User Manual Part 3

7-4

PATIENT DIAGNOSTICS

TRENDS

• HRV Footprint––displays the percentage of the graph area used by the

HRV plot. The graph area portrays a n “at-a-glance snapshot” of the

distribution of variability versus heart ra te over a 24-hour period. T h e

trended percentage is a normalized score based on the footprint in the

graph. If an HRV plot was not obtained for the 24-hour period, then the

HRV Footprint is not calculated and a value of “N/R” is displayed.

• ABM (Autonomic Balance Monitor)––a device calculation based on

R–R int erval mea surements; it mathe matically functions as a surroga te

measurement for LF/HF ratio.

Intervalsusedinthecalculationmustbe

valid sinus rhythm intervals as determin ed b y the HRV collection criteria. If

the H RV data is invalid for the 24-hour collection period, then the ABM is

not calculated for that collection period and a value of "N/R" is displayed.

• Amplitude––provides amplitude measurements

• Impedance––provides impedance measurements

Follow the steps below to access Trends:

1. From the Events screen, select the Trends Tab

2. Choose the Select Trends button to specify the trends you want to view.

You can choose from the following categories:

• Heart Failure––includes Heart Rate, SDANN, and HRV Footprint trends

• Atrial Arrhythmia––includes Events, Heart Rate, and Atrial Burden

trends

• Activity––includes Heart Rate, Activity Level, and Respiratory Rate

trends

• Custom –– allows you to select three tre nds t o custo mize t he information

displayed on the Trends screen

Thedisplayonthescreencanbeviewedinthefollowingmanners:

• Select the desired time on the View button to choose the length of visible

trend data.

1. Parasympathetic tone is prim arily reﬂected in the high-frequency ( HF) component of

pectral analysis. The low-frequency (LF) component is inﬂuenced by both the sympathetic

and parasympathetic nervous systems. The LF/HF ratio is c onsidered a measure of

sympathovagal balance and reﬂects sympathetic modulations. (Source: A CC/AHA Guidelines

for Ambulatory Electrocardiography—Part III, JACC VOL. 34, No. 3, September 1999:912–48)

- DRAFT -