Role of nonsustained ventricular tachycardia and programmed ventricular stimulation for risk stratification in patients with idiopathic dilated cardiomyopathy

Background: The prognostic role of asymptomatic nonsustained ventricular tachycardia (NSVT) and programmed ventricular stimulation (PVS) in patients with idiopathic dilated cardiomyopathy (IDC) remains controversial. Methods: The prognostic significance of ventricular arrhythmias, ejection fraction, NYHA class, atrial fibrillation and age for overall and sudden death mortality was prospectively studied in 157 patients with IDC (group 1) free of documented sustained ventricular arrhythmia and syncope. In 99 patients with asymptomatic NSVT (group 2), PVS with 2 – 3 extrastimuli was performed. Non-inducible patients were discharged without specific antiarrhythmic therapy, whereas those with inducible monomorphic ventricular tachycardia were implanted with an ICD. Results: In group 1, 48% of patients had NSVT. Overall and sudden death mortality were significantly higher in patients with NSVT (34.2 vs. 9.8%, p = 0.0001 and 15.8 vs. 3.7%, p = 0.0037; follow-up 22 ± 14 months). Multivariate analysis revealed that NSVT independently predicts both overall and sudden death mortality (p = 0.0021 and .0221, respectively; adjusted for EF, NYHA class and age). In group 2, inducibility of sustained ventricular tachyarrhythmia was 7%, but sustained monomorphic VT occurred in 3% only. Two of 7 inducible patients experienced arrhythmic events during a follow-up of 25 ± 21 months (positive predictive value 29%). Overall and sudden death mortality were 29% and 0% in the inducible group vs. 17 and 4% in the non-inducible group. Both overall and sudden death mortality were signi.cantly lower in non-inducible patients from group 2 as compared to patients from group 1 with NSVT (p = 0.0043 and 0.0048), most likely due to a more common use of betablockers and a higher EF in the former group (p < 0.001, respectively). Conclusions: In patients with IDC, NSVT independently predicts both overall and sudden death mortality. Due to a low inducibility rate and a poor positive predictive value, PVS seems inappropriate for further arrhythmia risk assessment. However, in spite of documented NSVT, the incidence of SCD in patients on optimized medical treatment including betablockers seems to be very low, questioning the need for specific arrhythmia risk stratification. Received: 21 August 2002, Returned for revision: 24 September 2002, Revision received: 8 October 2002, Accepted: 7 November 2002, Published online: 12 May 2003 Correspondence to: R. Becker, MD     

Prevalence and significance of nonsustained ventricular tachycardia in patients with premature ventricular contractions and heart failure treated with vasodilator therapy

Objectives. This study sought to determine the prevalence and significance of nonsustained ventricular tachycardia (NSVT) in patients with premature ventricular contractions (PVCs) and heart failure treated with vasodilator therapy.Background. Heart failure patients with ventricular arrhythmia and NSVT have a significantly increased risk of premature cardiac death. Recently there has been the question of whether these arrhythmias are expressions of a severely compromised ventricle or are they independent risk factors. We, therefore, determined the prevalence and significance of NSVT in patients with PVCs and heart failure and on vasodilator therapy.Methods. Twenty-four hour ambulatory recordings were done at randomization, at 2 weeks, at months 1, 3, 6, 9 and 12 and then every 6 months in 674 patients with heart failure and on vasodilator therapy. The median period of follow-up was 45 months (range 0 to 54).Results. Nonsustained ventricular tachycardia was present in 80% of all patients. Patients without (group 1) and with (group 2) NSVT were balanced for variables: age, etiology of heart disease, New York Heart Association (NYHA) functional class, use of amiodarone and diuretics and left ventricular diameter by echocardiogram. However, group 1 patients had significantly less beta-adrenergic blocking agent use and higher ejection fraction (EF) (p < 0.002 and p < 0.001, respectively). Survival analysis for all deaths showed a greater risk of death among group 2 patients (p = 0.01). Similarly, sudden death was increased in group 2 patients (p = 0.02, risk ratio 1.8). After adjusting for the above variables, only EF (p = 0.001) and NYHA class (p = 0.01) were shown to be independent predictors of survival. Nonsustained ventricular tachycardia showed a trend (p = 0.07) as an independent predictor for all-cause mortality but not for sudden death. Only EF was an independent predictor for sudden death.Conclusions. Nonsustained ventricular tachycardia is frequently seen in patients with heart failure and may be associated with worsened survival by univariate analysis. However, after adjusting other variables, especially for EF, NSVT was not an independent predictor of all-cause mortality or sudden death. These results have serious implications in that suppression of these arrhythmias may not improve survival.     

