Sleep and cardiac rhythm in healthy men

Cardiac rhythm during sleep was analysed in 168 healthy men aged 19 to 30 (mean 21.8) years using continuous nocturnal ECG recordings. Thirty five of the subjects were endurance athletes; 99 were recorded at home and 69 at a garrison during military service. The number of short term (less than one min) accelerations of heart rate of more than ten beats per minute ranged from 1.3 to 14.3 per hour; the number or accelerations (greater than one min) of more than 25 beats per minute typical of nocturnal restlessness ranged from zero to 6.1 per hour. The accelerations indicating nocturnal restlessness were more common during recordings done at the garrison than at home (2.2 per hour vs 1.3 per hour, P less than 0.01), whereas the short term accelerations were not (5.8 per hour vs 5.1 per hour, NS). Sinus pauses exceeding 2.00 sec occurred in 17 men (13 in athletes), occasional second degree atrioventricular block in 19 (eight in athletes) and ventricular premature beats in 37. Eighty-two per cent of sinus pauses, 83% of second degree atrioventricular blocks, and 81% of ventricular premature beats (when less than ten in the same subject) were associated with short term changes in heart rate. In conclusion, rapid changes in heart rate, presumably as a results of autonomic activation, are closely associated with most arrhythmias in healthy men during sleep, whereas changes in heart rate typical of nocturnal restlessness have little arrhythmogenic effect.     

Acute effects of lidocaine on repolarization and conduction in patients with coronary artery disease

Right ventricular repolarization and refractoriness were studied during continuous infusion of lidocaine in patients with coronary artery disease. Compared with baseline the duration of monophasic action potential was shortened (p less than 0.01) at constant and premature stimulation. Early premature action potentials were less shortened (p less than 0.05). Therefore the difference between the longest and shortest action potential duration elicited 2 to 150 msec after refractoriness decreased during lidocaine infusion (p less than 0.01). The right ventricular effective refractory period was shortened similarly to the action potential duration. Lidocaine did not change the conduction of constant paced beats, whereas the more rapid conduction of the midrange premature beats was inhibited (p less than 0.01). The inhibition of premature conduction 50 to 150 msec from the right ventricular effective refractory period may be attributed to the effect of lidocaine on the rate-dependent recovery from inactivation. The effect on the restitution curve indicates that lidocaine may influence the dispersion of premature action potentials in human beings.     

Antiarrhythmic Effects of VVI Pacing at Physiologic Rates: A Crossover Controlled Evaluation

Ventricular pacing can prevent bradycardia-dependent ventricular ectopic activity (VEA) and is helpful in some cases of drug-refractory venfricuiar tachycardia (VT). This study is a prospective evaluation of VVI pacing for the control of VEA not related to underlying bradycardia, drug side-effects, or prolonged QT interval syndromes. Twenty-nine patients undergoing serial electrophysioiogic-pharmacoiogic testing for VT control were studied. Eighteen of these patients (12 men; meon age = 60.1) both completed ihe protocol and had sufficient VEA for analysis. Coronary disease was present in 13 patients, cardiomyopathy in two patients, and one patient each had myocarditis, mitral valve prolapse, and no structural heart disease. Ambulatory (Holter) monitor recordings during VVI pacing were compared with control recordings made in the absence of pacing, VVI pacing rates were 10–15 bpm above the mean daily heart rate (mean = 92 bpm; range = 63–110). Hours from paced recordings were paired with hours from control (prior to analysis) according to time of day to reduce the effects of spontaneous variability in VEA frequency. Overall, VVI pacing reduced ventricular premature complexes (VPGs) 26% from 331 to 245/hour (p < 0.001). During pacing, couplets (pairs, successive VPGs) were reduced from 6.95 to 1.03/hour (p < 0.000001) and VT (≥3 successive VPCs) from 0.89 to 0.045 episodes/hour (p < 0.003). Of 13 patients with couplets, 11 had ≥50% reduction and five had ≥90% reduction. Baseline VT was eliminated in four out of nine patients during pacing. Pacing did not increase VEA significantly in any patient. In this group of patients, reduction of VEA by VVI pacing was significant and was comparable to pharmacologic interventions. Higher forms of VEA fcouplets and VT) appeared to respond better than single VPCs. Further studies may define patients with VEA who can benefit from pacing     

