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ECG MONITORING AND ECG CHANGES OF INTRAOPERATIVE MYOCARDIAL.pptx
1. ECG MONITORING AND ECG CHANGES
OF INTRAOPERATIVE MYOCARDIAL
INFARCTION
Dr.PRIYANGA RAVI,
SECOND YEAR ANAESTHESIA RESIDENT,
GOVERNMENT MEDICAL COLLEGE,
BHAVNAGAR.
2. STANDARD -12 LEAD
ELECTROCARDIOGRAM
• A graphical recording of the electrical activity of the
heart over time.
• It is a bedside investigation.
• Gold standard for diagnosis of cardiac arrythmias.
• Allows for detection of conduction abnormalities.
• Screening tool for ischemic heart disease during stress
tests.
• Helpful with non-cardiac diseases (e.g.pulmonary
embolism or hypothermia)
• Its a simple ,cheap and easily available investigation.
8. • Speed of the paper-25mm/sec
• 1 horizontal small box-0.04second
• 1 horizontal large box -0.2 second
• 1 vertical small box is 1mm-0.1 MV
9.
10. ELECTROCARDIOGRAM WAVES
• P WAVE-depolarization of atria (atria begin
contracting about 25msec after the start of the
p-wave.
• QRS –COMPLEX-ventricular
depolarization(ventricles begin contracting
shortly after the peak of the R wave)
• T WAVE-ventricular repolarization.
11. EINTHOVEN’S LAW
• In the ecg at any given instant ,the potential of
any wave in lead II is equal to sum of the
potentials in lead I and lead III.
• II=I+III
17. ECG INTERPRETATION
• Patient name and date
• Standardization
• Rate
• Rythm
• P wave
• PR segment
• QRS complex
• ST segment
• T wave
• QT interval
• U wave
19. OVERDAMPING AND
UNDERDAMPING
• Overdamping-When the pressure of the stylus
is too firm on the paper so that it’s movements
are retarded-deflection fractionally wider and
dimisnished amplitude.
• Underdamping-when the writing stylus is not
pressed firmly enough against the paper-sharp
spikes at the corners
20. RATE
• Formula 1: 300/number of big squares
between R-R
• Formula 2: 1500/small squares between R-R
• For irregular heart rates ,get the number of
QRS complexes in a 6-second strip;then
multiply by 10
47. HR->100BPM- ADULT PATIENT may be as high as 150bpm.
Rhythm-regular
DANGEROUS-IHD,MS,AS,OBSTRUCTIVE CARDIOMYOPATHY
48. CAUSES
• PHYSIOLOGICAL;excitement,exertion,pregnancy,pain,fever
• Lighter planes of anaesthesia
• DRUGS
• Cardiac vagal tone blockers(atropine,and other
anticholinergic agents)
• Sympathetic tone stimulants-(eg-
epinephrine,norepinephrine,dopamine,cocaine,amphetami
nes,ketamine,ether,pancuranium.
• Hypotension.
• Hyperthyroidism
• Pheochromocytoma
49. MANAGEMENT
• The underlying cause should be treated.
• Hypovolemia and lighter planes of anaesthesia
are the most common causes.
• In patient with ischemic and stenotic valvular
disease
• B adrenergic blockers.
57. • Origin is from a site in the atria other than the
SA node.
• Rate <100/min
• Rhythm-irregular
• P wavw –abnormal
• Printreval-variable
• QRS –normal configuration
• Incomplete compensatory pause
62. MANAGEMENT
• Hemodynaically stable,then
amiodarone,administered in one or more
doses of 150mg given iv in 100ml saline or
D5W over 10 minutes ,followed by an iv
infusion of 1 mg/min for 6 hours and
0.5mg/min thereafter.
• Hemodynamically unstable-synchronised
cardioversion (200J)
64. • A form of polymorphic VT
• RATE 150-200
• Rhythm may be irregular
• P waves absent
• Qrs complexes-wide appears twisting around a
central axis
• Can occur in patients with prolonged qt intrevel
• Responds to iv magnesium
• If unstable-electrical defibrillation
72. PERIOPERATIVE MYOCARDIAL
INFARCTION
• Defining PMI,however is often difficult because most
PMIs occur without clinical symptoms in
anaesthetiszed and sedated patients.
• ECG changes are subtle and or transient,the creatine
kinase –MB iso enzyme has limited sensitivity and
specificity because of co existing skeletal muscle
injury.
• The majority of patients with an acute MI will have
elevation in troponins within 2-3 hours of MI
• CTnl has been shown to be exclusive to cardiac muscle.
73. PATHOPHYSIOLOGY
– Two distinct mechanisms may lead to PMI
• Acute coronary syndrome.
• Prolonges myocardial oxygen supply demand
imbalance in the presence of stable coronary
artery disease,designated type 1 and type 2 by
the universal definition of MI.
74. ACUTE CORONARY SYNDROME
(TYPE 1 PMI)
• Acute coronary syndrome occurs when an
unstable or vulnarable plaque undergoes
spontaneous rupture,fissuring or erosion,leading
to acute coronary thrombosis,ischemia,and
infarction.
• Serial cTn concentration are necessary to
distinguish acute from chronic myocardial
injury,and preoperative cTn concentrations from
the interpretation of postoperative measurments.
76. • Leads to Increased coagulability and
decreased fibrinolysis .
ACUTE CORONARY THROMBOSIS
ACS-TYPE-1 MI
77. SEVERE ,YET STABLE CAD
• Increased sympathetic hyperactivity ,post
operative pain ,withdrawl of b-blockers leads
to increased myocardial 02 demand and
decreased 02 supply thereby leads to increase
in heart rate/arrythmia.
