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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2818_Библиотеки_им_академика_М_И_Перельмана
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26 Basic Aspects ofPacemaker
7. Magnet application over a pacemaker can temporarily deactivate the pacing
function and allow the patient’s intrinsic rhythm to be recorded on the ECG.True
or false?
8. Pacemaker syndrome refers to the presence of symptoms caused by improper
pacing, such as palpitations and dizziness. True or false?
9. Which component of an electrocardiogram (ECG) represents the electrical
activity generated by a temporary cardiac pacemaker?
a. P wave b. QRS complex c. Pacing spike d. T wave
10. In a temporary cardiac pacemaker, the pacing spike is typically followed
by which waveform?
a. P wave b. T wave c. QRS complex d. U wave
11. A pacing spike appearing before the P wave in an ECG indicates:
a. Atrial pacing b. Ventricular pacing c. Malfunction of the pacemaker d.
Normal sinus rhythm
12. A pacing spike appearing before the QRS complex in an ECG indicates:
a. Atrial pacing b. Ventricular pacing c. Normal sinus rhythm d.
Malfunction of the pacemaker
13. In a permanent cardiac pacemaker, the pacing spike is typically fol-
lowed by:
a. P wave b. U wave c. T wave d. QRS complex
14. A failure to capture malfunction in a pacemaker refers to:
a. Inability to detect intrinsic cardiac activity b. Inability to produce a T
wave c. Inability to produce a QRS complex d. Inability to generate a
pacing spike
15. A failure to sense malfunction in a pacemaker refers to:
a. Inability to generate a pacing spike b. Inability to detect intrinsic cardiac
activity c. Inability to produce a QRS complex d. Inability to produce
a T wave
Case Studies
1. Analyse the rhythm strip given in Fig.26.8.
2. Analyse the rhythm strip given in Fig.26.9 and identify the problem.
3. Examine the rhythm strip given in Fig.26.10 and identify the problem.
4. Examine the rhythm strip given in Fig.26.11 and identify the problem.
26.4 Pacemaker Malfunction
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Fig. 26.8 Analyse the rhythm strip
Fig. 26.9 Analyse the rhythm strip
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Fig. 26.10 Analyse the rhythm strip
Fig. 26.11 Analyse the rhythm strip
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26 Basic Aspects ofPacemaker
Answers
1. True 2. True 3. False 4. True 5. False 6. True 7. True 8. True 9.
c 10. c 11. a 12. b 13. d 14. c 15. b
Case Studies
1. The rhythm strip (Fig.26.8) shows pacing spike before every P wave and pacing
spike before every QRS complex. Hence it is a dual chamber pacing. The QRS
complex is wide. The ventricular rate is 88bpm. There is no problem including
failure to capture, failure to pace and failure to sense.
2. In ECG of Fig.26.9, all the QRS complexes are preceded by pacing spike. Hence
it is a single chamber pacing. However, after the third pacing spike QRS complex
is absent. Hence, the diagnosis is failure to capture.
3. The rhythm strip (Fig.26.10) shows ventricular pacing for the rst three QRS
complexes. After this, the fourth and the fth beats are intrinsic beats of the
patient having normal PQRS complexes. Here the pacemaker fails to sense the
intrinsic beats. The pacemaker continues to pace throughout the intrinsic beats
and ventricular pacing resumes for sixth and seventh beats. Hence, it is under-
sensing problem of the pacemaker.
4. The rhythm strip (Fig.26.11) shows pacing spikes before each QRS complexes.
The QRS complexes are paced at a rate of 125bpm. Hence, it is a case of pace-
maker mediated tachycardia.
Part VII
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Recording and Monitoring of ECG
Chapter 27
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Recording ofECG
Learning Objectives
After studying this chapter, the reader will learn about:
• Standardization of ECG
• Procedure of recording ECG
ECG should be recorded carefully and the technique of recording should be uniform
from one recording to another. It is a safe, painless and quick procedure that can
help detect various heart conditions such as arrhythmias, heart attacks and heart
failure. A good quality ECG recording is essential to ensure accurate diagnosis and
treatment of these conditions. A good quality recording is essential for correct interpretation. Any medical personnel who has received training on conducting an electrocardiogram can record an ECG, including a doctor, nurse and a qualied
technician. Usually, it is performed by the technicians in clinics or hospitals and
then interpreted by clinicians. Often, these ndings are conrmed by a cardiologist
in a hospital-based setting. Before recording ECG, it is essential to learn about standardization of ECG.
27.1 Standardization ofECG
Standardization of ECG is one of the most important but most often neglected
aspects of recording of ECG.If standardization is not perfect, it may lead to wrong
diagnosis.
Conventionally, ECG is standardized so that 1mV is equal to 10mm of upward
deection (Fig.27.1).
