Back To Basics: Cardiology Review I

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Back To BasicsCardiology Review I

• Michael Froeschl, MD FRCPC
• Assistant Professor of Medicine

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Overview

• CAD
• Atherosclerosis
• Stable Obstructive CAD
• Unstable CAD Acute Coronary Syndrome
• ECG/Arrhythmia
• Review
• Bradydysrhythmias
• Tachydysrhythmias
• Syncope

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NB Key Feature Questions

• Learn how to answer them!

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1. Two Concepts

• Ischemia Tissue oxygen demand exceeds tissue
  oxygen supply
• Infarction Tissue necrosis secondary to tissue
  ischemia

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1. Supply-Demand Mismatch

• ? Supply
• Coronary obstruction
• Microvascular obstruction
• ? Perfusion pressure
• ? PaO2
• ? Hemoglobin

• ? Demand
• ? Heart Rate
• ? Contractility
• ? Wall Tension

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1. CAD
Obstructive CAD ACS
Atherosclerosis
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1a. Atherosclerosis Targets

• Mode-of-Life Issues
• Smoking
• Diet
• Exercise
• Alcohol
• Stress

• Medical Issues
• Dyslipidemia
• Hypertension
• Diabetes Mellitus
• Obesity

INTERHEART, Lancet 2004
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1a. Atherosclerosis Targets

• Vascular Protection
• ASA
• Statins
• ACE-Inhibitors or ARBs
• Beta-Blockers

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1b. Stable Obstructive CAD

• Usual manifestation is Angina Pectoris
• (strangling) chest pain secondary to myocardial
  ischemia

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1b. Stable Obstructive CAD DX

• Clinical assessment in all
• Chest Pain
• Sqeezing retrosternal
• Brought on by stress
• Relieved by rest or NTG
• Patient (age, gender, vascular risk)
• Physical exam and basic blood work

3/3 Typical anginal CP 2/3 Atypical anginal
CP 0-1/3 Non-anginal CP
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1b. Stable Obstructive CAD DX

• Testing in some (for diagnosis and prognosis)
• Functional Assessment (stress test)
• Exercise ECG
• Dipyridamole Perfusion Scan
• Dobutamine Echocardiogram
• Anatomical Assessment
• Coronary Angiography (conventional, CT)

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1b. CCS Angina Severity Scale

• I Ordinary activity does not cause angina
  angina only with increased activity
• II Slight limitation of ordinary activity (gt 2
  blocks level, gt 1 flight of stairs)
• III Marked limitation of ordinary activity (lt 2
  blocks level, lt 1 flight of stairs)
• IV Inability to carry out any activity without
  discomfort symptoms may be present at rest

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1b. Stable Obstructive CAD MX

• Vascular Protection (ASA, statin, ACE-I/ARB)
• Beta-Blocker (non-DHP CCB if not tolerated)
• NTG
• Address Risk Factors
• Possibly Revascularize (PCI or CABG)

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1c. Acute Chest Pain

• Management
• ABC
• Vitals
• IV, O2, Monitor

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1c. Acute Chest Pain DDX

1. Myocardial Ischemia
2. PE
3. Aortic Dissection
4. Pneumothorax
5. GI Rupture
6. Other (pericarditis, pneumonia,
   GERD/PUD/gastritis, MSK, skin)

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1c. Acute Myocardial Ischemia

• ? Supply
• Coronary obstruction
• Microvascular obstruction
• ? Perfusion pressure
• ? PaO2
• ? Hemoglobin

• ? Demand
• ? Heart Rate
• ? Contractility
• ? Wall Tension

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1c. Acute Coronary Syndrome

• Definition myocardial ischemia due to acute
  coronary insufficiency
• 90 due to plaque rupture, thrombus /- spasm

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1c. Two Manifestations of ACS
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1c. Two Manifestations of ACS

• Complete Coronary Occlusion
• No blood flow beyond
• Transmural ischemia
• ST-elevation on ECG
• Localizes
• Reciprocates

• Threatened Coronary Occlusion
• Decreased blood flow
• Subendocardial ischemia
• ST-depression or normal
• Not localizing
• No reciprocal ST ?

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1c. ACS
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49M with chest pain X 1 hour
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1c. STEMI

• ABC Vitals IV, O2, Monitor
• HX, O/E, ECG STEMI
• Acute reperfusion therapy (ART) lytics vs PPCI
• ASA, NTG, BB (if safe), clopidogrel,
  anti-coagulation (UFH), morphine

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1c. STEMI

• Contraindications to Lytics
• 90-min assessment
• CP
• ECG
• /- Reperfusion Arrhythmia

1. Hemorrhagic stroke ever
2. Ischemic stroke lt 3 mos
3. Intracranial AVM
4. Intracranial malignancy
5. Head trauma lt 3 mos
6. Active bleeding
7. Aortic dissection

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1c. NSTE ACS

• ABC Vitals IV, O2, Monitor
• HX, O/E, ECG NSTE ACS
• ASA
• Risk Stratify (HX, PE, ECG, TNT)
• Treat accordingly

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Risk Assess High Interm Low
HX Ongoing CP CPgt20 min resolved New/progrCCS 3-4
O/E ?BP, S3, MR, rales N N
ECG ST? trans ST? T inv N
TNT gt0.1 0.01-0.1 lt0.01
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TX High Interm Low
Admit? Yes Yes No
RX ASA NTG BB clopidogrel ?-coag GP 2B3A-I ASA NTG BB clopidogrel ?-coag ASA NTG SL BB
IX Coronary Angio Inpt stress Outpt stress
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1c. Complications Post-MI

