Wim Anné

Atrial fibrillation after radiofrequency ablation of atrial flutter: preventive effect of angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, and diuretics

Objectives: To determine risk factors for the development of atrial fibrillation (AF) after atrial flutter (AFL) ablation; and to study the relation between AF development and periprocedural drug use. Methods: AFL ablation was performed in 196 patients. The relation between AF occurrence and clinical, echocardiographic, and procedural factors and periprocedural drug use was analysed retrospectively by a Cox proportional hazard method. Results: After a median follow up of 2.2 years, 114 patients (58%) developed at least one AF episode. Factors associated with AF development were the presence of preprocedural AF, a history of cardioversion, and the number of antiarrhythmic drugs used before the procedure. Use of angiotensin converting enzyme (ACE) inhibitors/angiotensin II receptor blockers and diuretics was significantly associated by univariate and multivariate analyses with less development of AF. Conclusions: A high proportion of patients develop AF after AFL ablation. The incidence of AF is related to pre-ablation AF and its persistence. ACE inhibitors/angiotensin II receptor blockers and diuretics seem to protect against AF.

Simultaneous Creation and Evaluation of Linear Radiofrequency Lesions

AbstractBackground: Catheter based “maze” procedures for atrial fibrillation have been hampered by difficult creation and evaluation of continuous and transmural linear lesions. Our aim was to develop an online evaluation method for effective lesion creation based on conventional techniques and using the multipolar ablation catheter, already in place. Methods and Results: We created 15 linear lines in right atria of 13 anesthetized sheep using three multipolar catheter designs (8 × 4 mm 7 Fr, 4 × 6 mm 7 Fr, 8 × 4 mm 3.7 Fr). The lesions were placed on the right posterolateral wall between the orifices of the superior and inferior vena cava. Radiofrequency energy was applied in the temperature-controlled mode to prespecified endpoints (electrogram amplitude decrease to ≤50%; pacing threshold increase by ≥100%; split potentials indicating conduction block). Macroscopically transmural and continuous lesions were achieved in only 3 experiments (29 ± 12 mm × 5 ± 1 mm), all created by 3.7 Fr octapolar catheters inserted through long sheaths. Preset temperature was reached in 96% of the electrodes (vs. 64% in the non-effective experiments; p < 0.01). Electrogram amplitude decrease (to ≤50%) and pacing threshold increase (by ≥100%) did not predict effectiveness. The only criterion that could reliably predict transmural continuous necrosis at histology was the development of split potentials (p ≤ 0.05). Conclusions: Effective creation of linear lesions is difficult. Pliable catheters that conform to the endocardial contour give the best results. The only endpoint that reliably predicted histological transmural continuous necrosis was development of split potentials indicating conduction block.

Long-term symptomatic benefit after radiofrequency catheter ablation for atrial flutter despite a high incidence of post-procedural atrial fibrillation.

Objective — A high proportion of patients develops atrial fibrillation (AF) after ablation for atrial flutter (AFL). Radiofrequency ablation for AFL therefore would only be useful if it leads to a better quality of life despite this high incidence of AF post-ablation. Methods — All patients who underwent AFL ablation in our centre before March 2002 (n = 203) were contacted by letter a median of 2.3 years after their ablation. Sixty-eight percent answered the questionnaire polling the perceived benefits of the procedure.The results were stratified according to the presenting arrhythmia before the ablation: only AFL, predominantly AFL, predominantly AF or class Ic-III AFL. Results — Despite a 60% incidence of AF, 84% considered the procedure to be beneficial during the 1st year and 77% during the 2nd year post-ablation. Patients with predominantly AF before the procedure showed significantly less overall improvement than the 3 other groups (50% and 33% after 1 year and 2 years, p< 0.01) and a smaller reduction in palpitations (50% and 29% after 1 year and 2 years, p< 0.01). The benefit of an ablation was also significantly less in patients who developed AF post-ablation than in patients who were completely arrhythmia free (75% versus 98% 1st year, 58% versus 91% 2nd year; p< 0.01); nevertheless 75% of these patients reported fewer palpitations and 56% tolerated symptoms better than before. Conclusions — Despite a high incidence of AF after AFL ablation, the majority of patients considered the intervention beneficial. Only in patients with predominantly AF before ablation the procedure does not seem beneficial.

