Kristina Wasmer

The ajmaline challenge in Brugada syndrome: Diagnostic impact, safety, and recommended protocol

AIMS The diagnostic ECG pattern in Brugada syndrome (BS) can transiently normalize and may be unmasked by sodium channel blockers such as ajmaline. Proarrhythmic effects of the drug have been well documented in the literature. A detailed protocol for the ajmaline challenge in Brugada syndrome has not yet been described. Therefore, we prospectively studied the risks of a standardized ajmaline test. METHODS AND RESULTS During a period of 60 months, 158 patients underwent the ajmaline test in our institution. Ajmaline was given intravenously in fractions (10mg every two minutes) up to a target dose of 1mg/kg. In 37 patients (23%) the typical coved-type ECG pattern of BS was unmasked. During the test, symptomatic VT appeared in 2 patients (1.3%). In all other patients, the drug challenge did not induce VT if the target dose, QRS prolongation >30%, presence/appearance of the typical ECG, or the occurrence of premature ventricular ectopy were considered as end points of the test. A positive response to ajmaline was induced in 2 of 94 patients (2%) with a normal baseline ECG, who underwent evaluation solely for syncope of unknown origin. CONCLUSION The ajmaline challenge using a protocol with fractionated drug administration is a safe method to diagnose BS. Because of the potential induction of VT, it should be performed under continuous medical surveillance with advanced life-support facilities. Due to the prognostic importance all patients with aborted sudden death or unexplained syncope without demonstrable structural heart disease and family members of affected individuals should presently undergo drug testing for unmasking BS.

Endocardial mapping of right ventricular outflow tract tachycardia using noncontact activation mapping

Introduction: Activation mapping and pace mapping identify successful ablation sites for catheter ablation of right ventricular outflow tract (RVOT) tachycardia. These methods are limited in patients with nonsustained tachycardia or isolated ventricular ectopic beats. We investigated the feasibility of using noncontact mapping to guide the ablation of RVOT arrhythmias.

Diastolic isthmus length and ‘vertical’ isthmus angulation identify patients with difficult catheter ablation of typical atrial flutter: a pre-procedural MRI study

AIMS Catheter ablation of isthmus-dependent atrial flutter is technically demanding in some patients and extremely simple in others. The intervention targets a defined anatomical structure, the so-called cavotricuspid isthmus (CTI). We sought to characterize CTI anatomy in vivo in patients with difficult and simple catheter ablation of atrial flutter. METHODS AND RESULTS Twenty-six patients were studied. Seven patients with difficult (n = 6) or extremely simple (n = 1) CTI ablation procedures were retrospectively selected from our catheter ablation database. Thereafter, we prospectively studied 19 patients undergoing CTI ablation in our department. We visualized CTI anatomy by ECG- and respiration-gated free precession 1.5 T cardiac magnetic resonance imaging (MRI). Magnetic resonance imaging was analysed for systolic and diastolic CTI length, the angle between the vena cava inferior and CTI, and pouch-like recesses. These parameters were compared between patients with difficult and simple procedures, split by the median number of energy applications. Patients with difficult procedures had a longer diastolic CTI length (diastolic isthmus length 20.3 +/- 1.8 mm) than those with simple procedures (diastolic isthmus length 16.6 +/- 1.7 mm, all data as mean +/- SEM, P < 0.05). Cavotricuspid isthmus angulation with respect to inferior vena cava was closer to 90 degrees in patients with difficult procedures (deviation from 90 degrees: 15 +/- 2 degrees) than those with simple procedures (deviation 23 +/- 4 degrees, P < 0.05). Systolic CTI length was not different between groups (32 +/- 2 mm in both groups, P > 0.2). CONCLUSION Longer diastolic, but not systolic, CTI length and a rectangular angle between CTI and inferior vena cava render CTI catheter ablation difficult. Visualization of isthmus anatomy may help to guide difficult CTI ablation procedures.

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.

