Alex Bittner

Randomized study comparing duty-cycled bipolar and unipolar radiofrequency with point-by-point ablation in pulmonary vein isolation

BACKGROUND Pulmonary vein (PV) electrical isolation is a therapeutic option in atrial fibrillation (AF). New technologies may reduce the complexity of the procedure. OBJECTIVE The aim of the present study was to compare immediate results and short-term efficacy of a new circular ablation catheter (PVAC) with a conventional point-by-point ablation. METHODS The prospective study enrolled 80 consecutive patients with paroxysmal AF or persistent AF, refractory to antiarrhythmic drugs, who were randomized to radiofrequency ablation using duty-cycled bipolar and unipolar radiofrequency by a decapolar circular catheter (PVAC group) or to point-by-point ablation supported by a 3-dimensional mapping system (3D group). RESULTS Forty patients per group were included. Mean age was 58 ± 10 years, 64% were male; 55% had paroxysmal AF, 45% had persistent AF. There were no significant differences between groups. Complete electrical isolation was reached in all but 1 PV, which was not isolated in the PVAC group because of phrenic nerve capture. Procedure and fluoroscopy times were lower in the PVAC group: 171 ± 40 minutes vs. 224 ± 27 minutes, P < .001; 26 ± 8 minutes vs. 35 ± 9 minutes, P < .001; respectively. There were no major complications. During a mean follow-up of 254 ± 99 days, 72% in the PVAC group and 68% in the 3D group were free of AF recurrences irrespective of the initial AF type (P = NS). CONCLUSION PVAC represents a safe alternative for PV isolation. It reduces both procedure and fluoroscopy time. The short- and middle-term efficacy is comparable to a conventional point-by-point antral ablation technique.

Damage to the esophagus after atrial fibrillation ablation: Just the tip of the iceberg? High prevalence of mediastinal changes diagnosed by endosonography.

Background—Radiofrequency catheter ablation is increasingly used in the treatment of atrial fibrillation. Esophageal wall changes varying from erythema to ulcers have been described by endoscopy in up to 47% of patients following pulmonary vein isolation (PVI). Although esophageal changes are frequently reported, the development of a left atrial (LA)-esophageal fistula is fortunately rare. Nevertheless, mucosal changes may just represent “the tip of the iceberg.” The aim of this study was, therefore, to investigate the more subtle changes of and injuries to the posterior wall of the LA, the periesophageal and mediastinal connective tissue, and the whole wall of the esophagus, including mucosal changes by esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS). Methods and Results—Twenty-nine patients (7 females; mean age, 57.7±10.5 years [range, 23–75 years]) underwent EGD and EUS before and after PVI within 48 hours. PVI was performed as a circumferential antral isolation of the septal and lateral pulmonary veins guided by a decapolar circular mapping catheter using a 3-dimensional mapping system with the integration of a preprocedurally acquired computed tomography scan of the left atrium. The maximum power applied was 30 W, with an open-irrigated catheter using a maximum flow rate of 30 mL/min. In all patients, the esophagus was reconstructed using the same computed tomography scan and displayed during the ablation procedure. In case of newly detected periesophageal changes, EGD and EUS were repeated 1 week after the PVI. In all patients, a regular contact area between the LA and the esophagus could be demonstrated before PVI. The mean vertical contact length was 4.4±1.5 cm (range, 2–10 cm); and the mean distance between the anterior wall of the esophagus and the endocardium was 2.6±0.8 mm (range, 1.4–4.0 mm). After PVI, morphological changes of the periesophageal connective tissue and the posterior wall of the LA were diagnosed by endosonography in 8 patients (27%; 95% confidence interval, 12.73–47.24). No mucosal changes of the esophagus in terms of erythema or ulcers were found. In all but one patient (who refused the control), all periesophageal and atrial changes had resolved within 1 week. No atrioesophageal fistula occurred during follow-up (mean follow-up, 294±110 days [range, 36–431 days]). Conclusions—Mucosal changes of the esophagus after PVI-like ulcers or erythema could not be demonstrated, yet structural changes of the mediastinum, which were only visible by endosonography, occurred in 27% of patients in the present study. This may indicate a higher than expected periesophageal injury because of PV ablation. Endosonography might prove to be a sensitive and reliable tool in the follow-up after PVI.Background— Radiofrequency catheter ablation is increasingly used in the treatment of atrial fibrillation. Esophageal wall changes varying from erythema to ulcers have been described by endoscopy in up to 47% of patients following pulmonary vein isolation (PVI). Although esophageal changes are frequently reported, the development of a left atrial (LA)-esophageal fistula is fortunately rare. Nevertheless, mucosal changes may just represent “the tip of the iceberg.” The aim of this study was, therefore, to investigate the more subtle changes of and injuries to the posterior wall of the LA, the periesophageal and mediastinal connective tissue, and the whole wall of the esophagus, including mucosal changes by esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS). Methods and Results— Twenty-nine patients (7 females; mean age, 57.7±10.5 years [range, 23–75 years]) underwent EGD and EUS before and after PVI within 48 hours. PVI was performed as a circumferential antral isolation of the septal and lateral pulmonary veins guided by a decapolar circular mapping catheter using a 3-dimensional mapping system with the integration of a preprocedurally acquired computed tomography scan of the left atrium. The maximum power applied was 30 W, with an open-irrigated catheter using a maximum flow rate of 30 mL/min. In all patients, the esophagus was reconstructed using the same computed tomography scan and displayed during the ablation procedure. In case of newly detected periesophageal changes, EGD and EUS were repeated 1 week after the PVI. In all patients, a regular contact area between the LA and the esophagus could be demonstrated before PVI. The mean vertical contact length was 4.4±1.5 cm (range, 2–10 cm); and the mean distance between the anterior wall of the esophagus and the endocardium was 2.6±0.8 mm (range, 1.4–4.0 mm). After PVI, morphological changes of the periesophageal connective tissue and the posterior wall of the LA were diagnosed by endosonography in 8 patients (27%; 95% confidence interval, 12.73–47.24). No mucosal changes of the esophagus in terms of erythema or ulcers were found. In all but one patient (who refused the control), all periesophageal and atrial changes had resolved within 1 week. No atrioesophageal fistula occurred during follow-up (mean follow-up, 294±110 days [range, 36–431 days]). Conclusions— Mucosal changes of the esophagus after PVI-like ulcers or erythema could not be demonstrated, yet structural changes of the mediastinum, which were only visible by endosonography, occurred in 27% of patients in the present study. This may indicate a higher than expected periesophageal injury because of PV ablation. Endosonography might prove to be a sensitive and reliable tool in the follow-up after PVI. Received October 19, 2009; accepted February 16, 2010. # CLINICAL PERSPECTIVE {#article-title-2}

