PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Arrhythmia risk”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2001

[Arrhythmia risk stratification in patients with heart failure: prognostic evaluation of arrhythmia risk].

Sudden cardiac death is one of the more frequent causes of death in patients with heart failure. Thus, identification of patients at risk is a major clinical problem not only for the unpredictability of the event but also for the continuous growth of patients' number. The most widely used parameter for risk stratification is ejection fraction. Unfortunately, its predictive accuracy is limited and often it is impossible to distinguish patients with an increased arrhythmic mortality from those with an increased mortality due to pump failure. Heart rate variability and baroreflex sensitivity analysis has been largely utilized to obtain information on autonomic modulation of sinus node as well as to identify patients at risk. However, at variance with results observed in post-myocardial infarction patients, lower values of both parameters have been reported in patients with either an increased total or arrhythmic mortality. More recently, T wave alternans analysis has been found effective in identifying patients with an increased arrhythmic risk. Ongoing studies will provide evidence to support the use of this non-invasive technique in patients with cardiac insufficiency. Finally, the role of programmed electrical stimulation in heart failure patients appears limited. Inducibility of monomorphic sustained ventricular tachycardia seems to correlate better with the presenting clinical arrhythmia than with patient outcome. In conclusion, our capability of identifying heart failure patients at risk for arrhythmic death is far from being satisfactory. It is possible that the combination of results of multiple non-invasive tests such as reduction in ejection fraction and positivity for T wave alternans may not only provide general prognostic information but also facilitate the appropriate identification of patients at risk who may benefit from antiarrhythmic therapy.

Arrhythmias, Cardiac↗
PubMed2003

Noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy: results of the Marburg Cardiomyopathy Study.

BACKGROUND: Arrhythmia risk stratification with regard to prophylactic implantable cardioverter-defibrillator therapy is a completely unsolved issue in idiopathic dilated cardiomyopathy (IDC). METHODS AND RESULTS: Arrhythmia risk stratification was performed prospectively in 343 patients with IDC, including analysis of left ventricular (LV) ejection fraction and size by echocardiography, signal-averaged ECG, arrhythmias on Holter ECG, QTc dispersion, heart rate variability, baroreflex sensitivity, and microvolt T-wave alternans. During 52+/-21 months of follow-up, major arrhythmic events, defined as sustained ventricular tachycardia, ventricular fibrillation, or sudden death, occurred in 46 patients (13%). On multivariate analysis, LV ejection fraction was the only significant arrhythmia risk predictor in patients with sinus rhythm, with a relative risk of 2.3 per 10% decrease of ejection fraction (95% CI, 1.5 to 3.3; P=0.0001). Nonsustained ventricular tachycardia on Holter was associated with a trend toward higher arrhythmia risk (RR, 1.7; 95% CI, 0.9 to 3.3; P=0.11), whereas beta-blocker therapy was associated with a trend toward lower arrhythmia risk (RR, 0.6; 95% CI, 0.3 to 1.2; P=0.13). In patients with atrial fibrillation, multivariate Cox analysis also identified LV ejection fraction and absence of beta-blocker therapy as the only significant arrhythmia risk predictors. CONCLUSIONS: Reduced LV ejection fraction and lack of beta-blocker use are important arrhythmia risk predictors in IDC, whereas signal-averaged ECG, baroreflex sensitivity, heart rate variability, and T-wave alternans do not seem to be helpful for arrhythmia risk stratification. These findings have important implications for the design of future studies evaluating prophylactic implantable cardioverter-defibrillator therapy in IDC.

Adolescent↗
PubMed1998

[The stratification and prevention of the arrhythmia risk in nonischemic dilated cardiomyopathy].

The challenge of preventing arrhythmic sudden death is one of the major issues in today's treatment of heart failure. To achieve this ambitious goal, an accurate selection of the candidates for sudden death is needed on the one hand, while on the other hand, the assessment of the real cost/benefit ratio of the implantable cardioverter-defibrillator in selected patients, as compared to ACE inhibitors, beta-blockers and antiarrhythmic drug therapy, should no longer be delayed. As is well known, the incidence of sudden death is higher in ischemic dilated cardiomyopathy than it is in non-ischemic dilated cardiomyopathy. Moreover, tachyarrhythmic sudden death is prevalent in NYHA classes I and II (80%), whereas its incidence is lower (50%) in NYHA classes III and IV, since bradyarrhythmia, electromechanical dissociation and thromboembolic events characterize the other 50% of sudden deaths in patients in the latter NYHA class. The stratification of arrhythmic risk in non-ischemic dilated cardiomyopathy is questionable from any point of view, considering the poor predictive power of invasive and non-invasive indexes. However, some subgroups of high-risk patients should be selected, such as patients waiting for heart transplant or those with a severe disease but without an extreme degree of ventricular dysfunction, in whom the prognosis in terms of pump failure events is better and life expectancy is longer if the risk of arrhythmia is properly assessed and sudden death prevented. Consequently, the ICD implant may be effective in order to pursue the aim of reducing the tachyarrhythmic and bradyarrhythmic mortality in patients with a more severe disease and of minimizing the tachyarrhythmic risk in those with a less severe disease. Further studies will be developed to identify the ideal candidates for ICD implants.

