The Effects On The Morphology And Function Of The Left Ventricle With Or Without Cardiac Axis Changes After Ablation Of Idiopathic Left Ventricular Tachycardia

Background and objectives: The treatment of idiopathic left ventricular tachycardia (ILVT) included drug therapy, cardioversion, radiofrequency catheter ablation and so on. In recent years,radiofrequency catheter ablation of idiopathic left ventricular tachycardia has achieved a high success and has become the first line treatment in most symptomatic patients because of its high success and low recurrence. However, there was obvious change of the cardiac axis in some patients after ablation of ILVT due to damaging the Purkinje fiber network or left posterior fascicle to some extent, and its clinical significance has not been clear yet. The purpose of this study was to observe whether the change of the cardiac axis would affect the morphology and function of the left ventricle in these patients by echocardiography and tissue echocardiography .Methods: The study population was composed of ILVT patients underwent catheter ablation in our hospital. The end point of ablation was that ILVT could not be reinduced after ablation. All the patients were divided into two groups. The first group was consisted of the patients receiving echocardiography before ablation and after a long term follow-up. The second group was consisted of the patients receiving tissue echo- cardiography before and after ablation. The patients in two groups were further divided into two subgroups according to whether there was cardiac axis change examined by the surface ECG after ablation. The surface ECG and echocardiography were compared before ablation and in a long term of follow-up after ablation. For each patient in two groups, the surface ECG, echocardiography and tissue echocardiography were compared before and after ablation.Results: There were 32 patients with ILVT (22 men, 10 women) in the first group in which there were 11 patients (Group 1A) who had obvious cardiac axis changes after ablation. The other 21 patients (Group 1B) had not. There were not significant differences in LVDD (45.27±3.07 mm vs 43.19±5.07 mm) and EF (0.60±0.08 vs 0.64±0.05) before ablation between Group A and Group B (p>0.05). During a mean follow-up of 18 months, there were not significant differences in the changes of LVDD (3.36±0.49mm vs 2.89±0.59mm) and EF (0.06±0.02 vs 0.05±0.01) between Group 1A and Group 1B (p>0.05). There were 13 patients with ILVT (10 men, 3 women) in the second group, in which there were 6 patients(Group 2A) who had obvious cardiac axis changes after ablation, and the other 7 patients (Group 2B)had not. There were not any differences in VLSM (3.07±0.65cm/s vs 3.73±0.72 cm/s ) ,VLSB(4.66±0.90 cm/s vs 5.81±1.58 cm/s), VLIM(3.28±0.69 cm/s vs4.22±0.96 cm/s), VLIB(5.53±1.73 cm/s vs 5.48±1.31 cm/s), VLLM (3.88±1.36 cm/s vs 5.24±2.24 cm/s), VLLB (4.94±1.71 cm/s vs 6.68±1.25 cm/s), before ablation between Group 2A and Group 2B (p>0.05). During a mean follow-up of 5 months, there were not significant differences in the changes of VLSM (0.45±0.20cm/s vs 0.97±0.15 cm/s), VLSB(0.44±0.20cm/s vs 1.26±0.43cm/s), VLIM (0.46±0.20 cm/s vs 0.82±0.27cm/s), VLIB(0.73±0.40cm/s vs 0.86±0.40cm/s), VLLM (0.98±0.36cm/s vs 2.45±0.61cm/s), VLLB(0.60±0.18cm/s vs 1.30±0.25 cm/s) between Group 2A and Group 2B (p>0.05).Conclusions: The obvious change of cardiac axis after radiofrequency catheter ablation of ILVT might not have harmful effects on the morphology and function of the left ventricle in a long term of follow-up.