Clinical Follow-up Study Of Non-sustained Ventricular Tachycardia Patients

BackgroundSudden cardiac death is a serious medical problem and ventricular tachycardia is one of its major causes.Investigating and treating ventricular tachycardia is of vital importance for sudden cardiac death.Patients who have sustained ventricular tachycardia lasting over 30 seconds accompanied by disturbance of hemodynamics and myocardial ischemia should be treated instantly.Drug therapy and AICD implantation has formed a consensus in cardiologists.The role that non-sustained ventricular tachycardia(NSVT) lasting less than 30 seconds(NSVT) plays in sudden cardiac death is still controvertial.Its clinical features and prognosis also remain unclear.Strong evidence and data for positive treatment for those NSVT paitents who has relatively good cardiac function(LVEF≥40%) is still not enough.Objects1.To investigate the etiology and clinical risk factors of NSVT patients with LVEF≥40%.2.To follow up and analysis the occurrence of clinical events in NSVT patients with LVEF≥40%in order to provide evidence for clinical intervention.Methods182 NSVT patients(LVEF≥40%) and 224 frequent premature ventricular beats (PVBs) patients who visited Huashan hospital from Jan 1st,2006 to Jan 31th,2009 were enrolled retrospectively.167 NSVT patients 192 PVBs patients who can be followed up by ways of OPD,hospitalization,phone,letters within them were enrolled into a prospective study.All cause of death,sudden cardiac death,coronary artery disease(CAD) and admission due to heart failure(HF) were recorded till Jan 31th 2009.Mono-variant analysis and multi-variant logistic regression analysis were used to identify clinical risk factors in NSVT patients.Baseline characteristics, auxiliary examination results and clinical events of NSVT paitents were documented and compared with PVBs patients who were set up as control group by means of T test.NSVT group was divided into 3 subgroups according to the presence of CAD, hypertension,and HF.Prognosis analysis were done by comparing the occurrence of clinical events repectively.ResultsThere are 182 NSVT patients and PVBs patients enrolled in the retrospective cohort.Clinical baseline analysis shows that in these two groups,there are 75.27% and 74.55%patients have hypertention,68.28%and 62.50%patients have CAD, 27.47%and 7.14%patients have cardiomypathy,respectively.The major cardiovascular causes of NSVT patients with LVEF＞40%and PVBs patients were hypertention and CAD.In NSVT group,the number of patients who have cardiomypathy was significantly larger than PVBs group(P＜0.05).There are 167 NSVT patients and 192 PVBs patients enrolled in the prospective cohort.Within them,follow-up can be finished in 163 NSVT patients and 191 PVBs patients while follow-up can not be done in 4 PSVT patients and 1 PVBs patient due to the lose of contact.Comparison of clinical baseline characteristics shows that there are significant statistical difference in LVIDs tested by cardiac transonogram,history of cardiomyopathy and total events of ventricular arrhythmia in 24h Holter records between two groups(P＞0.05) while the comparison of sex,age, and the history of diabetes,hypertension,HF,myocardial infarction,fasting plasma glucose,LVEF index,P-R interval,QRS duration,Q-T interval shows no statistical difference(P＞0.05).Multi-variant analysis by Logistic regression shows that cardiomypathy is an independent predictor of the occurance of NSVT(OR = 36.307).The result of clinical events demonstrats that there is no statistical difference in the incidence of total events(P = 0.362),the incidence of cardiac-event incidence(P = 0.904) and mortality(P = 0.294).The result of NSVT subgroup data shows:①Non-hypertention patients has higher clinical events incidence than hypertension patients(P＜0.005)②HF patients has higher events incidence than non-HF patients(P =0.042)③CAD patients has higher events incidence than non-CAD patients(P=0.012).Conclusions1.CAD and hypertension are the most important cardiac etiological factors in patients with NSVT(LVEF≥40%) and frequent PVBs.NSVT group comprises more cardiomypathy patients than PVBs group and this difference is of statistical meaning.2.NSVT patients accompanied with CAD and cardiac insufficiency lead to higher clinical events incidence.3.Compared with frequent PVBs group,NSVT patients with LVEF≥40%have good clinical prognosis.There is no statistical difference in clinical events incidence like cardiac death in two groups.4.The evidence of giving positive treatment to NSVT patients who were diagnosis by dynamic electrocardiogram is still insufficient.