QT dispersion in nonischemic dilated cardiomyopathy. A long-term evaluation

BACKGROUND: In idiopathic dilated cardiomyopathy (IDC), the predictive value of QT dispersion is still under debate. AIMS: This study assessed the role of QT dispersion for the long-term risk of cardiac death and of major arrhythmic events in IDC. METHODS AND RESULTS: In 162 patients with IDC (age 52+/-12 years), the QT interval on a 12-lead ECG was measured manually. QT dispersion was evaluated with QT range and QT standard deviation, for both QT and QTc (Bazett formula). With a follow-up of 53+/-41 months, QT dispersion was not a predictor of cardiac death in univariate or in multivariate analysis, and was of similar value for patients with or without bundle branch block. Using multivariate analysis, increased pulmonary capillary wedge pressure (p=0.003), decreased heart rate variability (Standard deviation of all NN intervals, p=0.01) and non-sustained ventricular tachycardia (NSVT) (p=0.03) were predictors of cardiac death. Sudden death and/or major arrhythmic events were independently predicted by NSVT (p=0.005), decreased heart rate variability (p=0.01) and late ventricular potentials on signal averaged ECG (p=0.02). CONCLUSION: This study confirms the poor prognostic value of QT dispersion in patients with IDC. Other methods to assess repolarization abnormalities need to be evaluated in such patients.     

Ambulatory ventricular arrhythmias in patients with heart failure do not specifically predict an increased risk of sudden death. PROMISE (Prospective Randomized Milrinone Survival Evaluation) Investigators

BACKGROUND: Ventricular arrhythmias are a frequent finding in congestive heart failure (CHF) patients and a cause of concern for physicians caring for them. Previous studies have reached conflicting conclusions regarding the importance of ventricular arrhythmias as predictors of sudden death in patients with CHF. This study examined the independent predictive value of ventricular arrhythmias for sudden death and all-cause mortality in PROMISE (Prospective Randomized Milrinone Survival Evaluation). METHODS AND RESULTS: Ventricular arrhythmias were analyzed and quantified by use of prespecified criteria on baseline ambulatory ECGs from 1080 patients with New York Heart Association (NYHA) class III/IV symptoms and a left ventricular ejection fraction 相似文献   

The Clinical Significance of Nonsustained Ventricular Tachycardia

Nonsustained Ventricular Tachycardia. Nonsustained ventricular tachycardia (NSVT) is an arrhythmia not often associated with symptoms; however, its occurrence in patients with structural heart disease is a prognostic indicator of an increased risk of mortality and sudden death. The management of asymptomatic patients with NSVT should first attempt to identify which patients are at highest risk for cardiac arrest, and second, devise a treatment that can reduce the incidence and/or mortality of cardiac arrest in this group. In patients with chronic coronary artery disease (CAD) and NSVT, programmed electrical stimulation identifies both a low and high risk group with respect to occurrence of ventricular arrhythmias. The negative predictive value of programmed electrical stimulation in patients with CAD and NSVT has been well established; however, uncertainty remains as to the optimal therapy for CAD patients with inducible ventricular arrhythmias. A number of reports suggest that patients whose inducible ventricular arrhythmias are rendered noninducible with antiarrhythmic drugs have a much lower risk of sudden death. It is yet to be resolved whether arrhythmias rendered noninducible identify a subgroup at low risk for cardiac arrest, independent of treatment. There is some evidence to suggest that the frequency of NSVT in patients with nonischemic dilated cardiomyopathy identifies a group at higher risk of sudden death. Programmed electrical stimulation adds little in helping to identify which of these patients are most likely to have cardiac arrest. The presence of NSVT in asymptomatic patients with hypertrophic cardiomyopathy may identify a group at higher risk for cardiac arrest. Further clinical studies are needed to define the best management strategy for NSVT in different types of structural heart disease.     

Clinical and electrophysiological spectrum of idiopathic ventricular outflow tract arrhythmias.

