Teiichi Yamane

Electrophysiological Breakthroughs From the Left Atrium to the Pulmonary Veins

Background—The extent of ostial ablation necessary to electrically disconnect the pulmonary vein (PV) myocardial extensions that initiate atrial fibrillation from the left atrium has not been determined. Methods and Results—Seventy patients underwent PV mapping with a circumferential 10-electrode catheter during sinus rhythm or left atrial pacing. After assessment of perimetric distribution and activation sequence of PV potentials, ostial ablation was performed at segments showing earliest activation, with the end point of PV disconnection. A total of 162 PVs (excluding right inferior PVs) were ablated. PV potentials were present at 60% to 88% of their perimeter, but PV muscle activation was always sequential from a segment with earliest activation (breakthrough). Radiofrequency (RF) application at this breakthrough eliminated all PV potentials in 34 PVs, whereas a secondary breakthrough required RF applications at separate segments in 77; in others, >2 segments were ablated. A median of 5, 6, and 4 bipoles from the circular catheter were targeted in the right superior, left superior, and inferior PVs, respectively, to achieve PV disconnection. Early recurrence of arrhythmia was observed in 31 patients as a result of new venous or atrial foci or recovery of previously targeted PVs, most related to a single recovered breakthrough that was reablated with local RF application. Conclusions—Although PV muscle covers a large extent of the PV perimeter, there are specific breakthroughs from the left atrium that allow ostial PV disconnection by use of partial perimetric ablation.

Role of Purkinje conducting system in triggering of idiopathic ventricular fibrillation

Ventricular fibrillation is the main mechanism of sudden cardiac death, but the source of its spontaneous initiation has not been mapped. 16 patients were investigated by electrography and radiofrequency ablation after resuscitation from recurrent idiopathic ventricular fibrillation. Triggers of ventricular fibrillation originated from various locations within the Purkinje system in 12 patients and from the ordinary myocardial muscle in four. The accuracy of mapping was confirmed by acute elimination of triggers by radiofrequency delivery, and there was no recurrence of ventricular fibrillation in 14 patients. Long-term follow-up is necessary to establish that ablation is curative and avoids use of a defibrillator.

