case_images: PMC10907803_01
case_images: Preoperative EKG showing normal sinus rhythm. There is no evidence of conduction disease, heart block, or significant ischemic changes on the EKG.
case_images: cureus-0016-00000053347-i01.jpg
case_images: PMC10907803_01_cureus-0016-00000053347-i01.jpg
case_images: FIG1
case_images: An EKG showed normal sinus rhythm, no significant ST-T changes, and no concern for conduction abnormalities (Figure 1).
case_images: Intraoperative TEE demonstrating significant septal bulge and transvalvular systolic gradient across the AV. A: Septal bulge (red arrow) with reduced systolic LVOT diameter (red bracket) at 0.81 cm (normal >2 cm);  B: Continuous wave Doppler across AV during systole. Subvalvular LVOT gradient at 84 mmHg (normal <30 mmHg) consistent with LVOT obstruction in the setting of septal HOCM. The interventricular septum diameter was 2 cm (not measured on the image).. TEE: Transesophageal echocardiogram, LVOT: Left ventricular outflow tract, AV: Aortic valve, HOCM: Hypertrophic obstructive cardiomyopathy
case_images: cureus-0016-00000053347-i02.jpg
case_images: PMC10907803_01_cureus-0016-00000053347-i02.jpg
case_images: FIG2
case_images: A subsequent transesophageal echocardiogram (TEE) before surgery demonstrated a calcific and restricted AV with an LVOT pressure gradient of 84 mmHg and a preserved ejection fraction (Figure 2). A preoperative left-heart catheterization revealed non-obstructive coronary artery disease.
case_images: Leads 2 and 3 on POD 2 telemetry demonstrating CHB developing into asystole (red brackets) and cardiac arrest. POD: Postoperative day, CHB: Complete heart block
case_images: cureus-0016-00000053347-i03.jpg
case_images: PMC10907803_01_cureus-0016-00000053347-i03.jpg
case_images: FIG3
case_images: Her telemetry monitor showed asystole/CHB (Figure 3).
case_images: Hematoxylin and eosin stain of the myocardial septum after surgery. The histopathological examination revealed focal scarring with neutrophilic infiltration (Aschoff bodies indicated by the red arrows), consistent with the history of rheumatic heart disease, with no overt evidence of hypertrophic cardiomyopathy. Light pink areas indicate fibrosis, dark pink regions suggest cardiomyocytes, and the blue specks mark the nuclei.
case_images: cureus-0016-00000053347-i04.jpg
case_images: PMC10907803_01_cureus-0016-00000053347-i04.jpg
case_images: FIG4
case_images: Histopathology slides from the operation resulted later in the hospital course, showing focal scarring with neutrophilic infiltration of the atrioventricular node in the septum, consistent with a history of rheumatic heart disease (Figure 4).