致心律失常性右室心肌病20例临床分析

目的:探讨致心律失常性右室心肌病(ARVC)的临床和心电图特点。方法:收集、查阅2002-2005年20例诊断为ARVC患者入院病例资料,常规行临床资料、心电图、超声心动图、X线胸片、24h动态心电图及心内电生理检查的资料分析。结果:20例ARVC患者中有晕厥发作(65%)、心悸(100%)、频发室性早搏(100%)、右心室源性短阵室速(85%)。20例患者常规心电图检查中15例(75%)有右束支传导阻滞(RBBB),12例(60%)电轴右偏,7例(35%)出现Epsilon波,17例(85%)胸前导联V1～V3T波倒置,13例(65%)V1导联QRS波时限≥110ms,12例(60%)(V1+V2+V3导联QRS波时限之和)/(V4+V5+V6导联QRS波时限之和)比值>1.2。在无RBBB时,18例(90%)胸前导联V1～V3均可见延长的S波升支≥55ms。超声心动图示右心房内径为(48.00±8.81)mm,右心室内径为(50.90±10.30)mm,右心功能减退,射血分数为0.301±0.090。结论:ARVC多有发作性晕厥,心电图上可出现频发室早及呈左束支传导阻滞型室速,窦性心律时伴RBBB型或电轴...     

Prognostic value of an exercise test one year after myocardial infarction

An exercise test was performed in 306 patients who had had acute myocardial infarction one year previously. The five year cumulative coronary heart disease mortality was 40.0%, when the test had to be discontinued because of ventricular arrhythmias but only 13.0% if discontinued because of fatigue (P less than 0.05). If the maximum work load was less than 80 W the mortality was 30.7% compared with 16.6% in patients who exercised at least 80 W (P less than 0.01). If maximum systolic blood pressure was less than or equal to 150 mmHg mortality was 40.3% compared with 8.5% in patients with greater than 200 mgHg (P less than 0.001). The mortality was 38.2% in patients having single monoform ventricular ectopic beats at a rate of three or more per minute or multiform, paired or early cycle ventricular ectopic beats or ventricular tachycardias: this compared with 14.1% (P less than 0.001) in patients having no or only single monoform ventricular ectopic beats at a rate of less than three per minute. ST-segment depression in univariate testing had no prognostic value. When both exercise test and clinical variables were used in survival analysis (Cox's regression) the most important variable was heart volume and after that ventricular arrhythmias. In multivariate regression analysis ST segment depression also had additional prognostic value. Thus ventricular arrhythmias turned out to be the most important prognostic factor measured during exercise test.     

Quantitative Analysis of Contribution of Rate Response in Three Different Ventricular Rate Responsive Pacemakers During Out of Hospital Activity

The contribution of rate response provided by three different types of rate responsive pacemaker (Sensolog, Meta, and Vitatron TX) was assessed in 25 patients during out of hospital activity. Pacemakers were optimally programmed and full disclosure 24-hour Holter ECG recordings were obtained during everyday activities. Close visual analysis of these tracings revealed that rate response is active for less than 15% of the 24-hour study period with high rate response (paced rate above 100 beats/min) for just 5% of the day showing peak activation between 1600 and 2000 hours. Low rate response (paced rate below 100 beats/min but 5 beats above base rate) was maximal between 0800 hours and midday and comprised 10% of all heart beats during the study period. Thirty percent of study patients were nonpacemaker dependent and rate response in these subjects was significantly (P less than 0.001) less active between 0800 hours and midday than in pacemaker dependent patients though it was equivalent at all other times. Nonpacemaker dependent patients achieved natural sinus response in the morning and tended to rely on pacemaker supplied rate response in the latter part of the day.     