Arrhythmias, Cardiac↗
PubMed2004

Electrocardiographic arrhythmia risk testing.

Among the most compelling challenges facing cardiologists today is identification of which patients are at highest risk for sudden death. Automatic implantable cardioverter-defibrillators are now indicated in many of these patients, yet the role of noninvasive risk stratification in classifying patients at high risk is not well defined. The purpose of this review is to evaluate the various electrocardiographic (ECG) techniques that appear to have potential in assessment of risk for arrhythmia. The resting ECG (premature ventricular contractions, QRS duration, damage scores, QT dispersion, and ST segment and T wave abnormalities), T wave alternans, late potentials identified on signal-averaged ECGs, and heart rate variability are explored. Unequivocal evidence to support the widespread use of any single noninvasive technique is lacking; further research in this area is needed. It is likely that a combination of risk evaluation techniques will have the greatest predictive power in enabling identification of patients most likely to benefit from device therapy.

Arrhythmias, Cardiac↗
PubMed2000

Arrhythmia risk stratification in idiopathic dilated cardiomyopathy based on echocardiography and 12-lead, signal-averaged, and 24-hour holter electrocardiography.

BACKGROUND: To date, considerable controversy exists regarding noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy (IDC). Methods and Results Between 1992 and 1997, 202 patients with IDC without a history of sustained ventricular tachycardia (VT) underwent echocardiography, signal-averaged electrocardiogram (ECG), and 24-hour Holter ECG in the absence of antiarrhythmic drugs. During 32 +/- 15 months of prospective follow-up, major arrhythmic events, including sustained VT, ventricular fibrillation, or sudden death, occurred in 32 (16%) of 202 patients. After adjusting for baseline medical therapy and antiarrhythmic therapy during follow-up, multivariate Cox regression analysis identified a left ventricular (LV) end-diastolic diameter >/=70 mm and nonsustained VT on Holter as the only independent arrhythmia risk predictors. The combination of an LV end-diastolic diameter >/=70 mm and nonsustained VT was associated with a 14. 3-fold risk for future arrhythmic events (95% confidence interval 2. 3-90). To further elucidate the prognostic value of LV ejection fraction, multivariate Cox analysis was repeated with ejection fraction forced to remain in the model. In the latter model, an ejection fraction </=30% combined with nonsustained VT on Holter was found to be a significant arrhythmia risk predictor with a relative risk of 14.6 (95% confidence interval 2.2-97). CONCLUSIONS: The combination of an LV end-diastolic diameter >/=70 mm and nonsustained VT on Holter, and the combination of LV ejection fraction </=30% and nonsustained VT on Holter, identify a subgroup of patients with IDC with a 14-fold risk for subsequent arrhythmic events. These findings have important implications for the design of future studies evaluating the role of prophylactic defibrillator therapy in patients with IDC.

Adolescent↗
PubMed2003

Prevalence of potential noninvasive arrhythmia risk predictors in healthy, middle-aged persons.

BACKGROUND: To date, prevalence and clinical significance of noninvasive arrhythmia risk predictors in apparently healthy, middle-aged persons are largely unknown. METHODS: A total of 110 apparently healthy persons 20-75 years old were enrolled in this prospective observational monocenter study and followed up for 32 +/- 15 months. Baseline investigations included symptom-limited bicycle ergometry, echocardiography, time-domain analysis, and spectral turbulence analysis of the signal-averaged electrocardiogram (ECG), ventricular arrhythmias, and heart rate variability on 24-hour Holter ECG, baroreflex sensitivity, and t-wave alternans in all persons. RESULTS: The prevalence of an abnormal signal-averaged ECG was 1% for spectral turbulence analysis and varied between 1% and 37% for time-domain analysis depending upon the definition used for an abnormal time-domain analysis. A reduced heart rate variability defined as a standard deviation of normal-to-normal intervals < or =105 ms, <100 ms and <70 ms was found in 12%, 9%, and 1% of persons. A baroreflex sensitivity <6 ms/mmHg and <3 ms/mmHg was present in 15% and 2% of persons. Microvolt t-wave alternans was found to be positive in 5%, negative in 88%, and indeterminate in 7% of persons, respectively. During the 32 +/- 15 months follow-up, no arrhythmic events and no cardiovascular mortality were observed in this population. CONCLUSIONS: Abnormal findings of noninvasive arrhythmia risk stratification can be found in 1-37% of healthy, middle-aged persons when previously reported cut-off values are used.

