Box Lesion Isolation of the Left Atrial Posterior Wall with Radiofrequency Ablation Restricted in Predetermined Lines for the Treatment of Persistent Atrial Fibrillation: The Prognostic Role of Acute Interventional Outcome and Trigger Identification.

The left atrial posterior wall (PW) is known to be a critical substrate for the initiation and perpetuation of atrial fibrillation (AF) and has been explored as a target for catheter ablation, particularly in persistent AF (PerAF). In this retrospective study, we investigate the clinical outcome of patients with PerAF who underwent PW isolation (PWI) restricted in predetermined lines in addition to pulmonary vein isolation (PVI). One hundred consecutive patients (64 ± 9.1 years, 66% male, 20% with previous PVI ablation) underwent PWI in a box lesion setting for PerAF lasting >3 months (34% long-standing PerAF). PW triggers were defined as either foci from the PW that repeatedly induced AF or as isolated AF or atrial tachycardia (AT) within the PW. After a mean follow-up period of 25.6 ± 6.7 months, 61% of the patients remained in sinus rhythm after the last procedure. In 79 patients, the PW was successfully isolated, while, in 21 patients, complete isolation was not possible due to failure in completion of the roof line (n = 16), the floor line (n = 7), or both (n = 2). Patients with incomplete isolation had similar AF/AT recurrence rates compared to those with complete PWI. In 12 patients, PW triggers were identified, and PWI in these patients was shown to have a significantly better prognosis in terms of sinus rhythm maintenance (P = .031). Failure of complete PWI does not predispose a patient to an inferior outcome nor is it responsible for iatrogenic ATs. The presence of AF triggers within the PW leads to a particularly favorable result after box lesion isolation.

Ping-pong guide catheter technique for facilitating antegrade crossing of a chronic total occlusion.

A 60-year-old man was referred for percutaneous coronary intervention of a proximal left circumflex (Cx) chronic total occlusion (CTO) with distal filling via epicardial collaterals from the left anterior descending (LAD) artery.

A simplified differential pacing technique for the evaluation of bidirectional cavo-tricuspid isthmus block during ablation of typical atrial flutter.

PURPOSE: Bidirectional block of the cavo-tricuspid isthmus (CTI) is an established endpoint of CTI-dependent atrial flutter (AFl) ablation. Differential pacing has been used to evaluate the CTI block. The purpose of this study is to describe a modified differential pacing technique to evaluate the CTI block. METHODS: Sixty-two patients underwent radiofrequency (RF) ablation of CTI-dependent AFl. The acute endpoints were non-inducibility of the AFl, and verification of the bidirectional CTI block by our methodology. Pacing was performed in the CS with an ablation catheter positioned immediately lateral to the CTI ablation line, and then 1-2 cm more laterally. The stimulus-to-ablation catheter atrial electrogram intervals were measured at these sites (StimCS-Abl1 and StimCS-Abl2, respectively). Pacing with the ablation catheter also was performed at these 2 sites, and the stimulus-to-CS electrogram intervals (StimABL1-CS and StimABL2-CS) were measured. The criteria for the bidirectional block were StimCS-Abl1 > StimCS-Abl2, and StimABL1-CS > StimABL2-CS. Clinical efficacy was defined as freedom from recurrent AFl during follow-up. RESULTS: Following 12.2 ± 3.7 min of RF delivery across the CTI, intervals were StimCS-Abl1 = 181.2 ± 22.7 ms and StimABL1-CS = 181.0 ± 23.6 ms, and StimCS-Abl2 = 152.2 ± 26.5 ms and StimABL2-CS = 151.2 ± 22.7 (P < 0.001). Atrial flutter was rendered not inducible in all patients, and no procedural complications were encountered. During the next 15.9 ± 0.7 months, two patients were lost to follow-up, and among the 62 other patients, one (1.7%) had flutter recurrence. CONCLUSIONS: The bidirectional CTI block can be assessed quickly and easily using only the ablation and CS catheters for differential pacing.