Data on procedural handling and complications of pulmonary vein isolation using the pulmonary vein ablation catheter GOLD

AIMS The second-generation multi-electrode-phased radiofrequency pulmonary vein ablation catheter (PVAC GOLD(®)) was redesigned with the intent to improve its safety and efficacy. METHODS AND RESULTS Using a prospectively designed single-centre database, we retrospectively analysed 128 consecutive patients (102 paroxysmal and 43 female) who underwent their first pulmonary vein isolation with the PVAC GOLD(®). The analysis focused on procedural data as well as in-hospital complications. Baseline characteristics of the patient collective were as follows: mean age 57.9 years, mean CHA2DS2-VASC was 1.73 ± 1.30; structural heart disease was present in seven patients. The PVAC GOLD(®) exhibited procedure durations of 123.1 min ± 27.9, duration of energy delivery was 18.3 min ± 11.4, and fluoroscopy duration was 16.0 min ± 7.7. The redesigned catheter shows major complication [major bleeding, transitory ischaemic attack (TIA), and pericardial tamponade] rates of 2.3% (n = 3). The overall rate of adverse events was 5.4% (n = 7). Bleeding complications were observed in three patients (2.3%), in particular there were two cases (1.6%) of minor bleeding and one case (0.8%) of major bleeding. Two patients suffered pericardial effusion, but there was no need for pericardiocentesis. Besides one TIA, there was no other thrombo-embolic event. Furthermore, one case of post-procedural fever was observed. No deaths, stroke, or haemorrhagic shock occurred. Of the 510 pulmonary veins, 508 could be reached with the PVAC GOLD(®) device using a non-steerable long sheath. CONCLUSION The PVAC GOLD(®) seems to have an acceptable safety profile. The handling is comparable with the previous generation PVAC(®).

Ventricular arrhythmias from the mitral annulus: Patient characteristics, electrophysiological findings, ablation, and prognosis

BACKGROUND Symptomatic, premature ventricular contractions (PVCs) frequently originate in the right ventricular outflow tract, less frequently in the left ventricular outflow tract, aortic root, or mitral annulus (MA). Little is known about the patient population presenting with MA PVC and/or ventricular tachycardia (VT). OBJECTIVE To characterize the subgroup of ventricular arrhythmias arising from the MA. METHODS Among 404 consecutive patients who presented for catheter ablation of idiopathic PVC/VT over a period of 9 years, patients who were found to have an ablation site at the MA were analyzed for clinical and electrophysiological parameters. RESULTS Twenty-two (5%) patients (mean age 45 ± 18 years; range 16-76 years; 14 [64%] men) had PVC/VT arising from the MA. History of PVC ranged from 2 days in a case with suspected focal myocarditis to 19 years. No patient had severely depressed left ventricular function or significant heart disease, which was determined by echocardiogram, magnetic resonance imaging, and/or coronary angiogram. Sites of origin were distributed around the MA with no preferential area. Ablation was successful in 13 of 16 (81%) patients. One 28-year-old female patient with normal magnetic resonance imaging and no structural heart disease died suddenly 3 months after ablation. CONCLUSIONS Ventricular arrhythmias from the MA represent a rare subgroup of idiopathic PVC/VT. They appear to occur at any age and do not indicate underlying structural heart disease. Catheter ablation has a success rate comparable to that of outflow tract tachycardia. Prognosis remains unclear.

Right Atrial Scar Detection after Catheter Ablation: Comparison of 2D and High Spatial Resolution 3D-late Enhancement Magnetic Resonance Imaging

RATIONALE AND OBJECTIVES To prospectively compare the diagnostic performance of two-dimensional (2D) and high spatial resolution three-dimensional (3D) late enhancement magnetic resonance imaging (MRI) for the detection of scar tissue caused by catheter ablation of the right atrium in patients with atrial flutter. MATERIALS AND METHODS Forty-seven patients were enrolled. In 16 patients, imaging of the cavotricuspid isthmus was performed before and after catheter ablation, 16 subjects were imaged before, and 15 after catheter ablation, resulting in a total of 63 examinations. MRI included a standard 2D breathhold and a high-resolution navigator-gated 3D T1-weighted gradient-echo inversion-recovery sequence in right and left anterior oblique views. Two readers assessed the subjective image quality on a 4-point scale (1 = excellent) and the presence of late enhancement (blinded/ in consensus). RESULTS The average image quality was 1.6 for both imaging approaches. In consensus reading, the sensitivity was 83% versus 100%, specificity 97% versus 89%, accuracy 90% versus 94%, positive predictive value 96% versus 89%, negative predictive value 86% versus 100% for 2D and 3D, respectively. The interobserver agreement was 0.86 for 2D and 0.78 for 3D imaging. CONCLUSIONS For the noninvasive identification of scars in the cavotricuspid isthmus after right atrial flutter, ablation 2D imaging was more consistent, whereas 3D sequences showed superior sensitivity for the depiction of late enhancement.