病毒性心肌炎的室性心律失常与窦性心率震荡的关系及药物干预研究

目的:探讨病毒性心肌炎患者24小时动态心电图(DCG)中室性心律失常与心率震荡(HRT)的关系。方法:56例临床诊断室性心律失常患者分为病毒性心肌炎组(A组)和无器质性病变者组(B组),均行DCG监测,计算心率震荡的初始值(TO)、斜率(TS)。A组患者口服美托洛尔(25mg/次,每天二次)1月后复查24hDCG。结果:A组TO、TS分别较B两明显升高和降低,且A组口服美托洛尔1月后明显改善。结论:自主神经调节功能受损是病毒性心肌炎发生室性心律失常的重要原因,HRT可作为病毒性心肌炎判断预后的重要指标,口服美托洛尔可改善HRT。     

Sotalol Is More Powerful Than Propranolol in Suppressing Complex Ventricular Arrhythmias

BACKGROUND: Sotalol has combined type II and type III antiarrhythmic properties. Although the beta-blocking action of sotalol is thought to contribute to its antiarrhythmic actions, few data are available from direct comparative clinical trials with pure beta-blocking drugs. METHODS AND RESULTS: In this double-blind, randomized, multicenter, placebo-controlled, parallel study, we have compared the antiarrhythmic efficacy and safety of treatment with sotalol vs propranolol in 181 patients with organic heart disease and frequent (>30 ventricular premature complexes [VPCs]/h) repetitive ventricular premature complexes. Eighty-seven were randomized to receive sotalol and 94 received propranolol. The demographic and clinical characteristics of the two groups were identical, and the majority of patients had coronary artery disease or hypertensive heart disease. Most patients had a long-standing history (>5 years) of ventricular arrhythmias and, in a significant proportion, antiarrhythmic therapy with other drugs had failed in the past. After withdrawal of all antiarrhythmic drugs and 1 week of placebo, qualified patients were randomized to sotalol (320 mg/day) or propranolol (120 mg/day). patients not achieving adequate response were given higher doses of sotalol (640 mg/day) or propranolol (240 mg/day)At baseline, both groups had comparable frequency of total VPCs/hour (274/h and 255/h for sotalol and propranolol groups, respectively) which was reduced to 71 VPCs/h and 109/VPCs/h, respectively, at the end of phase 1. At final evaluation there was a significantly greater response to sotalol as demonstrated by 80% reduction in VPCs/hour with sotalol compared with only 50% reduction noted in the propranolol group. Adequate therapeutic response was also achieved in a significantly greater percentage of patients on sotalol compared with propranolol (56% vs 29%, P =.02). Sotalol was also superior to propranolol in suppressing the VT events/day during phase 1 (89% vs 78% reduction in VT events/day, P <.05). Sotalol was more effective than propranolol in all subgroups and in patients with heart rate <75 beats per minute. CONCLUSIONS: Sotalol is more powerful than propranolol in suppressing ventricular arrhythmias documented on Holter recordings. The superiority of sotalol appears to be related to its combined class II and class III antiarrhythmic actions.     

射频消融对右室流出道室性早搏的疗效及心肌损伤标记物和自主神经的影响

目的:观察射频消融治疗右室流出道室性早搏的有效性和安全性。方法:对36例症状明显的右室流出道单形性室性早搏患者进行射频消融治疗,观察即刻及术后2月的疗效;测定射频消融术前以及术后检测高敏C反应蛋白(hs-CRP)、血清肌钙蛋白I(cTnI)和磷酸肌酸激酶同工酶(CK-MB)观察心肌损伤。另设健康体检者30例作为正常对照组。结果:射频消融能有效治疗右室流出道室性早搏,消融即刻成功率为100%,远期成功率为94.4%。hs-CRP、CK-MB和cTnI射频消融术后1d较术前明显升高,7d后恢复正常。结论:射频消融术治疗右室流出道室性早搏安全有效。     

Measurement of Differences in Timing and Sequence Between Two Ventricular Electrodes as a Means of Tachycardia Differentiation