Electrophysiological characteristics of ventricular tachyarrhythmias in cardiac sarcoidosis versus arrhythmogenic right ventricular cardiomyopathy

BACKGROUND Recent evidence suggests that cardiac sarcoidosis (CS) and arrhythmogenic right ventricular cardiomyopathy (ARVC) can manifest very similarly. OBJECTIVE To investigate whether there are significant demographic and electrophysiological differences between patients with CS and ARVC. METHODS We prospectively compared patients with proven CS or ARVC who underwent radiofrequency catheter ablation of ventricular tachycardias by using 3-dimensional electroanatomical mapping. Furthermore, we evaluated whether the diagnostic criteria for ARVC would have excluded ARVC in patients with CS. RESULTS Eighteen patients (13 men; mean age 44.9 years) were included. All 18 patients had mild to moderately reduced right ventricular ejection fraction. Patients with cardiac sarcoidosis (n = 8) had a significantly lower mean left ventricular ejection fraction (35.6±19.3 vs 60.6±9.4; P = .002). Patients with CS had a significantly wider QRS (0.146 vs 0.110s; P = .004). Five of 8 (63%) patients with CS fulfilled the diagnostic ARVC criteria. Ventricular tachycardias (VTs) with a left bundle branch block pattern were documented in all but one patient (with CS). Programmed ventricular stimulation induced an average of 3.7 different monomorphic VTs in patients with CS vs 1.8 in patients with ARVC (P = .01). VT significantly more often originated in the apical region of the right ventricle in CS vs ARVC (P = .001), with no other predilection sites. Ablation success and other electrophysiological parameters were not different. CONCLUSIONS The current diagnostic ARVC guidelines do not reliably exclude patients with CS. Clinical and electrophysiological parameters that were characteristic of CS in our patients include reduced left ventricular ejection fraction, a significantly wider QRS, right-sided apical VT, and more inducible forms of monomorphic VT.

Incidence, characteristics, and outcome of left atrial tachycardias after circumferential antral ablation of atrial fibrillation.

