PMC10308008_01
Twelve-lead synchronous ECG shows sinus node conduction abnormalities. (A) An increase in the P-P intervals and the rhythm of <60 beats/min represent sinus bradycardia (take longer horizontal red arrow blue in the lead II as the example); the third P-wave (P') in all 12 leads that occurred earlier indicates premature atrial beats (take shorter horizontal blue arrow in the lead II as the example). (B) A single missed beat occurred between the third and fourth P-waves, but the increase in P-P interval is twice as long as the previous P-P intervals in all 12 leads (take longer horizontal green arrow in the lead II as the example), indicating the occurrence of type II second-degree sinoatrial block. ECG, electrocardiogram.
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F1
Previous medical records showed temporary sinus bradycardia with premature atrial beats on electrocardiogram (ECG) (Figure 1A), which spontaneously recovered to a normal rhythm after rest. ECG showed a type II second-degree sinoatrial block (Figure 1B).
Morphological and histological examination of the heart. (A) Small off-white tubercles dotted the epicardium of the right auricle and right atrium. (B) The cut section of the myocardium of the interventricular septum and the anterior wall of the left ventricle shows whitish lesions (black arrow). (C) Several caseating epithelioid granulomas infiltration (black arrow) around the sinoatrial node artery (black triangle) using HE staining. (D) Numerous caseating necrotizing epithelioid cell granulomas in the myocardium of the left ventricle using HE staining. HE, hematoxylin-eosin staining.
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F2
The autopsy revealed that the epicardium of the right auricle and right atrium were studded with slightly off-white tubercles (Figure 2A). The cut surface of the myocardium showed irregular gray-white lesions on the ventricular wall (Figure 2B). Histological examination of the sinus node region revealed granulomas, focal fibrosis, and fatty infiltration (Figure 2C). The myocardium also showed a broad context of fibrosis with infiltrated lymphocytes, many Langhans giant cells, and caseating epithelioid granulomas (Figure 2D).
Positive Ziehl-Neelsen staining for tubercle bacilli in both lungs (oil immersion).
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F3
Tubercle bacilli were detected in the granulomatous areas of the lung tissue using Ziehl-Neelsen (ZN) staining (Figure 3).