2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation

During the past three decades, catheter and surgical ablation of atrial fibrillation (AF) have evolved from investigational procedures to their current role as effective treatment options for patients with AF. Surgical ablation of AF, using either standard, minimally invasive, or hybrid techniques, is available in most major hospitals throughout the world. Catheter ablation of AF is even more widely available, and is now the most commonly performed catheter ablation procedure. In 2007, an initial Consensus Statement on Catheter and Surgical AF Ablation was developed as a joint effort of the Heart Rhythm Society (HRS), the European Heart Rhythm Association (EHRA), and the European Cardiac Arrhythmia Society (ECAS).1 The 2007 document was also developed in collaboration with the Society of Thoracic Surgeons (STS) and the American College of Cardiology (ACC). This Consensus Statement on Catheter and Surgical AF Ablation was rewritten in 2012 to reflect the many advances in AF ablation that had occurred in the interim.2 The rate of advancement in the tools, techniques, and outcomes of AF ablation continue to increase as enormous research efforts are focused on the mechanisms, outcomes, and treatment of AF. For this reason, the HRS initiated an effort to rewrite and update this Consensus Statement. Reflecting both the worldwide importance of AF, as well as the worldwide performance of AF ablation, this document is the result of a joint partnership between the HRS, EHRA, ECAS, the Asia Pacific Heart Rhythm Society (APHRS), and the Latin American Society of Cardiac Stimulation and Electrophysiology (Sociedad Latinoamericana de Estimulacion Cardiaca y Electrofisiologia [SOLAECE]). The purpose of this 2017 Consensus Statement is to provide a state-of-the-art review of the field of catheter and surgical ablation of AF and to report the findings of a writing group, convened by these five international societies. The writing group is charged with defining the indications, techniques, and outcomes of AF ablation procedures. Included within this document are recommendations pertinent to the design of clinical trials in the field of AF ablation and the reporting of outcomes, including definitions relevant to this topic. The writing group is composed of 60 experts representing 11 organizations: HRS, EHRA, ECAS, APHRS, SOLAECE, STS, ACC, American Heart Association (AHA), Canadian Heart Rhythm Society (CHRS), Japanese Heart Rhythm Society (JHRS), and Brazilian Society of Cardiac Arrhythmias (Sociedade Brasileira de Arritmias Cardiacas [SOBRAC]). All the members of the writing group, as well as peer reviewers of the document, have provided disclosure statements for all relationships that might be perceived as real or potential conflicts of interest. All author and peer reviewer disclosure information is provided in Appendix A and Appendix B. In writing a consensus document, it is recognized that consensus does not mean that there was complete agreement among all the writing group members. Surveys of the entire writing group were used to identify areas of consensus concerning performance of AF ablation procedures and to develop recommendations concerning the indications for catheter and surgical AF ablation. These recommendations were systematically balloted by the 60 writing group members and were approved by a minimum of 80% of these members. The recommendations were also subject to a 1-month public comment period. Each partnering and collaborating organization then officially reviewed, commented on, edited, and endorsed the final document and recommendations. The grading system for indication of class of evidence level was adapted based on that used by the ACC and the AHA.3,4 It is important to state, however, that this document is not a guideline. The indications for catheter and surgical ablation of AF, as well as recommendations for procedure performance, are presented with a Class and Level of Evidence (LOE) to be consistent with what the reader is familiar with seeing in guideline statements. A Class I recommendation means that the benefits of the AF ablation procedure markedly exceed the risks, and that AF ablation should be performed; a Class IIa recommendation means that the benefits of an AF ablation procedure exceed the risks, and that it is reasonable to perform AF ablation; a Class IIb recommendation means that the benefit of AF ablation is greater or equal to the risks, and that AF ablation may be considered; and a Class III recommendation means that AF ablation is of no proven benefit and is not recommended. The writing group reviewed and ranked evidence supporting current recommendations with the weight of evidence ranked as Level A if the data were derived from high-quality evidence from more than one randomized clinical trial, meta-analyses of high-quality randomized clinical trials, or one or more randomized clinical trials corroborated by high-quality registry studies. The writing group ranked available evidence as Level B-R when there was moderate-quality evidence from one or more randomized clinical trials, or meta-analyses of moderate-quality randomized clinical trials. Level B-NR was used to denote moderate-quality evidence from one or more well-designed, well-executed nonrandomized studies, observational studies, or registry studies. This designation was also used to denote moderate-quality evidence from meta-analyses of such studies. Evidence was ranked as Level C-LD when the primary source of the recommendation was randomized or nonrandomized observational or registry studies with limitations of design or execution, meta-analyses of such studies, or physiological or mechanistic studies of human subjects. Level C-EO was defined as expert opinion based on the clinical experience of the writing group. Despite a large number of authors, the participation of several societies and professional organizations, and the attempts of the group to reflect the current knowledge in the field adequately, this document is not intended as a guideline. Rather, the group would like to refer to the current guidelines on AF management for the purpose of guiding overall AF management strategies.5,6 This consensus document is specifically focused on catheter and surgical ablation of AF, and summarizes the opinion of the writing group members based on an extensive literature review as well as their own experience. It is directed to all health care professionals who are involved in the care of patients with AF, particularly those who are caring for patients who are undergoing, or are being considered for, catheter or surgical ablation procedures for AF, and those involved in research in the field of AF ablation. This statement is not intended to recommend or promote catheter or surgical ablation of AF. Rather, the ultimate judgment regarding care of a particular patient must be made by the health care provider and the patient in light of all the circumstances presented by that patient. The main objective of this document is to improve patient care by providing a foundation of knowledge for those involved with catheter ablation of AF. A second major objective is to provide recommendations for designing clinical trials and reporting outcomes of clinical trials of AF ablation. It is recognized that this field continues to evolve rapidly. As this document was being prepared, further clinical trials of catheter and surgical ablation of AF were under way.

Mapping-guided ablation of pulmonary veins to cure atrial fibrillation.