BACKGROUND Antral pulmonary vein isolation (PVI) for treatment of atrial fibrillation may induce left atrial tachycardias (ATs). OBJECTIVE To determine the prevalence, time course of occurrence, mechanisms, and correlation with the electrocardiogram as well as the outcome of ablation of these tachycardias. METHODS AND RESULTS Out of the 839 patients who underwent circumferential antral radiofrequency PVI guided by a circumferential pulmonary vein catheter at our institution between February 2005 and April 2011, 35 patients (4%) developed AT during follow-up. Six patients with left AT and a previous PVI at other institutions were also included. Of these 41 patients (26 men, 63%; age 59 ± 10 years), 26 (63%) had underlying paroxysmal atrial fibrillation and 15 (37%) had persistent atrial fibrillation. AT ablation was performed 47 ± 60 weeks after initial PVI, within the first 3 months in 16 patients (39%). The tachycardia mechanism was focal in 15 patients (37%), macroreentry in 25 patients (61%), and undetermined in 1 (2%). Focal tachycardias had an isoelectric line between distinct P waves in 13 of the 15 patients (87%), while only 4 (16%) with a macroreentrant mechanism had an isoelectric line (P <.001). Although difficult to measure, a P-wave width of >140 ms had the highest sensitivity and specificity to identify macroreentrant mechanism. Ablation was acutely successful in 32 patients (78%) and not successful in 4 (10%). In 5 patients, success could not be determined as the tachycardia terminated or degenerated during mapping. During a mean follow-up of 31 ± 17 months, 11 patients (27%; n = 9 [82%] with macroreentry) underwent repeat ablation procedure for AT. Eight patients had true recurrence, for example, the same AT, and 3 patients had a second mechanism of AT. CONCLUSIONS With the use of an identical ablation protocol, it was found that approximately 4% of the patients developed AT after mere circumferential antral PVI. The majority of ATs developed within a few months after ablation but occurred as late as several years after the initial PVI. Macroreentry was more frequent than a focal mechanism. Broad P waves and isoelectric lines between P waves help to distinguish a focal mechanism from a macroreentrant mechanism. Ablation has a high acute success rate, and AT recurrence occurs predominantly in macroreentrant AT.

Successful treatment of catecholaminergic polymorphic ventricular tachycardia with flecainide: a case report and review of the current literature

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disease that can cause sudden cardiac death due to ventricular fibrillation (VF). While pharmacological therapy with beta-blockers and/or Ca(2)(+) antagonists is often unreliable, a recent study has demonstrated that flecainide can effectively suppress arrhythmia in a murine model of CPVT as well as clinically in two human subjects suffering from CPVT. We here present the case of an 11-year-old boy suffering from CPVT-1 as well as a review of the current relevant literature. After resuscitation due to VF at age 9, an automated implantable cardioverter-defibrillator (ICD) was implanted in 2007. Under beta-blocker therapy, repeated shocks were delivered due to either fast ventricular tachycardia (VT) or VF. This persisted under additional therapy with verapamil. Implantable cardioverter-defibrillator routine interrogations showed frequent non-sustained VT with an average of 8.8 per day. Additionally, the patient suffered from impaired physical performance due to decreased chronotropic competence. In July 2009, flecainide was added to the beta-blocker/verapamil regimen, resulting in a plasma level of 0.20 mg/L. No ICD shock or sustained VT occurred until December 2010. Genetic testing revealed an RyR2 receptor mutation. The case demonstrates the challenge of diagnosis and management of CPVT. It furthermore supports recent experimental evidence that the class 1 antiarrhythmic drug flecainide can suppress CPVT. The presented case supports a novel strategy in treating CPVT with the class I antiarrhythmic agent flecainide.

Isthmus-dependent right atrial flutter as the leading cause of atrial tachycardias after surgical atrial septal defect repair

OBJECTIVES The purpose of this study was to evaluate clinical and electrophysiologic characteristics of AT in patients after surgical ASD repair as well as outcome after ablation. BACKGROUND Atrial tachycardias (AT) are a common complication after surgical closure of an atrial septal defect (ASD). METHODS From a prospective ablation database we analyzed data of patients with a history of ASD repair who presented to our institution for AT ablation. We investigated ECG characteristics and the electrophysiologic mechanism of AT in this collective and analyzed follow-up data. RESULTS Data of 54 patients (47.3 ± 14.5 years, 35 females) were included. In 30 patients (55.6%) ASD had been closed by direct suture, 24 patients (44.4%) had a patch for ASD repair without significant difference in terms of gender and age at the time of the procedure (p=0.234, p=0.231). In 42 patients (77.8%), electrophysiological studies were performed in AT. All patients had right atrial macro-reentrant AT. The leading mechanism was isthmus-dependent right atrial flutter in 29 patients (69.0%) with clockwise atrial activation in 41%. The mechanism of AT (typical atrial flutter (n=29), atriotomy-dependent flutter (n=7), and double loop flutter (n=5)) did not differ with regard to type of surgery. Only 70.6% of patients with proven isthmus dependent counter-clockwise atrial flutter presented with an ECG morphology typical for this mechanism. However, all clockwise typical atrial flutter patients showed the characteristic positive P-waves in the inferior leads. Of note, 83.3% of clockwise typical flutter ECGs had long isoelectric lines (mean 74.5 ms). Follow-up was complete in 45 of 54 patients. During a mean follow-up of 7.7 ± 3.7 years, 27 patients (60%) remained free of any arrhythmia, two patients had AT recurrence with different mechanisms compared to the first procedure and underwent successful ablation. Five patients (11%) developed atrial fibrillation. CONCLUSION Isthmus dependent right atrial flutter is the leading AT mechanism in patients with a history of ASD repair. The mechanism of atrial flutter did not differ in relation to the mode of ASD closure (direct suture versus patch closure). ECG characteristics of the tachycardia may be misleading as they are more often atypical in patients after ASD repair.