Spatial characterization of the tachycardia circuit of atrioventricular nodal re-entrant tachycardia.

AIMS: The exact circuit of atrioventricular nodal re-entrant tachycardia (AVNRT) remains elusive. To assess the location and dimensions of the AVNRT circuit. METHODS AND RESULTS: Both typical and atypical AVNRT were induced at electrophysiology study of 14 patients. We calculated the activation time of the fast and slow pathways, and consequently, the length of the slow pathway, by assuming an average conduction velocity of 0.04 mm/ms in the nodal area. The distance between the compact atrioventricular node and the slow pathway ablating electrode was measured on three-dimensionally reconstructed fluoroscopic images obtained in diastole and systole. We also measured the length of the histologically discrete right inferior nodal extension in 31 human hearts. The length of the slow pathway was calculated to be 10.8 ± 1.3 mm (range 8.2-12.8 mm). The distance from the node to the ablating electrode was measured in five patients 17.0 ± 1.6 mm (range 14.9-19.2 mm) and was consistently longer than the estimated length of the slow pathway (P < 0.001). The length of the right nodal inferior extension in histologic specimens was 8.1 ± 2.3 mm (range 5.3-13.7 mm). There were no statistically significant differences between these values and the calculated slow pathway lengths. CONCLUSION: Successful ablation affects the tachycardia circuit without necessarily abolishing slow conduction, probably by interrupting the circuit at the septal isthmus.

The Electrophysiology of Atrial Fibrillation: From Basic Mechanisms to Catheter Ablation.

The electrophysiology of atrial fibrillation (AF) has always been a deep mystery in understanding this complex arrhythmia. The pathophysiological mechanisms of AF are complex and often remain unclear despite extensive research. Therefore, the implementation of basic science knowledge to clinical practice is challenging. After more than 20 years, pulmonary vein isolation (PVI) remains the cornerstone ablation strategy for maintaining the sinus rhythm (SR). However, there is no doubt that, in many cases, especially in persistent and long-standing persistent AF, PVI is not enough, and eventually, the restoration of SR occurs after additional intervention in the rest of the atrial myocardium. Substrate mapping is a modern challenge as it can reveal focal sources or rotational activities that may be responsible for maintaining AF. Whether these areas are actually the cause of the AF maintenance is unknown. If this really happens, then the targeted ablation may be the solution; otherwise, more rough techniques such as atrial compartmentalization may prove to be more effective. In this article, we attempt a broad review of the known pathophysiological mechanisms of AF, and we present the recent efforts of advanced technology initially to reveal the electrical impulse during AF and then to intervene effectively with ablation.

Incidence, electrophysiological characteristics, and long-term follow-up of perimitral atrial flutter in patients with previously confirmed mitral isthmus block.

INTRODUCTION: After mitral isthmus (ΜΙ) catheter ablation, perimitral atrial flutter (PMF) circuits can be maintained due to the preservation of residual myocardial connections, even if conventional pacing criteria for complete MI block are apparently met (MI pseudo-block). We aimed to study the incidence, the electrophysiological characteristics, and the long-term outcome of these patients. METHODS: Seventy-two consecutive patients (mean age 62.4 ± 10.2, 62.5% male) underwent MI ablation, either as part of an atrial fibrillation (AF) ablation strategy (n = 35), or to treat clinical reentrant atrial tachycardia (AT) (n = 32), or to treat AT that occurred during ablation for AF (n = 5). Ιn all patients, the electrophysiological characteristics of PMF circuits were studied by high-density mapping. RESULTS: Mitral isthmus block was successfully achieved in 69/72 patients (95.6%). Five patients developed PMF after confirming MI block. In these patients, high-density mapping during the PMF showed a breakthrough in MI with extremely low impulse conduction velocity (CV). In contrast, in usual PMF circuits that occurred after AF ablation, the lowest CV of the reentrant circuit was of significantly higher value (0.07 ± 0.02 m/s vs 0.25 ± 0.07 m/s, respectively; P < .001). Patients presented with clinical AT had better prognosis in maintaining sinus rhythm after MI ablation compared with patients presented with AF. CONCLUSION: Perimitral atrial flutter with MI pseudo-block may be present after MI ablation and has specific electrophysiological features characterized by remarkably slow CV in the MI. Thus, even after MI block is achieved, a more detailed mapping in the boundaries of the ablation line or reinduction attempts may be needed to exclude residual conduction.

