Influence of Heart Rate and Change in Wavefront Direction through Pacing on Conduction Velocity and Voltage Amplitude in a Porcine Model: A High-Density Mapping Study.

BACKGROUND: Understanding the dynamics of conduction velocity (CV) and voltage amplitude (VA) is crucial in cardiac electrophysiology, particularly for substrate-based catheter ablations targeting slow conduction zones and low voltage areas. This study utilizes ultra-high-density mapping to investigate the impact of heart rate and pacing location on changes in the wavefront direction, CV, and VA of healthy pig hearts. METHODS: We conducted in vivo electrophysiological studies on four healthy juvenile pigs, involving various pacing locations and heart rates. High-resolution electroanatomic mapping was performed during intrinsic normal sinus rhythm (NSR) and electrical pacing. The study encompassed detailed analyses at three levels: entire heart cavities, subregions, and localized 5-mm-diameter circular areas. Linear mixed-effects models were used to analyze the influence of heart rate and pacing location on CV and VA in different regions. RESULTS: An increase in heart rate correlated with an increase in conduction velocity and a decrease in voltage amplitude. Pacing influenced conduction velocity and voltage amplitude. Pacing also influenced conduction velocity and voltage amplitude, with varying effects observed based on the pacing location within different heart cavities. Pacing from the right atrium (RA) decreased CV in all heart cavities. The overall CV and VA changes in the whole heart cavities were not uniformly reflected in all subregions and subregional CV and VA changes were not always reflected in the overall analysis. Overall, there was a notable variability in absolute CV and VA changes attributed to pacing. CONCLUSIONS: Heart rate and pacing location influence CV and VA within healthy juvenile pig hearts. Subregion analysis suggests that specific regions of the heart cavities are more susceptible to pacing. High-resolution mapping aids in detecting regional changes, emphasizing the substantial physiological variations in CV and VA.

[Isthmus-dependent right atrial flutter : Clinical course after isthmus ablation]. / Rechtsatriales isthmusabhängiges Vorhofflattern : Klinischer Verlauf nach Isthmusablation.

Ablation of the cavotricuspid isthmus (CTI) to create bidirectional isthmus blockade is the most effective way to achieve rhythm control in typical atrial flutter. Compared with drug therapy, ablation reduces cardiovascular mortality, all-cause mortality, stroke risk, and the risk of cardiac decompensation. Concomitant arrhythmia of atrial flutter is atrial fibrillation (AF); therefore the duration of oral anticoagulation should be adapted according to the risk of stroke and bleeding. A combined procedure of CTI ablation and pulmonary vein isolation (PVI) in patients with typical atrial flutter but without evidence of AF should be evaluated individually especially in patients aged > 54 years depending on (cardiac) comorbidities. The comprehensive diagnostic view should keep in mind not only arrhythmias but also possibly underlying coronary artery disease.

Electroanatomical Conduction Characteristics of Pig Myocardial Tissue Derived from High-Density Mapping.

BACKGROUND: Ultra-high-density mapping systems allow more precise measurement of the heart chambers at corresponding conduction velocities (CVs) and voltage amplitudes (VAs). Our aim for this study was to define and compare a basic value set for unipolar CV and VA in all four heart chambers and their separate walls in healthy, juvenile porcine hearts using ultra-high-density mapping. METHODS: We used the Rhythmia Mapping System to create electroanatomical maps of four pig hearts in sinus rhythm. CVs and VAs were calculated for chambers and wall segments with overlapping circular areas (radius of 5 mm). RESULTS: We analysed 21 maps with a resolution of 1.4 points/mm2. CVs were highest in the left atrium (LA), followed by the left ventricle (LV), right ventricle (RV), and right atrium (RA). As for VA, LV was highest, followed by RV, LA, and RA. The left chambers had a higher overall CV and VA than the right. Within the chambers, CV varied more in the right than in the left chambers, and VA varied in the ventricles but not in the atria. There was a slightly positive correlation between CVs and VAs at velocity values of <1.5 m/s. CONCLUSIONS: In healthy porcine hearts, the left chambers showed higher VAs and CVs than the right. CV differs mainly within the right chambers and VA differs only within the ventricles. A slightly positive linear correlation was found between slow CVs and low VAs.

