Pathophysiological mechanism of cardiac arrhythmias as a key for optimal nonpharmacological treatment.
Pathological automatism and triggered activity had focal origin. Thus, the treatment has to be aimed at ablation of the arrhythmogenic region. Some arrhythmogenic places can be precisely characterized by analysis of ECG patterns. Among them are foci located close to the pulmonary veins, sinus node, ventricular outflow tracts or mitroaortic commissura. Classical ablation of these loci is highly successful. In other types of focal arrhythmias electro anatomical systems make possible to create 3D map, with activation sequence allowing for identification of the place where the arrhythmia could be eliminated. In reentrant mechanism of the arrhythmia the impulse circulates around the loop via the cardiac muscle. In case of the atrioventricular nodal reentrant tachycardia, atrial flutter or bundle branch ventricular tachycardia the loop can be easily outlined. Ablation can be performed using the anatomical method without induction of the tachycardia. In patients with the ventricular tachycardia with multiple forms or hemodynamically unstable it is possible to perform electro anatomical map with visualization of the scar and the border zones. In this case the proarrhythmic region in the borderline zone is the aim of linear ablation without induction of tachycardias. In the chaotic tachycardias (atrial or ventricular fibrillation), the arrhythmogenic substrate is too much dispersed to destroy them. Therefore, the ablation is aimed at the trigger which is initiating the arrhythmia (for instance the pathological Purkinje fibers). The excitability of the substrate may be also modified by pacemakers (ventricular or atrial resynchronization). In the life-threatening arrhythmias implantable cardioverter-defibrillator is necessary.
Kozluk
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I Chair and Department of Cardiology, Medical University of Warsaw, Poland. ekozluk@amwaw.edu.pl
D001145:Arrhythmias, Cardiac / Q000503:physiopathology* / Q000628:therapy*; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D017147:Defibrillators, Implantable; D004554:Electric Countershock; D006801:Humans; D010138:Pacemaker, Artificial