Ventricular ectopy from the non-coronary cusp: Pathophysiological and anatomical considerations.

Non-coronary cusp (NCC) is a rare site for ventricular arrhythmias because it does not come into direct contact with the ventricular myocardium. Instead, the NCC comes in contact with the membranous septum near the His region. We describe a case of a young man with a ventricular ectopy who was successfully ablated in the NCC. In our case the much greater prematurity in the NCC than in the His region suggests that the arrhythmic site of origin is not in the peri-His area but most likely a myocardial extension adjoining the aortic root.

Anatomic and Flow Characteristics of Left Anterior Descending Coronary Artery Angiographic Stenoses Predisposing to Myocardial Infarction.

The impact of the anatomic characteristics of coronary stenoses on the development of future coronary thrombosis has been controversial. This study aimed at identifying the anatomic and flow characteristics of left anterior descending (LAD) coronary artery stenoses that predispose to myocardial infarction, by examining angiograms obtained before the index event. We identified 90 patients with anterior ST-elevation myocardial infarction (STEMI) for whom coronary angiograms and their reconstruction in the three-dimensional space were available at 6 to 12 months before the STEMI, and at the revascularization procedure. The majority of culprit lesions responsible for STEMI occurred between 20 and 40 mm from the LAD ostium, whereas the majority of stable lesions not associated with STEMI were found in distances >60 mm (p < 0.001). Culprit lesions were significantly more stenosed (diameter stenosis 68.6 ± 14.2% vs 44.0 ± 10.4%, p < 0.001), and significantly longer than stable ones (15.3 ± 5.4 mm vs 9.2 ± 2.5 mm, p < 0.001). Bifurcations at culprit lesions were significantly more frequent (88.8%) compared with stable lesions (34.4%, p < 0.001). Computational fluid dynamics simulations demonstrated that hemodynamic conditions in the vicinity of culprit lesions promote coronary thrombosis due to flow recirculation. A multiple logistic regression model with diameter stenosis, lesion length, distance from the LAD ostium, distance from bifurcation, and lesion symmetry, showed excellent accuracy in predicting the development of a culprit lesion (AUC: 0.993 [95% CI: 0.969 to 1.000], p < 0.0001). In conclusion, specific anatomic and hemodynamic characteristics of LAD stenoses identified on coronary angiograms may assist risk stratification of patients by predicting sites of future myocardial infarction.

Prospective Assessment of Biomarkers of Hypercoagulability for the Identification of Patients With Severe Coronary Artery Disease. The ROADMAP-CAD Study.

In patients with stable coronary artery disease (CAD) blood hypercoagulability figures among factors leading to thrombosis. Tissue factor (TF) exposure at ruptured plaque initiates blood coagulation and hypercoagulability is responsible for thrombus formation. Early identification of patients eligible for angiography is a challenging issue for effective prevention of ACS. This pilot study aimed to identify biomarkers of hypercoagulability that can be prospectively used in risk assessment tools for the evaluation of CAD severity. Biomarkers of hypercoagulability could be a used for the evaluation of CAD severity. Platelet-poor plasma from 66 patients who were referred to coronary angiography was assessed for thrombin generation, phospholipid-dependent clotting time (Procoag-PPL ® ) and D-Dimers, and evaluated against atherosclerotic burden. Patients with CAD, as compared to controls, showed attenuated thrombin generation lag time: 4.7 (3.8-5.4) min versus 2.5 (2.1-2.9) min; p < 0.0001, shorter Procoag-PPL® clotting time 55.0(32-66) s versus 62.8 (42-85) s; p = 0.001), and higher D-Dimer levels 0.509 (0.27-2.58) µg/ml versus 0.309 (0.23-0.39) µg/ml; p = 0.038. Multivariate logistic regression model showed excellent discriminatory value in predicting CAD severity. The ROADMAP-CAD study showed that the Procoag-PPL® clotting time and thrombin Peak are informative for the the burden of the coronary atherosclerotic disease. The clinical relevance of this observation in the development of a new clinic-biological risk assessment model for early diagnosis of severe CAD has to be examined in a prospective study.

