Cardiol Res

Cardiology Research, ISSN 1923-2829 print, 1923-2837 online, Open Access

Article copyright, the authors; Journal compilation copyright, Cardiol Res and Elmer Press Inc

Journal website https://www.cardiologyres.org

Original Article

Volume 11, Number 6, December 2020, pages 370-375

A Novel Non-Invasive Assessment of Cardiac Hemodynamics in Patients With Heart Failure and Atrial Fibrillation

Figure 1. Impedance cardiography. Impedance cardiography is a non-invasive method to record changes in thoracic impedance using transmitting and sensing electrodes that are applied to the bases of the neck and thorax bilaterally.

Figure 2. Association between hemodynamic parameters and heart rhythm. This figure shows the differences between the groups in terms of cardiac hemodynamics. Patients with atrial fibrillation exhibited lower stroke volume, lower stroke work index, lower velocity, and lower total arterial compliance, as well as higher systemic stroke resistance index. Error bars indicate ± SE. SE: standard error.

Figure 3. Discriminant value of ICG to identify patients with AF. This figure shows the discriminant value of ICG parameters reported in Table 1 for separating patients with and without AF. ROC corresponds to the predicted probability value of a multivariate logistic regression model. ICG: impedance cardiography; AF: atrial fibrillation; ROC: receiver operating characteristic; AUC: area under the ROC curve.

**Table 1.** Selected Hemodynamic Parameters Obtained by Impedance Cardiography (ICG)
ICG variable	Definition
BSA: body surface area.
Stroke volume (SV)	Blood volume pumped in a single beat (absolute) and after adjustment to BSA (indexed).
Systemic vascular resistance (SVR)	The vascular resistance of the systemic vasculature as seen by the left ventricle (absolute) and after adjustment to BSA (indexed).
Left stroke work index (LSWI)	The measure of work which the left ventricle must expend to pump blood per heartbeat.
Velocity index (VI)	A normalized peak aortic flow as a preload volume-dependent measure of contractility.
Systemic stroke resistance Index (SSRI)	A measure of afterload on a per beat basis.
Total arterial compliance (TAC)	An index of the elasticity of large arteries measured based on the ratio between SV-to-aortic pulse pressure.

Table 1. Selected Hemodynamic Parameters Obtained by Impedance Cardiography (ICG)

ICG variable

Definition

BSA: body surface area.

Stroke volume (SV)

Blood volume pumped in a single beat (absolute) and after adjustment to BSA (indexed).

Systemic vascular resistance (SVR)

The vascular resistance of the systemic vasculature as seen by the left ventricle (absolute) and after adjustment to BSA (indexed).

Left stroke work index (LSWI)

The measure of work which the left ventricle must expend to pump blood per heartbeat.

Velocity index (VI)

A normalized peak aortic flow as a preload volume-dependent measure of contractility.

Systemic stroke resistance Index (SSRI)

A measure of afterload on a per beat basis.

Total arterial compliance (TAC)

An index of the elasticity of large arteries measured based on the ratio between SV-to-aortic pulse pressure.

**Table 2.** Baseline Sample Characteristics
Variable	Total (n = 32)
NYHA: New York Heart Association; ICG: impedance cardiography; SV: stroke volume; SVR: systemic vascular resistance; LSWI: left stroke work index; VI: velocity index; SSRI: systemic stroke resistance index; TAC: total arterial compliance.
Age (years)	62 ± 14
Male sex	21 (66%)
Class I NYHA	28 (88%)
Ejection fraction	0.33 ± 0.13
Comorbidities
Diabetes mellitus	10 (31%)
Hypertension	22 (69%)
Coronary artery disease	6 (19%)
Valvular heart disease	4 (13%)
Pulmonary hypertension	6 (19%)
Renal disease	9 (28%)
ICG parameters
SV (mL)	80 ± 29
SVR (dynes s cm^-5)	1,237 ± 362
LSWI (g m/m²)	42 ± 13
VI (/s)	37 ± 13
SSRI (dyne s cm^-8 L min^-1 m²)	166 ± 56
TAC (mL/mm Hg)	18.5 ± 7.8

Table 2. Baseline Sample Characteristics

Variable

Total (n = 32)

NYHA: New York Heart Association; ICG: impedance cardiography; SV: stroke volume; SVR: systemic vascular resistance; LSWI: left stroke work index; VI: velocity index; SSRI: systemic stroke resistance index; TAC: total arterial compliance.

Age (years)

62 ± 14

Male sex

21 (66%)

Class I NYHA

28 (88%)

Ejection fraction

0.33 ± 0.13

Comorbidities

Diabetes mellitus

10 (31%)

Hypertension

22 (69%)

Coronary artery disease

6 (19%)

Valvular heart disease

4 (13%)

Pulmonary hypertension

6 (19%)

Renal disease

9 (28%)

ICG parameters

SV (mL)

80 ± 29

SVR (dynes s cm^-5)

1,237 ± 362

LSWI (g m/m²)

42 ± 13

VI (/s)

37 ± 13

SSRI (dyne s cm^-8 L min^-1 m²)

166 ± 56

TAC (mL/mm Hg)

18.5 ± 7.8