The Value of Exercise Test, Hotter Monitoring, and Programmed Electrical Stimulation in Detection of Ventricular Arrhythmias in Patients with Hypertrophic Cardiomyopathy

To determine the best way to detect serious ventricular arrhythmia in patients with hypertrophic cardiomyopathy (HCM), 15 patients with HCM performed an exercise test, had Holter monitoring during 24 hours, and programmed electrical stimulation (PES) in a randomized order, and the presence and type of ventricular arrhythmia was noted. During exercise testing, only one patient demonstrated ventricular tachycardia (VT) just prior to the test. By Holter monitoring, four patients had short episodes of asymptomatic VT. PES, using up to three extrastimuli induced VT or ventricular fibrillation (VF) in ten patients including those with VT during exercise testing and Holter monitoring. There were no differences between patients with and without ventricular arrhythmia during PES regarding age, left ventricular outflow obstruction, thickness of interventricular septum, interventricular septum/posterior wall thickness ratio, corrected QT interval, or the amplitude of the R wave in lead aVR in electrocardiography. Our results indicate that inducible VT/VF during PES is a common finding in patients with HCM. Twenty-four hour Holter monitoring was superior to exercise testing in revealing serious ventricular arrhythmia in those patients.     

Selection of Patients with Recurrence of Ventricular Tachyarrhythmias for Electrical Studies

Clinical cardiac electrophysiologic testing has been employed in the evaluation and treatment of patients with tachyarrhythmias. In patients with recurrent supraventricular tachyarrhythmias, electrophysiologic study is indicated when the arrhythmia is life-threatening or significantly disruptive to lifestyle, when empiric therapy has failed to control the arrhythmia, or when supraventricular tachycardia complicates the Wolff-Piarkinson-White syndrome. In patients with ventricular tachyarrhythmias, electrophysiologic study should be undertaken when life-threatening sustained ventricular tachyarrhythmias are documented or where a substantial risk of developing these arrhythmias is noted.     

Value of Serial Electropharmacological Testing in Managing Patients Resuscitated from Cardiac Arrest

Electrophysiologic studies were performed in 11 patients (9 men, 2 women; mean age: 59.9 yrs) who had survived an episode of cardiac arrest due to ventricular tachycardia (VT) or ventricular fibrillation. The purpose of the studies was to evaluate the usefulness of serial acute drug testing in selecting an effective chronic antiarrhythmic regimen. Ten of the patients were suffering from chronic ischemic heart disease with one or more previous myocardial infarctions while one had no evidence of structural heart disease. A ventricular aneurysm was present in four of them. During control electrophysiologic study, a sustained VT was induced by ventricular stimulation (single and double extrastimuli at various paced ventricular cycle lengths plus bursts of rapid ventricular pacing) in nine of the ten patients (90%) who were studied while not receiving antiarrhythmic drugs; a non-sustained VT was induced in one of them (10%). In three patients (30%) VT could be initiated only by right ventricular stimulation at a side different from the apex (outflow tract). No arrhythmia was observed in the only patient who was studied while taking amiodarone orally (400 mg/day for more than three months). During serial acute drug testing a totally effective drug regimen (successful in preventing the induction of any ventricular arrhythmia) was found in seven of the ten patients (70%) who underwent this procedure and a partially effective drug regimen (a sustained VT was no longer inducible; it was easier to interrupt and it was considerably slower) was found in two patients (20%). None of the nine patients who received chronic antiarrhythmic therapy based on the results of serial acute drug testing died suddenly during a mean follow-up of 14 months (range: 3-28) and only one had a recurrence of cardiac arrest. The latter, however, was taking antiarrhythmic drugs at a dosage less than that proved to be effective during electropharmacological testing. The only patient who refused serial acute drug testing and received an empiric antiarrhythmic therapy died suddenly at the 21st month of follow-up. These results indicate that serial electropharmacological testing is useful in selecting an effective long-term drug regimen in survivors of cardiac arrest.     

