Retrospective Study Of Idiopathic Ventricular Tachycardia Treated By Radiofrequency Catheter Ablation

Objectives: To retrospectively explore electrocardiogram characteristics, electrophysiological characteristics and the originals of Idiopathic ventricular tachycardia (IVT); to analyze the efficacy and safety of radiofrequency catheter ablation for idiopathic ventricular tachycardia.Method: the study population comprised of 107 idiopathic ventricular patients treated by radiofrequency catheter ablation in the First Affiliated Hospital of Guangxi Medical University from January 2005 to December 2010. To retrospectively analyze the electrocardiogram characters, electrophysiological characteristics, the target spots of the successful radiofrequency catheter ablation of IVT, the success rate and the treatment associated complications of radiofrequency catheter ablation for all kinds of idiopathic ventricular tachycardia separately. Pacing mapping and activation sequence mapping were used to locate the origins of IVT, and ablated with temperature of 45~55℃.? Ventricular? tachycardia? disappeared? when? ablating,?and?immediately?or?30?minutes?later?can't?induced?ventricular?tachycardia?(VT),?even?isoproterenol was?injected?to?elevate?the?heart?rate. Results: 1.107 cases of idiopathic ventricular tachycardia were ablated, of which 67 originated from right ventricular outflow tract (RVOT), 2 located on right ventricular inflow tract (RVIT), only 1 originated from right ventricular free wall, 23 were idiopathic left ventricular tachycardia (ILVT), 7 originated from left ventricular outflow tract (LVOT), 7 located on left ventricular free wall. 2. ILVT exhibited with ventricular tachycardia with QRS duration of 118±12ms, and the QRS morphology was usually right bundle branch and left anterior fascicular block configuration with left electrical axis deviation(≤-30°); Left outlet ventricular tachycardia (LOVT) often presented with wide QRS complex tachycardia, and the general characteristics of LOVT were that the QRS duration was 135±13ms, the QRS morphology was usually right bundle branch block configuration with an inferior (right or left) axis and the inferior leads presented with R. Right outlet ventricular tachycardia (ROVT) often presented with wide QRS complex tachycardia, and the general characteristics of ROVT were that the QRS duration was 145±15ms, the QRS morphology was usually left bundle branch block configuration with an inferior (right or left) axis and the inferior leads presented with R. When differentiating RVOT-VT originating from septum from rising from free wall based on the electrocardiogram characters, all three following criteria were significantly different. the sensitivity of amplitude of lead I≥0.25mV, notch in lead II or III or aVF and the difference of amplitude between aVR and aVL (aVR–aVL) >0.20mV were 84.6%, 76.9% and 84.6% separately, the specificity of them were 83.3%, 73.3% and 73.3%. 3. The electrophysiological characteristics of fascicular ventricular tachycardia were ventricular tachycardia could be induced or terminated with programmed stimulation, it satisfied the entrainment criteria and the earliest Purkinje potential could be recorded in the inferoposterior left ventricular septum, successful termination of VT at which suggested that it's the exit of VT. It showed that the mechanism of fascicular VT was reentry exiting from the sites recording the earliest Purkinje potential. The electrophysiological characteristics of OVT were that rapid burst pacing was easier to initiate OVT than programmed ventricular extrastimuli did, rapid burst pacing could prompt tachycardia but no entrainment and it was easier to initiate VT with isoproterenol. Those showed the mechanism of OVT was triggered activity. 4. The general success rate of RFCA for IVT was 85.0%, but the success rates were different based on the different origination. The success rate of RVOT-VT was 89.6%, IVT was 91.3% and LOVT was 85.7%, while the other origination was 40.0%. 4. Only 1 of 107 patients developed complete atrioventricular block after RFCA requiring the implantation of permanent pacemaker.Conclusions: Radiofrequency catheter ablation is a reliable and safe strategy for curing of idiopathic ventricular tachycardia. To analyze Electrocardiogram is a way to locate the origin of right ventricular outflow tract ventricular tachycardia.