• Recurrent ischemia
• HF/shock
• Arrhythmia
• Mechanical
• Thromboembolic
• Pericarditis
• Depression

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1c. Prognosis Post-MI

• LV systolic function remains the most important
  determinant of prognosis post-MI
• Usually assessed by means of echocardiogram prior
  to discharge

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1c. Secondary Prevention RX

• ASA in all
• Statin in almost all (LDL lt 2)
• ACE-I in most
• Beta-Blocker
• NTG if angina
• Clopidogrel x 1 year post-ACS, post-stent
• Treat risk factors

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1c. Secondary Prevention Life

• Smoking
• Diet
• Exercise
• Weight
• Alcohol
• Stress

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2. ECG EKG

• Identify the study
• Setting
• Technical Details
• Read rate, rhythm, axis, alphabet
• Interpret
• Previous

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2a. Electrical Anatomy
The heart is a pump coordinated and powered by an
integral electrical system
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2a. Electrical Anatomy
The SA Node has the steepest slope of spontaneous
Phase 4 depolarization and therefore is the
dominant pacer
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2a. Electrical Anatomy
Atrial depolarization normally flows from top to
bottom and from right to left
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2a. Electrical Anatomy
The AV Node delays then relays electrical
activation to the ventricles
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2a. Electrical Anatomy
The His-Purkinje System conducts electrical
activation to all areas of both ventricles
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2a. Electrical Anatomy

• Three phases of ventricular depolarization
• Septum L?R
• (atrial repolarization occurs simultaneously)

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2a. Electrical Anatomy
2. Depolarization of both ventricles
simultaneously from endocardium to epicardium
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2a. Electrical Anatomy
Ventricular repolarization ensues, from
epicardium to endocardium
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2a. The 12-Lead ECG
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2a. PQRSTU
QRS
Segments
Intervals
PR
ST
TP
PR
QT
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2a. PQRSTU
PR
ST
TP
Segments
Intervals
PR
ST
PR
QT
QRS
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2a. Reading an ECG

1. Rate
2. Rhythm
3. Axis
4. Alphabet

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1. Rate Count-Off Method
Start
150
75
Normal Rate 60-100 bpm
100
60
300
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2. Rhythm

• Normally, the sinus node controls the entire
  heart
• This is known as Normal Sinus Rhythm (NSR)
• P wave axis is normal (0-90)
• Each P is followed by a QRS
• Each QRS is preceded by a P

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3. QRS Axis

1. If QRS in I AND II, QRS axis is normal
2. If QRS not in I AND II, you must calculate QRS
   axis
3. To do so, use leads I and aVF to identify the
   90-quadrant
4. Then use the isoelectric lead to quantify QRS
   axis (to nearest 30)

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4. Alphabet

• P waves
• PR (segments and intervals)
• QRS (Qs, height, width)
• ST segments
• T waves
• QT interval

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Arrhythmia Dysrhythmia

1. Slow
2. Fast
3. Normal rate

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2b. Bradydysrhythmias

• Sinus Node
• Sinus brady, pause, arrest, block
• AV Node
• 2 AVB (Type I and Type II)
• 3 AVB

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2b. AV Block
Nodal 1 AVB 2 AVB I 3 AVB
Infra-Nodal 2 AVB II 3 AVB
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2b. AV Block

• Nodal AVB is more benign because
• Causes are often functional (as opposed to
  infranodal block which is almost always
  structural)
• If progression to CHB, nodal escapes available

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90F presents with fatigue
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2c. Tachydysrhythmia
SVT NCT WCT
VT WCT
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2c. NCT

• Regular Irregular
• AVN-Indep AVN-Dep AF
• ST AVNRT MAT
• AFL AVRT AFL/AT
• AT variable block

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75F to ER with palpitations
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25F to ER with palpitations
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72M without symptoms
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2c. Atrial Fibrillation 2 Issues

• Symptoms
• Rate Control
• (BB, CCB, dig)
• vs
• Rhythm Control
• (e.g. amiodarone)

• Stroke Risk (CHADS2)
• CHF/LVEF lt 35 1
• Hypertension 1
• Age gt 75 1
• Diabetes 1
• Stroke (embolic) 2

2 OAC 1 ASA or OAC 0 ASA
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2c. WCT

• VT
• AV Dissociation
• Fusion/Capture Beats
• Bizarre QRS Axis
• Wide QRS
• QRS Concordance

• DDX
• SVT Aberrancy
• Accessory Pathway
• Pacemaker
• Bundle Branch Block
• Metabolic derangement

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66M prior MI with palpitations
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2c. Torsades de Pointes

• Polymorphic VT due to a long QTc (often with a
  characteristic appearance)
• Causes
• Congenital
• Acquired
• Electrolyte disturbances (Hypo K, Ca, Mg)
• Drugs (antipsychotics, antidepressants,
  antibiotics, antiarrhythmics)
• Other

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3. Syncope
Neurocardiogenic CSH Vasovagal Situational
Pipes Subclavian Steal VBI Migraine
Pump Obstruction Arrhythmia
Fluid Hypovolemia
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Questions?