Adult↗
PubMed1998

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 < or = 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 < or =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.

Adolescent↗
PubMed2002

[Arrhythmia risk and noninvasive markers in hypertensive left ventricular hypertrophy].

OBJECTIVE: Several studies have evidenced that hypertensive patients with severe left ventricular hypertrophy have an increased incidence of malignant ventricular arrhythmia and sudden death. However arrhythmia risk in mild to moderate hypertrophy is uncertain. This study aims to investigate the risk of ventricular arrhythmias in hypertensive patients with mild to moderate hypertrophy and evaluate the role of noninvasive arrhythmia markers and ambulatory blood pressures. METHODS: Ninety-nine hypertensive patients (35 male, mean age 57.3 +/- 9.6) without coronary heart disease were included the study. All subjects underwent an echocardiography for measurement of LV mass index (LVMI) and were classified in two groups; hypertrophic (LVH(+) n:43) and nonhypertrophic (LVH(-) n:56). Ambulatory blood pressure monitoring, 24 hour ECG, signal averaged ECG, and 12 lead ECG were performed in each group seeking to identify the arrhythmogenic risk. RESULTS: Holter ECG showed that 20.1% patients had Lown class II and 12.1% patients had Lown class IVa-IVb arrhythmia (potentially malignant ventricular arrhythmia; PMVA). PMVA incidence was significantly higher in hypertrophic groups (20.9%) compared to nonhypertrophic groups (6.5%) (p < 0.05). Ambulatory systolic and diastolic blood pressures were similar in PMVA(+) and PMVA(-) patients. At least two parameters of ventricular late potentials were significantly higher in LVH(+) group (25.7%) compared to LVH(-) group (4.9%) (p < 0.01). HRV parameters were not different between two groups. QTcd was significantly increased in LVH(+) than in LVH(-) patients (54.1 +/- 16.7 vs. 47.5 +/- 17.7 ms) (p < 0.05) The frequency of PMVA was significantly higher in increased QTcd compared to normal QTcd (24.3%-3.4%; p < 0.01) and LP(+) patients (16.2%) compared to LP(-) patients (8.7%; p < 0.05). CONCLUSION: Our data suggest that hypertension may be associated with high risk of PMVA in patients with mild to moderate LVH particularly in presence of LP and QTcd > 50 ms. QTcd and at least 2 factors of LP were increased in mild to moderate LVH. Arrhythmogenecity does not seem to be related with autonomic dysregulation and ambulatory blood pressure level in hypertensive patients.

Arrhythmias, Cardiac↗
PubMed2000

A comparison of T-wave alternans, signal averaged electrocardiography and programmed ventricular stimulation for arrhythmia risk stratification.

OBJECTIVES: The goal of this study was to compare T-wave alternans (TWA), signal-averaged electrocardiography (SAECG) and programmed ventricular stimulation (EPS) for arrhythmia risk stratification in patients undergoing electrophysiology study. BACKGROUND: Accurate identification of patients at increased risk for sustained ventricular arrhythmias is critical to prevent sudden cardiac death. T-wave alternans is a heart rate dependent measure of repolarization that correlates with arrhythmia vulnerability in animal and human studies. Signal-averaged electrocardiography and EPS are more established tests used for risk stratification. METHODS: This was a prospective, multicenter trial of 313 patients in sinus rhythm who were undergoing electrophysiologic study. T-wave alternans, assessed with bicycle ergometry, and SAECG were measured before EPS. The primary end point was sudden cardiac death, sustained ventricular tachycardia, ventricular fibrillation or appropriate implantable defibrillator (ICD) therapy, and the secondary end point was any of these arrhythmias or all-cause mortality. RESULTS: Kaplan-Meier survival analysis of the primary end point showed that TWA predicted events with a relative risk of 10.9, EPS had a relative risk of 7.1 and SAECG had a relative risk of 4.5. The relative risks for the secondary end point were 13.9, 4.7 and 3.3, respectively (p < 0.05). Multivariate analysis of 11 clinical parameters identified only TWA and EPS as independent predictors of events. In the prespecified subgroup with known or suspected ventricular arrhythmias, TWA predicted primary end points with a relative risk of 6.1 and secondary end points with a relative risk of 8.0. CONCLUSIONS: T-wave alternans is a strong independent predictor of spontaneous ventricular arrhythmias or death. It performed as well as programmed stimulation and better than SAECG in risk stratifying patients for life-threatening arrhythmias.

