Feasibility of complex transfemoral electrophysiology procedures in patients with inferior vena cava filters.

BACKGROUND: The presence of inferior vena cava filters (IVCFs) has been considered a relative contraindication to electrophysiology (EP) procedures that require transfemoral venous placement of multiple catheters and/or long sheaths. There are inadequate data related to complex EP procedures in this population. OBJECTIVE: The purpose of this study was to describe the experience of a single high-volume center with respect to complex EP procedures in patients with IVCFs. METHODS: Patients with IVCFs undergoing complex EP procedures between 2004 and 2018 were identified. Clinical characteristics, IVCF type, procedural findings, and complications were analyzed. RESULTS: Fifty complex ablation procedures were performed in 40 patients (mean age 63.8 ± 10.9 years; 68% men). The mean IVCF dwell time was 69.1 ± 19.1 months, and 48 patients (96%) were on chronic oral anticoagulation. Procedures included ablation of atrial fibrillation (n = 21), ventricular tachycardia (n = 20), supraventricular tachycardia (n = 3), cavotricuspid isthmus flutter (n = 3), supraventricular tachycardia and cavotricuspid isthmus flutter (n = 1), and transvenous lead extraction (n = 3). Twenty procedures included quadripolar catheters (mean 1.4 ± 0.75), and 33 procedures involved deflectable decapolar catheters (mean 1.7 ± 0.47). Long sheaths were used in 35 cases (mean 1.63 ± 0.49) and intracardiac echocardiography in 38. In 4 cases (involving 3 patients), the IVCF was occluded and could not be crossed. There were no procedural complications related to the IVCF. CONCLUSION: The substantial majority of IVCFs in patients presenting for complex EP procedures were patent and easily crossed under fluoroscopic guidance. The presence of an IVCF should not discourage operators from performing procedures that require transfemoral deployment of multiple catheters and/or sheaths.

Performance of an automatic arrhythmia classification algorithm: comparison to the ALTITUDE electrophysiologist panel adjudications.

INTRODUCTION: Adjudication of thousands of implantable cardioverter defibrillator (ICD)-treated arrhythmia episodes is labor intensive and, as a result, is most often left undone. The objective of this study was to evaluate an automatic classification algorithm for adjudication of ICD-treated arrhythmia episodes. METHODS: The algorithm uses a machine learning algorithm and was developed using 776 arrhythmia episodes. The algorithm was validated on 131 dual-chamber ICD shock episodes from 127 patients adjudicated by seven electrophysiologists (EPs). Episodes were classified by panel consensus as ventricular tachycardia/ventricular fibrillation (VT/VF) or non-VT/VF, with the resulting classifications used as the reference. Subsequently, each episode electrogram (EGM) data was randomly assigned to three EPs without the atrial lead information, and to three EPs with the atrial lead information. Those episodes were also classified by the automatic algorithm with and without atrial information. Agreement with the reference was compared between the three EPs consensus group and the algorithm. RESULTS: The overall agreement with the reference was similar between three-EP consensus and the algorithm for both with atrial EGM (94% vs 95%, P = 0.87) and without atrial EGM (90% vs 91%, P = 0.91). The odds of accurate adjudication, after adjusting for covariates, did not significantly differ between the algorithm and EP consensus (odds ratio 1.02, 95% confidence interval: 0.97-1.06). CONCLUSIONS: This algorithm performs at a level comparable to an EP panel in the adjudication of arrhythmia episodes treated by both dual- and single-chamber ICDs. This type of algorithm has the potential for automated analysis of clinical ICD episodes, and adjudication of EGMs for research studies and quality analyses.

Quickly finding a needle in a haystack: a new automated cardiac arrhythmia detection software for preclinical studies.