The use of two ventricular sensing electrodes to determine electrical activation sequence could provide a method for differentiation of normal from abnormal rhythms by implantable antitachycardia devices. Simultaneous recordings from two ventricular sites were obtained during dual chamber pacemaker implantation (5/8 patients), cardioverter-defibrillator implantation (2/8 patients), or programmed electrical stimulation study (1/8 patients). Recordings were made in normal sinus rhythm (NSR) (5 beats each in 8/8 patients), during ventricular tachycardia (VT) (38 beats with 7 morphologies in 3 patients) and during premature ventricular contractions (PVCs) (20 beats with 8 morphologies in 6 patients). Leads were placed transvenously in the right ventricle in 6 patients, and epicardially on the left ventricle in two. Intervals between the intrinsic deflection of the two ventricular electrograms ranged from 0 to 91 ms (mean of 26 ms) during NSR, from 13 to 141 ms (mean of 66 ms) during VT, and from 10 to 72 ms (mean of 40 ms) during PVCs and were reproducible within each patient for each type of rhythm. In all patients, the difference in sequence and timing between the dual electrograms in NSR beats vs. ectopic beats allowed for the differentiation of normal and abnormal complexes. These differences in each patient ranged from 23 to 210 ms (mean of 81 ms) during VT and from 3 to 89 ms (mean of 44 ms) during PVCs. Fourteen of the 15 ectopic morphologies exhibited greater than 20 ms difference in timing compared to their corresponding NSR beats. Combined with the appropriate software, multiple ventricular leads may be used by antitachycardia devices to discriminate between normal and abnormal ventricular activity.     

Phenytoin in the Treatment of Inducible Ventricular Tachycardia: Results of Electrophysiologic Testing and Long-Term FoUow-Up

Phenytoin treatment of inducible ventricular tachyarrhythmias was assessed by serial electrophysiologic studies (EPS) in 64 patients with spontaneous ventricular tachycardia, cardiac arrest, or symptoms compatible with a ventricular tachyarrhythmia. Coronary artery disease was the primary cardiac disease in 75% of the patients. All subjects had either inducible ventricular tachycardia (greater than or equal to 10 repetitive beats) or ventricular fibrillation at electrophysiologic study. Phenytoin was administered intravenously in 38 studies and orally in 31 studies. The mean serum phenytoin level was 19.5 +/- 4.7 mcg/ml. Only seven patients (11%) had a negative electrophysiologic study (less than or equal to 10 repetitive beats) after the administration of phenytoin and were classified as phenytoin responders (group I). The remaining 54 patients (89%) were classified as nonresponders (group II). For the nonresponders, phenytoin increased the cycle length of identical monomorphic ventricular tachycardias from a mean of 31 ms to a mean of 327 ms (p less than 0.001). For the four patients tested receiving both intravenous and oral phenytoin, the intravenous response always predicted the oral response. For the seven patients in whom electrophysiologic study indicated phenytoin efficacy, two are alive and arrhythmia-event free, two had sudden death when the regimen was changed (one case, quinidine added; one case, subtherapeutic serum level), and three died from nonarrhythmic causes. For the 10 patients treated empirically with phenytoin, either alone (seven patients) or in combination with another antiarrhythmic agent (three patients), four died secondary to an arrhythmic event.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lorcainide in the prophylaxis of ventricular arrhythmias in acute myocardial infarction

Lorcainide, a new class I antiarrhythmic agent, was administered intravenously to eight patients with acute myocardial infarction for 24 hours, and thereafter given by mouth, 200 mg daily for ten days. Ten control infarction patients were given lidocaine 3 mg/min during the first 24 hours and the oral betablocking agent, pindolol, for the following ten days. The two groups were comparable with respect to age, sex, onset-admission interval, and site and size of infarction. Ventricular premature beats were monitored with a 24-hour continuous ECG recording on days 1, 6 and 10. Complex ventricular premature beats were common during the first 24 hours of infarction; their occurrence and severity were similar in both groups, as judged by the Lown grading system. The plasma levels of lorcainide after the 24-hour infusion ranged 72-144 ng/ml (mean 95 ng/ml). On the sixth day, 12 hours after previous oral dose, lorcainide plasma levels ranged 11-82 ng/ml (mean 42 ng/ml). No major adverse effects were noticed, mild insomnia being the most disturbing reaction. It is concluded that lorcainide is an acceptable alternative to lidocaine in the treatment of ventricular arrhythmias in the acute stage of myocardial infarction. It has the advantage of being effective by oral route, too.     

