten RCTs with a total of 1,446 patients were included in the meta‐analysis. The pooled analysis of five trials concerning persistent AF (PeAF) patients (400 in PVI plus LL group and 182 in PVI alone group) suggested that the addition of LL following PVI does not lead to a significant reduction in recurrent atrial tachyarrhythmias compared with PVI alone (relative ratio [RR] = 0.73, 95% confidence interval [CI]: 0.44–1.21, P = 0.22). Similarly, there was no incremental benefit of additional LL in long‐term outcomes in paroxysmal AF (PAF) patients (RR = 0.85, 95% CI: 0.68–1.05, P = 0.13). Pooling the results of all eligible trials suggested that PVI plus LL compared with PVI alone significantly increased radiofrequency time (P = 0.0002), fluoroscopy time (P < 0.00001), and procedure time (P < 0.0001). This meta‐analysis suggests that LL following PVI does not provide additional benefit to sinus rhythm maintenance in patients with PeAF and PAF.     

Epicardial Macroreentrant Ventricular Tachycardia Associated with a Left Ventricular Aneurysm

A 62‐year‐old man with severe coronary artery disease and a left ventricular aneurysm underwent catheter ablation of ventricular tachycardia (VT) with right bundle branch block QRS morphology. Endocardial bipolar voltage mapping with standard threshold settings demonstrated no low‐voltage areas within the aneurysm. Catheter ablation of the epicardial surface of the aneurysm eliminated the VT. Endocardial bipolar voltage mapping with any other settings could not predict the site of the epicardial arrhythmogenic substrate whereas endocardial unipolar voltage mapping could. Endocardial unipolar voltage mapping may be helpful for predicting epicardial arrhythmogenic substrates. (PACE 2012; 35:e13–e16)     

Ablating the Imperceptible: A Novel Application of Para‐Hisian Pacing

In some elderly patients with atrial fibrillation, especially in combination with heart failure, a rate control strategy may be preferred. When pharmacological therapy is ineffective or not tolerated, it is reasonable to perform atrioventricular (AV) node ablation with ventricular pacing. We describe a case in which this approach was necessary for management. However, the presence of periprocedural, drug‐induced AV block just before ablation provided a unique and challenging circumstance. We discuss the steps taken to ensure a successful procedure.     

Impact of Image Integration on Catheter Ablation for Atrial Fibrillation Using Three‐Dimensional Electroanatomic Mapping: A Meta‐Analysis

Background: Studies comparing the procedural and clinical outcomes of catheter ablation for atrial fibrillation (AF) guided by CartoMerge and that by Carto have achieved mixed results (Carto, Biosense Webster, Diamond Bar, CA, USA). We collected these studies and conducted a meta‐analysis to determine whether CartoMerge results in better procedural and clinical outcomes. Methods and Results: Three randomized controlled trials and two controlled observational studies were collected for analysis. The clinical and procedural outcomes of interest were AF recurrence after catheter ablation, major complications, procedure durations, and fluoroscopy time. Meta‐analysis was performed using RevMan 5.0.18 software (The Cochrane Collaboration, Copenhagen, Denmark) and pooled estimates of effect were reported as risk ratios with 95% confidence intervals (CI). The overall results of this meta‐analysis indicate that catheter ablation for AF guided by CartoMerge is insignificantly associated with a decreased risk of recurrences (RR = 0.76; 95% CI: 0.55–1.04; P = 0.09) and major complications (RR = 0.73; 95% CI: 0.37–1.45; P = 0.37) compared with that by Carto. Conclusion: The image integration using CartoMerge guiding catheter ablation for AF does not improve the main clinical outcomes significantly compared with that by Carto in centers with experienced operators. (PACE 2012; 35:1242–1247)