Aged↗
PubMed1990

QT dispersion: an indication of arrhythmia risk in patients with long QT intervals.

Homogeneity of recovery time protects against arrhythmias whereas dispersion of recovery time is arrhythmogenic. A single surface electrocardiographic QT interval gives no information on recovery time dispersion but the difference between the maximum and minimum body surface QT interval may be relevant. This hypothesis was tested by measuring the dispersion of the corrected QT interval (QTc) in 10 patients with an arrhythmogenic long QT interval (Romano Ward and Jervell and Lange-Nielsen syndromes or drug arrhythmogenicity) and in 14 patients without arrhythmias in whom the QT interval was prolonged by sotalol. QTc dispersion was significantly greater in the arrhythmogenic QT group than in the sotalol QT group. In patients with prolonged QT intervals, QT dispersion distinguished between those with ventricular arrhythmias and those without. This supports the hypothesis that QT dispersion reflects spatial differences in myocardial recovery time. QT dispersion may be useful in the assessment of both arrhythmia risk and the efficacy of antiarrhythmic drugs.

Adolescent↗
PubMed1999

Postoperative atrial arrhythmias: risk factors and associated adverse outcomes.

Atrial arrhythmias are the most common complication of cardiac surgical procedures today. Because of the additional hospital costs associated with these arrhythmias, owing to increased use of antiarrhythmic medications, diagnostic studies, and prolonged hospitalization, this subject continues to draw the interest of cardiac surgeons, cardiologists, insurance companies, and hospital administrators, among others. Despite many clinical studies, there is still no consensus regarding the best prevention strategy for these arrhythmias. We recently reviewed our experience with these arrhythmias, with the intent of identifying risk factors for the development of these arrhythmias and identifying any associated, potentially adverse, outcomes. We found that the incidence of postoperative atrial arrhythmias has increased to more than 35% in recent years. Risk factors for the development of postoperative atrial arrhythmias include increasing patient age, preoperative use of digoxin, history of rheumatic heart disease, chronic obstructive pulmonary disease, and increasing aortic cross-clamp (ischemic) time. Among patients with postoperative atrial arrhythmias, there was an increased rate of perioperative stroke, increased frequency of ventricular arrhythmias, increased need for the placement of a permanent pacemaker, and prolongation of the intensive care unit and total hospital length of stay.

Aged↗
PubMed1998

Noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy: design and first results of the Marburg Cardiomyopathy Study.

The Marburg Cardiomyopathy Study (MACAS) is a prospective, observational study designed to determine the value of the following potential noninvasive arrhythmia risk predictors in at least 200 patients with idiopathic dilated cardiomyopathy (IDC) over a 5-year follow-up period: NYHA-class, left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter, left bundle branch block and atrial fibrillation on ECG, QT/JT dispersion on 12-lead ECG, signal-averaged ECG, ventricular arrhythmias and heart rate variability (HRV) on 24-hour Holter ECG, baroreflex sensitivity, and microvolt T wave alternans during exercise. This article describes the findings among the first 159 patients with IDCs enrolled in MACAS until May 1998 (40 women, 119 men; age: 49 +/- 12 years; LVEF: 32 +/- 10%). Twenty-nine patients (18%) had atrial fibrillation and 130 patients (82%) were in sinus rhythm. Patients with sinus rhythm were further stratified according to LVEF < 30% (n = 54) versus LVEF > or = 30% (n = 76). Compared to patients with LVEF > or = 30%, patients with LVEF < 30% more often had left bundle branch block (43% vs 25%, P < 0.05), nonsustained VT (44% vs 22%, P < 0.05), decreased HRV (SDNN: 95 +/- 39 vs 128 +/- 42 ms, P < 0.01), decreased baroreflex sensitivity (5.6 +/- 4 vs 8.3 +/- 6 ms/mmHg, P < 0.01), and T wave alternans (59% vs 37%, P < 0.05). The prognostic significance of these findings will be determined by multivariate Cox analysis at the end of a 5-year follow-up. Primary endpoints in MACAS are overall mortality and arrhythmic events (i.e., sustained VT or VF, or sudden cardiac death).

