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.