This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
[{'content': 'ECG feature of acute cor pulmonale (e.g. Pulmonary embolism) \nSelect and explain. \nA. S1Q3T3 pattern, B. Slow "r" wave progression in leads V1 to V4, C. Atrial fibrillation, D. All of the above three', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. d (All of the above three) (Ref. H-17th/139l).Harrison-17th/p. 1391:ECG in Acute cor pulmonale due to pulmonary embolism# Normal ECG may be seen# Sinus tachycardia (most common arrhythmia)# Tachyarrhythmias, such as atrial fibrillation or flutter# The QRS axis may shift to the right, sometimes in concert with the so-called S1Q3T3 pattern (prominence of the S wave in lead I, Q wave in lead III, with T-wave inversion in lead III).# Acute right ventricular dilation may also be associated with slow R-wave progression and T-wave inversions in V1 to V4 simulating acute anterior infarction.# A right ventricular conduction disturbance may appear.Chronic cor pulmonale due to obstructive lung disease# Usually does not produce the classic ECG patterns of right ventricular hypertrophy.# Instead of tall right precordial R waves, chronic lung disease more typically is associated with small R waves in right-to-midprecordial leads (slow R-wave progression) due in part to downward displacement of the diaphragm and the heart.# Low-voltage complexes are commonly present, owing to hyperaeration of the lungs.Characteristic ECG features of few conditionsDigitalis intoxication# "Hockey stick" pattern # short QT interval # Scooping of ST-T wave complexSAH# CVA T wave pattern.Hypercalcemia# Short ST segment and reduced QT intervalHypocalcemia# Prolonged QT intervalTCA overdose# QRS and QT prolongation with sinus tachycardiaHypothermia# Convex jump at J point (Osborn wave)Hypokalemia/ Quinidine excess# Prolonged QT, prominent U waves and susceptible to torsadesHyperkalemia# Tenting of T-waves (r) wide QRS interval and reduced P wave amplitude, prolonged PR interval (r) Sine-wave pattern (r) asystole.Acute cor pumonale# S1Q3T3 pattern# Slow "r" wave progression in leads V1 to V4# Atrial fibrillationWPW# Wide QRS complex# RR interval is Relatively short# Wave delta (Slurring of the initial part of the QRS).ALSO KNOW# P wave = represents atrial depolarization# QRS complex = represents ventricular depolarization# ST-T-U complex (ST segment, T wave, and U wave) = represents ventricular repolarization.# J point = is the junction between the end of the QRS complex and the beginning of the ST segment.# There are four major ECG intervals: R-R, PR, QRS, and QT.- The heart rate (beats per minute) can be readily computed from the interbeat (R-R) interval by dividing the number of large (0.20 s) time units between consecutive R waves into 300 or the number of small (0.04 s) units into 1500.- The PR interval measures the time (normally 120-200 ms) between atrial and ventricular depolarization, which includes the physiologic delay imposed by stimulation of cells in the AV junction area.- The QRS interval (normally 100-110 ms or less) reflects the duration of ventricular depolarization.- The QT interval includes both ventricular depolarization and repolarization times and varies inversely with the heart rate. A rate-related ("corrected") QT interval, QTc, can be calculated and normally is 0.44 s. (Some references give QTc upper normal limits as 0.43 s in men and 0.45 s in women.)', 'role': 'assistant'}]