Pulmonary vein variants predispose to atrial fibrillation: a case-control study using multislice contrast-enhanced computed tomography

AIMS Pulmonary veins (PV) play a pivotal role in atrial fibrillation (AF). Anatomical variants of PV have been described and related to a higher arrhythmogenic potential. The aim of this study was to compare the prevalence of PV variants and diameters of PV ostia in AF patients and controls. METHODS AND RESULTS Variants of PV were defined as right or left common ostia (RCO, LCO), a right middle or right top PV . A long common trunk (LCT) was defined as an LCO with a distance to the first branching ≥ 10 mm. Multislice contrast-enhanced thoracic computed tomography was performed prior to AF ablation in 166 consecutive patients, 47.6% with paroxysmal, 52.4% with persistent AF, as well as in a sex- and age-matched control group without AF, for non-cardiological indications. Images were evaluated by two independent observers. The mean age was 59 ± 10 years, 108 were men (65.1%). A higher prevalence of LCO was found in the AF group: 33.7 vs. 19.9% (P= 0.004), odds ratio (OR) 2.1; 15.4% in patients vs. 10.2% in controls had an LCT (P= 0.14). No differences in other PV variants were found. The ostial diameters were greater in AF-patients (P< 0.001). CONCLUSIONS To the best of our knowledge, the present study shows for the first time a higher prevalence of an LCO in patients with AF as compared with controls, with an OR of 2.1. This suggests a pre-disposing role of LCO in the development of AF.

Idiopathic ventricular outflow tract arrhythmias from the great cardiac vein: challenges and risks of catheter ablation.

INTRODUCTION Catheter ablation for idiopathic ventricular arrhythmia is well established but epicardial origin, proximity to coronary arteries, and limited accessibility may complicate ablation from the venous system in particular from the great cardiac vein (GCV). METHODS Between April 2009 and October 2010 14 patients (56 ± 15 years; 9 male) out of a total group of 117 patients with idiopathic outflow tract tachycardias were included undergoing ablation for idiopathic VT or premature ventricular contractions (PVC) originating from GCV. All patients in whom the PVC arose from the GCV were subject to the study. In these patients angiography of the left coronary system was performed with the ablation catheter at the site of earliest activation. RESULTS Successful ablation was performed in 6/14 (43%) and long-term success was achieved in 5/14 (36%) patients. In 4/14 patients (28.6%) ablation was not performed. In another 4 patients (26.7%), ablation did not abolish the PVC/VT. In the majority, the anatomical proximity to the left coronary system prohibited effective RF application. In 3 patients RF application resulted in a coronary spasm with complete regression as revealed in repeat coronary angiography. CONCLUSION A relevant proportion idiopathic VT/PVC can safely be ablated from the GCV without significant permanent coronary artery stenosis after RF application. Our data furthermore demonstrate that damage to the coronary artery system is likely to be transient.

Matrix metalloproteinase-9 activity is associated to oxidative stress in patients with acute coronary syndrome

Abstract In the present work we evaluate the relationship between oxidative stress and matrix metalloproteinases-2 and -9 (MMP-2 and -9) activities in 44 patients with non ST-elevation acute coronary syndrome. We found an early increase in malondialdehyde (MDA) levels (oxidative stress marker) and MMP-9, with decrease of both at day five. A positive correlation was found between fractional changes of MDA and MMP-9, suggesting a common role in the pathophysiology of the acute coronary syndrome.

Unidad de dolor torácico: primera experiencia en Chile

In large series, nearly 60% of admissions forsuspected acute coronary syndrome (ACS) had a non-coronary etiology of the pain. However,short term mortality of non recognized ACS patients, mistakenly discharged from the emergencyroom is at least twice greater than the expected if they would had been admitted. The concept ofa chest pain unit (CPU) is a methodological approach developed to address these issues.