ABSTRACT
A 69 year old man with ischemic heart disease underwent electrophysiologic evaluation for paroxysmal wide QRS tachycardia, the configuration of which was identical to that recorded during sinus rhythm, that is, right bundle branch block, left anterior fascicular block and anterior myocardial infarction. Electrocardiographic recordings during tachycardia showed atrioventricular dissociation and His bundle activation occurring 5 ms after the onset of the QRS complex recorded on the surface electrocardiogram, consistent with a left posterior fascicular tachycardia. All traditional therapeutic attempts failed to prevent frequent recurrences of tachycardia, which was finally ablated by three 300 J shocks delivered through an electrode catheter positioned in the posterobasal region of the left ventricular septum.
Subject(s)
Cardiac Catheterization/instrumentation , Electrophysiology , Tachycardia, Paroxysmal/physiopathology , Aged , Electrocardiography , Electrodes/therapeutic use , Follow-Up Studies , Humans , Male , Tachycardia, Paroxysmal/drug therapy , Tachycardia, Paroxysmal/therapyABSTRACT
The endomyocardial residual effects of left ventricular endocardial electrical ablation utilizing unipolar and bipolar electrode catheters were studied in 15 dogs. Histopathologic techniques specific for contraction band necrosis revealed that the mean maximal depth and breadth of necrosis was 0.63 +/- 0.44 and 1.23 +/- 0.82 cm, respectively. The dimensions of necrosis were significantly increased when utilizing larger energy discharges, especially through unipolar electrodes. Four dogs died during the procedure, three from ventricular fibrillation and one from asystole, and two died suddenly within the succeeding 24 hours. Endocardial thrombi were noted at necropsy in two dogs. In conclusion, transcatheter endocardial electrical ablation may destroy a sufficient mass of myocardium to interrupt arrhythmogenic conduction tissue, especially when larger currents are delivered through unipolar electrodes. However, serious ventricular arrhythmias and endocardial thrombi should be anticipated.
Subject(s)
Cardiac Catheterization/instrumentation , Cardiac Pacing, Artificial , Endocardium/pathology , Animals , Arrhythmias, Cardiac/etiology , Cardiac Catheterization/adverse effects , Cardiac Pacing, Artificial/adverse effects , Cardiac Pacing, Artificial/methods , Dogs , Electrodes/adverse effects , Electrodes/therapeutic use , Myocardium/pathology , Necrosis , Splenic Infarction/etiology , Thrombosis/etiologyABSTRACT
A 10 year old patient with right atrial automatic ectopic tachycardia underwent successful transvenous catheter ablation after endocardial mapping. Tachycardia had been present for 7 years before ablation and associated with development of dilated cardiomyopathy. A single 50 J discharge at the point of earliest atrial activation was followed by the establishment of sinus rhythm that remains at 10 months' follow-up. This case represents the first reported successful catheter ablation of an atrial automatic ectopic tachycardia. Specific anatomic factors favoring successful ablation and improvement in technique are discussed.
