Intracardiac Pressures Measured Using an Implantable Hemodynamic Monitor: Relationship to Mortality in Patients With Chronic Heart Failure.

Background: The purpose of this analysis was to examine whether implantable hemodynamic monitor-derived baseline estimated pulmonary artery diastolic pressure (ePAD) and change from baseline ePAD were independent predictors of all-cause mortality in patients with chronic heart failure.

Methods And Results: Retrospective analysis used data from 3 studies (n=790 patients; 216 deaths). Baseline ePAD was related to mortality using a multivariable model including baseline and demographic data.

Prediction of All-Cause Mortality Based on the Direct Measurement of Intrathoracic Impedance.

Background: Intrathoracic impedance-derived OptiVol fluid index calculated using implanted devices has been shown to predict mortality; direct measurements of impedance have not been examined. We hypothesized that baseline measured impedance predicts all-cause mortality; changes in measured impedance result in a change in the predicted mortality; and the prognostic value of measured impedance is additive to the calculated OptiVol fluid index.

Methods And Results: A retrospective analysis of 146,238 patients within the Medtronic CareLink database with implanted devices was performed.

Hemodynamic factors associated with acute decompensated heart failure: part 2--use in automated detection.

Background: The purpose of this study was to develop an automated surveillance system, using pressure-based hemodynamic factors that would detect which patients were making the transition from compensated to decompensated heart failure before they developed worsening symptoms and required acute medical care.

Methods And Results: Intracardiac pressures in 274 patients with heart failure were measured using an implantable hemodynamic monitor (IHM) and were analyzed in a retrospective manner. An automated pressure change detection (PCD) algorithm was developed using the cumulative sum method.

Hemodynamic factors associated with acute decompensated heart failure: part 1--insights into pathophysiology.

Background: The purpose of this study was to determine which pressure-based hemodynamic factor was most closely associated with the transition from chronic compensated to acute decompensated heart failure.

Methods And Results: Intracardiac pressures were retrospectively examined in 274 heart failure patients using an implantable hemodynamic monitor. The relationship between the development of a heart failure-related event (HFRE) and 3 pressure variables were analyzed: peak estimated pulmonary artery diastolic pressure (ePAD) at the time of an HFRE, change in ePAD from baseline to peak pressure, and the product of ePAD pressure and time (P×T) calculated as the area under the pressure-versus-time curve from baseline to peak pressure.

Chronic ambulatory intracardiac pressures and future heart failure events.

Background: Intracardiac pressures in heart failure (HF) have been measured in patients while supine in the hospital but change at home with posture and activity. The optimal level of chronic ambulatory pressure is unknown. This analysis compared chronic intracardiac pressures to later HF events and sought a threshold above which higher pressures conferred worse outcomes.

Application of implantable hemodynamic monitoring in the management of patients with diastolic heart failure: a subgroup analysis of the COMPASS-HF trial.

Background: Nearly half of all patients with chronic heart failure (HF) have a normal ejection fraction (EF), and abnormal diastolic function (ie, diastolic heart failure [DHF]). However, appropriate management of DHF patients remains a difficult and uncertain challenge.

Methods And Results: The Chronicle Offers Management to Patients with Advanced Signs and Symptoms of Heart Failure (COMPASS-HF) trial was designed to evaluate whether an implantable hemodynamic monitor (IHM) was safe and effective in reducing the number of heart failure-related events (HFRE) in patients with chronic HF.

Transition from chronic compensated to acute decompensated heart failure: pathophysiological insights obtained from continuous monitoring of intracardiac pressures.

Background: Approximately half of all patients with chronic heart failure (HF) have a decreased ejection fraction (EF) (systolic HF [SHF]); the other half have HF with a normal EF (diastolic HF [DHF]). However, the underlying pathophysiological differences between DHF and SHF patients are incompletely defined. The purpose of this study was to use echocardiographic and implantable hemodynamic monitor data to examine the pathophysiology of chronic compensated and acute decompensated HF in SHF versus DHF patients.

Continuous hemodynamic monitoring in patients with pulmonary arterial hypertension.

Background: The purpose of this study was to determine whether an implantable hemodynamic monitor (IHM) could be used to judge the response of pulmonary arterial hypertension (PAH) patients to changes in therapy.

Methods: A prospective, non-randomized, multi-center study evaluated physical examination, functional class, echocardiography, brain natriuretic peptide (BNP) levels, exercise capacity assessed by 6-minute walk and cardiopulmonary exercise tests, and quality of life at baseline and at 12 weeks. IHM measurements were continuously available to clinicians between clinic visits.

Right ventricular pressure waveform and wave reflection analysis in patients with pulmonary arterial hypertension.

Background: Cardiac index is an important determinant of outcome in patients with idiopathic pulmonary artery hypertension (IPAH). An implantable hemodynamic monitor (IHM) [Chronicle; Medtronic; Minneapolis, MN; a system limited to investigational use only] that records right ventricular (RV) pressure waveforms continuously may increase our understanding of IPAH and improve therapeutic selections and outcomes. The aim of this study was to investigate whether the RV pressure waveform utilizing an IHM can be used to estimate the magnitude of pressure wave reflection and cardiac index in patients with IPAH in acute settings.

A right ventricular pressure waveform based pulse contour cardiac output algorithm in canines.

Tracking changes in stroke volume or cardiac output (CO) can be useful in the diagnosis and treatment of various cardiac illnesses. Existing arterial pressure waveform based pulse contour CO algorithms perform poorly during altered systemic hemodynamics. In this study, a right ventricular pressure waveform based pulse contour CO algorithm was developed to estimate the amplitude and duration of a hypothetical triangular flow waveform in the pulmonary artery.