Potential of remote monitoring to prevent sensing and detection failures in implantable cardioverter defibrillators.

BACKGROUND: Sensing malfunction and misinterpretation of intracardiac electrograms (IEGMs) in patients with implantable cardioverter defibrillators (ICDs) may lead to inadequate device activity such as inappropriate shock delivery or unnecessary mode-switching. Remote monitoring has the potential for early detection of sensing malfunction or misclassification and may thus prevent adverse device activity. Therefore, the authors analyzed the amount, nature, and distribution of misclassification in current ICD and cardiac resynchronization therapy defibrillator technology using the device transmissions of the IN-TIME study population. METHODS: All transmitted tachyarrhythmic episodes in the 664 IN-TIME patients, comprising 2214 device-classified atrial fibrillation (DC-AF) episodes lasting ≥ 30 s and 1330 device-classified ventricular tachycardia or fibrillation (DC-VT/VF) episodes, were manually analyzed by two experienced cardiologists. RESULTS: After evaluation of all DC-VT/VF episodes, a total of 300 VT/VF events (23.1%) were false-positive, with supraventricular tachycardia being the most frequent cause (51.7%), followed by atrial fibrillation (21.3%) and T­wave oversensing (21.0%). A total of 15 patients with false-positive DC-VT/VF received inappropriate shocks. According to the inclusion criteria, 616 IEGMs with DC-AF were assessed. A total of 19.7% were false-positive AF episodes and R­wave oversensing was the most common reason (55.9%). CONCLUSIONS: Remote monitoring offers the opportunity of early detection of signal misclassification and thus early prevention of adverse device reaction, such as inappropriate shock delivery or mode-switching with intermittent loss of atrioventricular synchrony, by correcting the underlying causes.

[Clinical differential indication : Wearables vs implantables]. / Klinische Differenzialindikation : Wearables vs. Implantables.

In order to document arrhythmias, indicated due to symptoms or for prognostic purposes, both invasive and noninvasive possibilities for ECG monitoring are available. The choice of the device for monitoring depends mainly on the frequency of arrhythmias. If they occur less than once a month, long-term monitoring becomes necessary which either continuously monitors the rhythm by an implantable device (implantables) or by wearable systems (wearables) which usually register the ECG discontinuously. Because wearables, e.g. smartphones, are basically ubiquitously available, they may be used for ECG monitoring. This paper comments on the use of implantables and wearables for the detection of atrial fibrillation and the documentation of symptomatic arrhythmias in syncope or palpitations.

[Implantable ECG monitors]. / Implantierbare EKG-Monitore.

Implantable loop recorders are a diagnostic tool for detecting cardiac arrhythmias and are independent of the patient's compliance. Automatic algorithms lead to a preselection of arrhythmic events that are transferred by telemonitoring to the cardiac specialists. This article describes the available loop recorders on the market, the respective implantation techniques, the indication, and reimbursement.

Ticagrelor and Rivaroxaban Elimination With CytoSorb Adsorber Before Urgent Off-Pump Coronary Bypass.

CytoSorb hemoadsorption (CytoSorbents Inc, Monmouth Junction, NJ) was performed shortly before an urgent off-pump coronary artery bypass operation in a 58-year-old man at high risk of bleeding as a result of treatment of coronary artery disease with ticagrelor and treatment of atrial fibrillation with rivaroxaban. The patient experienced dissection of the left anterior descending artery during a percutaneous coronary intervention. Preoperatively, CytoSorb hemoadsorption was applied to eliminate the coagulative active medications. His intraoperative and postoperative courses were uneventful, with adequate bleeding control. This case highlights a promising approach for managing antiplatelet drugs and anticoagulant agents such as ticagrelor and rivaroxaban before off-pump coronary artery bypass.

Preparation of PCI Balloons: What Is the Best Method to Avoid Air in the Balloon? A Comparison of Different Methods of Connecting PCI Balloons and the Inflation Syringe while Removing Air from the Balloon.