OBJECTIVES: This study sought to compare and contrast the clinical and electrophysiological characteristics of outflow tract arrhythmias. BACKGROUND: Idiopathic ventricular outflow tract arrhythmias manifest clinically in 3 forms: 1) paroxysmal sustained monomorphic ventricular tachycardia (SMVT), 2) repetitive nonsustained ventricular tachycardia (NSVT), or 3) premature ventricular contractions (PVCs). Although these arrhythmias have a similar site of origin, it is unknown whether they share a common mechanism or similar clinical features. METHODS: A total of 127 patients (63 female [50%], mean age 51 +/- 15 years) were evaluated for outflow tract arrhythmias. RESULTS: A total of 36 (28%) presented with the index clinical arrhythmia of SMVT, 46 (36%) with NSVT, and 45 (35%) with PVCs. The sites of origin of the arrhythmias were similar among the 3 groups, occurring in the right ventricular outflow tract in 82%. Sustained ventricular tachycardia was more likely to be induced during exercise in the SMVT (10 of 15 patients [67%]) than NSVT or PVCs groups (p < 0.01). Sustained outflow tract ventricular tachycardia was induced at electrophysiology study in 78% of SMVT patients, 48% of NSVT patients, and 4% of PVCs patients. Adenosine was similarly effective in all 3 groups (p = NS). CONCLUSIONS: Patients with outflow tract arrhythmias can be differentiated based on the subtype of arrhythmia. However, the observation that approximately 50% of patients with NSVT and approximately 5% of patients with PVCs have inducible sustained ventricular tachycardia that behaves in an identically unique manner to those who present with sustained ventricular tachycardia (e.g., adenosine-sensitive) suggests that rather than representing distinct entities, outflow arrhythmias may be considered a continuum of a single mechanism.     

不同起源部位室性早搏对心力衰竭患者预后的影响

目的:探讨不同起源部位的室性早搏对心力衰竭(心衰)患者预后的影响。方法:回顾性分析2007-11到2010-12期间在我院住院患者中左心室射血分数≤40%的心衰患者206例,随访1年,8例失访。分析临床各项指标和不同起源部位室性心律失常与心血管死亡间的关系。根据患者是否死亡,将患者分为生存组(n=161)和心血管死亡组(n=37)。结果:与生存组比较,心血管死亡组房室传导阻滞(AVB),24小时平均心率,室性早搏(室早)LOWN分级4A、4B级,室早,非持续性室速发生率;非持续性室速阵数及最快频率,起源于左心室流入道的室早、起源于左心室流入道的非持续性室速均增加,无房室传导阻滞,室早LOWN分级0、1、2、3级发生率均减少,差异有统计学意义(P<0.05)。logistic回归分析表明:收缩压、糖尿病、Ca2+、左心室射血分数、24小时平均心率、室早次数、起源左心室流入道的室早、非持续性室速的阵数是心血管死亡的独立危险因素。结论:室早对判断患者预后有重要价值,起源于左心室流入道室早增加心衰患者心血管死亡率。     

Cardiac autonomic tone and its relation to nonsustained ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy

BACKGROUND: In contrast to postinfarct patients, little is known about cardiac autonomic tone and its relation to spontaneous ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy (IDC). Both heart rate variability (HRV) and baroreflex sensitivity (BRS) are indices of autonomic innervation of the heart. HYPOTHESIS: The aim of the present study was to determine the relation between cardiac autonomic tone assessed by HRV and BRS and spontaneous nonsustained ventricular tachycardia (NSVT) on Holter in a large patient population with IDC. METHODS: 24-h digital Holter recordings including HRV analysis and BRS testing were prospectively performed in 137 patients with IDC and preserved sinus rhythm. Mean age was 48 +/- 12 years, and mean left ventricular (LV) ejection fraction was 32 +/- 9%. The HRV analysis on Holter included the mean RR interval (RRm), the standard deviation of all normal RR intervals (SDNN), the square root of the mean of the squared differences between adjacent normal RR intervals (rMSSD), and the proportion of adjacent normal RR intervals differing more than 50 ms (pNN50). Testing for BRS was performed noninvasively using the phenylephrine method. RESULTS: Of 137 study patients, 42 (31%) had spontaneous NSVT on 24-h Holter. Compared with patients without NSVT, patients with NSVT on Holter had a higher New York Heart Association (NYHA) functional class (NYHA III: 40 vs. 18%, p < 0.01), a lower ejection fraction (29 +/- 9 vs. 34 +/- 9%, p = 0.01), and an increased LV end-diastolic diameter (69 +/- 8 mm vs. 66 +/- 7 mm, p = 0.03). The HRV variables rMSSD, pNN50, RRm, and BRS did not differ significantly between patients with and without spontaneous NSVT. Only SDNN on Holter was slightly lower in patients with versus without NSVT (106 +/- 45 vs. 121 +/- 46 ms, p = 0.08). CONCLUSIONS: Patients with IDC and spontaneous NSVT on Holter are characterized by a higher NYHA functional class, a lower LV ejection fraction, an increased LV end-diastolic diameter, and a tendency toward a lower SDNN value compared with patients without NSVT. The remaining measures of HRV including rMSSD and pNN50 reflecting primarily tonic vagal activity, as well as BRS reflecting predominantly reflex vagal activity, were similar in patients with and without NSVT. The prognostic significance of these findings in patients with IDC is currently under investigation in the Marburg Cardiomyopathy Study (MACAS) at our institution.     

