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Fundamentals of ECG, Part 4 Now test yourself MCQs
Fundamentals of ECG · MBBS / Medicine · 23 practice questions
- ECG interpretation - clinical vignette correlation
- ECG rhythm and axis interpretation across cases
- ECG pattern recognition - rhythm and infarction correlation
- ECG diagnosis correlated with clinical scenario
- Chest pain radiating to back - differential of aortic dissection vs MI
- ECG interpretation - coarctation of aorta and LVH
- Anterolateral STEMI - localization and timing
- LBBB with angina and dizziness - aortic stenosis
1. An elderly woman with known heart failure on furosemide and digoxin presents feeling generally unwell and nauseated. Her ECG shows an irregular narrow-QRS rhythm with a well-controlled ventricular rate, downward-sloping ST segments in the lateral chest leads, and U waves in V2. Which of the following is the most appropriate immediate investigation?
- A24-hour ambulatory ECG monitoring
- BSerum potassium level
- CThyroid function tests
- DSerum digoxin level only
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B. Serum potassium level The combination of nausea in a patient on digoxin with ECG evidence suggesting hypokalaemia (U waves) points to digoxin toxicity precipitated by diuretic-induced hypokalaemia, so urgent serum potassium must be checked and corrected. A digoxin level alone would not address the reversible precipitant (hypokalaemia) that needs urgent correction. Thyroid function tests are relevant for finding the cause of the atrial fibrillation but are not the most urgent immediate step given her acute symptoms of toxicity. Ambulatory monitoring is unnecessary since the rhythm has already been captured and the priority is addressing suspected toxicity.
2. A 58-year-old man presents with ongoing central chest pain. His ECG shows sinus rhythm at 81 bpm, normal conduction intervals, normal QRS complexes, ST depression in lead V4, and T-wave inversion in leads VL and V2-V4, consistent with an anterior NSTEMI of uncertain age. Which of the following is the most appropriate immediate combination of treatments for this patient?
- AUrgent CT aorta followed by surgical repair if dissection is confirmed
- BPain relief, oxygen, beta-blocker, nitrate, aspirin, ticagrelor and low-molecular-weight heparin
- CImmediate permanent pacemaker insertion plus aspirin and a beta-blocker
- DImmediate thrombolysis with alteplase plus aspirin and a beta-blocker
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B. Pain relief, oxygen, beta-blocker, nitrate, aspirin, ticagrelor and low-molecular-weight heparin The source states this man must be admitted and given pain relief and oxygen, anti-ischaemic medications (beta-blockers and nitrates), anti-thrombotic agents (aspirin and ticagrelor) and anticoagulation (LMWH) for anterior NSTEMI. A permanent pacemaker is the management for complete heart block (a different ECG), not NSTEMI. Thrombolysis is reserved for STEMI, not NSTEMI, where ST depression rather than elevation is present. CT aorta is used when aortic dissection is suspected, which is not indicated here since this is an NSTEMI picture.
3. A 68-year-old man presents with exertional chest tightness and dizziness on exertion. His ECG shows normal sinus rhythm, a normal PR interval, and wide QRS complexes with an 'M' pattern in the lateral leads with inverted T waves in those leads. Which of the following is the most appropriate next step in management?
- ACoronary angiography to assess for underlying coronary artery disease
- BUrgent investigation with a view to early aortic valve replacement
- CExercise tolerance testing to confirm inducible ischaemia
- DReassurance that the T wave inversion is a benign finding of no further significance
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B. Urgent investigation with a view to early aortic valve replacement The ECG shows LBBB (M pattern in V6), and angina combined with dizziness on exertion should raise suspicion for aortic stenosis, which can cause angina even with normal coronary arteries and carries a high risk of sudden death when dizziness occurs on exertion - this mandates urgent investigation and consideration of valve replacement. Exercise testing is inappropriate and potentially dangerous in suspected severe aortic stenosis. Reassurance is wrong because although LBBB T wave inversion itself is not significant, the underlying combination of symptoms is highly concerning and must be investigated, not dismissed. Coronary angiography alone would miss the more urgent diagnosis of valvular disease suggested by the symptom combination, and in the presence of LBBB the ECG cannot be assessed for ischaemia anyway.
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