Ablation of Ventricular Arrhythmias in Arrhythmogenic Right Ventricular Dysplasia

VT Ablation in Right Ventricular Dysplasia. Arrhythmogenic right ventricular dysplasia (ARVD) is a genetically determined myocardial disease characterized by fibrofatty replacement of the right ventricular wall. Ventricular tachyarrhythmias can be seen in the early stages of the disease, which is one of the most important causes of sudden death in young healthy individuals. Radiofrequency (RF) catheter ablation is an option for the treatment of medically refractory ventricular arrhythmias and it has shown to successfully abolish recurrent ventricular tachycardias (VT) as well as reduce the frequency in defibrillator therapies. However, variable acute and long‐term success rates have been reported. The current mapping and ablation techniques include activation and entrainment mapping during tolerated VT and substrate ablation using 3‐dimensional electroanatomic mapping systems. This article aims at providing a comprehensive review of RF catheter ablation of ventricular arrhythmias in the context of ARVD. (J Cardiovasc Electrophysiol, Vol. 21, pp. 473‐14, April 2010)     

Coronary Venous Mapping and Catheter Ablation for Ventricular Arrhythmias

Catheter ablation is an effective treatment method for ventricular arrhythmias (VAs). These arrhythmias can often be mapped and targeted with ablation from the left and right ventricular endocardium. However, in some situations the VA site of origin or substrate may be intramural or epicardial in nature. In these cases, the coronary venous system (CVS) provides an effective vantage point for mapping and ablation. This review highlights situations in which CVS mapping may be helpful and discusses techniques for CVS mapping and ablation.     

Infusion Needle Radiofrequency Ablation for Treatment of Refractory Ventricular Arrhythmias

Background

Catheter ablation is effective for eliminating most drug-refractory ventricular arrhythmias (VA). However, a major reason for procedural failure is arrhythmia originating deep within the myocardium where it is inaccessible to conventional endocardial or epicardial approaches. Affected patients have limited therapeutic options.

冠心病心肌梗死后室性心律失常经射频导管消融的进展

冠心病心肌梗死后室性心律失常包括急性和陈旧性心肌梗死后的室性心律失常,可导致心功能恶化、猝死、生活质量下降等不良后果,近年来由于对其发病机制的进一步了解,同时在应用心脏三维标测系统引导心肌梗死后室性心律失常的标测和消融、经心外膜标测和消融室性心律失常和应用盐水灌注导管消融等方面有很大进展,心肌梗死后室性心律失常的经射频导管消融已取得较好效果。     

Radiofrequency Ablation Guided by Mechanical Termination of Idiopathic Ventricular Arrhythmias Originating in the Right Ventricular Outflow Tract

Mapping of Idiopathic Ventricular Arrhythmias. Background: Termination of ventricular tachycardia (VT) by mechanical pressure has been described for fascicular and postinfarction VT. Mechanical interruption of idiopathic ventricular arrhythmias (VT/premature ventricular complexes [PVCs]) arising in the right ventricular outflow tract (RVOT) has not been described in systematic fashion. Methods: Eighteen consecutive patients (13 females, age 49 ± 13 years, ejection fraction 0.55 ± 0.12) underwent mapping and ablation of RVOT VT or PVCs. In 7 patients, 9 distinct VTs (mean cycle length 440 ± 127 ms), and in 11 patients, 11 distinct PVCs originating in the RVOT were targeted. Mechanical termination was considered present if a reproducibly inducible VT was no longer inducible or if frequent PVCs suddenly ceased with the mapping catheter at a particular location. Endocardial activation time, electrogram characteristics, and pace‐mapping morphology were assessed at this location. Radiofrequency energy was delivered if mechanical termination was observed. Results: All targeted arrhythmias were successfully ablated. In 7 of 18 patients (39%), catheter manipulation terminated the arrhythmia with the mapping catheter located at a particular site. Local endocardial activation time was earlier at sites of mechanical termination (?31 ± 7 ms) compared with effective sites without termination (?25 ± 3 ms, P = 0.04). The 10‐ms isochronal area was smaller in patients with mechanical interruption (0.35 ± 0.2 cm²) than in patients without mechanical termination (1.33 ± 0.9 cm², P = 0.01). At all sites susceptible to mechanical trauma, the pace map displayed a match with the targeted VT/PVC. All sites where mechanical termination of VT or PVCs occurred were effective ablation sites. Conclusions: Mechanical suppression at the site of origin of idiopathic RVOT arrhythmias frequently occurs during the mapping procedure and is a reliable indicator of effective ablation sites. Mechanical termination of RVOT arrhythmias may be indicative of a more localized arrhythmogenic substrate. (J Cardiovasc Electrophysiol, Vol. 21, pp. 42–46, January 2010)     

Parenteral Antiarrhythmics for Life-Threatening Ventricular Arrhythmias

Parenteral Antiarrhythmics for Ventricular Arrhythmias. The acute management of life-threatening ventricular tachyarrhythmias often includes the use of parenteral antiarrhythmics. There are a number of agents currently available for this purpose. They are used to suppress inducible monomorphic ventricular tachycardia during programmed electrical stimulation, they terminate spontaneous sustained ventricular tachycardia, and prevent ventricular fibrillation in the setting of an acute myocardial infarction. Serious adverse reactions include proarrhythmia, hypotension, severe bradyarrhythmias, and precipitation of congestive heart failure. A comparative evaluation of intravenous antiarrhythmics is difficult due to inherent differences in the choice of agents for study, protocol design, patient population, defined endpoints, and serum drug levels. Likewise, the reported adverse reaction rates vary from 0.4% to 75%. To understand the difficulties in clinical decision-making in this problem area, particularly drug selection, we present here a review of pertinent clinical trials evaluating parenteral drug efficacy and adverse effects.     