Fractal analysis and time- and frequency-domain measures of heart rate variability as predictors of mortality in patients with heart failure

Time-domain measures of heart rate (HR) variability provide prognostic information among patients with congestive heart failure (CHF). The prognostic power of spectral and fractal analytic methods of HR variability has not been studied in the patients with chronic CHF. The aim of this study was to assess whether traditional and fractal analytic methods of HR variability predict mortality among a population of patients with CHF. The standard deviation of RR intervals, HR variability index, frequency-domain indexes, and the short-term fractal scaling exponent of RR intervals were studied from 24-hour Holter recordings in 499 patients with CHF and left ventricular ejection fraction < or =35%. During a mean follow-up of 665 +/- 374 days, 210 deaths (42%) occurred in this population. Conventional and fractal HR variability indexes predicted mortality by univariate analysis. For example, a short-term fractal scaling exponent <0.90 had a risk ratio (RR) of 1.9 (95% confidence interval [CI] 1.4 to 2.5) and the SD of all RR intervals <80 ms had an RR of 1.7 (95% CI 1.2 to 2.1). After adjusting for age, functional class, medication, and left ventricular ejection fraction in the multivariate proportional-hazards analysis, the reduced short-term fractal exponent remained the independent predictor of mortality, RR 1.4 (95% CI 1.0 to 1.9; p <0.05). All HR variability indexes were more significant univariate predictors of mortality in functional class II than in class III or IV. Among patients with moderate heart failure, HR variability measurements provide prognostic information, but all HR variability indexes fail to provide independent prognostic information in patients with the most severe functional impairment.     

Long-term follow up of 115 patients with ischemic heart disease and ventricular flutter induced by programmed ventricular stimulation in the absence of ventricular arrhythmia

The clinical significance of rapid monomorphic ventricular tachycardia (VT) (> 270 beats/min), also called ventricular flutter, remains controversial in patients without documented spontaneous sustained VT. The aim of this study was to evaluate the outcome of 115 patients with ischaemic heart disease, aged 58 +/- 10 years, without spontaneous ventricular arrhythmias, but who had inducible ventricular flutter during programmed ventricular stimulation. The patients underwent stimulation to evaluate the prognosis after myocardial infarction or to investigate a malaise with or without loss of consciousness. Sustained ventricular flutter was the only inducible arrhythmia in all patients. The mean left ventricular ejection fraction (LVEF) was 42 +/- 14%. During an average follow-up period of 66 +/- 43 months, 31 deaths, including 27 of cardiac causes, were observed. The 1, 5, and 11 year survival of the whole population was 94, 79 and 64% respectively. In univariate analysis, anterior wall myocardial infarction, a low LVEF, the presence of non-sustained ventricular tachycardia (NSVT) on 24 hour Holter monitoring and Class III antiarrhythmic treatment, were poor prognostic factors (p 0.05). In multivariate analysis, the only independent predictive factors of mortality were low LVEF (p = 0.006), the presence of NSVT on Holter monitoring (p = 0.003) and the absence of betablocker therapy (p = 0.015). Medical therapy with betablockers or the implantation of an automatic defibrillator may be indicated in these patients at higher risk.     