Ltd. 2024
T. K. Koley, Rapid Review of ECG,
https://doi.org/10.1007/978-981-99-9116-7_27
357© The Author(s), under exclusive license to Springer Nature Singapore Pte
358
Correct Overdamping Overshoot
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Fig. 27.1 Diagram showing normal standardization, overdamping and overshoot
Overdamping: It is due to the stylus pressing too hard on paper and platform,
resulting in rounded edges. It leads to widening of the complex.
Underdamping or overshoot: This happens when the stylus becomes too loose
and causes spikes on the comer. The amplitude of the waves and complexes will
increase as a result.
27 Recording ofECG
27.2 Procedure ofRecording ECG
The procedure of recording a good quality of ECG is learnt by practice only.
However, the theoretical aspect is essential for everyone involved in the process of
recording ECG. A sound knowledge gets translated into an excellent ECG strip
which in turn helps in making the exact diagnosis. The basic steps that need to be
followed sequentially are discussed here.
27.2.1 Gather andCheck All theEquipment
The rst step in recording a good quality ECG is to gather the proper equipment and
check them thoroughly. Check the ECG machine and the leads properly before
starting the procedure. Collect self-adhesive electrodes, razor and alcohol swipes
which are essential to obtain a good ECG record.
27.2.2 Introduction andConsent
The rst step in recording a very good quality ECG is to prepare the patient for the
procedure. Introduce yourself to the patient including your name and conrm the
identity of the patient. A brief history regarding drugs and allergies to adhesive gel is
27.2 Procedure ofRecording ECG
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necessary. Explain the patient the procedure of recording the ECG in a patient
friendly language, preferably in the mother tongue of the patient including what to
expect and how long it will take. They should be asked about any medical conditions,
allergies, or medications they are taking that could affect the ECG results. The patient
should know that certain electrodes are going to be attached to the chest and limbs
and electrical activity of the heart will be recorded in the ECG machine. It must be
explained that he will not feel any electric current. After this obtain a verbal consent.
Female attendant should be present during recording of ECG in a female patient.
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27.2.3 Preparation
At the very beginning, wash your hands cleanly with soap and running water and
dry them properly. Patient must lie down comfortably and relax. The patient should
be instructed to remove all clothing from the waist up and put on a gown or loosetting clothing. Any metallic object, like jewellery or a watch requires removal. The
patient’s skin should be clean, dry and free from any lotions, oils or powders that
can affect the electrode’s adhesion. Wipe the patient’s skin with alcohol and allow it
to dry. The patient should be advised not to move or talk during the recording, as
this can cause interference.
27.2.4 Electrode Placement
The next step is to place the electrodes on the patient’s body. The standard ECG uses
ten electrodes that are attached to the patient’s chest, arms and legs. The electrode
placement is critical in recording a very good quality ECG.The electrodes must be
placed correctly to ensure accurate results. Attach the four electrodes on the four
limbs and the six chest electrodes on the designated areas on the anterior chest wall.
The limb leads include I, II, III, aVL, aVR and aVF and the electrodes are named
RA, LA, RL and LL.It is important to ensure each electrode has very good skin
contact, which may involve cleaning or shaving the areas where you need to place
electrodes. The need for shaving of chest hairs with razor should be explained to the
patient properly and consent should be taken for it. If the skin is very oily, it should
be cleaned with alcohol wipe properly and allowed to dry prior to electrode attachment. If the skin is visibly soiled, it should be cleaned, ideally with soap and water
and dried properly prior to electrode application.
Properly check the colour codes of the limb leads and attach them to the electrodes. The limb lead and the chest lead cables should be properly attached to the
ECG machine. There should not be any loose attachment.
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27 Recording ofECG
27.2.5 Recording theECG
Turn the ECG machine on and ensure ECG paper has been properly loaded into the
machine. Next instruct the patient to remain still and not to talk or move during
recording. It is essential to check the machine’s calibration. The calibration ensures
that the ECG machine is recording accurate results. The calibration should be
checked regularly, preferably before each use, to ensure that the machine is functioning correctly. The paper speed should be set at 25 mm/s and standardization
should be 10mm=1mV.It is also essential to check that the machine is properly
grounded and any electric equipment that may cause electrical interference should
be removed.
Press the start button on the ECG machine to record the ECG trace. If the ECG
trace is of poor quality, double-check the connections to ensure there is good skin
contact. Once a good quality ECG is obtained, switch off the ECG machine and
detach the ECG leads from the electrodes and then remove the electrodes carefully
and discard them properly. Label the ECG with patient details like name, age, sex,
date and time of ECG and hospital admission number.