PROLONGED ST DEPRESSION ISCHEMIA>> TYPE II MI
78. NON –CARDIAC SURGERY
BASELINE RISK +INTRAOPERATIVE FACTORS
SURGICAL TRAUMA
INFLAMMATION/CYTO
KINE RELEASE
PLATELET ACTIVATION
CATECHOLAMINE/COR
TISOL
SURGE/BLEEDING
HYPERTENSION
HYPOTENSION
TACHYCARDIA
BRADYCARDIA
HYPOXEMIA
ANEMIA
HEART
FAILURE
SEPSIS
RENAL
FAILURE
VOLUME
OVERLOAD
PULMONARY
EMBOLISM
VALVULAR
HEART
DISEASES
NON ISCHEMIC
MYOCARDIAL
INJURY
ATHEROSCLEROTIC
CORONARY PLAQUE
DISRUPTION
MYOCARDIAL
OXYGEN
DEMAND
MISMATCH WITH
STABLE CAD
MYOCARDIAL INJURY AFTER NON-CARDIAC SURGERY
79. ECG CRITERIA TO DIAGNOSE
ACUTE MYOCARDIAL ISCHEMIA
• Atleast 2 anatomical contiguous lead with
the following
1. ST elevation at the J point of atleast1mm (depending on location)
2. ST DEPRESSION of atleast 0.5 mm and or T wave inversion of atleast
1mm
80.
81. ACUTE MI
• MI is defined as myocardial cell death due to prolonged
myocardial ischemia.It is diagnosed by a rise of cardiac
biomarker value above the 99th percentile limit with at least 1
of the following
1. Symptoms of ischemia
2. New ST segment T wave changes or new left bundle branch
block
3. New pathological Q waves
4. Imaging evidence of new loss of viable myocardium or new
regional wall motion abnormality
5. Identification of an intracoronary thrombus by angiography or
autopsy OR;cardiac death with symptoms suggestive
myocardial ischemia.
82. NON SURGICAL MI
1. Typical presentation
,hence early
diagnosis
1. Commonly occurs
outside the hospital
2. ST segment elevation
3. Q wave MI
4. Atherosclerotic
thrombus
obstructing coronary
artery
PERIOPERATIVE MI
1. Mostly silent,Atypical
presentation and
difficult to diagnose
2. Usually in the
hospitalised patients
within few days of
surgical procedure
3. ST segment
depression
4. None Q wave MI
5. Mismatch between
oxygen supply and
demand
83.
84. INTRAOPERATIVE MONITORS
FOR ISCHEMIA
ELECTROCARDIOGRAPHY
MYOCARDIAL ISCHEMIA
DRUG EFFECTS(DIGITALIS)
MYOCARDIAL ISCHEMIA
CONDUCTION CHANGES
LEFT VENTRICULAR HYPERTROPHY
PULMONARY CAPILLARY WEDGE PRESSURE
•MYOCARDIAL ISCHEMIA
•MITRAL REGURGITATION
•INCREASE IN AFTERLOAD
•DECREASE IN PULMONARY COMPLIANCE
TRANSESOPHAGEAL ECHOCARDIOGRAPHY
• Myocardial ischemia
• Acute hypovolemia
• Pre existing myocardial disease
85.
86. MANAGEMENT OF MYOCARDIAL
ISCHAEMIA IN NON CARDIAC
SURGICAL PATIENTA
1. CONFIRM DIAGNOSIS
• Obtain 12 lead ECG
• Consider transoesophageal or transthoracic
echocardiogram if hemodynamic instability is
detected.
• Obtain baseline and 4 hour troponin levels.
87. OPTIMISE MYOCARDIAL
OXYGEN SUPPLY AND DEMAND
BALANCE
• Pause the surgery if appropriate while the situation is stabilized
• Achieve physiologic goals as mentioned earlier;low/normal heart
rate,normal blood pressure,normal oxygen saturations with the least
FIO2 possible,avoid hypothermia,avoid excessive fluid.
• Administer medications ;beta blockers to achieve low or normal
heart rate provided no hypotension,consider giving aspirin (via
nasogastric tube if under general anaesthesia)and a glyceryl
trinitrate infusion
• Consider use of intra-aortic balloon pump,as guided by
cardiologisits.
89. PROVEN INDICATIONS FOR
REVASCULARISATION
• Significant left main disease
• 3 vessel CAD and LV dysfunction
• 2 vessel CAD with proximal LAD
involvement
• Intractable ischemia
90.
91. • CONSIDER ABANDONING SURGERY
This will be situation-specific and involve a multidisciplinary
discussion.consider include the following
1. How unstable is the patient?
2. How urgent is the surgery?
3 .Can the surgery stio rapidly if the patient deteriorates?
If the surgery is continued ,having an experienced surgeon to
ensure shortest surgical time might be benefit to the patient.
92. CONSULT CARDIOLOGIST
• If the evidence of ST elevation MI is present
on ECG,or there is haemodynamic instability
,emergent cardiologist opinion is
recommended to consider need for PCI
• Thrombolysis is usually contraindicated if
surgical incision has been made except in
minimally invasive surgeries.
93. POST OPERATIVE
CONSIDERATONS
1. Postoperative management will be patient specific but
considerations include-
• Postoperative placement ;consider more intensive monitoring as
appropriate ,including need for telemetry.
• Consider need for seriel ECG monitoring or troponin depending on
index of suspicion of MI
• Ensure cardiology follow up or in-patient review if infarct is
suspected.
• Ensure good analgesia,euvolaemia.and the ddition of beta
blockers(blood pressure allowing )to minimise tachycardia.
• Maintain normal oxygen saturations with judicious oxygen
therapy.
• Commence aspirin and consider PGY12 inhibitor as guided by
cardiology opinion.