Nonsustained ventricular tachycardia in dilated cardiomyopathy

In patients with structural heart disease, ventricular arrhythmias are associated with an increased risk of overall mortality and sudden cardiac death (SCD). Nonsustained ventricular tachycardia (NSVT) is common in patients with dilated cardiomyopathy of both ischemic and nonischemic origin. Recent studies suggest that NSVT may be a marker, but not a significant predictor, of mortality and SCD in that suppression of NSVT in these patients using antiarrhythmic drugs is of questionable benefit. Additionally, indications for implantable cardioverter defibrillator implantation do not include NSVT. This article focuses on the prognostic significance and treatment of patients with NSVT and ischemic or nonischemic dilated cardiomyopathy.     

Unsustained ventricular tachycardia and accelerated idioventricular rhythm--clinical and electrocardiographic features]

OBJECTIVE: To compare clinical and electrocardiographic characteristics of Nonsustained Ventricular Tachycardia (NSVT) and Idioventricular Accelerated Rhythm (IVAR). MATERIAL AND METHODS: We studied 155 patients, 113 men and 42 women, with mean age 54 +/- 14 retrospectively, of these, 108 had NSVT and 47 IVAR. The arrhythmias were defined as follows: NSVT-more than 3 ventricular consecutive beats with an heart rate superior to 110 b/m and lasting less than 30 s.; IVAR-3 or more ventricular consecutive beats with an heart rate equal or superior to 50 and lower than 110 b/m, lasting less than 30 s. We evaluated clinical data (symptoms, functional class and anti-arrhythmic therapy), electrocardiographic data (rhythm, changes in conduction and repolarization) and ventricular function (with ECO, Radionuclide Angiography or Ventriculography). In the Holter recording (ECG-H), we analysed the presence of associated ventricular arrhythmias, their electrocardiographic characteristics (number of episodes, number of beats per episode, previous arrhythmia rate, morfology, regularity) and the relations of the arrhythmia with symptoms. RESULTS: Analysis of underlying pathology showed in both groups, the importance of coronary artery disease (44.5% vs 40%) followed by valvular heart disease (24% vs 27.6%) and cardiomyopathy (22.2% vs 17%) respectively to NSVT and IVAR. Only in the NSVT group there were patients without cardiac pathology (3.6%). Comparing with one control group of our department, this distribution was substantially different (p less than 0.0001). All IVAR episodes were assympthomatic compared with 90% of NSVT. Ventricular premature beats were found in all NSVT patients and in 90% of IVAR patients, and were frequent (greater than 10/h) in 79% and 60%, couplets in 84% and 53% respectively (ns). The previous rate of the arrhythmia was 85.3 +/- 20 b/m in NSVT against 68.7 +/- 14 in IVAR (p less than 0.0001). We found left ventricular disfunction in 60% of NSVT patients and in 63.7% in IVAR patients, being serious in 35% and 39% respectively. The follow-up was of 18.5 months (1-72) and posterior evolution showed 14.8% and 17% of deaths with no relation to the arrhythmia, although in NSVT the number of complexes and episodes were related with the ventricular disfunction (p = 0.02 and p = 0.05). CONCLUSION: Both arrhythmias appeared in patients with similar clinical and arrhythmic setting and identified a population with structural cardiopathy, bad function and poor outcome.     

Amiodarone versus implantable cardioverter-defibrillator:randomized trial in patients with nonischemic dilated cardiomyopathy and asymptomatic nonsustained ventricular tachycardia--AMIOVIRT

OBJECTIVES: The purpose of this multicenter randomized trial was to compare total mortality during therapy with amiodarone or an implantable cardioverter-defibrillator (ICD) in patients with nonischemic dilated cardiomyopathy (NIDCM) and nonsustained ventricular tachycardia (NSVT). BACKGROUND: Whether an ICD reduces mortality more than amiodarone in patients with NIDCM and NSVT is unknown. METHODS: One hundred three patients with NIDCM, left ventricular ejection fraction < or =0.35, and asymptomatic NSVT were randomized to receive either amiodarone or an ICD. The primary end point was total mortality. Secondary end points included arrhythmia-free survival, quality of life, and costs. RESULTS: The study was stopped when the prospective stopping rule for futility was reached. The percent of patients surviving at one year (90% vs. 96%) and three years (88% vs. 87%) in the amiodarone and ICD groups, respectively, were not statistically different (p = 0.8). Quality of life was also similar with each therapy (p = NS). There was a trend with amiodarone, as compared to the ICD, towards improved arrhythmia-free survival (p = 0.1) and lower costs during the first year of therapy ($8,879 US dollars vs. $22,039 US dollars, p = 0.1). CONCLUSIONS: Mortality and quality of life in patients with NIDCM and NSVT treated with amiodarone or an ICD are not statistically different. There is a trend towards a more beneficial cost profile and improved arrhythmia-free survival with amiodarone therapy.     

