This function allows for WFDB files to be read from any WFDB-compatible system, and also allows writing out WFDB-compatible files from specific EP recording systems, as indicated in the details section. Writing WFDB leads to creation of both a dat (signal) and hea (header) file. These are both required for reading in files as well.
write_wfdb(
data,
record,
record_dir,
wfdb_path = getOption("wfdb_path"),
header = list(frequency = 250, gain = 200L, label = character()),
info_strings = list(),
...
)read_wfdb(
record,
record_dir = ".",
annotator = NA_character_,
wfdb_path = getOption("wfdb_path"),
begin = 0,
end = NA_integer_,
interval = NA_integer_,
units = "digital",
channels = character(),
...
)
read_signal(
record,
record_dir = ".",
wfdb_path = getOption("wfdb_path"),
begin = 0L,
end = NA_integer_,
interval = NA_integer_,
units = "digital",
channels = character(),
...
)
read_header(record, record_dir = ".", wfdb_path = getOption("wfdb_path"), ...)
Depends on if it is a reading or writing function. For writing, will
output an WFDB-based object reflecting the function. For reading, will
output an extension of a data.table object reflecting the underlying
function (e.g. signal_table() will return an object of class).
Can either be an egm object, or a data.frame (or similar)
object. The function will appropriately set defaults based on the type.
egm = Will extract signal and header data directly from object, and thus is simplest to convert to a WFDB format
signal_table = This is a customized data.table class that has an invariant column containing sample information.
data.frame or data.table = Must have a column that represents a time point or index, and columns that represent signal values (preferably integers)
String that will be used to name the WFDB record. Cannot include extensions, and is not a filepath. alphanumeric characters are acceptable, as well as hyphens (-) and underscores (_)
File path of directory that should be used read and write files. Defaults to current directory.
Path that leads to installed wfdb software package on
device. Needs to be directly set using set_wfdb_path(). Obtained from the
system options on loading of the package, getOption('wfdb_path')
A header file is an optional named list of parameters that will be used to organize and describe the signal input from the data argument. If the type is given, specific additional elements will be searched for, such as the low or high pass filters, colors, or other signal attributes. At minimum, the following elements are required (as cannot be calculated):
frequency = sample frequency in Hertz as integer
label = vector of names for each channel as character
start_time = date/time object
A list of strings that will be written as an appendix
to the header file, usually containing information about the channels,
(e.g. list of colors, extra labels, etc).
Additional arguments to be passed to the function
String that is the name of a WFDB-compatible annotation
type, serving as the extension for the file that is written containing that
annotation. Please see read_annotation() and write_annotation() for
further details.
Timepoint as an integer (representing seconds),
which is converted to an index position based on sampling frequency. The
default is to start at the beginning of the record. If end or interval
are given, the earlier of the two will be returned. The end argument
gives a time index to read until. The interval argument is the length of
time past the start point.
A character string representing either digital (DEFAULT) or physical
units that should be used, if available.
digital = Index in sample number, signal in integers (A/D units)
physical = Index in elapsed time, signal in decimal voltage (e.g. mV). This will include 1 additional row over the header/column names that describes units
Either the signal/channel in a character vector as a name or number.
Allows for duplication of signal or to re-order signal if needed. If
nothing is given, will default to all channels available.
write_wfdb(): Writes out signal and header data into a WFDB-compatible
format from R.
read_wfdb(): Reads a multicomponent WFDB-formatted set of files
directly into an egm object. This serves to pull together
read_signal(), read_header(), and read_annotation() for simplicity.
read_signal(): Specifically reads the signal data from the WFDB binary
format, returning a signal_table object for evaluation in the R
environment
read_header(): Specifically reads the header data from the WFDB header
text format, returning a header_table object for evaluation in the R
environment
Type of signal data, as specified by the recording system, that are currently supported.
lspro = LabSystem Pro, e.g. read_lspro()
muse = GE MUSE, e.g. read_muse()