A case report of a patient with a large aneurysmatic coronary artery fistula.

A coronary artery fistula is a rare congenital malformation, which can become symptomatic in adulthood. This report describes a 65-year-old patient with a large aneurysmatic fistula who presented with signs of heart failure. Angiographically a large aneurysmatic fistula was found running from the left coronary artery to the junction of the superior vena cava and the right atrium.

Determination of atrial fibrillation frequency using QRST-cancellation with QRS-scaling in standard electrocardiogram leads

Non-invasive assessment of the atrial cycle length can be obtained through QRST-cancellation algorithms. The main spectral component of the QRST-cancelled ECG gives an indication of the atrial cycle length. Due to QRS amplitude variations (eg caused by respiration) small residuals of QRS complexes can remain in the final ECG. We applied a QRST scaling algorithm to minimize these effects. Standard 12-lead ECG was recorded, simultaneous with both left (LA) and right (RA) intracardiac atrial electrograms. We applied a QRST-cancellation algorithm with automatic QRS-amplitude correction on both atrial fibrillation signals and atrial flutter signals. On average over all leads the percentual deviation between the intracardiac right atrial dominant frequency and the frequency measured on the standard ECG leads was 1.04% for atrial flutter and 2.16% for atrial fibrillation. For comparison with the LA fibrillation frequency, errors were slightly higher (flutter: 3.05%, fibrillation 2.31%). It is concluded that the QRST-cancellation algorithm with automatic QRS amplitude adjustment performs accurate on both atrial fibrillation signals and atrial flutter signals. These methods can have substantial clinical importance in monitoring non-invasively the atrial cycle length after interventional procedures or medication administration

ST-deviation reconstruction in missing leads on the 12-lead ECG: applicability in studies on ST-segment resolution during thrombolysis

Quantitative analysis of ST-segment deviations (STdev) and their resolution by treatment (STR; calculated from a combined sum of STdev in multiple leads) are used in trials on reperfusion for myocardial infarction (MI). Unreadable or unavailable electrocardiogram (ECG) leads are a common reason for exclusion, decreasing the statistical power of the trials. We developed mathematical formulas for reconstruction of immeasurable STdev based on STdev from other available leads on the 12-lead ECG. Formulas were deducted from a database of computer-assisted STdev measurements in 2 ECGs (baseline and 180 min after thrombolysis) of 1121 pts. Their accuracy was later evaluated on a second dataset of 377 pts. Acceptable fits could be derived for absent single leads, or for groups of absent limb leads (I-II-III or aVL-aVF). The intraclass correlation coefficient between real and calculated STdev was >or= 0.80 for each (0.77 for V1 in inferior MI). The correlations between STR calculated from original data and from reconstructed STdev were very strong (all intraclass correlation >or=0.97), and discordance in STR subgroup categorization occurred in <or=10% of pts in all but one of the scenarios (I-II-III substituted in 180 min ECG in inferior MI). Scenarios with multiple missing precordial leads however are not substitutable, nor are calculated STdev reliable for STR evaluation in only the lead with highest elevation in baseline. STdev reconstruction formulas can reliably be used in trials where analysis of aggregate STR is an endpoint. Reliable substitution can significantly increase the number of evaluable patients and therefore strengthen the statistical power of these trials.

