Myocardial Ischemia as a Genuine Cause Responsible for the Organization and "Fertilization" of Conflictogenic Atrial Fibrillation:New Conceptual Insights Into Arrhythmogenicity

Particularities of Catheter Ablation in Women with Atrial Fibrillation and Associated Ischemic Heart Disease

BACKGROUND

Atrial fibrillation is more common in men, but in the presence of ischemic heart disease, this arrhythmia is more frequent in women. However, like in coronary heart disease, women with atrial fibrillation are suboptimally treated.

METHODS

To identify particularities of ablation, in women with atrial fibrillation and ischemic heart disease.

RESULTS

29 women and 26 men, with documented ischemic heart disease and atrial fibrillation, who underwent catheter ablation, were admitted in the study. No significant differences were registered regarding the heart rate control treatment. Electrical cardioversion was significantly higher in men, while pharmacological cardioversion was predominantly recommended in women. The ablation was performed later in women, after 2.55 ± 1.84 years versus 1.80 ± 1.05 in men (p = 0.05). The time elapsed until the ablation was performed was statistically correlated with atypical symptomatology and with the number of antiarrhythmics used prior to the ablation. There were no significant differences for the relapse of atrial fibrillation at 3 months. Quality of life at 3 months after ablation was increased in both groups.

CONCLUSION

Catheter ablation is performed much later in women, and the causes responsible for this delay would be more atypical symptoms and a greater number of antiarrhythmics tried before the ablation.

Destruction Of Medium Already Afected By Destructive Disorder: Fibrillating Atria Conceptually Need Therapeutic Help Rather Than Surgical Or Ablative Destruction

Atrial fibrillation (AF) as the most common supraventricular arrhythmia is scarcely amenable to contemporary treatment. Due to the diverse origin and variable clinical course of AF there is a broad spectrum of therapy options. However, optimal AF management has not become a gold standard yet. In general, the recurrence rate of AF is most often clinically unacceptable despite drug, surgical and/or ablation therapy. Substrate-based approach and ongoing ablation of atrial wall in its selected areas including the vicinity of pulmonary veins can be harmful. Applied physical factors do produce total disintegration of cardiomyocites - both intra- and inter-cellular damage which, in turn, leads to functional hypo-/inactivation of atria irrespective of whether the sinus rhythm is restored or not. In fact, iatrogenic phenomenon of ablation-induced atrial incompetence did emerge. Heterogeneity in clinical results reflects the uncertainty regarding the efficacy, risks and benefits of invasive AF therapy. In this regard the overall burden of AF may increase when using current therapy methods. Applicability of destructive techniques is yet to be fully elucidated and discussed. We hypothesize that currently used ablation and/or surgical techniques are potentially harmful since the success rates are likely achieved through violation of atrial myocardium. That is why a new and well-designed therapeutic strategy is needed. Invention of highly selective curative methods producing fibrillatory/electric blockage with concomitant saving of atrial transport function is to be encouraged.

Cardiac Events Theoretically Cannot Be Produced By Non-Ischemic And/Or Iso-Ischemic Myocardium: Challenging Postulations And Vitality Of The Concept Of "Ischemia-Dependent Conflictogenic Arrhythmias"

Ischemia plays a key role in cardiac arrhythmogenesis, particularly in elderly patients. Healthy, non-ischemic and structurally normal myocardium is universally free from dysrhythmias. Thereby intact coronary blood flow prevents potential cardiac events. Hypothetically, ischemia-related electrophysiological differences are responsible for the supraventricular and/or ventricular rhythm irregularities. The goal of this review is to determine the role of systemic and coronary circulatory peculiarities and their association with heart rhythm abnormalities. The current analytical review extends and enriches previous knowledge about the influence of these peculiarities on the genesis of ischemia-dependent conflictogenic arrhythmias. Different intensity of coronary blood flow resulting from stenotic obstacles or vasospasm potentially leads to the non-uniform perfusion of myocites thus creating albeit subtle but vulnerable and powerful electrophysiologic substrate impending cardiac rhythm disturbances. Apparently, the behavior of both non-ischemic and iso-ischemic myocardium in respect to electric cardiac activity is very similar, at least theoretically. Some different clinical entities, e.g. arterial hypotension and/or anemia containing ischemic component, in most cases are free from arrhythmias. This postulation may be helpful in furthering arrhythmogenicity insights which have been generated previously. On the contrary, increased blood pressure often concurs with the supraventricular and/or ventricular arrhythmias; this pattern also favorably reflects our previous hypothetical assumptions associated with the mechanisms of arrhythmogenesis. Conclusively, both non-ischemic and iso-ischemic myocardium may be attributed to nonarrhythmogenic milieu. Nevertheless, the inventive analysis and more explorative data are required to support the suggested postulations.

Homogenization of Atrial Electrical Activities: Conceptual Restoration of Regional Electrophysiological Parameters to Deter Ischemia-Dependent Conflictogenic Atrial Fibrillation

Atrial fibrillation (AF) as a severe arrhythmia is now spreading worldwide at overwhelmingly high rates, particularly in elderly patients. Despite new insights, the mechanisms underlying AF are not conclusively determined yet. Taking into account the ischemic origin of arrhythmia induction (according to the so-called conflictogenic atrial fibrillation, declared recently) restoration of regional electrophysiological parameters is essential in tackling AF. We hypothesized that some atrial electrophysiological parameters, preferably the effective refractory period, might need to be controlled to prevent AF. All the remaining parameters - conduction velocity, conduction time, recovery time, vulnerability, excitability, repolarization etc. being as if secondary and less important could be ignored. Homogenization of the milieu producing AF might be implemented, at least theoretically, through restoration of blood supply in ischemic areas and/or via attenuation of electrophysiological differences between conflicting regions by delivery of atrial sub-threshold non-captured pulse-trains. Adjunctive therapy by drugs containing vasodilatory features and affecting the effective refractory period appears to be fundamental. Thus, stabilization of disorganized atrial cellular activities likely may lead to the recovery of atrial excitable characteristics. Despite the lack of compelling evidence, the application of the concept may be helpful in order to search for more precise and more effective methods to favorably change the refractory period. Further studies are necessary to determine whether restoration or improvement of blood circulation of atrial wall is feasible. Based on such considerations a novel preventive AF strategies are to be designed.