Programmed ventricular stimulation for arrhythmia risk prediction in patients with idiopathic dilated cardiomyopathy and nonsustained ventricular tachycardia

Objectives. This study investigated the role of programmed ventricular stimulation (PVS) for arrhythmia risk prediction in patients with idiopathic dilated cardiomyopathy (IDC) and spontaneous nonsustained ventricular tachycardia (VT).Background. Nonsustained VT in patients with IDC has been associated with a high incidence of sudden cardiac death.Methods. Over the course of 4 years, 34 patients with IDC, a left ventricular (LV) ejection fraction ≤35%, and spontaneous nonsustained VT underwent PVS. All patients were prospectively followed for 24 ± 13 months.Results. Sustained ventricular arrhythmias were induced in 13 patients (38%). Sustained monomorphic VT was induced in three patients (9%), and polymorphic VT or ventricular fibrillation (VF) in another 10 patients (29%). No sustained ventricular arrhythmia could be induced in 21 study patients (62%). Prophylactic implantation of third-generation defibrillators (ICDs) with electrogram storage capability was performed in all 13 patients with inducible sustained VT or VF, and in nine of 21 patients (43%) without inducible sustained VT or VF. There were no significant differences between the additional use of amiodarone, d,I-sotalol, and beta-blocker therapy during follow-up in patients with and without inducible VT or VF. During 24 ± 13 months of follow-up, arrhythmic events were observed in nine patients (26%) including sudden cardiac deaths in two patients and ICD shocks for rapid VT or VF in seven patients. Arrhythmic events during follow-up occurred in four of 13 patients with inducible ventricular arrhythmias compared with five of 21 patients without inducible ventricular arrhythmias at PVS (31% vs. 24%, p = NS).Conclusion. PVS does not appear to be helpful for arrhythmia risk stratification in patients with IDC, a left ventricular ejection fraction ≤35%, and spontaneous nonsustained VT. Due to the limited number of patients, however, the power of this study is too small to exclude moderately large differences in outcome between patients with IDC with and without inducible VT or VF.     

慢性心力衰竭患者QT间期频率依赖性与室性心律失常的关系

目的探索慢性心力衰竭患者QT问期频率依赖性与室性心律失常的关系。方法选31例慢性心力衰竭患者有效病例资料。检测左心室舒张末期内径（LVEDD）、左心室射血分数（LVEF）、QT间期离散度（QTd）、心率变异性（HRV）、QT／RR相关直线的斜率、24h室性早搏（VPB）和非持续性室性心动过速（NSVT）的次数。比较有NSVT和无NSVT患者上述指标的差别,研究上述指标与NSVT的相关性。结果31例心力衰竭患者中,有17例动态心电图记录到NSVT。有NSVT与无NS—VT的患者比较,VPB次数[（5631．2±7218．0）对（285．9±371．7）,P〈0．05],QTe／RR斜率[（0．210±0．049）对（0．161±0．058）,P〈0．05]和QTp／RR斜率[（0．195±0．046）对（0．151±0．041）,P〈0．05]的差异有统计学意义。在全部31例患者中,QTd（r=0．414）、VPB次数（r=0．768）、QTe／RR斜率（r=0．380）、QTp／RR斜率（r=0．433）和NSVT有显著的相关性（P〈0．05）。结论QT间期频率依赖性是反映QT间期动态变化的指标,慢性心力衰竭患者的QT／RR斜率与室性心律失常有较好的相关性,在心脏性猝死的风险评估中有一定价值。     

Prognostic significance of nonsustained ventricular tachycardia during dobutamine stress echocardiography

