心电图教程7

Lead Systems
• Use 5 or 7 leads • Records signals from 2 or 3 bipolar leads
onto 2 or 3 channels • Variety of bipolar lead configurations used • Most common:
Procedure – Electromagnetic Tape
• Before patient arrives: • Select tape of proper length
60 min for 24 hours, 120 min for 48 hours
• Advance tape so that the calibration signal will be recorded on the brown magnetic tape • Label tape with:
iseasemanagement/cardiology/arrhyth mias/arrhythmias.htm
AECG Monitoring
Ambulatory ECG Monitoring 2 types: 1. Continuous recorders (Holter): 24 or 48 hours
Corday, E. JACC 1991;17:286-292
Holter Monitor
2 formats: 1. Magnetic cassette tape
• • • • • Permanent record of all ECG during recording Records onto a 60 or 90 min cassette tape Tape speed very slow (1mm/sec) Works well for arrhythmia detection May not work for ST analysis as ST segment may be distorted
Agenda
• Continuous (Holter) Monitors • Theory • Procedures • Intermittent Monitors • Theory • Procedures • Lab Session • Holter • Event Monitor • Exercise Testing
Procedure – Digital Monitor
• Before patient arrives: • Initialize Flash Card by:
Entering patient information Selecting number of leads/channels
• System may initialize with:
• • • •
Palpitations Syncope, presyncope, lightheadedness Antiarrhythmic therapy evaluation Assessing risk in patients with or without symptoms
• MI survivors at increased risk of sudden death
http://www.clevelandclinicmeded.com/diseasemanagement/cardiology/arrhythmias/arrhythmias.htm
VT Terminated by ICD
Holter demonstrating termination of sustained VT with a synchronized shock from an ICD
Relationship Between ECG and Symptoms
• No symptoms and normal ECG • Symptoms coincide with and are explained
by ECG abnormality • Symptoms during normal sinus rhythm • No symptoms but abnormal ECG
Norman Holter
• Invented ambulatory ECG • • • •
monitor in 1947 Weighed 85 lbs Generated power by pedaling bicycle By 1952, it weighed 2.6 lbs By 1961, it could record 10 hours of ECG
External device attached to PC or Handheld device
• Investigate symptoms or ECG events likely to occur within that time frame
AECG Monitoring
2. Intermittent recorders:
weeks to months
• Provide brief, intermittent recordings of infrequent events Two types:
http://www.danleemedical.com/index.asp?categor y=14641
Holter Monitor
2. Digital recording
• • • •
Extremely accurate recording of ECG signal Can analyze ST segment deviation Storage on flash card (removed from recording device and downloaded for analysis) Alternatively, may be stored on a miniature hard drive
• Myocardial ischemia (accurate with new
technology) • Pacemaker function • AICD function • Heart rate variability
Rhythms Associated with Palpitations
HLT0073 Cardiac Diagnostics Instrumentation
Class 7
Instructor: Joanne Lambley, MSc (Kin)
Previous Class
• Exercise Standards for Testing and
Training: A Statement for Healthcare Professionals From the American Heart Association Circulation, Oct 2001; 104: 1694 - 1740 • http://circ.ahajournals.org/
• Modified V5 • Modified V3 • Modified inferior lead
ACC/AHA Practice Guidelines (Circulation. 1999;100:886-893.)
Example of 2 Channel Placement
• Channel 1 • White (-) (• Red (+) • Channel 2 • Brown (-) (• Black (+) • Ground • Green
• Sinus rhythm or tachycardia • PAC’s • Atrial Fibrillation • Supraventricular Tachycardia • PVC’s • Ventricular Tachycardia
Ventricular Tachycardia
Holter showing ventricular tachycardia degenerating to ventricular fibrillation
http://www.medicalsolutionsinc.com
Holter Application
• Quality of recording dependent on proper • • • •
preparation of sites Shave sites if necessary Clean sites with alcohol and gauze Gently abrade with fine sandpaper or commercial prep tape Apply electrodes on top of bone to reduce artifact (avoid skin folds and creases)
http://www.clevelandclinicmeded.com/diseasemanagement/cardiology/arrhythmias/arrhythmias.htm
Rhythms Associated with Syncope
• Sinus bradycardia/arrest • 2nd or 3rd degree heart block • Ventricular Tachycardia • Supraventricular Tachycardia • Pacemaker Malfunction
Sources
• ACC/AHA Guidelines for Ambulatory
Electrocardiography: Executive Summary and Recommendations
(Circulation. 1999;100:886-893.) 1999;100:886-
• http://www.clevelandclinicmeded.com/d
Holter Application
• Press firmly around circumference of
electrodes to ensure adhesion • Skin resistance may be checked with an impedance meter • If electrodes may not adhere for entire recording period (humid environment, patient sweaty) apply tincture of benzoin where electrode adhesive will be placed • Attach lead wires
Syncope due to Heart Block
Holter demonstrating intermittent complete heart block in patient with syncope
http://www.clevelandclinicmeded.com/diseasemanagement/cardiology/arrhythmias/arrhythmias.htm
Name of Patient Hospital Unique Number Date of Test
• Install fresh 9 Volt battery • Engage tape head – 8 min of calibration signals will start recording
• •
•
Loop recorder: worn continuously Event recorde来自百度文库: attached by patient
http://www.cvtoolbox.com/cvtoolbox2/card_test s/ct_3.html
Indications for AECG