The postimplantation electrocardiogram predicts clinical response to cardiac resynchronization therapy.

Background: Biventricular (BiV) pacing for cardiac resynchronization therapy (CRT) is intended to improve left ventricular function by coordinating systolic activity of the septum and free walls. Optimal resynchronization should be manifested by 12-lead electrocardiogram (ECG) patterns consistent with resynchronized activation, a tall (≥4 mm) R wave in V1, and predominant negative deflection in lead I (RV1SI). We investigated whether the presence or absence of RV1SI predicts heart failure outcomes within 1 year of CRT implant.

Characteristics of the electrocardiogram in patients with continuous-flow left ventricular assist devices.

Background: Electrocardiograms (ECGs) are routinely obtained in patients with advanced congestive heart failure (CHF) before and after surgical implantation with a left-ventricular assist device (LVAD). As the number of patients with CHF is increasing, it is necessary to characterize the changes present in the ECG of patients with LVADs.

Methods: ECGs of 43 patients pre- and postimplantation of a HeartMate II LVAD were compared to characterize the presence of an LVAD using the following six criteria (LVADS2 ): low limb-lead voltage, ventricular pacing, artifact (electrical), duration of the QRS > 120 milliseconds, ST-elevation in the lateral leads, and splintering of the QRS complex.

Novel measures of heart rate variability predict cardiovascular mortality in older adults independent of traditional cardiovascular risk factors: the Cardiovascular Health Study (CHS).

Unlabelled: Novel HRV Predicts CV Mortality in the Elderly.

Background: It is unknown whether abnormal heart rate turbulence (HRT) and abnormal fractal properties of heart rate variability identify older adults at increased risk of cardiovascular death (CVdth).

Methods: Data from 1,172 community-dwelling adults, ages 72 +/- 5 (65-93) years, who participated in the Cardiovascular Health Study (CHS), a study of risk factors for CV disease in people >or=65 years.

Diastolic dysfunction and autonomic abnormalities in patients with systolic heart failure.

Background: Patients with systolic heart failure (SHF) often have concomitant diastolic dysfunction (DD). SHF is associated with decreased heart rate variability (HRV), but the impact of degree of DD on HRV in SHF is unclear.

Methods And Results: HRV was measured in 139 patients, aged 64+/-12 years, 74% male, LVEF 30+/-8%.

Traditional and nonlinear heart rate variability are each independently associated with mortality after myocardial infarction.

Introduction: Decreased heart rate variability (HRV) and abnormal nonlinear HRV shortly after myocardial infarction (MI) are risk factors for mortality. Traditional HRV predicts mortality in patients with a range of times post-MI, but the association of nonlinear HRV and outcome in this population is unknown.

Methods And Results: HRV was determined from 740 tapes recorded before antiarrhythmic therapy in Cardiac Arrhythmia Suppression Trial patients with ventricular premature contractions (VPCs) suppressed on the first randomized treatment.

Heart rate variability: measurement and clinical utility.

Electrocardiographic RR intervals fluctuate cyclically, modulated by ventilation, baroreflexes, and other genetic and environmental factors that are mediated through the autonomic nervous system. Short term electrocardiographic recordings (5 to 15 minutes), made under controlled conditions, e.g.

Including patients with diabetes mellitus or coronary artery bypass grafting decreases the association between heart rate variability and mortality after myocardial infarction.

Background: Decreased heart rate variability (HRV) is often assumed to be associated with mortality in all patients after myocardial infarction (MI), independent of clinical factors or time after MI.

Method: HRV was determined from Holter tapes in the Cardiac Arrhythmia Suppression Trial (CAST). Patients were 71 +/- 120 days after MI.

Early invasive versus ischaemia-guided strategies in the management of non-Q wave myocardial infarction patients with and without prior myocardial infarction; results of Veterans Affairs Non-Q Wave Infarction Strategies in Hospital (VANQWISH) trial.

Aims: To compare the role of early invasive vs conservative management strategies in treating patients with non-Q wave myocardial infarction with or without a prior myocardial infarction.

Background: In patients recovering from non-Q wave myocardial infarction, the prognosis among patients with a first non-Q wave myocardial infarction is significantly better than in patients with a prior myocardial infarction, yet physicians often adopt an early invasive strategy to treat patients with a first non-Q wave myocardial infarction.

Methods: Non-Q wave myocardial infarction patients enrolled in the VANQWISH trial with a history of prior myocardial infarction were compared to those with a first non-Q wave myocardial infarction, for the trial primary end-point of death or myocardial infarction at 1 and 12 months, as well as for the initial randomized treatment strategy.

Severe depression is associated with markedly reduced heart rate variability in patients with stable coronary heart disease.

Objective: The purpose of this study was to investigate the relationship between depression and heart rate variability in cardiac patients.

Methods: Heart rate variability was measured during 24-hour ambulatory electrocardiographic (ECG) monitoring in 40 medically stable out-patients with documented coronary heart disease meeting current diagnostic criteria for major depression, and 32 nondepressed, but otherwise comparable, patients. Patients discontinued beta-blockers and antidepressant medications at the time of study.

Clinical and demographic determinants of heart rate variability in patients post myocardial infarction: insights from the cardiac arrhythmia suppression trial (CAST).

Background: Clinical and demographic determinants of heart rate variability (HRV), an almost universal predictor of increased mortality, have not been systematically investigated in patients post myocardial infarction (MI).

Hypothesis: The study was undertaken to evaluate the relationship between pretreatment clinical and demographic variables and HRV in the Cardiac Arrhythmia Suppression Trial (CAST).