Arrhythmias, Cardiac↗
PubMed2002

Optimizing ambulatory ECG monitoring of T-wave alternans for arrhythmia risk assessment.

Considerable scientific data support the potential value of T-wave alternans (TWA) as an index of vulnerability to ventricular fibrillation. This chapter summarizes our state of knowledge regarding the use of routine ambulatory ECGs to evaluate TWA and discusses recent methodologic approaches designed to optimize AECG-based TWA analysis for arrhythmia risk stratification. Newer methods, including the nonspectral technique of Modified Moving Average analysis, appear promising in detecting TWA during the changing conditions associated with daily activities. The Modified Moving Average approach does not require specialized electrodes and is not encumbered by the need to achieve target heart rates, as is the case for conventional spectral-based methods. Guidelines are provided for evaluating latent cardiac electrical instability using AECG-based TWA testing. These recent developments make possible the TWA analysis of ambulatory ECGs not only in prospective trials but also in vast stores of archival data.

Arrhythmias, Cardiac↗
PubMed2004

Arrhythmia risk stratification with regard to prophylactic implantable defibrillator therapy in patients with dilated cardiomyopathy. Results of MACAS, DEFINITE, and SCD-HeFT.

To date, generally accepted indications for prophylactic defibrillator implantation in patients with dilated cardiomyopathy do not exist. Recently, the Marburg Cardiomyopathy Study (MACAS) revealed left ventricular ejection fraction to be the only significant arrhythmia risk predictor in a relatively large patient population with dilated cardiomyopathy. Meanwhile, the preliminary results of two prospective randomized trials evaluating prophylactic defibrillator therapy in dilated cardiomyopathy have been reported. The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation study (DEFINITE) randomized 458 patients with a history of symptomatic heart failure, a left ventricular ejection fraction < or = 35% and arrhythmias on Holter to an ICD versus no ICD. As a result, ICD therapy was associated with a significant reduction of arrhythmic deaths, which failed to result in a significant decrease in total mortality due to an insufficient number of patients in DEFINITE. The Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) was a three-arm study comparing placebo to amiodarone to prophylactic ICD therapy in a total of 2,521 patients with ischemic cardiomyopathy (51%) or nonischemic dilated cardiomyopathy (49%). All patients in SCD-HeFT had a left ventricular ejection fraction inverted exclamation mark U 35% despite optimized medical heart failure therapy. SCD-HeFT showed a significant reduction of total mortality in the ICD group, whereas amiodarone did not improve survival.

Arrhythmias, Cardiac↗
PubMed2000

[Stratification of the arrhythmia risk after acute myocardial infarct].

Recent studies clearly support the role of the cardioverter implantable defibrillator in reducing arrhythmic and all-cause mortality in patients with a previous myocardial infarction. However, the use of the cardioverter implantable defibrillator cannot be extended to all myocardial infarction patients despite its effectiveness because implantation is an invasive procedure and the cost of the device is high. Thus, the correct and effective identification of patients at high risk of life-threatening ventricular arrhythmias represents a clinically relevant problem owing to the availability of an effective but expensive therapeutic tool. Many non-invasive tests have been studied in past years to assess the risk of ventricular arrhythmias after myocardial infarction; moreover, also programmed ventricular stimulation has been used to evaluate inducibility of ventricular tachycardia. Nevertheless, the positive predictive value of both non-invasive and invasive testing is low and not adequate to make a clinical decision. This finding is probably related to the multifactorial genesis of malignant ventricular arrhythmias which need several concomitant factors to trigger arrhythmias. For this reason the combined use of multiple risk markers is needed in order to improve diagnostic accuracy and identify subgroups of patients at high enough risk to define specific prophylactic options. In this scenario, according to available data, patients with two or more non-invasive risk markers should undergo electrophysiologic testing. In fact, patients with a recent myocardial infarction who have positive non-invasive tests and also show inducibility of sustained monomorphic ventricular tachycardia at programmed ventricular stimulation have a high incidence of arrhythmic events during the subsequent follow-up period and, in the author's opinion, should undergo a cardioverter defibrillator implantation. In the present review, an analysis of the main diagnostic tests for risk stratification of postinfarction patients will be performed and operative suggestions will be provided.

Bundle-Branch Block↗