Catheter ablation of triggers inducing paroxysms of atrial fibrillation (AF) is an emerging therapy for this common arrhythmia. In a series of 225 consecutive patients with AF resistant to multiple drugs, 96% presented with triggering foci originating from 1 or multiple pulmonary veins (PV), independently of whether or not the patient had ectopy or structural heart disease. The present article describes the mapping and ablation techniques applicable to individual patients: (1) criteria to define an arrhythmogenic PV; (2) use of provocative maneuvers; and (3) the role of circumferential mapping catheters to provide extent, distribution, and activation of PV muscle as well as monitoring distal PV potentials (PVP) during ablation. Radiofrequency ablation can be performed by targeting the PVP during sinus rhythm (right PV) or left atrial pacing (left PV) with the procedural endpoint of PVP elimination, which is more effective in predicting a successful outcome than suppression of acute ectopy. Complete elimination of AF is presently obtained in 70% of patients, allowing interruption of arrhythmias and in use anticoagulants. It is anticipated that continued technologic improvements will improve and facilitate this technique of curative treatment of AF.

Functional linkage of the cardiac ATP-sensitive K^+ channel to the actin cytoskeleton

The role of the cytoskeleton in the rundown and reactivation of adenosine triphosphate (ATP) sensitive K+ channels (KATP channels) was examined by perturbing selectively the intracellular surface of inside-out membrane patches excised from guinea-pig ventricular myocytes. Actin filament-depolymerizing agents (cytochalasins and desoxyribonuclease I) accelerated channel rundown, while actin filament stabilizer (phalloidin) or phosphatidylinositol biphosphate (PIP2; inhibitor of F-actin-severing proteins) inhibited spontaneous and/or Ca2+-induced rundown. When rundown was induced by cytochalasin D or by long exposure to high Ca2+, channel activity could not be restored by exposure to MgATP, but application of F-actin with MgATP could reinstitute channel activity. The processes of rundown and reactivation of cardiac KATP channels may thus be influenced by the assembly and disassembly of the actin cytoskeletal network, which provides a novel regulatory mechanism of this channel.

Left Ventricular Diastolic Dysfunction in Patients with So‐Called Lone Atrial Fibrillation

LV Diastolic Dysfunction in Lone AF. Lone atrial fibrillation (AF) is defined by the absence of identifiable causes of AF, but its hemodynamics have not been investigated. Twenty‐eight patients with lone AF were compared with 14 control patients referred for for Woff‐Parkinson‐White ablation. Transthoracic and transesophageal echocardiography were performed to rule out structural heart disease, followed by transseptally performed complete hemodynamic evaluation of the left heart systolic and diastolic function. There was no evidence of diastolic dysfunction according to echocardiographic criteria in AF and control patients. There was no difference in echocardiographic measurements, except for a significantly higher inferosuperior left atrial dimension seen in the four‐chamber apical view in AF patients (51 ± 10 vs 40 ± 6 mm, P = 0.03). Hemodynamic evaluation showed that end‐diastolic left ventricular pressure and the nadir of the left atrial Y descent were significantly higher in lone AF patients versus controls: 13 ± 5 versus 8 ± 3 mmHg (P = 0.001) and 6.7 ± 3 versus 4.6 ± 2.7 mmHg (P = 0.05). Our results demonstrated the presence of diastolic left heart dysfunction in patients with so‐called lone AF.

Mid-term follow-up of endocardial biventricular pacing.