Methods: CAST patients were post MI and had > or =6 ventricular premature complexes/h on pretreatment recording.

Morphology of right ventricular paced beats in posterior myocardial infarction.

Premature ventricular beats or paced beats can unmask new or old myocardial infarction when sinus beats fail to exhibit the typical infarct pattern. Knowledge of their morphology is vital, since they may be the earliest or even the only evidence of a myocardial infarction in certain cases. Morphology of premature ventricular beats or paced beats in anterior, anteroseptal, and inferior infarct has been described but not in the setting of a posterior infarct.

Assessment of ultra low frequency band power of heart rate variability: validation of alternative methods.

Unlabelled: Alternative methods for assessing ULF spectral power using data from commercial Holter analysers were studied. Different heuristics for ULF calculation were compared with standard research software-based determination of ULF.

Setting: University Hospital.

Effect of exercise training on heart rate variability in healthy older adults.

Objective: To determine the effect of exercise training on cardiac autonomic modulation in normal older adults by using analysis of heart rate variability.

Subjects: The exercise group consisted of 7 men and 9 women aged 66 +/- 4 years. The comparison group consisted of 7 men and 9 women also aged 66 +/- 4 years.

Comparison based on age of baseline electrocardiographic abnormalities in non-Q-wave myocardial infarction. VANQWISH Trial Research Investigators. Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital.

Objective: To compare the incidence of electrocardiographic abnormalities between older (age > or = 70 years) and younger patients presenting with acute non-Q-wave myocardial infarction.

Design: Retrospective review of qualifying electrocardiograms in 918 patients enrolled in the multicenter Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) study.

Setting: Seventeen Department of Veterans Affairs medical centers.

Changes in 24-hour heart rate variability during normal pregnancy.

Objective: We studied the effects of normal pregnancy on heart rate variability as a noninvasive index of maternal cardiovascular autonomic modulation.

Study Design: Twenty-four-hour Holter recordings were obtained for 8 healthy pregnant volunteers during early pregnancy ( View Article and Find Full Text PDF

Mechanisms of death in the CABG Patch trial: a randomized trial of implantable cardiac defibrillator prophylaxis in patients at high risk of death after coronary artery bypass graft surgery.

Background: The CABG Patch trial compared prophylactic implantable cardiac-defibrillator (ICD) implantation with no antiarrhythmic therapy in coronary bypass surgery patients who had a left ventricular ejection fraction <0.36 and an abnormal signal-averaged ECG. There were 102 deaths among the 446 ICD group patients and 96 deaths among the 454 control group patients, a hazard ratio of 1.

Insights from the study of heart rate variability.

Indices of heart rate variability (HRV) provide a window onto autonomic modulation of the heart. HRV indices, determined in either the time or frequency domain, are closely related and reflect parasympathetic, mixed sympathetic, and parasympathetic and circadian rhythms. In population studies, decreased HRV has had predictive value for mortality among healthy adults.

RR interval dynamics before atrial fibrillation in patients after coronary artery bypass graft surgery.

Background: Atrial fibrillation/flutter (AF) is a frequent complication of coronary artery bypass graft surgery (CABG) that leads to increased costs and morbidity. We hypothesized that heart rate variability (HRV), an indicator of cardiac sympathovagal balance, is altered before the onset of postoperative AF. Because nonlinear methods of HRV analysis provide information about heart rate dynamics not evident from usual HRV measures, we also hypothesized that approximate entropy (ApEn), a nonlinear measure of HRV, might have predictive value.

Outcomes in patients with acute non-Q-wave myocardial infarction randomly assigned to an invasive as compared with a conservative management strategy. Veterans Affairs Non-Q-Wave Infarction Strategies in Hospital (VANQWISH) Trial Investigators.

Background: Non-Q-wave myocardial infarction is usually managed according to an "invasive" strategy (i.e., one of routine coronary angiography followed by myocardial revascularization).

Heart rate variability reflects severity of COPD in PiZ alpha1-antitrypsin deficiency.

Background: Analysis of heart rate variability (HRV) is a powerful method of assessing severity of conditions affecting the autonomic nervous system.

Study Objective: To determine if HRV is decreased and if HRV reflects severity in COPD.

Design: Prospective determination of HRV from 24-h outpatient Holter recordings.

Design and baseline characteristics of the Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) trial. VANQWISH Trial Research Investigators.

Objectives: The Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) trial was designed to compare outcomes of patients with a non-Q wave myocardial infarction (NQMI) who were randomized prospectively to an early "invasive" strategy versus an early "conservative" strategy. The primary objective was to compare early and late outcomes between the two strategies using a combined trial end point (all-cause mortality or nonfatal infarction) during at least 1 year of follow-up.

Background: Because of the widely held view that survivors of NQMI are at high risk for subsequent cardiac events, management of these patients has become more aggressive during the last decade.

Differing effects of age on heart rate variability in men and women.

Gender and age are both known to affect heart rate variability (HRV). Their interaction is not known. HRV, determined from 24-hour Holter recordings, was compared between gender-matched older (15 men and 15 women, aged 67 +/- 3 years, range 64 to 76) and younger (15 men and 15 women, aged 33 +/- 4 years, range 26 to 42) subjects selected for an age difference of approximately 35 years.

Heart rate variability is independent of age, gender, and race in congestive heart failure with a recent acute exacerbation.

Among normal adults, indexes of heart rate variability are affected by age, gender, and race. These effects are not seen among patients with congestive heart failure with a recent acute exacerbation, in whom indexes of heart rate variability are remarkably uniform and appear to be determined primarily by their recent cardiac failure.