Left atrial diverticulum-An unexpected finding in routine transesophageal echocardiography.

We report a 55-year-old male patient with lone paroxysmal atrial fibrillation who underwent routine transesophageal echocardiography (TOE) at our institution. In a mid-esophageal 125° three-chamber angulation, a distinct thinning of the left atrial (LA) wall was observed, forming a 7 × 4 mm canal with only a small membrane separating the LA from the pericardial space. Cardiac magnetic resonance imaging diagnosed a small LA diverticulum. To the best of our knowledge, this is the first manuscript describing detection of a small LA diverticulum via TOE.

Myocarditis and inflammatory cardiomyopathy: current evidence and future directions.

Inflammatory cardiomyopathy, characterized by inflammatory cell infiltration into the myocardium and a high risk of deteriorating cardiac function, has a heterogeneous aetiology. Inflammatory cardiomyopathy is predominantly mediated by viral infection, but can also be induced by bacterial, protozoal or fungal infections as well as a wide variety of toxic substances and drugs and systemic immune-mediated diseases. Despite extensive research, inflammatory cardiomyopathy complicated by left ventricular dysfunction, heart failure or arrhythmia is associated with a poor prognosis. At present, the reason why some patients recover without residual myocardial injury whereas others develop dilated cardiomyopathy is unclear. The relative roles of the pathogen, host genomics and environmental factors in disease progression and healing are still under discussion, including which viruses are active inducers and which are only bystanders. As a consequence, treatment strategies are not well established. In this Review, we summarize and evaluate the available evidence on the pathogenesis, diagnosis and treatment of myocarditis and inflammatory cardiomyopathy, with a special focus on virus-induced and virus-associated myocarditis. Furthermore, we identify knowledge gaps, appraise the available experimental models and propose future directions for the field. The current knowledge and open questions regarding the cardiovascular effects associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are also discussed. This Review is the result of scientific cooperation of members of the Heart Failure Association of the ESC, the Heart Failure Society of America and the Japanese Heart Failure Society.

Quantitative evaluation of different high-density 3D mapping modes for atrial and ventricular substrate assessment of cardiac arrhythmias with the HD grid catheter.

BACKGROUND: Atrial and ventricular arrhythmias significantly contribute to morbidity and mortality of patients with cardiac disease. Ablation of these arrhythmias has shown to improve clinical outcomes, yet targeted ablation strategies rely on proper mapping capabilities. In the present study, we compare different modes of high-resolution mapping in clinically relevant arrhythmias using HD grid. METHODS AND RESULTS: Using the Advisor™ HD Grid Mapping Catheter in either the standard, the wave (bipolar along spline and bipolar orthogonal) or the wave diagonal setting, low-voltage areas were determined. Low-voltage was defined as local electrograms with an amplitude <0.5 mV (bipolar; atria/ventricle) or <4 mV (unipolar; ventricle). Ultra high-density mapping in 47 patients with ventricular tachycardia, ventricular premature beats, atrial fibrillation and atrial tachycardia provided reliable information for the understanding of the arrhythmia mechanism resulting in safe ablation procedures. Regions of low voltage were significantly decreased by 14 ± 2% and 31 ± 3% with wave and wave diagonal settings as compared to standard settings, respectively. CONCLUSION: Substrate mapping and risk stratification relies on proper low voltage discrimination. Even though the Advisor™ HD Grid Mapping Catheter was safely used in all cases, the extent of low voltage areas was mapping-mode dependent.

The force stability of tissue contact and lesion size index during radiofrequency ablation: An ex-vivo study.

INTRODUCTION: Radiofrequency (RF) ablation is a commonly used tool in the invasive electrophysiology laboratory to treat a variety of rhythm disorders. Reliable creation of transmural ablation lesions is crucial for long-term success. Lesion size index (LSI) is a multiparametric index that incorporates time, power, contact force (CF), and impedance data recorded during RF ablation in a weighted formula and has been shown to predict the extent of myocardial tissue lesions. Whether the force stability of contact influences lesion size in LSI-guided ablations is unknown. OBJECTIVES: The aim of this study was to analyze the influence of the force stability of contact on lesion size during LSI-guided ablations in an ex-vivo model. METHODS AND RESULTS: A total of 267 RF lesions (n = 6 hearts) were created on porcine myocardial slabs by using an open-tip irrigated ablation catheter with the following settings: 35 W with either intermittent (varied between 0 and up to 20 g), variable (10 to 20 g), or constant tissue contact (15 g) in a perpendicular or parallel fashion (applied manually) up to a target LSI of either 5 or 6. Subsequently, lesion width and depth were determined. Lesion width was mainly influenced by catheter tip orientation and LSI, whereas lesion depth was mainly influenced by LSI alone. The force stability of catheter contact had no relevant impact on lesion width or depth. CONCLUSION: The force stability of catheter contact has only little effect on lesion depth or width in LSI-guided catheter ablation while the catheter orientation primarily affects lesion width.