Distal Radial Access for Percutaneous Endovascular Repair of a Radial Artery Pseudoaneurysm.

Percutaneous pseudoaneurysm repair through the ipsilateral ulnar artery is an alternative to surgical repair; however, distal radial access, as described in this case, may offer increased safety.

First Reported Case of Skin Necrosis Due to Prolonged Mechanical Compression After Transradial Catheterization.

We present a patient under triple-antithrombotic therapy who underwent prolonged mechanical compression after radial intervention; the subsequent necrosis at the access site required surgical repair.

Dissection Re-entry Technique: How is it Really Looking?

Dissection re-entry is a widely used technique in many chronic total occlusion centers. This account of a failed re-entry attempt provides in vivo photographic evidence of how the vessel looked after such an attempt. Operators are advised to keep dissection of subintimal space and hematoma limited and use dedicated materials and techniques for controlled re-entry.

Endpoints for Successful Slow Pathway Catheter Ablation in Typical and Atypical Atrioventricular Nodal Re-Entrant Tachycardia: A Contemporary, Multicenter Study.

OBJECTIVES: This study sought to investigate markers of success following slow pathway ablation for atrioventricular nodal re-entrant tachycardia (AVNRT). BACKGROUND: Published data are conflicting. METHODS: The authors studied 1,007 patients with typical AVNRT and 77 patients with atypical AVNRT. RESULTS: Following ablation, tachycardia was rendered not inducible in all patients. One case of transient (0.09%) and 1 of permanent (0.09%) atrioventricular (AV) block were encountered. At a 3-month follow-up, arrhythmia recurrence was noted in 21 (2.10%) patients in the typical and 3 (3.90%) patients in the atypical group (odds ratio: 0.525; 95% confidence interval [CI]: 0.153 to 1.802; p = 0.298). To predict absence of recurrence in 3 months, the induction of junctional rhythm (95.70% in typical and 96.10% in atypical groups) had sensitivity of 95.9% (95% CI: 94.6% to 97.0%) and specificity of 4.20% (95% CI: 0.11% to 21.10%), while the absence of dual AV nodal conduction post-ablation had sensitivity of 65.2% (95% CI: 62.2% to 68.1%) and specificity of 33.30% (95% CI: 15.60% to 55.30%). Neither junctional rhythm nor residual dual AV nodal pathway conduction were predictive of arrhythmia recurrence by univariate analysis. In long-term follow-up data available for 239 patients, arrhythmia-free survival was not associated with the induction of junctional rhythm or the absence of residual dual AV nodal conduction (log-rank test, p = 0.819 and p = 0.226, respectively). CONCLUSIONS: Induction of a junctional rhythm during ablation is a sensitive but not a specific marker of success. Residual dual AV nodal conduction is not predictive of recurrence. Noninducibility of the arrhythmia, usually after ablation-induced junctional rhythm, and despite isoproterenol challenge, is the most credible endpoint for success.

Biomarkers in Atrial Fibrillation and Heart Failure.

