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151

What are the indications for CTCA outside of chest pain?

Evaluation of suspected coronary anomalies/complex congenital heart disease.

Exclusion of CAD in new-onset heart failure/cardiomyopathy.

Assessment of CABG patency and vascular mapping before repeat CABG surgery.

Exclusion of significant CAD before non-coronary cardiac surgery.

Investigation of left bundle branch block for suspected CAD as an aetiology.

152

What is the most appropriate application of CTCA?

It is used most appropriately in symptomatic patients with low to intermediate pretest probability of CAD.

153

When should CTCA not be used?

It should not be used in asymptomatic subjects, patients with known significant CAD or patients with a high pretest probability of CAD.

154

How does the radiation dose of CTCA compare with invasive coronary angio?

The radiation dose of CTCA was previously two to three times that of invasive coronary angiography but with modern protocols, it is similar or lower.

155

What are the absolute contraindications to thrombolysis?


    Any previous history of hemorrhagic stroke
    History of stroke, dementia, or central nervous system damage within 1 year
    Head trauma or brain surgery within 6 months
    Known intracranial neoplasm
    Suspected aortic dissection
    Internal bleeding within 6 weeks
    Active bleeding or known bleeding disorder
    Major surgery, trauma, or bleeding within 3 weeks
    Traumatic cardiopulmonary resuscitation within 3 weeks

156

What are the indications for digoxin?

CHF (regardless of side) particularly due to chronic overload and supply of energy is not impaired (i.e impaired in hypoxia, thiamine deficiency, thyrotoxicosis

AF - depresses conduction in the AV bundle --> slower ventricular beat.  Converts flutter to fibrillation and may restore SR on withdrawal - but not first line.

Not for prevention of paroxysmal AF

157

What does the ECG show?

QRS > 120ms w/ abnormal morphology

Steep R-wave and absent S wave in leads 1 and V6

Deep rapid S wave in V1 (arrow)

Multiple ST segment elevation (mild), and T-wave polarity is opposite to the ventricular complex

LBBB - reversal of interventricular septum activation with delayed impulse to the LV

158

What are the limitations of coronary artery calcium scoring?

Current expert consensus does not recommend CAC measurement in asymptomatic low-risk (a 10-year risk less than 10%) or high-risk (a 10-year risk more than 20%) patients, in those with a documented history of CVD or to establish the presence of obstructive coronary artery disease.

159

What are the indications for coronary calcium scoring?

CAC scoring is only recommended for asymptomatic men aged 45-75 (or women aged 55-75) with an intermediate Framingham score (10-year risk of 10%) in whom a high-risk CAC (more than 100) may prompt a more aggressive approach to risk factor modification. CAC assessment may also be reasonable for assessment of symptomatic patients in the setting of an equivocal treadmill or other functional test.

160

What are the scoring categories of the Framingham Risk Score?

Individuals with low risk have 10% or less CHD risk at 10 years, with intermediate risk 10-20%, and with high risk 20% or more. However it should be remembered that these categorisations are arbitrary.

161

Give a scenario where a coronary calcium score would be useful

The type of clinical situation where CAC scoring can be useful is the following: an asymptomatic 45-year-old male smoker with a systolic BP of 120mmHg, no history of diabetes or hypertension, without left ventricular hypertrophy criteria on ECG, and normal cholesterol (eg, total cholesterol 6.0mmol/L, HDL-C 1.0mmol/L) has a 10-year Framingham risk score of 10% (ie, intermediate risk) and lifestyle measures only would be prescribed.

A high CAC score above 100 AU would yield a post-test probability of more than 2% per year for a coronary event and would move the patient into the high-risk category (a 10-year risk above 20%). Such a patient would require the adoption of aggressive secondary (as opposed to primary) prevention strategies.

Goals for blood pressure and lipid levels may be tightened to those of someone known to have coronary artery disease (eg, LDL-cholesterol less than 1.8mmol/L) and medications, along with lifestyle measures, prescribed.

f the CAC score was either very low (less than 10) or zero, the patient's post-test risk for CHD would be lower than 10% per 10-year period (ie, low risk) and lifestyle-only measurements would be prescribed.

162

What is CHD risk equivalent?

Some patients without known CHD have risk of cardiovascular events that is comparable to that of patients with established CHD. Cardiology professionals refer to such patients as having a CHD risk equivalent. These patients should be managed as patients with known CHD.

CHD risk equivalents are patients with a 10-year risk for MI or coronary death >20%. CHD risk equivalents are primarily other clinical forms of atherosclerotic disease.