[Catheter ablation of ventricular tachycardia : Clinical outcome]. / Katheterablation bei ventrikulärer Tachyarrhythmie : Klinische Ergebnisse.

Catheter-based ablation of ventricular tachycardia (VT) is increasingly used in clinical practice. The reported success rates are especially high in idiopathic VT. In randomized controlled clinical trials like VANISH, ablation of scar-associated VT was superior in terms of mortality when compared to antiarrhythmic therapy. Treatment at experienced centers, e.g., using state-of-the-art electroanatomical mapping systems, is a promising option for these complex and often multimorbid patients.

Implantable loop recorders in patients with unexplained syncope: Clinical predictors of pacemaker implantation.

BACKGROUND: Implantable loop recorders (ILR) are a valuable tool for the investigation of unexplainedsyncopal episodes. The aim of this retrospective single center study was to identify predictive factors for pacemaker implantation in patients with unexplained syncope who underwent ILR insertion. METHODS: One hundred six patients were retrospectively analyzed (mean age 59.1 years; 47.2% male) with unexplained syncope and negative conventional testing who underwent ILR implantation. The pri- mary study endpoint was detection of symptomatic or asymptomatic bradycardia requiring pacemaker implantation. RESULTS: The average follow-up period after ILR implantation was 20 ± 15 months. Pacemaker im- plantation according to current guidelines was necessary in 22 (20.8%) patients, mean duration until index bradycardia was 81 ± 88 (2-350) days. Ten (45.5%) patients received a pacemaker due to sinus arrest, 7 (31.8%) patients due to third-degree atrioventricular block, 2 (9.1%) patients due to second- degree atrioventricular block and 1 (4.5%) patient due to atrial fibrillation with a slow ventricular rate. Three factors remained significant in multivariate analysis: obesity, which defined by a body mass index above 30 kg/m2 (OR: 7.39, p = 0.014), a right bundle branch block (OR: 9.40, p = 0.023) and chronic renal failure as defined by a glomerular filtration rate of less than 60 mL/min (OR: 6.42, p = 0.035). CONCLUSIONS: Bradycardia is a frequent finding in patients undergoing ILR implantation due to un- explained syncope. Obesity, right bundle branch block and chronic renal failure are independent clinical predictors of pacemaker implantation.

Safety and efficacy of catheter-based left atrial appendage closure in patients with contraindications for long-term anticoagulation.

BACKGROUND: Percutaneous left atrial appendage closure (LAAC) and the role of postinterventional anticoagulation often evokes controversy in daily practice. This study aimed to evaluate LAAC in patients with non-rheumatic atrial fibrillation, high thromboembolic risk and contraindications for long-term anticoagulation in a clinical scenario. METHODS: Between 2010-2015, LAAC was attempted in 118 patients (47 women). RESULTS: Devices were successfully implanted in 95% (Watchman™ device: N.=97; Amplatzer™ Cardiac Plug/Amulet: N.=14; Amplatzer PFO Occluder: N.=1). Mean age was 75±8.35 years. Mean HAS-BLED and CHA2DS2VASc scores were 4.3 and 4.9, respectively. Median follow-up was 447 days (IQR: 183-789 days). The primary safety endpoint was defined as major bleeding according to the International Society on Thrombosis and Hemostasis. The combined efficacy endpoint included ischemic strokes, transitory ischemic attacks (TIA) and systemic embolisms. Procedural complication rate was 3.4%. After successful intervention, either a therapy with anticoagulants (N.=62) or dual antiplatelet therapy (DAPT, N.=50) was prescribed temporarily. Medication was reduced if implantation proved satisfying in a 6-week follow-up transesophageal echocardiography, which was the case in 79% of these patients. During follow-up, one patient suffered a TIA (0.6%/year). No other efficacy event was observed. Eleven major bleedings occurred (6.6%/year): one each under DAPT plus phenprocoumon, DAPT plus rivaroxaban, acetylsalicylic acid (ASA) plus rivaroxaban, two under DAPT, two under ASA plus low molecular weight heparin, and four under ASA only. CONCLUSIONS: In the present study, catheter-based LAA occlusion prevented thromboembolisms with high efficacy. Major bleedings were however common in patients with, but also without anticoagulation, independent from time course.

Third-degree AV block sensitive to prednisolone 72 hours post AVNRT ablation.