Biventricular (BV) pacing is a promising treatment of end‐stage heart failure. This article describes our experience with a strictly endocardial BV pacing system in patients with severe congestive heart failure. Three women and eight men (age 65 ± 9 years) with drug‐resistant end‐stage CHF underwent implantation of an endocardial BV pacing system. In the first seven patients, the left ventricular lead was placed via a combined femoral and internal jugular approach. In the last four patients, the transseptal puncture was directly performed via the right internal jugular vein with a dedicated kit. The procedure was successful in all 11 patients. The acute left ventricular and BV thresholds were 1.3 ± 0.6 V and 2.4 ± 1 V, respectively. The QRS duration decreased from 214 ± 57 to 176 ± 25 ms. A functional improvement was noted in ten patients with a decrease in mean NYHA functional class from 3.7 ± 0.5 before, to 2.6 ± 0.9 after system implantation. A significant decrease in pulmonary capillary wedge pressure and increase in cardiac output were measured in eight patients. During follow‐up, four patients died from CHF (n = 3) or ventricular fibrillation (n = 1). Under oral anticoagulation, no thromboembolic event was observed but one transient ischemic attack occurred in one patient whose anticoagulation was interrupted. Endocardial BV pacing is technically feasible and appears safe, though further studies are needed before it is used on a larger scale.

Morphological characteristics of P waves during selective pulmonary vein pacing

OBJECTIVES We sought to assess the value of 12-lead electrocardiogram (ECG) P-wave morphology to recognize the paced pulmonary vein (PV). BACKGROUND Prediction of arrhythmogenic PVs producing ectopy or initiating atrial fibrillation (AF) using 12-lead ECG may facilitate curative ablation. METHODS In 30 patients P-wave configurations were studied during sinus rhythm and during pacing at six sites from the four PVs: top and bottom of each superior PV and both inferior PVs. The P-wave amplitude, duration and morphology were assessed, and predictive accuracies were calculated for the most significant parameters. An algorithm predicting the paced PV was developed and prospectively evaluated in a different population of 20 patients. RESULTS; Three criteria were used to distinguish right from left PV: 1) a positive P-wave in lead aVL and the amplitude of P-wave in lead I > or =50 microV indicated right PV origin (specificity 100% and 97%, respectively); 2) a notched P-wave in lead II was a predictor of left PV origin (specificity 95%); and 3) the amplitude ratio of lead III/II and the duration of positivity in lead V(1) were also helpful in distinguishing left versus right PV origin. In addition, superior PVs could be distinguished from inferior according to the amplitude in lead II (> or =100 microV). In prospective evaluation, an algorithm based on the above four criteria identified 93% of left versus right PV and totally 79% of the specific PVs paced. CONCLUSIONS Pacing from the different PVs produced a P-wave with distinctive characteristics that could be used as criteria in an algorithm to identify the PV of origin with an accuracy of 79%.

Left atrial appendage activity masquerading as pulmonary vein potentials.

Background—Despite extensive proximal ablation, all potentials frequently cannot be eliminated from the left pulmonary veins (PV). Methods and Results—PV electrograms were analyzed during sinus rhythm, coronary sinus, and left atrial appendage (LAA) pacing, and PV and LAA angiography performed. During pacing, an initial low-amplitude slow potential was recorded on the anterior aspect of the left superior PV and anticipated with shortest activation time by LAA pacing. Its timing coincided with posterior LAA activation, shown to be immediately adjacent to the left superior PV by angiography. In the left inferior PV, the first potential was smaller and less sharp, coinciding with adjacent low LA activation. Angiographically, the LAA was at least 15 mm from the left inferior PV. The second sharper potential in both left PVs was eliminated by proximal ablation. Conclusion—Far field LAA activity consistently adds to PV myocardial electrograms in the left superior PV whereas lower, less sharp extravenous potentials in the left inferior PV originate from the inferior LA. They can be identified by LAA and coronary sinus pacing.

Curative catheter ablation of paroxysmal atrial fibrillation in 200 patients: strategy for presentations ranging from sustained atrial fibrillation to no arrhythmias.

Recent reports have described the consistent initiation of paroxysmal atrial fibrillation (PAF) by trains of ectopic discharges from the pulmonary veins (PVs) and the results of curative ablation in these patients. Since frequent ectopy or short bursts of nonsustained AF typically provide the ideal situation for mapping the source of initiation, the applicability of these techniques to a broad spectrum of patients with PAF has been questioned and the practical techniques used to deal with patients with a wide range of arrhythmia presentations have not been described. This article describes the application and results of curative catheter ablation in 200 patients with a wide range of presenting arrhythmias (in the electrophysiological laboratory), including those with none at all.