Influence of a Third Extrastimulus in Deflning Effective Drug Therapy During Serial Electrophysioiogicai Testing

Many electrophysiology laboralories use three extrastimuli in all patients with ventricular tachyarrhythmias during antiarrhythmic drug testing, regardless of the mode of arrhythmia induction in the baseline state. The purpose of this study was to compare this pacing protocol (full protocol) with a protocol in which three extrastimuli were only used during drug tests, if they were required in the baseline state for arrhythmia induction (limited protocol). There were 181 electrophysiology lests performed on 69 patients with ventricular tachyarrhythmias that were retrospectively analyzed. In all studies the full protocol was used, but the results of stimulation were also analyzed assuming the limited protocol had been used. In the baseline state, sustained ventricular tachyarrhythmias were reproducibly inducible with one or two extrastimuli in 38 (55%) patients. Of these patients, six (16%) achieved a drug efficacy prediction using the full protocol versus 15 (39%) patients using the limited protocol (P < 0.001). In all 69 patients, the drug response rate increased from 25% to 38% (P < 0.01) using the limited protocol. Overall, the cycle length of induced ventricular tachycardia during drug testing was longer than during baseline testing (352 ± 8vs 296 ± 7 msec, P < 0.001); however, the cycle length of ventricular tachycardia induced by three extrastimuli during drug restudies in patients in whom tachycardia had only required one or two extrastimuli to induce in the baseline state was not significantly different from the baseline tachycardia cycle length (303 ± 15 vs 318 ±11 msec, P = NS). and was significantly shorter than the cycle length of tachycardia induced by one or two extrastimuli during drug testing (303 ± 15 vs 385 ± 15 msec, P < 0.01). Using three extrastimuli in all patients during drug testing decreases the yield of drug efficacy predictions, but whether predictive value is improved or made worse cannot be answered from this study.     

植物神经功能与冠心病患者室性心律失常的相关性研究

目的：探讨植物神经功能与冠状动脉粥样硬化性心脏病（简称冠心病）患者室性心律失常的关系。方法：对我院126例进行了动态心电图检查及心率变异性（heartrate variability,HRV）分析的冠心病患者的室性心律失常和HRV指标进行回顾性分析。并应用Logistic回归筛选冠心病患者室性心律失常的HRV预测指标。结果：HRV各项时域指标和频域指标中的LF、VLF、HF均有随着室性心律失常程度的加重而降低的趋势．时域指标中的SDNN、SDANN、ASDNN、PNN50b与室性心律失常程度呈弱负相关（P〈0．01或P〈0．05）。Logistic回归结果表明SDANN为冠心病患者室性心律失常的保护因素。结论：HRV与冠心病患者室性心律失常程度呈弱负相关。SDANN为冠心病患者室性心律失常的保护因素。早期对植物神经功能紊乱进行干预治疗,可能有利于减少冠心病患者室性心律失常的发生     

Spontaneously terminating apparent ventricular fibrillation during transesophageal electrophysiological testing in infants with Wolff-Parkinson-White syndrome

This article describes two infants with Wolff-Parkinson-White (WPW) syndrome in whom apparent VF occurred without antecedent AF or atrial flutter during routine transesophageal electrophysiological testing. Remarkably, this arrhythmia terminated spontaneously in both infants. The documentation of self-limited apparent VF, or polymorphic ventricular tachycardia close to VF, in transesophageal testing adds another dimension to the management of WPW.     

Preventing sudden death in coronary cardiomyopathy: implantable defibrillators lead the way

The Multicenter Unsustained Tachycardia Trial (MUSTT) demonstrated that electrophysiologic testing (EP)-guided therapy significantly reduces arrhythmic death and cardiac arrest in patients with coronary artery disease, a left ventricular ejection fraction of 40% or less, nonsustained ventricular tachycardia, and inducible ventricular arrhythmia on EP testing-but only if the therapy includes an implantable defibrillator. All patients who meet the MUSTT inclusion criteria should undergo an EP test and if positive, should undergo defibrillator implantation.     

Predictors of Device Activation for Ventricular Arrhythmias and Survival in Patients with Implantable Pacemakers/Defibrillators