Propafenone for the treatment of refractory complex ventricular ectopic activity

The results of therapy with propafenone were evaluated in 45 patients with complex ventricular ectopic activity that had been refractory to a mean of 3.8 antiarrhythmic drugs. The cardiac diagnoses were ischemic heart disease (in 16 patients), cardiomyopathy (in 7), mitral valve prolapse (in 7), mitral valve prolapse (in 7), idiopathic ventricular ectopic beats (in 6), valvular heart disease (in 5), and hypertension (in 4). The frequency of ventricular ectopic beats was established after therapy with antiarrhythmic agents had been discontinued. Patients then received propafenone during a dose-ranging protocol. An effective response was defined as a reduction in total ventricular ectopic beats of 80% or more. During dose ranging, therapy failed in four patients because of side effects, in eight because of a reduction in ventricular ectopic beats of less than 80%, and in three because of an aggravation of the arrhythmia. Thirty patients had a reduction in total ventricular ectopic beats of 80% or more. During a mean follow-up of 12.4 months, therapy failed in 1 patient because of sustained ventricular tachycardia and in 7 because of intolerable side effects; 22 patients continued to receive propafenone. PR and QRS intervals were significantly prolonged (P = 0.001), but the corrected QT interval and the heart rate were unchanged. The mean trough plasma level of propafenone associated with an effective response was 756 ng/ml, and that associated with intolerable side effects was 920 ng/ml. Thus, in patients with refractory complex ventricular ectopic beats, propafenone was effective and well tolerated initially in 67% of patients and during long-term administration in 49%, and toxicity was minor in most patients.     

Acute therapy of maternal and fetal arrhythmias during pregnancy

Atrial premature beats are frequently diagnosed during pregnancy. Supraventricular tachycardia (atrial tachycardia, atrioventricular nodal reentrant tachycardia, circus movement tachycardia) is diagnosed less frequently. For acute therapy, electrical cardioversion with 50 to 100 J is indicated in all unstable patients. In stable supraventricular tachycardia, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during pregnancy and are benign in most patients; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia, ventricular flutter, or ventricular fibrillation) may occur. Electrical cardioversion is necessary in all patients who are hemodynamically unstable with life-threatening ventricular tachyarrhythmias. In hemodynamically stable patients, initial therapy with ajmaline, procainamide, or lidocaine is indicated. In patients with syncopal ventricular tachycardia, ventricular fibrillation, ventricular flutter, or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In patients with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of pregnancy. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.     

稳心颗粒治疗围绝经期综合征心律失常的初步研究

目的：观察稳心颗粒治疗围绝经期综合征心律失常的疗效及不良反应.方法：选择有房性早搏、交界性早搏、室性早搏等心律失常的绝经期综合征妇女72例.随机分为治疗组和对照组,治疗组使用稳心颗粒,对照组使用普罗帕酮.两组均观察4周.治疗前、治疗2周及治疗后各做常规心电图及24 h动态心电图.结果：症状改善情况：治疗组总显效率85.56%,对照组总显效率61.14%.治疗组比对照组治疗后症状明显改善（P〈0.01）.动态心电图结果：治疗组及对照组每组自身治疗前后比较,室性早搏、房性早搏、交界性早搏均显著减少（P〈0.01）.治疗组与对照组两组间治疗前后比较差异无显著性意义（P〉0.05）.不良反应：治疗组较对照组不良反应为少（P〈0.01）.结论：稳心颗粒治疗围绝经期综合征心律失常疗效确切,安全性较好,总疗效优于普罗帕酮.     

室性早搏与心肌电生理异质性关系的研究

目的：研究不同起源部位室性早搏发生率与心室肌细胞电生理异质性的关系。方法：应用12导联同步动态心电图检测482例室性早搏患者,计算各起源部位室性早搏发生率。结果：右心室流出道早搏发生率最高,为34.02%;左心室流出道早搏发生率为9.13%;右心室各部位早搏总发生率62.86%;左心室各部位早搏总发生率37.14%;右心室早搏发生率明显高于左心室。结论：不同起源部位室性早搏发生率与心肌细胞电生理异质性相一致。     

Extracorporeal Shock Wave Lithotripsy and Cardiac Arrhythmias

Holter monitoring was performed in 400 patients undergoing extracorporeal shock wave lithotripsy (ESWL). The highest heart rate occurred before and after ESWL. During respiratory-triggered ESWL, 30% of the patients had one or more ventricular premature beats (VES), and 7% had couplets of VES. The number of ventricular and supraventricular premature contractions was significantly lower during ECG-triggered ESWL. Ventricular tachycardia occurred in seven patients during respiratory-triggered ESWL, and in one patient during nontriggered ESWL. All ventricular tachycardias were nonsustained, asymptomatic, and slow. Supraventricular tachycardia was seen in nine patients. The preference of the urologist for respiratory-triggered ESWL, conflicts with its higher incidence of ventricular arrhythmias.     