A patient developed a transient first-degree AV block during a radiofrequency ablation of an atrioventricular nodal reentrant tachycardia. Three days later the patient presented with a third-degree AV block. It resolved within 24 h under antiphlogistic therapy. Patient was asymptomatic without necessity for pacemaker implantation at 12 months follow-up.

The Lewis Lead for Detection of Ventriculoatrial Conduction Type.

BACKGROUND: Identification of a possible ventriculoatrial (VA) dissociation in wide QRS complex tachycardias is one of the most reliable criteria for differentiation of tachycardia origin. The Lewis lead has been proposed for detection of atrial activity during ventricular tachycardias. HYPOTHESIS: A modified Lewis-lead-ECG will be superior to the standard-lead ECG for detection of ventriculoatrial conduction during ventricular tachycardia. METHODS: Forty-seven patients underwent electrophysiological study, stimulated with a fixed cycle length of 400 ms in the ventricle. During stimulation, a standard-lead ECG and a modified Lewis-lead ECG were recorded. Simultaneously, VA conduction was documented by intracardiac electrograms. Surface ECGs were presented to 6 blinded examiners for VA conduction assessment. RESULTS: Type of VA conduction was correctly diagnosed in significantly more ECGs in the Lewis-lead ECG group (mean, 35.0 [75%]) than in the standard-lead ECG group (mean, 29.2 [62%]; P = 0.045). Ventriculoatrial dissociation also was significantly more often correctly diagnosed in the Lewis-lead ECG group (mean, 17.7 [71%]) than in the standard-lead ECG group (mean, 12.7 [49%]; P = 0.014). Interobserver agreement was moderate in both groups (κ = 0.45 and κ = 0.49, respectively). CONCLUSIONS: Compared with standard-lead ECG, modified Lewis-lead ECG is associated with significantly improved detection of VA conduction type during fast ventricular pacing and thus may help improve ECG diagnosis.

Mid-regional proadrenomedullin levels predict recurrence of atrial fibrillation after catheter ablation.

BACKGROUND: We evaluated the prognostic value of mid-regional proadrenomedullin (MR-proADM) in atrial fibrillation (AF) patients undergoing radiofrequency ablation. METHODS: Plasma concentrations of MR-proADM were measured at baseline and after 12months in 87 AF patients in whom radiofrequency ablation was performed. The association between MR-proADM and AF recurrence was tested by univariable and multivariable Cox models. RESULTS: In all 87 patients radiofrequency ablation was successfully performed. Of the total population 54% had paroxysmal AF. The mean left ventricular ejection fraction was 54% (minimum 25%). After 12months of follow-up, 71% of the patients were free of AF recurrence. At baseline, mean MR-proADM in the total population was 0.72nmol/l±0.22. Patients with AF recurrence had significantly higher baseline MR-proADM (0.89nmol/l±0.29) as compared with patients without AF recurrence (0.65nmol/l±0.14; p<0.001). After 12months, mean MR-proADM plasma concentration remained higher in patients with AF recurrence (0.81nmol/l±0.22 as compared with patients free of AF 0.54nmol/l±0.20; p<0.001). Receiver operating characteristic (ROC) curve analysis for MR-proADM yields a specificity of 98% and a sensitivity of 64% with an optimal cut-off value of 0.82nmol/l to predict recurrence of AF after catheter ablation. In the logistic regression analysis only MR-proADM remained independently predictive for AF recurrence. CONCLUSION: This is the first study revealing the association between MR-proADM elevation before ablation and poor outcomes after ablation of AF. Larger studies are needed to validate these results.

Mapping of the left-sided phrenic nerve course in patients undergoing left atrial catheter ablations.

BACKGROUND: Catheter ablation of atrial fibrillation has been associated with left-sided phrenic nerve palsy. Knowledge of the individual left phrenic nerve course therefore is essential to prevent nerve injury. The aim of this study was to test the feasibility of an intraprocedural pace mapping and reconstruction of the left phrenic nerve course and to characterize which anatomical areas are affected. METHODS: In patients undergoing left atrial catheter ablation, a three-dimensional map of the left atrial anatomical structures was created. The left-sided phrenic nerve course was determined by high-output pace mapping and reconstructed in the map. RESULTS: In this study, 40 patients with atrial fibrillation or atrial tachycardias were included. Left phrenic nerve capture was observed in 23 (57.5%) patients. Phrenic nerve was captured in 22 (55%) patients inside the left atrial appendage, in 22 (55%) in distal parts, in 21 (53%) in medial parts, and in two (5%) in ostial parts of the appendage. In three (7.5%) patients, capture was found in the distal coronary sinus and in one (2.5%) patient in the left atrium near the left atrial appendage ostium. Ablation target was changed due to direct spatial relationship to the phrenic nerve in three (7.5%) patients. No phrenic nerve palsy was observed. CONCLUSIONS: Left-sided phrenic nerve capture was found inside and around the left atrial appendage in the majority of patients and additionally in the distal coronary sinus. Phrenic nerve mapping and reconstruction can easily be performed and should be considered prior catheter ablations in potential affected areas.