In ECG, artifact is often recorded. The artifacts originate from sources other than
electrical activity in the heart. The common causes are shivering, muscle tremor,
loose electrodes, electrical equipment interference and improper grounding of ECG
machine (Fig.27.2).
Tips and Tricks
• Check calibration properly and standardization should be perfect for good
recording.
• The ECG machine should be properly grounded.
• There should not be any loose connections and electrical interference.
• The colour codes should be checked properly.
• Patient should be absolutely comfortable.
Lead II 25 mm/s. 10 mm = 1 mV
Fig. 27.2 Shivering artifacts
Chapter 28
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Bedside Cardiac Monitoring
Learning Objectives
After studying this chapter, the reader will learn about:
• Indications for cardiac monitoring
• Types of bedside cardiac monitoring
• Setting up of cardiac monitoring
• Monitor problems and their solutions
Bedside cardiac monitoring is an important aspect of management of a critical cardiac patient. Cardiac monitoring is a useful, noninvasive diagnostic tool to monitor
the wide array of patient conditions. In this chapter, basic information will be provided for careful monitoring of sick patients. By this process, one can continuously
monitor the electrical activity of the heart, which is useful for identication of
arrhythmias and heart blocks, acute myocardial ischaemia, evaluate response of
drugs and pacemaker function. Major improvements have occurred in cardiac monitoring systems, including computerized arrhythmia detection algorithms, S-T segment/ischaemia monitoring software, improved noise-reduction strategies, multilead
monitoring and reduced lead sets for monitoring-derived 12-lead ECGs with a minimal number of electrodes. It is useful in coronary care unit, intensive care units,
emergency departments, anaesthesia recovery rooms and operation theatres. Lead II
is used more frequently for monitoring because most of the heart’s electrical current
ows toward its positive axis. This lead gives the best view of the ECG waves and
best reects the activity of the cardiac conduction system.
Ltd. 2024
T. K. Koley, Rapid Review of ECG,
https://doi.org/10.1007/978-981-99-9116-7_28
361© The Author(s), under exclusive license to Springer Nature Singapore Pte
362
https://t.me/med1917
28 Bedside Cardiac Monitoring
28.1 Indications forCardiac Monitoring
Cardiac monitoring is not required for all patients coming to the emergency of a
hospital or admitted in a hospital. American College of Cardiology Emergency
Cardiac Care Committee for cardiac monitoring has developed the following categories for indications of cardiac monitoring.
• Class I: Cardiac monitoring is indicated in most, if not all, patients in this group.
• Class II: Cardiac monitoring may be benecial to some patients but not consid-
ered essential for all patients.
• Class III: Cardiac monitoring is not indicated because a patient’s risk of a serious
event is so low that monitoring has no therapeutic monitoring benet.
Cardiac monitoring is indicated in most, if not all, patients in the following patients:
• Patients resuscitated from cardiac arrest
• Patients in the early phase of acute coronary syndrome
• Patients with major trauma, acute respiratory failure, sepsis, shock, pulmonary
embolus, major noncardiac surgery, drug overdose or other indications for inten-
sive care
• Patients with acute heart failure, pulmonary oedema
• Patients with any haemodynamically unstable arrhythmia
• Patients after cardiac surgery
• Patients with temporary or transcutaneous pacemaker
• Patients with AV block after myocardial infarction
• Patients with drug-induced long Q-T syndrome
Often patients present with features suggestive of acute coronary syndrome.
However, ECG does not reveal any change. In these patients, serial ECG is required
every 5–10min to make the right diagnosis. Continuous S-T segment monitoring is
extremely valuable for these patients until they become symptom free for 12–24h.
For patients suffering from uncomplicated acute myocardial infarction, it is recommended that monitoring begins as soon as the patient presents to the ED and
continues uninterrupted for a minimum of 24 h. All patients who receive early
reperfusion therapy should undergo uninterrupted ECG monitoring. In patients with
a more complicated course, such as those with ongoing or recurrent ischaemia,
development of acute heart failure or cardiogenic shock, and arrhythmias requiring
an intervention such as temporary pacing, debrillation or intravenous antiarrhythmics, monitoring should continue for 24h after complications have resolved.
Cardiac monitoring is indicated for patients with Mobitz type II block, advanced
(2:1 or higher) second-degree AV block, complete heart block or new-onset bundlebranch block in the setting of acute (especially anterior wall) myocardial infarction.
Q-T interval monitoring is an extremely important indication of cardiac monitoring. Q-T interval prolongation is associated with Torsade de Pointes which is often
associated with sudden cardiac death.
Acute heart failure is a major risk factor for atrial and ventricular arrhythmias.
Some therapies for heart failure, especially intravenous positive inotropic drugs
including milrinone and dobutamine, have signicant proarrhythmic properties.
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