Predictors of survival and arrhythmia recurrence for patients with implanted defibrillators have been reported but patients with sustained, well-tolerated ventricular tachycardia were often excluded from these trials. Arrhythmia recurrence and survival in populations including these patients have been less well studied. The purpose of the present study was to examine predictors of spontaneous ventricular arrhythmias and mortality in patients who received a tiered therapy antitachycardia pacemaker/defibrillator for ventricular tachycardia, fibrillation, or both. Three hundred thirty-seven patients who received a Ventritex CADENCE® tiered therapy antitachycardia device at one of 19 participating centers between July 11, 1989 and March 4, 1991 are included in this retrospective analysis. Diagnostic summary data and stored electrograms telemetered from the implanted device were assessed to determine characteristics of recurrent arrhythmias. Mean follow-up was 360 ± 10 (SEM) days. Thirty-three patients died during follow-up. At least one recurrent ventricular arrhythmia was observed in 205 patients (61 %). A total of 7,539 episodes were observed with a mean of 37 ± 5 per patient. Patients with recurrent ventricular arrhythmias were slightly but significantly older (64 ± 0.7 vs 59 ± 1.2 years; P < 0.001) but were not distinguished by gender or underlying structural disease. Patients whose presenting arrhythmia was monomorphic ventricular tachycardia were more likely to experience recurrent ventricular arrhythmias (69% recurrence rate) than patients presenting with ventricular fibrillation or polymorphic ventricular tachycardia (46% recurrence rate; P < 0.001). Cycle length of spontaneous tachycardia was also a predictor of arrhythmia recurrence. Patients having slower ventricular arrhythmias were less likely to remain recurrence free. Mean left ventricular ejection fraction was similar for patients with and without recurrences. Younger age and absence of arrhythmia recurrence but not presenting arrhythmia were predictors of survival. We conclude that age and presentation with monomorphic ventricular tachycardia are important predictors of arrhythmia recurrence for this patient population. Exclusion of patients with monomorphic ventricular tachycardia underestimates the rate of recurrent ventricular arrhythmias and utilization of device therapy.     

Electrophysiological Evaluation of Sustained Ventricular Tachyarrhythmias in Idiopathic Dilated Cardiomyopathy

Sustained ventricular tachyarrhythmias and sudden death are particularly prevalent in patients with idiopathic dilated cardiomyopathy (IDC). In contrast to patients with ischemic heart disease, the value of electrophysiological stimulation (EPS) in patients with IDC has not yet been established. To clarify the role of EPS in these patients, we studied 19 patients (58 +/- 11 years) with IDC who had symptomatic ventricular tachycardia (VT) or ventricular fibrillation (VF). The mean left ventricular ejection fraction was 26 +/- 9%. Ten patients had survived out-of-hospital cardiac arrest, eight had documented sustained monomorphic VT and one patient had non-sustained VT associated with syncope. Thirteen of the 19 patients (68%) had their clinical ventricular tachyarrhythmias induced at EPS (12 VT, 1 VF). In nine of 13 patients (69%), the arrhythmias were subsequently suppressed during serial electrophysiological drug testing. During 17 +/- 11 months of follow-up, 10/19 (53%) patients experienced recurrence of their arrhythmias and nine out of 19 (47%) patients died; six died suddenly and three secondary to heart failure. There was no difference in arrhythmia recurrence between patients with and without inducible ventricular tachyarrhythmias at initial study. Furthermore, suppression of arrhythmia during serial testing did not predict outcome; recurrences were observed in five out of nine patients whose arrhythmias were suppressed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sinus Mapping in Patients with Cardiac Arrest and Coronary Disease—Results and Correlation with Outcome

Electrophysiological testing and left ventricular endocardial mapping in sinus rhythm were performed in 61 patients with coronary artery disease who presented with cardiac arrest in an attempt to relate the results of these studies to clinical outcome. Forty-one patients (67%) had inducible sustained arrhythmias (18 uniform ventricular tachycardia, 23 polymorphic ventricular tachycardia/ventricular fibrillation) and 20 had no inducible arrhythmia. Patients with inducible arrhythmia had 45% abnormal and 6% fractionated electrograms versus 31% and 0% for those without inducible arrhythmia (P greater than 0.05 for both comparisons). Sixteen of 59 patients (27%) with adequate follow-up had arrhythmia recurrence (11/39 [31%] with inducible arrhythmia and 5/20 [25%] without inducible arrhythmia) over a mean follow-up period of 27 months. Of five patients without inducible arrhythmia who experienced recurrence, two did so despite the anti-ischemic therapy. In the 20 patients without inducible arrhythmia, the 15 who remained arrhythmia-free had a mean of 78 +/- 22% normal sites versus 46 +/- 24% normal sites in those with recurrence (P greater than 0.05). We conclude that in patients with coronary artery disease and cardiac arrest: 1) patients without inducible arrhythmia have less marked endocardial electrical abnormality than those with inducible arrhythmia, 2) those patients who have marked endocardial abnormality despite the lack of inducible arrhythmia are at risk for clinical recurrence which suggests that these abnormalities may represent an anatomic substrate for arrhythmia which cannot be identified by programmed stimulation. These patients are candidates for AICD implantation and 3) patients with relatively normal endocardial electrograms do well with anti-ischemic therapy alone.     

