{'fraction_non_alphanumeric': 0.02629757785467128, 'fraction_numerical': 0.007612456747404845, 'mean_word_length': 5.127118644067797, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A Patient With Hypertrophic Cardiomyopathy Presenting in Cardiac Arrest.

A man in his 40s with self-reported hypertrophic cardiomyopathy, hypertension, and obstructive sleep apnea presented in cardiac arrest owing to ventricular tachycardia/fibrillation. He reported feeling unwell on the afternoon of presentation with dizziness and blurry vision, and then abruptly lost consciousness with seizure-like activity. On the arrival of emergency services, he was found to be pulseless with a rhythm of ventricular fibrillation; he was resuscitated with return of spontaneous circulation, intubated, and brought to the emergency department where cooling was initiated. His initial electrocardiogram (ECG) is shown in the Figure, A. Questions: What is the rhythm? Interpretation This ECG demonstrates a sinus rhythm at a rate of 47. The PR interval is prolonged at 204 milliseconds (ms). There is left anterior fascicular block, as evidenced by qR complexes in leads I and aVL, and rS complexes in leads II, III, and aVF. The axis is borderline leftward at −30 degrees with left atrial abnormality. This ECG was initially interpreted as a sinus bradycardia with a long QT interval and U wave owing to cooling. Further investigation revealed second degree 2:1 atrioventricular (AV) block—after each QRS complex, there is a second P wave with the same morphology and not followed by a QRS complex. This second P wave was initially misinterpreted as the