Nonsustained ventricular tachycardia (NSVT) is a well-recognized side effect during dobutamine stress echocardiography (DSE). This study sought to evaluate the prognostic implications of NSVT during DSE on 1,266 consecutive dobutamine stress echocardiograms performed over 1 year. NSVT, defined as > or =3 consecutive ventricular premature beats, occurred in 65 of 1,266 patients (5.1%). There was no absolute increased risk in all-cause mortality between the NSVT and no NSVT groups (22% vs 17%, p = 0.15) during the 3-year follow-up. Survival curves generated by the Kaplan-Meier method also demonstrated no increased risk in mortality between the NSVT and no NSVT groups (p = 0.43). When only studies with negative results for inducible ischemia were taken into account, survival curves showed no significant difference in all-cause mortality (p = 0.26). Studies with negative results for inducible ischemia were also stratified according to the ejection fraction (EF). Patients without inducible ischemia and mildly reduced to normal EFs (>0.45) did not have significant differences in survival between the NSVT and no NSVT groups over the 3-year follow-up (p = 0.86). However, patients without inducible ischemia and moderately reduced EFs (0.35 to 0.45) who had NSVT during DSE had significantly reduced survival over the follow-up (p = 0.01).     

Sudden death in hypertrophic cardiomyopathy: identification of high risk patients

OBJECTIVES

We sought to identify patients with hypertrophic cardiomyopathy (HCM) at high risk of sudden death (SD).

BACKGROUND

Relatively low mortality rates in HCM make conventional analysis of multiple clinical risk markers for SD problematic. This study used a referral center registry to investigate a smaller number of generally accepted noninvasive risk markers.

METHODS

We studied 368 patients (14 to 65 years old, 239 males) with HCM. There were five variables: nonsustained ventricular tachycardia (NSVT), syncope, exercise blood pressure response (BPR), family history of sudden death (FHSD) and left ventricular wall thickness (LVWT).

RESULTS

During follow-up (3.6 ± 2.5 years [range 2 days to 9.6 years]), 36 patients (9.8%) died, 22 of them suddenly. Two patients received heart transplants. The six-year SD-free survival rate was 91% (95% confidence interval [CI] 87% to 95%). In the Cox model, there was a significant pairwise interaction between FHSD and syncope (p = 0.01), and these were subsequently considered together. The multivariate SD risk ratios (with 95% CIs) were 1.8 for BPR (0.7 to 4.4) (p = 0.22); 5.3 for FHSD and syncope (1.9 to 14.9) (p = 0.002); 1.9 for NSVT (0.7 to 5.0) (p = 0.18) and 2.9 for LVWT (1.1 to 7.1) (p = 0.03). Patients with no risk factors (n = 203) had an estimated six-year SD-free survival rate of 95% (95% CI 91% to 99%). The corresponding six-year estimates (with 95% CIs) for one (n = 122), two (n = 36) and three (n = 7) risk factors were 93% (87% to 99%), 82% (67% to 96%) and 36% (0% to 75%), respectively. Patients with two or more risk factors had a lower six-year SD survival rate (95% CI) compared with patients with one or no risk factors (72% [56% to 88%] vs. 94% [91% to 98%]) (p = 0.0001).

CONCLUSIONS

This study demonstrates that patients with multiple risk factors have a substantially increased risk of SD sufficient to warrant consideration for prophylactic therapy.     

Risk Stratification for Serious Arrhythmic Events Using Nonsustained Ventricular Tachycardia and Heart Rate Turbulence Detected by 24‐Hour Holter Electrocardiograms in Patients with Left Ventricular Dysfunction

Background: Previous studies have described the clinical usefulness of the presence of nonsustained ventricular tachycardia (NSVT) and defined heart rate turbulence (HRT) in stratifying patients at risk. We prospectively assessed whether HRT can facilitate the predictive accuracy of NSVT for identifying patients at risk for serious arrhythmic events in patients with left ventricular (LV) dysfunction. Methods: We enrolled 299 consecutive patients with LV dysfunction (ejection fraction ≤ 40%) including ischemic (n = 184) and nonischemic causes (n = 115). The presence of NSVT was assessed on Holter electrocardiograms (ECGs). HRT was simultaneously measured from Holter ECGs, assessing two parameters: turbulence onset (TO) and turbulence slope (TS). HRT was considered positive when both TO and TS were abnormal. The end point was defined as of sudden cardiac death (SCD) and sustained ventricular tachyarrhythmias (VTs). Results: NSVT was documented in 93 patients (32.7%). For HRT assessment, 17 patients (5.6%) were not utilized. Of 282 patients, 68 (24.1%) were HRT positive. During follow‐up of 960 ± 444 days, 14 patients (5.0%) reached the end point. NSVT, HRT, and diabetes were significantly associated with the end point. On multivariate analysis, NSVT had the strongest value for the end point, with an HR of 4.4 (95%CI, 1.4–14.3; P = 0.0138). When NSVT combined with HRT, the predictive accuracy is more increased, with an HR of 8.2 (95%CI, 2.9–23.3; P < 0.0001). The predictive values of the combination were higher than single use of NSVT or HRT. Conclusions: HRT can facilitate the predictive accuracy of NSVT for identifying patients at risk for serious arrhythmic events in patients with LV dysfunction.     