Ventricular arrhythmias

Sudden cardiac death remains a leading cause of death in the United States. It is usually due to ventricular arrhythmia, either ventricular tachycardia or ventricular fibrillation. The probability of life threatening ventricular arrhythmia correlates closely with underlying structural heart disease. In any patient presenting with a ventricular arrhythmia, a careful search for underlying causes is required, and treatment should be considered primarily if it will prolong survival. Treatment of patients without underlying heart disease who are experiencing ventricular ectopy, and/or nonsustained ventricular tachycardia, consists of reassurance and education. If symptoms are severe, a beta-blocker is an appropriate choice for drug treatment. Patients with ventricular arrhythmia and structural heart disease are generally best managed in conjunction with a cardiologist.     

Arrhythmia Risk: Eiectrophysiological Studies and Monophasic Action Potentials

Shortly after in the introduction of progrommed electrical stimulotion (PES) of the heart to study and localize cardiac arrhythmias in the intact human heart, the technique was used for risk stratification of the arrhythmia patient. Two decades later we have to conclude that especially in ventricular arrhythmias the technique of PES did not live up to our expectations and the left ventricular function is a better long-term predictor than the induction of ventricular arrhythmias or the ability to find an antiarrhythmic drug able to prevent the initiation of the classically documented ventricular arrhythmia. Another sobering finding come from the analysis of the characteristics of the patient dying suddenly out-of-hospital, which showed that most of those patients could not be classified before the event as being at high risk using noninvasive or invasive testing, not even in those with o previous cardiac history. Monomorphic action potential (MAP) recordings have been of importance in our understanding of torsade de pointe arrhythmias in congenital and acquired QT prolongation. A major problem in case of a less generalized electrophysiological abnormality is the identification of the appropriate place where to put the MAP-electrode.     

Drug Therapy for Survivors of Sudden Cardiac Death

The proliferation of standard as well as novel community based systems for resuscitation of victims of out-of-hospital cardiac arrest has provided a large group of sudden cardiac death survivors who present a therapeutic challenge. The nature and severity of the underlying heart disease must be delineated. Particularly, myocardial ischemia and congestive heart failure must be controlled. Prior to considering device therapy of surgical intervention, pharmacologic therapy should be evaluated. Baseline electrophysiological studies determine the applicability of serial pharmacologic testing. In patients with inducible VT/VF, serial electrophysiological testing can identify drug regimens that prevent the arrhythmia in approximately 40% of patients. In an additional 20% of patients, regimens which slow the ventricular tachycardia and significantly reduce the arrhythmia related mortality can be identified. Three to 5-year follow-up has shown such an approach can reduce the sudden death mortality in these patients to less than 3% per year. It has been suggested that certain medication, most notably amiodarone, electrophysiological testing has not been useful in assessing efficacy. Several recent studies, however, have shown that electrophysiological testing is indeed useful even in evaluating the efficacy of amiodarone. In patients in whom ventricular tachycardia/ventricular fibrillation cannot be prevented or significantly slowed, medical therapy is generally ineffective and the sudden death mortality is 20% to 40% per year. In such patients, other therapeutic modalities should be considered.     

急性心肌梗死患者QT离散度与室性心律失常的关系

目的探讨急性心肌梗死(AMI)患者QT间期离散度(QTd)与室性心律失常的关系。方法测量42例AMI患者心电图的QTd,对有室性心律失常组与无室性心律失常组进行比较。结果AMI有室性心律失常组的QTd高于无室性心律失常组的QTd。结论AMI患者发生室性心律失常与QTd增大有关。     

临时心脏起搏治疗长间歇依赖室早诱发恶性快速性室性心律失常（附14例报告）

目的探讨临时心脏起搏救治长间歇依赖早搏诱发的恶性快速性室性心律失常的疗效及安全性。方法长间歇依赖室性早搏诱发的恶性快速性室性心律失常所导致的心源性晕厥或猝死患者共14例，包括尖端扭转型室性心动过速（TdP）8例，室颤（w）5例（2例由TdP转化而来），持续性单形性室性心动过速（VT）1例，呈反复发作的特点，予临时心脏起搏治疗。结果临时心脏起搏救治长间歇依赖室早诱发的恶性快速性室性心律失常疗效明显，8例TdP和1例VT的治愈率100％，5例VF的治愈率40％，死亡3例。结论临时心脏起搏救治长间歇依赖室早诱发的恶性快速性室性心律失常安全有效。     