Percutaneous Left Cardiac Sympathetic Denervation in a Patient With Long-QT Syndrome

URRENT TREATMENT GUIDELINES for patients with an established diagnosis of long-QT syndrome (LQTS) recommend beta-blockers in all patients and advise against participation in competitive sports. An implantable cardioverter-defibrillator (ICD) is indicated for survivors of cardiac arrest, for patients with syncope while receiving betablockers, and for primary prevention of cardiac events in highrisk patients. 1 Left cardiac sympathetic denervation (LCSD) is viewed as an alternative to ICD treatment in patients with syncope despite full-dose beta-blocker therapy or as an adjunct therapy to reduce the frequency of appropriate ICD shocks. In contrast to ICD use, LCSD prevents rather than treats malignant arrhythmias. Several surgical techniques are described to perform an LCSD, ranging from an isolated left stellate ganglionectomy to the resection of the first 4 or 5 thoracic ganglia on the left side with or without a complete or partial left stellate ganglion denervation. 2,3 In this case report, the authors describe, for the first time, a percutaneous approach for LCSD in a highly symptomatic long-QT syndrome patient.

Just another case of lead dislocation

A dual-chamber rate-responsive pacemaker (Telectronics Tempo DR 2102) was implanted for sick sinus syndrome in an 87-year-old woman and programmed in a DDD-R mode with a lower rate of 60 bpm and a paced AV delay of 160 ms. One year later, she presented with a pacemaker syndrome with complaints of exercise intolerance, fatigue, palpitations, and dyspnea. The ECG on admission and the rhythm strip during atrial threshold testing in a DDD mode at a lower rate of 100 bpm and an AV delay of 200 ms are shown in Figures 1 and 2, respectively. Can you identify the problem?

Visualizing electrocardiographic information on a patient specific model of the heart

The treatment of atrial tachycardia by radio-frequency ablation is a complex and minimally invasive procedure. In most cases the surgeon uses fluoroscopic imaging to guide catheters into the atria. After recording activation potentials from the electrodes on the catheter, which has to be done for different catheter positions, the physiologist has to fuse both the activation times derived from the potentials with the fluoroscopic images and extract from these a 3D anatomical model of the atrium. This model will provide him with the necessary information to locate the ablation regions. To alleviate the problem of mentally reconstructing these different sources of information, we propose a virtual environment that has the ability to visualize the electrodes information onto a patient specific model of the atria. This 3D atrium surface model is derived from pre-operatively taken MR-images. Within the system this model is visualized in 3 different ways: two views correspond to the 2 fluoroscopes images, which are shown registred in the background while the third one can be freely manipulated by the physiologist. The system allows to annotate measurements onto the 3D model. Since the heart is not a static organ, tools are provided to modify previous annotations interactively. The information contained in the measurements can than be dispersed across the heart after extrapolation and interpolation and subsequently visualized by color coding the surface model. Preliminary clinical evaluation on 30 patients indicates that the combined representation of the activation times and the heart model provides a thorough and more accurate insight into the possible causes and solutions to the tachycardia than would be obtained using solely the fluoroscopes images and mental reconstruction. Unlike other tachycardia visualization software, our approach starts with a patient specific surface model which in itself provides extra insight into the problem. Furthermore it can be used very interactively by the physiologist as a kind of 3D sketchbook where he can enter, delete, ... different measurements, tissue types. Finally, the system can visualize at any stage of the surgery a model containing all information at hand. In this paper we present a system to represent electrocardiographic information that allows the physiologist to mark measurements which can than be visualized on a patient specific atrium model by color coding. First clinical evaluation indicates that this approach offers a considerable amount of added value.

An augmented reality approach using pre-operative patient specific images to guide thermo-ablation procedures

We present a system to assist in the treatment of tachycardia patients by catheter ablation. In an augmented reality framework we combine a patient specific preoperative MR model, constructed from a set of transverse, coronal and sagittal images, with intra-cardial voltage potential measurements and fluoroscopic imaging to guide the electrophysiologist. The registration of the model and the fluoroscopic images, which is done by a visual matching technique, enables an easy transfer of the measurement to the pre-operative model. By visualizing annotations of different tissue types and of the measurements, extra insight is gathered about the problem, resulting in improved patient care. Because of its low cost and similar advantages we believe our approach can compete with existing commercial solutions, which rely on dedicated hardware and costly catheters. First clinical evaluation on 31 patients indicate a considerable advantage in the diagnosis and treatment. Our future work will consist of improving 2D-3D registration and further automating the measurement procedure.