Heart rate recovery after exercise is a predictor of mortality,independent of the angiographic severity of coronary disease

OBJECTIVES: We sought to determine whether abnormal heart rate recovery predicts mortality independent of the angiographic severity of coronary disease. BACKGROUND: An attenuated decrease in heart rate after exercise, or heart rate recovery (HRR), has been shown to predict mortality. There are few data on its prognostic significance once the angiographic severity of coronary artery disease (CAD) is ascertained. METHODS: For six years we followed 2,935 consecutive patients who underwent symptom-limited exercise testing for suspected CAD and then had a coronary angiogram within 90 days. The HRR was abnormal if < or =12 beats/min during the first minute after exercise, except among patients undergoing stress echocardiography, in whom the cutoff was < or =18 beats/min. Angiographic CAD was considered severe if the Duke CAD Prognostic Severity Index was > or =42 (on a scale of 0 to 100), which corresponds to a level of CAD where revascularization is associated with better long-term survival. RESULTS: Severe CAD was present in 421 patients (14%), whereas abnormal HRR was noted in 838 patients (29%). There were 336 deaths (11%). Mortality was predicted by abnormal HRR (hazard ratio [HR] 2.5, 95% confidence interval [CI] 2.0 to 3.1; p < 0.0001) and by severe CAD (HR 2.0, 95% CI 1.6 to 2.6; p < 0.0001); both variables provided additive prognostic information. After adjusting for age, gender, standard risk factors, medications, exercise capacity, and left ventricular function, abnormal HRR remained predictive of death (adjusted HR 1.6, 95% CI 1.2 to 2.0; p < 0.0001); severe CAD was also predictive (adjusted HR 1.4, 95% CI 1.1 to 1.9; p = 0.008). CONCLUSIONS: Even after taking into account the angiographic severity of CAD, left ventricular function, and exercise capacity, HRR is independently predictive of mortality.     

Spectrum and prognostic significance of arrhythmias on ambulatory Holter electrocardiogram in hypertrophic cardiomyopathy

OBJECTIVES: The goal of this study was to assemble a profile and assess the significance of arrhythmias in a nontertiary-based hypertrophic cardiomyopathy (HCM) cohort. BACKGROUND: Hypertrophic cardiomyopathy is associated with arrhythmia-related consequences, particularly sudden death. Ventricular tachyarrhythmias on Holter electrocardiograms (ECG) have been reported as markers for sudden death in highly selected HCM populations. METHODS: We assessed the profile of ventricular and supraventricular ectopy and bradyarrhythmia on ambulatory 24-h Holter ECG and also related these findings to clinical outcome in 178 HCM patients. RESULTS: Of the 178 study patients, 157 (88%) had premature ventricular complexes (PVCs), including 21 (12%) with >/=500 PVCs, 74 (42%) had couplets, 67 (37%) had supraventricular tachycardia (SVT), and 56 (31%) had nonsustained ventricular tachycardia (NSVT). Mean number of PVCs was 330 +/- 763 (range 1 to 5,435) and increased with age (p < 0.01); NSVT was associated with greater left ventricular hypertrophy (p = 0.01) and severe symptoms (New York Heart Association functional classes III and IV) (p = 0.04); SVT occurred more commonly in patients with outflow obstruction (p = 0.02). Over a follow-up of 5.5 +/- 3.4 years, 11 (6%) patients died suddenly (annual mortality rate, 1.1%) including 5 patients with NSVT. For sudden death, NSVT on Holter ECG had negative and positive predictive values of 95% and 9%, and sensitivity and specificity of 45% and 69%, respectively. CONCLUSIONS: In this nontertiary-based HCM cohort, ventricular and supraventricular tachyarrhythmias were particularly frequent and demonstrated a broad spectrum on ambulatory (Holter) ECG. Paradoxically, despite such a highly arrhythmogenic substrate, sudden death events proved to be relatively uncommon. Ventricular tachyarrhythmias had a low positive and relatively high negative predictive value for sudden death in this HCM population.