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Chapter 2
•
Cardiovascular Care
Holter Monitoring
(Ambulatory ECG Monitoring)
Ambulatory ECG monitoring records
the heart’s activity as the patient
follows his normal routine. The
patient wears a small electronic
recorder connected to electrodes
placed on his/her chest and keeps a
diary of his activities and associated
symptoms. This test can be worn
from 24 to 48 hours and for as long
as months to years offering the ability
to monitor cardiac ECG data during
normal routine activity, including any
physical and psychological stresses.
Normal Conduction Intervals in Adults
PA interval
AH interval
HV interval
PA interval
= conduction from sinatrial (SA) node to atrioventricular (AV) node
= 20 to 40 msec
AH interval
= conduction from AV node to bundle of His
= 4 to 150 msec
HV interval
= conduction from bundle of His to ventricles
= 35 to 55 msec
Catheter
SA node
AV node
Bundle
of His
ELECTROPHYSIOLOGY
STUDIES
Electrophysiology studies are used
to help determine the cause of an
arrhythmia and the best treatment
for it. A bipolar or tripolar electrode
catheter is threaded into a vein,
through the right atrium, and across
the septal leaflet of the tricuspid valve.
The femoral vein is the most common
choice for the catheter insertion.
However, the subclavian, internal
jugular, or brachial vein may also be
used. The heart’s usual conduction
is recorded first. The catheter sends
electrical signals to the heart to
change the heart rate and initiate an
arrhythmia. Various drugs are then
tried to terminate the arrhythmia.
Also, sometimes the cardiologist
can induce an arrhythmia and
then immediately treat it using
radiofrequency ablation, a
pacemaker, or an implantable
cardioverter defibrillator (ICD).
IMAGING TESTS
Various imaging and radiographic
tests are used to help visualize
heart structures and blood vessels
throughout the cardiovascular system.
Although many of these tests are
noninvasive and quick to perform,
some require the insertion of a cardiac
catheter, injection of a contrast
medium, or nuclear medicine to
further enhance the image.
Cardiac Catheterization
Cardiac catheterization (cardiac
catheterization or heart
catheterization) is an invasive
procedure to examine how well
the heart is working. A catheter
is inserted into a large blood
A Look at a Holter Monitor
Portable ECG recorder
Patient event marker button
ECG leadwires