The NCEP's ATP III guidelines also list diabetes as a CHD risk equivalent since it also has a 10-year risk for CHD around 20%. NCEP ATP III CHD risk equivalents are:

    clinical coronary heart disease (CHD)
    symptomatic carotid artery disease (CAD)
    peripheral arterial disease (PAD)
    abdominal aortic aneurysm (AAA)
    diabetes mellitus
    Chronic Kidney Disease

163

What are the ECG changes in LVH?

Increased R wave amplitude in the left-sided ECG leads (I, aVL and V4-6) 

Increased S wave depth in the right-sided leads (III, aVR, V1-3).

164

How do you recognise left axis deviation on ECG?

 QRS is positive (dominant R wave) in leads I and aVL
  QRS is negative (dominant S wave) in leads II and aVF

165

What are the causes of left axis deviation?

LVH
Inferior MI
LBBB
WPW

166

What ECG finding is suggestive of left main coronary artery occlusion?

A pattern of widespread ST depression plus ST elevation in aVR > 1 mm is suggestive of left main coronary artery occlusion.

167

What do you make of ST depression localised to a specific territory on ECG?

ST depression localised to a particular territory (esp. inferior or high lateral leads only) is more likely to represent reciprocal change due to STEMI. The corresponding ST elevation may be subtle and difficult to see, but should be sought.

168

When is T-wave inversion considered to be evidence of myocardial ischemia?

        At least 1 mm deep
        Present in ≥ 2 continuous leads that have dominant R waves (R/S ratio > 1)
        Dynamic — not present on old ECG or changing over time

NB. T wave inversion is only significant if seen in leads with upright QRS complexes (dominant R waves). T wave inversion is a normal variant in leads III, aVR and V1.

169

What is Mobitz II heart block?

Significance?

A-V block
PR of constant interval

Constant PR interval until P waved dropped with P-P interval twice normal

Likely to progress to CHB

170

What does the ECG show?

Constant PR interval until P waved dropped with P-P interval twice normal

This the Mobitz II (the bad one)

171

What is Wenkebach block?

Significance?

Lengthening PR interval until P waved dropped with P-P interval variable. Grouped beats.

Need follow up but less likely to progress to CHB

172

What does this ECG show?

ST elevation primarily localised to leads I and aVL is referred to as a high lateral STEMI.
It is usually associated with reciprocal ST depression and T wave inversion in the inferior leads.

Occlusion of the first diagonal branch (D1) of the left anterior descending artery (LAD) may produce isolated ST elevation in I and aVL

Occlusion of the circumflex artery may cause ST elevation in I, aVL along with leads V5-6.

173

What ECG findings are best used to differentiate PE from ACS?

Negative T waves in both leads III and V1 (Part of an RV strain pattern - can be in other right sided things too)

174

How do you recognise right axis deviation?

        QRS is positive (dominant R wave) in leads III and aVF
        QRS is negative (dominant S wave) in leads I and aVL

175

What does the ECG show?

QRS is positive (dominant R wave) in leads III and aVF
QRS is negative (dominant S wave) in leads I and aVL

Right axis deviation

176

How is the cardiac axis defined?


RA is negative
LA is positive

A depolarization wave is always positive on ECG when it is heading toward the left.

V1 and V2 are always negative for this reason and reflect the septum

Leads II and II are the feet leads and are always positive

177

Name the different infarct patterns on ECG

The different infarct patterns are named according to the leads with maximal ST elevation:

        Septal = V1-2
        Anterior = V2-5
        Anteroseptal = V1-4
        Anterolateral = V3-6, I + aVL
        Extensive anterior  / anterolateral = V1-6, I + aVL

178

ECG findings in PE

Sinus tachycardia - the most common abnormality; seen in 44% of patients.

Complete or incomplete RBBB - associated with increased mortality; seen in 18% of patients.

Right ventricular strain pattern –  T wave inversions in the right precordial leads (V1-4) ± the inferior leads (II, III, aVF). This pattern is seen in up to 34% of patients and is associated with high pulmonary artery pressures.

Right axis deviation – seen in 16% of patients. 

Dominant R wave in V1 - a manifestation of acute right ventricular dilatation.

SI QIII TIII  pattern – deep S wave in lead I, Q wave in III, inverted T wave in III. This "classic" finding is neither sensitive nor specific for pulmonary embolism; found in only 20% of patients with PE.

179

What are the causes of acute cor pulmonale (i.e. any disease that causes right ventricular strain / hypertrophy due to hypoxic pulmonary vasoconstriction)?

    Severe pneumonia
    Exacerbation of COPD / asthma
    Pneumothorax
    Recent pneumonectomy
    Upper airway obstruction

180

How do you define a low-voltage ECG?

Peak-to-peak QRS <5mm in the limb leads or <10mm in the precordial leads