Association of Impedance Cardiography Parameters With Changes in Functional and Quality‐of‐Life Measures in Patients With Chronic Heart Failure

Abstract

Assessment and prognosis of chronic heart failure is often difficult due to a lack of objective and easily obtainable parameters that accurately reflect disease status. This study was conducted to determine whether impedance cardiography (ICG) parameters were associated with changes in functional and quality-of-life measures in chronic heart failure patients. Retrospective chart review identified 64 patients (73% male, aged 73+/-13 years) with paired ICG measurements followed for 180+113 days. Outcome measures were changes in New York Heart Association class, 6-minute walk distance, patient visual analog scale score, and Minnesota Living with Heart Failure Questionnaire score. Measures of ICG, heart rate and blood pressure, left ventricular ejection fraction, and B-type natriuretic peptide levels were assessed for their association with outcome measures. From baseline to final evaluation, there were significant changes (p<0.05) in New York Heart Association class (from 3.2+/-0.5 to 3.0+/-0.6), 6-minute walk distance (from 668+/-380 m to 874+/-390 m), patient visual analog scale score (from 49+/-10 to 64+/-20), Minnesota Living with Heart Failure Questionnaire score (from 54+/-22 to 39+/-22), and ICG parameters of stroke index (from 38+/-9 to 41+/-8), left ventricular ejection time (from 273+/-42 to 291+/-33), and systolic time ratio (from 0.56+/-0.2 to 0.52+/-0.2). Changes in multivariate ICG parameters were significantly correlated to changes in New York Heart Association class (R, 0.80), 6-minute walk distance (R, 0.94), patient visual analog scale score (R, 0.69), and Minnesota Living with Heart Failure Questionnaire score (R, 0.67). ICG provides objective data that reflects changes in chronic heart failure disease status and treatment effectiveness.

Systolic Time Ratio by Impedance Cardiography to Distinguish Preserved vs Impaired Left Ventricular Systolic Function in Heart Failure

“…The role of ICG in the evaluation and management of patients with HF has been previously reviewed 14 . More recent, Vijayaraghavan and colleagues 15 demonstrated that hemodynamic variables obtained by ICG correlated with changes in functional status, including various quality‐of‐life measures. Specifically, improvement in STR was shown to correlate with improvement in New York Heart Association functional class ( r =0.70) and the 6‐minute walk test ( r =0.68).…”

Continuous infusion of furosemide versus intermittent boluses in acute decompensated heart failure: Effect on thoracic fluid content

“… 29 , 30 The TFC is one of the hemodynamic parameters which is measured by IC that reflects interstitial, intra-vascular and intra-alveolar fluid within the thorax. It was used effectively in ADHF patients 29 , 30 , 31 and was found to be comparable to the PAC for the evaluation of cardiac output 32 , 33 and pulmonary capillary wedge pressure. 34 It was also seen to be correlated with serum BNP levels in heart failure patients.…”

Utility of Impedance Cardiography for the Identification of Short-Term Risk of Clinical Decompensation in Stable Patients With Chronic Heart Failure

“…In one retrospective chart review of 13 patients (17), a relationship was observed between changes in impedance parameters and changes in ejection fraction over six months. In a second retrospective chart review of 64 patients (18), changes in impedance variables were related to changes in NYHA functional class, corridor walk distance, visual analog score, and quality of life over 6 months. In a third study of 98 men seen in an emergency department (19), a combination of brain natriuretic peptide and ICG variables was reported to identify patients at risk of death and hospitalization, but the independent contribution of ICG measurements was not assessed (20).…”