As the techniques to connect percutaneous coronary intervention (PCI) balloons and the inflation syringe vary in the instructions for use and in practice, we measured the amount of air in PCI balloons after testing three connection methods to an inflation syringe. Following the preparation using one of the three methods, 114 balloons and stent balloons were tested four times. Method 1 connected the syringe and the balloon catheter directly after purging and filling the lumen, while method 3 omitted the purging and filling process. With method 2, the catheter lumen was purged, filled and fully vented via a three-way valve. The primary endpoint answered whether air remained in the balloon, and if so, the secondary endpoint indicated the total volume of remaining air. The connection with a three-way valve achieved significantly less air in the inflated balloon as compared with either direct connection approach (27% vs. 44% and 51%; p = 0.015). For the direct connection, no significant difference between purging and filling the lumen prior to making the connection or not existed. According to these findings, the best method to connect a PCI balloon to the inflation syringe while removing air involves using a three-way valve.

Cardioverter-defibrillator does not improve short-term survival among patients with non-ischemic cardiomyopathy and reduced left ventricular ejection fraction.

INTRODUCTION: The DANISH trial raised doubts about the effectiveness of primary prevention of sudden cardiac death by ICD implantation among patients with non-ischemic heart failure. We sought to analyse data from the EVITA-HF registry to give an answer from real-world registry data to the DANISH trial. METHODS: 1804 patients were identified from the EVITA-HF registry with chronic heart failure (CHF) due to ischemic or dilated heart disease and reduced left ventricular ejection fraction of ≤ 35%. The patients were divided into two groups: Patients with newly implanted cardioverter-defibrillator (ICD group; mean age 66 ± 12 years, 77% male) and without ICD (no-ICD group; mean age 66 ± 14 years, 77% male). The subgroups were compared with regard to mortality and predictive parameters affecting survival. RESULTS: Cardiovascular risk factors were similar among patients in the non-ICD group (n = 1473) compared to ICD group (n = 331). After 1-year follow-up patients with ischemic heart disease showed a significant improved survival in the ICD group compared to non-ICD group [92.1% vs. 80.6%, HR 0.37 (0.22-0.62)]. Patients with non-ischemic cardiomyopathy did not show a difference with regard to survival between the ICD and the non-ICD group [93.7% vs. 93.1%, HR 0.92 (0.43-1.97)]. The data were stable in a Cox-regression model. CONCLUSION: In a real-world setting, no benefit was evident for patients with non-ischemic cardiomyopathy and reduced left ventricular ejection fraction by adding ICD therapy in a short-term follow-up of 12 months in contrast to patients with ischemic cardiomyopathy.

[Catheter ablation of atrial fibrillation : Status quo]. / Katheterablation von Vorhofflimmern : Aktueller Stand.

Catheter ablation of atrial fibrillation (AF) is a standard part of treatment with respect to rhythm control. In this article, the authors provide a review of the state-of-the-art knowledge of AF catheter ablation including current indications, possible energy forms, procedural methods and endpoints as well as follow-up and further anticoagulation.

[Dizziness As A Symptom Of Cardiac Diseases]. / Schwindel bei kardiologischen Erkrankungen.

Dizziness is a symptom that may be of cardiac origin. Diagnosis and treatment of cardiac diseases is of important prognostic impact. Dizziness may be caused due to two different cardiac disorders: (1) as symptom of a cardioembolic event or (2) as a symptom of a low cardiac output leading to an intermittent global cerebral hypoperfusion. This review article presents diagnostic as well as therapeutic pathways in a comprehensive tabular overview.

Pulmonary vein reconnections or substrate in the left atrium: what is the reason for atrial fibrillation recurrences? A dialogue on a pressing clinical situation.