INTRODUCTION: The occurrence of drug-induced arrhythmias in safety pharmacology or toxicology studies is a primary safety concern. The risk assessment requires an accurate knowledge of background arrhythmia incidence and frequency in the test system/species, as well as a rigorous evaluation of the effects of the potential new medical entities on the electrocardiogram (ECG). However, the direct assessment of arrhythmia in ECG recordings is a time-consuming effort and is rarely achieved due to lack of suitable automated tools. A new software application named ARR30a was developed for fast automated detection in preclinical studies, for the five major arrhythmia types, namely sinus pauses, atrial beats, junctional beats, ventricular beats and type 2 atrio-ventricular blocks (AV-blocks II). The purpose of this study was to characterize the performance of ARR30a in large and small animal species. METHODS: Detection sensitivity and predictivity were evaluated on a database of 84 ECG recordings representative of each animal species and experimental protocols typically used in efficacy, safety pharmacology and toxicology studies. Automated arrhythmia detection was compared with manual analysis. RESULTS: In large animals such as dogs, non-human primates and pigs, ARR30a sensitivity reached 90.6%, 82.2% and 78.0% for ventricular beats, AV-blocks II and junctional beats with predictivity of 83.4%, 94.4% and 93.5%, respectively. Significantly lower sensitivity was observed in rats for junctional beats due to challenging problems of detection for low amplitude P-waves. Robustness to noise was assessed by adding increasing noise levels to ECG signals and showed no significant impact on arrhythmia detection at moderate noise levels. Processing time for a 24 hour recording was approximately 4 min for dogs and 6 min for rats on a 3 GHz processor. DISCUSSION: This newly validated ECG arrhythmia detector ARR30a allows evaluating all major ECG signal abnormalities and enhances the quantification of arrhythmia incidence in all major laboratory animal species. The mark editor RME10a enables manual validation of the automated analysis and refinement of the arrhythmia classification.

Spontaneous cardiac arrhythmias recorded in three experimentally- and drug-naive laboratory species (canine, primate, swine) during standard pre-study screening.

INTRODUCTION: The purpose of this study was to collect and estimate the general prevalence of spontaneous irregularities in cardiac rhythms in three standard laboratory animal species: Beagle dog (N=2450), cynomolgus monkey (N=1563), and domestic swine (N=704) during standard preclinical screening. METHODS: Standard prestudy Lead II hardwire ECG tracings were collected in purpose-bred, drug-, and experimentally-naive animals following receipt from an institutionally-approved vendor and prior to placement onto general toxicology or safety pharmacology studies over the course of 18 months. The ECGs were independently reviewed by two veterinary cardiologists/internists for the presence or absence of arrhythmias (dysrhythmia), conduction disturbances, or other normal variants or clinically significant waveform changes. RESULTS: Greater than 98% of all ECGs recorded in animals bred for laboratory use demonstrated sinus rhythms without morphologic abnormalities or arrhythmias.

Risk stratification for arrhythmic events in patients with idiopathic dilated cardiomyopathy: a review of the literature and current perspectives.

The prognosis for patients with idiopathic dilated cardiomyopathy (DCM) has markedly improved during the last decade, mainly because of advancements in therapeutic strategies. However, sudden death still accounts for a significant part of the total mortality in patients with moderate disease. Recent primary prophylactic trials failed to demonstrate any benefit of cardioverter-defibrillator implantation in an unselected group of idiopathic DCM patients and thus the identification of the subgroup of patients at high arrhythmic risk is crucial. Although different risk stratification methods have been evaluated in risk assessment, the reported clinical value differs in studies, mainly because of differences in either methodology and/or patient selection. The present review focuses on arrhythmic events in idiopathic DCM and on the value of noninvasive methods and electrophysiological study in the risk stratification of this group of patients.

Atrial flutter: arrhythmia circuit and basis for radiofrequency catheter ablation.

The term atrial flutter was introduced 90 years ago for an arrhythmia with a unique electrocardiographic pattern. The development of endocardial mapping techniques in the last decade allowed the detailed characterization of the tachycardia circuit and the identification of the cavotricuspid isthmus as its critical part. This review stresses the position of atrial flutter in the new classification of atrial tachycardias and focuses on its unique electrophysiological characteristics and different variants described in humans. Transcatheter radiofrequency ablation across the cavotricuspid isthmus constitutes a feasible and safe therapy, which prevents flutter recurrences during the long-term follow-up. This paper describes the different techniques that validate bidirectional isthmus block, which is an important endpoint for successful ablation.

Bradiarritmias: abordagem clínica e tratamento / Bradiarrhythmias: clinical approach and treatment

Este artigo revisa a abordagem clínica das bradiarritmias, com ênfase no diagnóstico, ressaltando a importância da anamnese, exame físico e das alteraçöes eletrocardiográficas como principais orientadores da terapêutica