In vitro modeling of ryanodine receptor 2 dysfunction using human induced pluripotent stem cells.

BACKGROUND/AIMS: Induced pluripotent stem (iPS) cells generated from accessible adult cells of patients with genetic diseases open unprecedented opportunities for exploring the pathophysiology of human diseases in vitro. Catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) is an inherited cardiac disorder that is caused by mutations in the cardiac ryanodine receptor type 2 gene (RYR2) and is characterized by stress-induced ventricular arrhythmia that can lead to sudden cardiac death in young individuals. The aim of this study was to generate iPS cells from a patient with CPVT1 and determine whether iPS cell-derived cardiomyocytes carrying patient specific RYR2 mutation recapitulate the disease phenotype in vitro. METHODS: iPS cells were derived from dermal fibroblasts of healthy donors and a patient with CPVT1 carrying the novel heterozygous autosomal dominant mutation p.F2483I in the RYR2. Functional properties of iPS cell derived-cardiomyocytes were analyzed by using whole-cell current and voltage clamp and calcium imaging techniques. RESULTS: Patch-clamp recordings revealed arrhythmias and delayed afterdepolarizations (DADs) after catecholaminergic stimulation of CPVT1-iPS cell-derived cardiomyocytes. Calcium imaging studies showed that, compared to healthy cardiomyocytes, CPVT1-cardiomyocytes exhibit higher amplitudes and longer durations of spontaneous Ca(2+) release events at basal state. In addition, in CPVT1-cardiomyocytes the Ca(2+)-induced Ca(2+)-release events continued after repolarization and were abolished by increasing the cytosolic cAMP levels with forskolin. CONCLUSION: This study demonstrates the suitability of iPS cells in modeling RYR2-related cardiac disorders in vitro and opens new opportunities for investigating the disease mechanism in vitro, developing new drugs, predicting their toxicity, and optimizing current treatment strategies.

Findings and outcome of fluoroscopic visualization of the oesophageal course during catheter ablation of atrial fibrillation.

AIMS: The close topographic relationship between the left atrial posterior wall (LAPW) and the oesophagus creates a potential hazard of thermal lesions to the oesophagus during radiofrequency (RF) catheter ablation of atrial fibrillation (AF). The purpose of the study was to describe topographic relation of the oesophagus behind the left atrium in the ablation situation, and to evaluate the clinical outcome of subsequent modifications to the strategy using continuous real-time fluoroscopic visualization of the oesophageal course. METHODS AND RESULTS: In 214 consecutive patients, a gastric tube (GT) was inserted before circumferential pulmonary vein isolation (CPVI) for the treatment of paroxysmal (n= 160) or persistent (n= 54) AF. In the real-time mapping situation at the LAPW, the tissue interface between catheter tip and oesophagus lumen measured only 2.9 ± 1.9 mm, and 2.5 ± 1.2 mm at the level of the upper and lower pulmonary vein (PV) ostia, respectively. Modifications of the intended antral CPVI approach due to an oesophageal course close to the left or right PV ostia (in 76.6% of patients) were associated with reduced success rate (sustained sinus rhythm) after one (54.9 vs. 72.0%, P = 0.03), or 1-3 ablation procedures (85.4 vs. 96.0%, P = 0.04) during a mean follow-up of 13 ± 10 months. CONCLUSION: Continuous real-time fluoroscopic visualization using a GT emphasizes the very small distance of the catheter tip and oesophageal lumen that may be present in the real-ablation situation and may help to avoid RF lesion application in close proximity to the oesophagus. However, accordant modification of AF ablation strategy may reduce efficacy of the procedure.

Mutational analysis of the PITX2 and NKX2-5 genes in patients with idiopathic atrial fibrillation.

Atrial fibrillation (AF) is the most frequently encountered arrhythmia in clinical practice. In a subgroup of patients, AF is regarded as idiopathic when no signs of structural heart disease or other causes of the arrhythmia can be identified during conventional clinical work-up. Recent studies have demonstrated that AF has a substantial genetic basis in a number of cases. The entire coding sequences, including intron-exon boundaries, of the genes PITX2 and NKX2-5 were screened for genetic variants by means of initial polymerase chain reaction followed by DNA sequencing in 96 patients with idiopathic AF. Although we detected a number of variants, our candidate gene approach did not result in identification of mutations associated with AF in the coding regions of PITX2 or NKX2-5 in our well characterized AF cohort.