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice and an important contributor to cardiovascular morbidity and mortality. Although the exact mechanisms behind AF are not completely elucidated, the underlying pathophysiological changes have been well described. Predisposal factors for AF include the older age, the increased left atrial size, the decreased left atrial function, the presence of heart failure and left ventricular systolic dysfunction and the presence of coronary heart disease or pulmonary or mitral valve disease. In addition to these factors, emerging evidence demonstrate that myocardial strain, fibrosis and inflammation, are associated with AF as well as the pathogenesis of the arrhythmia. The natruretic peptide system including Atrial Natriuretic Peptide (ANP), Brain Natriuretic Peptide (BNP) and C-type Natriuretic Peptide (CNP) is indicative of the level of myocardial strain which may predispose to AF. As a result, the aforementioned peptides are increased in AF patients. The levels of myocardial fibrosis biomarkers, such as ST2 and Galectin-3, are elevated suggesting atrial structural abnormalities, while the increased levels of CRP and Interleukin-6 supplement the inflammatory profile of AF patients. Emerging data for the aforementioned biomarkers are discussed in the present review.

Effects of omega-3 polyunsaturated fatty acids on fibrosis, endothelial function and myocardial performance, in ischemic heart failure patients.

BACKGROUND & AIMS: Polyunsaturated fatty acids (PUFAs) may affect the cardiovascular system with a multiplicity of mechanisms. We assessed the effects of omega-3 PUFAs supplements on inflammation, fibrosis, left ventricle performance and endothelial function of ischemic heart failure (HF) patients. METHODS: In this double-blind, placebo controlled, cross-over trial we enrolled 31 patients with ischemic HF, followed by a 6-week wash-out period. Omega-3 PUFAs (2 g daily, 8 weeks) were administered PO in the intervention arm. Left ventricle ejection fraction (EF), global longitudinal strain and the ratio E/e' (early ventricular filling to early mitral annulus velocities)were measured. Endothelial function was evaluated by flow mediated dilation and myocardial fibrosis by soluble ST2. High sensitive C Reactive protein (hsCRP) levels were measured as an inflammatory marker. RESULTS: Treatment with omega-3 PUFA, compared to placebo, improved: left ventricle EF (percent increased by 4.7% vs 1.7%); global longitudinal strain (decreased by -10.6% vs -2.3%); the E/e' ratio (decreased by -9.47% vs -2.1%); ST2 levels (decreased by -4.53% vs -2.37%); flow mediated dilation (percent increased by 44% vs. 11% and hsCRP levels (decreased by -6.13% vs 4.35%) (p < 0.05 for all). CONCLUSION: Short term treatment with omega-3 PUFAs in subjects with stable ischemic HF improved inflammatory and fibrotic status as well as endothelial function in parallel with systolic and diastolic performance of left ventricle. These findings provide further insights regarding the impact of omega-3 PUFAs administration on left ventricle performance indices, systemic inflammation and fibrosis biomarkers in patients with ischemic HF.

Compartment Syndrome: A Rare and Frightening Complication of Transradial Catheterization.

The compartment syndrome is a severe complication of transradial approach and can be prevented by prompt treatment of forearm hematoma; otherwise, fasciotomies are urgent.

Coronary artery ectasia in Crohn's disease.

Coronary artery ectasia (CAE) can be ascribed, in the majority of cases, to coronary atherosclerosis. Nevertheless, the presence of isolated ectatic lesions without obstructive coronary artery disease and the association of CAE with several autoimmune diseases characterised by systemic vascular involvement suggest that the pathogenesis of CAE may extend beyond coronary atherosclerosis. We herein report the case of a 56-year-old male patient with Crohn's disease and isolated CAE, who has been found positive for IgM and IgA antiendothelial cell antibodies, and discuss a potential pathogenic mechanism.

Rotational Atherectomy and Simultaneous Temporary Transvenous Pacing Through a Forearm Approach.

This is the first reported rotational atherectomy procedure with transvenous pacing utilizing a complete forearm approach. An imaging series illustrates the feasibility of this procedure and its advantages for the patient.