Inappropriate shock in a subcutaneous ICD due to interference with a street lantern

The totally subcutaneous implantable defibrillator (S-ICD, Boston Scientific, Natick, MA, USA) has recently been introduced as a new alternative to the conventional transvenous defibrillator system. The obvious advantages of this system are marketed as a minimization of lead complications and systemic infections. This innovative system can particularly be considered in young patients and special cohorts with anatomic variations. Inappropriate shock delivery has been

Novel surface ECG criteria for differentiation between left- and right-sided manifest inferoseptal accessory pathways

Differentiation between left- and right-sided inferoseptal accessory pathways by existing ECG algorithms is unsatisfactory. We reviewed the 12-lead ECGs of 113 consecutive patients undergoing successful ablation of a single manifest inferoseptal pathway (40% at the mitral, 60% at the tricuspid annulus). For prediction of a right-sided location, the most useful criteria were a) a negative QRS polarity in all three inferior leads and in V1 (positive predictive value (PPV) 0.90, negative predictive value (NPV) 0.51) and b) a negative QRS polarity in > or =2 inferior leads and in V1 (PPV 0.80, NPV 0.56). A positive QRS polarity in > or =1 inferior lead predicted a left-sided location (PPV 0.54, NPV 0.80). A new algorithm had an accuracy of 76%.

Broad antiarrhythmic effect of mexiletine in different arrhythmia models

Aims Experimental studies and clinical reports suggest antiarrhythmic properties of mexiletine in different arrhythmias. We aimed at investigating mexiletine in experimental models of atrial fibrillation (AF) as well as in long-QT- (LQTS) and short-QT-syndrome (SQTS). Methods and results In 15 isolated rabbit hearts, erythromycin (300 µM) was infused for simulation of long-QT-2-syndrome. In further 13 hearts, veratridine was administered to simulate long-QT-3-syndrome. Both drugs induced a significant QT-prolongation (erythromycin: +87 ms, P < 0.01; veratridine: +19 ms, P < 0.05) and increased dispersion of repolarization (erythromycin: +55 ms, P < 0.01; veratridine +31 ms, P < 0.01). Additional infusion of mexiletine (25 µM) resulted in a significant reduction of dispersion (erythromycin: -43 ms, P < 0.01; veratridine: -26 ms, P < 0.05). Reproducible induction of torsade de pointes was observed in 13 of 15 erythromycin-treated hearts (192 episodes) and 6 of 13 veratridine-treated hearts (36 episodes). Additional infusion of mexiletine significantly reduced ventricular tachycardia (VT) incidence. With mexiletine, only 3 of 15 erythromycin-treated hearts (27 episodes) and 1 of 13 veratridine-treated hearts (2 episodes) presented polymorphic VT. In additional 9 hearts, the IK-ATP-channel-opener pinacidil was employed to simulate SQTS and significantly abbreviated ventricular repolarization (QT-interval: -18 ms, P < 0.05) and enhanced induction of ventricular fibrillation (VF). Mexiletine reversed the effects of pinacidil, increase refractory period (+127 ms, P < 0.01) and significantly suppressed induction of VF. In further 13 hearts AF was induced by combined treatment with acetylcholine/isoproterenol. Mexiletine also increased atrial refractory period (+80 ms, P < 0.01) and thereby effectively suppressed atrial fibrillation. Conclusion Acute infusion of mexiletine significantly reduced the occurrence of polymorphic VT in the presence of pharmacologically simulated LQTS. Furthermore, mexiletine demonstrated potent antiarrhythmic properties in a model of SQTS and in AF.