早搏灵胶囊对肾上腺素诱导室性心律失常家兔的影响及作用机制的研究

目的:通过观察早搏灵胶囊对肾上腺素诱导的家兔的室性心律失常出现时间、持续时间及心肌钠钾ATP酶活性的影响,探讨早搏灵胶囊治疗室性心律失常的作用机制。方法:选取新西兰家兔32只,随机分成4组,每组均为8只,分别为空白组、模型组、普萘洛尔组、早搏灵胶囊组。连续灌胃7d后,以肾上腺素造模,统计家兔的室性心律失常出现时间、室性心律失常持续时间,以及通过定磷法测定心肌钠钾ATP酶活性。结果:与模型组相比,早搏灵胶囊组和普萘洛尔组能明显延迟室性心律失常出现时间,缩短室性心律失常持续时间,有显著性差异;早搏灵胶囊组与普萘洛尔组在室性心律失常持续时间上无明显差异,但其延迟室性心律失常出现时间的作用低于普萘洛尔组,具有显著性差异;与模型组比较,早搏灵胶囊组与普萘洛尔组钠钾ATP酶活性明显增高,具有显著性差异;早搏灵胶囊组钠钾ATP酶活性低于普萘洛尔组,有显著性差异。结论:早搏灵胶囊能够抵抗肾上腺素诱导的家兔的室性心律失常发生;早搏灵胶囊具有保护肾上腺素诱导的家兔心肌钠钾ATP酶活性的作用。     

Effectiveness of Noninvasive Programmed Stimulation for Initiating Ventricular Tachyarrhythmias in Patients with Third-Generation Implantable Cardioverter Definrillators

Previous generations of implantable cardioverter defibrillators (ICDs) required invasive electrophysiological testing to assess defibrillator function. Newer third-generation ICDs include the capability for performing noninvasive programmed stimulation (NIPS) and may reduce the need for invasive studies to assess tachycardia recognition and antitachycardia therapy algorithms. The effectiveness of ICD-based NIPS for the induction of ventricular arrhythmias has not, however, been formally assessed. Third-generation ICDs were implanted in 79 patients, who underwent a total of 166 postoperative defibrillator tests. NIPS with rapid ventricular pacing was performed in all patients in an attempt to induce ventricular fibrillation. In patients with prior sustained uniform ventricular tachycardia, programmed stimulation with up to three extrastimuli was performed in order to attempt to initiate the clinical ventricular tachcardia. Ventricular fibrillation was induced with NIPS in 146 of 166 studies (88%). Ventricular tachycardia was initiated with NIPS in 104 of 123 studies (85%). The type of defibrillator and the use of endocardial or epicardial rate sensing/ pacing leads did not influence the efficacy of NIPS. NIPS with third-generation ICDs is generally effective at inducing ventricular fibrillation and clinically relevant ventricular tachycardias, and reduces the need to perform invasive electrophysiological testing following device implantation. In a minority of patients temporary transvenous pacing catheters must still be used to facilitate arrhythmia induction.     

Frequency of spontaneous and inducible atrioventricular nodal reentry tachycardia in patients with idiopathic outflow tract ventricular arrhythmias

OBJECTIVES: We sought to assess the frequency of spontaneous or inducible atrioventricular nodal reentry tachycardia (AVNRT) in patients referred for radiofrequency ablation (RFA) of idiopathic outflow tract ventricular arrhythmias. BACKGROUND: In patients with no obvious heart disease, AVNRT and outflow tract ventricular tachycardia (VT) are the most frequently encountered supraventricular and ventricular tachycardias, respectively. An increased coexistence of the two arrhythmias has been recently suggested. METHODS: In 68 consecutive patients referred for RFA of an idiopathic ventricular outflow tract arrhythmia, a stimulation protocol including repeated bursts of rapid atrial pacing, up to triple atrial extrastimuli during sinus rhythm and rapid ventricular pacing was performed before and after isoproterenol infusion following RFA of the ventricular arrhythmia. In patients with inducible AVNRT, RFA of the slow pathway was performed. RESULTS: Of the 68 study patients, 17 (25%) had either spontaneous AVNRT documented prior to RFA of the ventricular arrhythmia (n = 4) or inducible AVNRT at the time of RFA of the ventricular arrhythmia (n = 13). AVNRT was induced by atrial pacing in 15 (88%) of 17 patients: in 3 patients without isoproterenol and in 12 patients during isoproterenol infusion. Uncomplicated RFA of the slow pathway was successfully achieved in all patients with inducible AVNRT. CONCLUSION: Spontaneous or inducible AVNRT is relatively common in patients with idiopathic outflow tract ventricular arrhythmias. Atrial stimulation, especially when performed after isoproterenol infusion plays a major role in AVNRT inducibility. Although we performed RFA of the slow pathway in patients with inducible AVNRT and no prior tachycardia documentation, the question whether this is mandatory remains unsettled.