Pulmonary vein isolation (PVI) has long been held as the cornerstone for atrial fibrillation (AF) ablation. There are patients who do not have successful AF ablations though, especially among those with persistent AF. At the same time, the evidence suggests that ablating beyond the pulmonary veins does not improve success rates. Two possibilities for the incomplete success rates from the procedure are discussed: that more attention needs to be paid to PVI, optimizing delivery of durable, transmural lesions; or alternatively, shifting the focus away from just PVI and addressing the left atrial substrate itself. These two approaches are likely complementary though, and high-density mapping may offer us the ability to undertake them more effectively. The conclusion from this dialogue is that AF is a heterogenous disease and key is to recognize this heterogeneity and respond to it, rather than have a standardized, dogmatic approach. Durable PVI is clearly an important determinant of success but concurrently, we would suggest we need to go beyond this where appropriate to maximize success rates. Clearly the challenge is defining which patients this is appropriate for and how best to do this. Consequently, rather than being 'the' cornerstone of AF ablation, it is more appropriate to consider PVI as 'a' cornerstone of the procedure going forwards and high-density mapping may be the key to optimizing both aspect of the procedure and in so doing improve long term success rates.

[Exposure Therapy with the Help of a Wearable Defibrillator Device used in the Treatment of Severe Obsessive-Compulsive Disorder and Congenital LQTS - An Example for Interdisciplinary Treatment]. / Expositionsbehandlung mithilfe einer Defibrillatorweste bei schwerer Zwangsstörung und angeborenem Long-QT-Syndrom.

We report on a case of a young female suffering from both obsessive-compulsive disorder (OCD) and a severe underlying cardiac disease. Due to the somatic comorbidity, treatment according to guidelines with exposure and reaction prevention was not initially conducted, due to potentially fatal risks to the patient. However, through collaboration with a cardiology clinic, we were able to find an innovative solution which allowed for the continuation of the exposure therapy. This case report demonstrates a successful interdisciplinary collaboration and is intended to sensitize the reader to the need for checking for somatic contraindications before conducting exposure therapy.

Exclusion of left atrial thrombus by dual-source cardiac computed tomography prior to catheter ablation for atrial fibrillation.

OBJECTIVES: Thromboembolic complications during atrial fibrillation (AF) ablation due to mobilisation of a pre-existing thrombus formation (TF) in the left atrium (LA) are devastating. The gold standard to exclude LA TF is transesophageal echocardiography (TEE). The present study compares sensitivity and specificity of a dual-source cardiac-computed tomography (DS-CT) with TEE for TF exclusion prior to AF ablation. In addition, CT protocols with and without ECG synchronized were evaluated. METHODS: In 622 patients, DS-CT as well as TEE to exclude TF was performed less than 48 h prior to AF ablation. Mean age of patients was 60 ± 10 years (69% males, 61% paroxysmal AF). During DS-CT, 280 patients (45%) were in AF. An ECG-synchronized DS-CT was performed in 332 patients, whereas 290 patients underwent DS-CT without ECG synchronization. RESULTS: In all patients without suspected TF on DS-CT (n = 552; 88.7%), no thrombus was found on TEE. A TF was suspected on DS-CT in 70 patients, of whom only three patients showed TF on TEE. No TF was detected in the other 67 patients (Fig. 1). Overall, sensitivity for TF detection in DS-CT was 100% and specificity was 89.2% (positive predictive value 4.3%, negative predictive value 100%). The CT protocol (ECG-synchronized versus non-ECG-synchronized) had no significant influence on diagnostic accuracy. Mean dose length product during DS CT was 282 ± 287 mGy cm (synchronized) versus 136 ± 55 mGy cm (non-synchronized) with p < 0.0001. CONCLUSIONS: DS-CT is a highly sensitive method for LA thrombus detection in patients undergoing AF ablation. It delivers additional anatomic details of pulmonary veins and LA anatomy with an acceptable radiation exposure. Non-ECG-synchronized DS-CT showed a significantly lower radiation exposure, whereas diagnostic accuracy was comparable. Therefore, DS-CT might serve as primary method to exclude LA TF in patients undergoing AF ablation.

[Current indications for left atrial appendage occlusion]. / Aktuelle Indikationsstellung zur Vorhofohrokkluderimplantation.

Among patients with atrial fibrillation, the bleeding risk is linked to the stroke risk. Left atrial appendage (LAA) occlusion may reduce bleeding risk in high-risk patients. On the basis of a literature analysis and the Consensus Document of European Heart Rhythm Association (EHRA), the indications for a LAA occluder are clarified and a clear decision strategy for daily clinical practice is presented.