心室重构和室性心律失常

心室肌在受到损伤时发生的电、结构和功能的适应变化称心室重构,心室重构后室性心律失常的发生率升高了.目前研究发现,室性心律失常的发生与心室重构有关.心室重构在室性心律失常的病理生理过程中具有重要作用.抑制心室重构可能是更有效的治疗、预防心律失常的方法.     

Electroanatomic Mapping for Radiofrequency Ablation of Cardiac Arrhythmias

Radiofrequency catheter ablation is the current treatment of choice for several cardiac arrhythmias. The conventional approach utilizing intracardiac electrograms during sinus rhythm and during tachycardia has inherent limitations including limited two-dimensional fluoroscopic imaging and the ability to evaluate several potential sites for ablation and to go precisely to the most suitable site. Recently, a nonfluoroscopic three-dimensional electroanatomic system has been developed for mapping arrhythmias. We describe in this report the advantage of utilizing the system in facilitating a successful outcome in three patients with different arrhythmias.     

Ablation Approaches for Ventricular Fibrillation

Invasive electrophysiology (EP) mapping and catheter ablation has increasingly become the standard of care for many cardiac arrhythmias like supraventricular tachycardias, atrial fibrillation, premature ventricular complexes (PVC), and monomorphic ventricular tachycardia. In this review, we discuss the recent progress made in the mapping and ablation of ventricular fibrillation (VF). Ventricular activation during VF is apparently disorganized, making mapping and interpretation difficult. Prolonged mapping during VF would require mechanical circulatory support as VF causes complete hemodynamic collapse. These limitations have been addressed by the realization that there is often a reliable trigger arrhythmia that initiates the clinical VF episodes, and an approach to map and ablate this trigger can be successful. Such triggers can be PVCs localizing to the Purkinje/fascicular system, and in other cases can be ectopy from outflow tracts or intracavitary structures like papillary muscles, false tendons or moderator band, or can be monomorphic VT or preexcited atrial fibrillation that degenerate into VF. More recently, approaches beyond trigger elimination directly targeting the VF substrate have been devised. This includes elimination of the arrhythmogenic substrate localizing to the epicardial right ventricular outflow tract in patients with Brugada syndrome, akin to elimination of the arrhythmogenic substrate harbored by regions within scar in ischemic and non-ischemic cardiomyopathies. Further, recent attempts have been made to try to identify and ablate rotors during VF that may be important in perpetuating the VF episode. Such exciting advances in “curing” VF are proving to be life saving for resuscitated survivors of arrhythmic death.     

Mental Stress and Ventricular Arrhythmias

Anger and other negative emotions can precipitate sudden death, as shown in studies of population stressors. Clinical studies of patients with implantable defibrillators demonstrate that anger can trigger ventricular arrhythmias. Long-term negative emotions also increase vulnerability to arrhythmias. Mechanisms linking anger and arrhythmias include autonomic changes, which alter repolarization, possibly enhanced in patients with sympathetic denervation, which in turn trigger potentially lethal polymorphic ventricular tachycardias. Interventions which decrease negative emotions and resultant autonomic responses may be therapeutic in patients with implantable cardioverter defibrillators.     

Catheter Ablation of Idiopathic Epicardial Ventricular Arrhythmias Originating from the Vicinity of the Coronary Sinus System

Catheter Ablation of Idiopathic Epicardial Ventricular Arrhythmias. Idiopathic epicardial ventricular arrhythmias (IEVAs) originating from the vicinity of the coronary sinus system are not uncommon, accounting for about 9% of idiopathic ventricular arrhythmia cases. IEVAs share clinical presentation and electrophysiological characteristics with ventricular arrhythmias arising from the right ventricular outflow tract possibly as manifestations of cAMP‐mediated triggered activity and delayed after‐depolarizations. Detailed analysis of standard 12‐lead electrocardiogram morphology by using unique variables and algorithms allows clinicians to predict probable location of epicardial foci and informs optimal catheter ablation strategy. Epicardial mapping and ablation through the coronary sinus and its branches is effective and safe, and increasingly favored. However, it is important because of the common perivascular origin of IEVAs to perform coronary angiography prior to or after ablation and to select the appropriate ablation energy form to avoid serious complications.     

Genetic Basis of Ventricular Arrhythmias

Sudden cardiac death (SCD) is a leading cause of total and cardiovascular mortality, and ventricular fibrillation is the underlying arrhythmia in the majority of cases. In the young, where the incidence of SCD is low, a great proportion of SCDs occur in the context of inherited disorders such as cardiomyopathy or primary electrical disease, where a monogenic hereditary component is a strong determinant of risk. Marked advancement has been made over the past 15 years in the understanding of the genetic basis of the primary electrical disorders, and this has had an enormous impact on the management of these patients. At older ages, the great majority of SCDs occur in the context of acute myocardial ischemia and infarction. Although epidemiologic studies have shown that heritable factors also determine risk in these cases, inheritance is likely complex and multifactorial, and progress in understanding the genetic and molecular mechanisms that determine susceptibility to these arrhythmias, affecting a greater proportion of the population, has been very limited. We review the most recent insights gained into the genetic basis of both the monogenic and the more complex ventricular arrhythmias.