MS-0459
A study investigates a novel diagnostic test for myocardial infarction (MI) in elderly patients. What metric would indicate the proportion of elderly patients without MI who received a negative test result?
Archives: Medical Student Years 1-3
MS-0437
A 45-year-old patient presents to the emergency department with increasing dyspnea on exertion and swelling in both legs. A recent outpatient echocardiogram revealed a left ventricular ejection fraction of 31%. During chest examination, an extra heart sound is detected just prior to the first.
What is the cause of this additional heart sound?
MS-0438
A 67-year-old man is admitted for a below knee amputation. He is taking digoxin. The patient presents with an irregularly irregular pulse. What would be your expectation when examining the jugular venous pressure?
MS-0439
Following a minor heart attack, how does atorvastatin work to reduce the risk of a subsequent MI in a 65-year-old patient?
MS-0440
A 56-year-old male comes to your clinic complaining of occasional chest pain that usually occurs after meals and typically subsides within a few hours. He has a medical history of bipolar disorder, osteoarthritis, gout, and hyperparathyroidism. Currently, he is undergoing a prolonged course of antibiotics for prostatitis.
During his visit, an ECG reveals a QT interval greater than 520 ms.
What is the most likely cause of the observed ECG changes?
– Lithium overdose
– Paracetamol use
– Hypercalcemia
– Erythromycin use
– Amoxicillin use
Explanation: The most probable cause of the prolonged QT interval is erythromycin use, which is commonly associated with this ECG finding. Given the patient’s medical history, it is likely that he is taking erythromycin for his prostatitis. Amoxicillin is not known to cause QT prolongation. Lithium toxicity typically presents with symptoms such as vomiting, diarrhea, tremors, and agitation. Hypercalcemia is more commonly associated with a short QT interval, making it an unlikely cause. Paracetamol is not known to cause QT prolongation.
MS-0441
Electrophysiology studies are being conducted in a young boy with suspected Wolff-Parkinson-White syndrome, who has experienced recurrent episodes of sudden palpitations. The procedure involves catheterization within the heart to evaluate the electrical activity and determine the conduction velocity of various parts of the conduction pathway.
Which segment of this pathway exhibits the highest conduction velocity?
MS-0442
A 24-year-old male patient arrives at the emergency department complaining of dizziness and palpitations. Upon triage, cardiac monitoring reveals supraventricular tachycardia with a heart rate of 200 beats per minute. This rapid heart rate is facilitated by the specialized cells and nerve fibers in the heart that conduct action potentials during systole.
What type of cells and nerve fibers in the heart have the highest conduction velocities?
MS-0443
A 67-year-old man presents to the emergency department with chest pain. He describes this as crushing central chest pain which is associated with nausea and sweating.
Blood results are as follows:
Hb 148 g/L Male: (135-180)
Female: (115 – 160)
Platelets 268 * 109/L (150 – 400)
WBC 14.6 * 109/L (4.0 – 11.0)
Na+ 136 mmol/L (135 – 145)
K+ 4.7 mmol/L (3.5 – 5.0)
Urea 6.2 mmol/L (2.0 – 7.0)
Creatinine 95 µmol/L (55 – 120)
Troponin 4058 ng/L (< 14 ng/L)
An ECG is performed which demonstrates:
Current ECG Sinus rhythm, QRS 168ms, dominant S wave in V1
Previous ECG 12 months ago No abnormality
Which part of the heart’s conduction system is likely to be affected?
MS-0444
An 82-year-old woman visits her doctor with a medical history of myocardial infarction that has resulted in permanent damage to the conduction system of her heart. The damage has affected the part of the conduction system with the highest velocities, causing desynchronisation of the ventricles.
What is the part of the heart that conducts the fastest?
MS-0445
What is the average stroke volume in a resting 75 Kg man?