Prediction of efficacy and tolerance of oral mexiletine by intravenous lidocaine application

In a controlled crossover trial, 15 patients with frequent ventricular arrhythmias were treated with lidocaine to predict efficacy and safety of oral mexiletine. After an initial control period, patients received intravenous lidocaine (bolus infusion of 200 mg/20 min followed by 3.6 gm/24 hr and for 7 days oral mexiletine (200 mg four times a day). Efficacy was controlled by 24-hour Holter monitoring (responders = suppression of single premature ventricular beats [PVB] greater than 84% and of complex PVB greater than 90%). After lidocaine, 10 of 15 patients (67%) were responders (mean PVB reduction: 97%). After mexiletine, five of 15 patients (33%) were responders (mean PVB reduction: 81%); efficacy was closely related to the plasma concentration. When efficacy of both agents was compared, lidocaine infusion had a positive predictive value of only 50%; however, the negative predictive value was 100%. Thus in nonresponders to lidocaine, mexiletine is very likely to fail in the suppression of ventricular ectopy.     

Efficacy, safety, hemodynamic effects, and pharmacokinetics of high-dose moricizine during short- and long-term therapy

Moricizine, 15 mg/kg, was given to 10 patients with frequent ventricular ectopic depolarizations, eight of whom had previously been treated unsuccessfully with antiarrhythmic drugs. A single-blind inpatient study was followed by therapy for up to 6 months. Two patients developed aggravation of arrhythmia during inpatient therapy. Of the eight patients who completed the inpatient study, seven achieved greater than or equal to 80% suppression of total ventricular ectopic depolarizations (P less than 0.001). During inpatient therapy the mean of the individual patients' suppression of total ventricular ectopic depolarizations was 87.9%, paired ventricular beats 99.3%, nonsustained ventricular tachycardia 99.6%, and premature atrial contractions 89.0%. Suppression was maintained during long-term therapy. The PR interval increased 27% (P less than 0.001), QRS interval increased 10% (P less than 0.0001), QTc increased 1% (P not significant), and JTc decreased 2% (P not significant). Heart rate, blood pressure, and left ventricular performance at rest and exercise were unchanged by moricizine. Moricizine half-life was 9.2 +/- 3.4 hours. Plasma levels of moricizine decreased after 10 days of therapy, suggesting induction of metabolic enzyme systems.     

特发性频发室性早搏患者经导管射频消融术后血浆BNP水平变化的临床研究

【目的】探讨心功能正常的特发性频发室性早搏（FVC）患者经射频消融术（RFcA）后血浆脑钠肽（BNP）的变化及其意义。【方法]33例接受RFCA成功治疗的特发性频发PVC患者为室早组，总数为（16391．03±10873．01）个／天。另选53例健康体检者作为对照组，两组均检查心脏彩超、动态心电图及血浆BNP浓度，室早组术后3个月复查，分别比较术前、术后及对照组左室射血分数（LVEF）、左室舒张末内径（LVEDd）及血浆BNP浓度。【结果】对照组血浆BNP水平显著低于室早组术前水平（P〈0．01）；室旱组患者手术后血浆BNP水平较手术前明显降低（P〈0．01）；对照组与室早组术后相比血浆BNP水平无显著差异（P〉0．05）；对照组与室早组术前相比、室旱组手术前后比较及对照组与室早组术后相比LVEF及LVEDd差异均不明显（P〉0．05）。【结论】心功能正常的特发性频发PVC患者血浆BNP水平升高，RFCA有效治疗PVC后可使患者血浆BNP降低，在心脏超声检查心脏结构改变不明显的情况下采用BNP来判断PVC患者病情严重程度、发展及预后情况有重要意义。