Introduction: Thyrotoxicosis typically manifests as a hypermetabolic state characterized by tachyarrhythmias, such as sinus tachycardia or atrial fibrillation. Bradyarrhythmia, specifically atrioventricular block (AVB), is a rare and atypical cardiac manifestation. While Graves’ disease is the leading cause of hyperthyroidism, non-autoimmune etiologies must be considered when thyroid-stimulating antibodies are absent. The exact mechanism for AVB in thyrotoxicosis remains unclear but may involve myocardial inflammation of the conduction system or autonomic dysfunction. Case: A 16-year-old male with no previous medical history presented with a sudden syncopal attack. Clinical evaluation revealed a complete heart block (CHB) in association with biochemical evidence of thyrotoxicosis, requiring a temporary transcutaneous pacemaker insertion. There were no features of Graves’ disease, such as exophthalmos and thyroid acropachy, and further investigation showed a negative thyroid receptor antibody (TRAb) titer with no family history of thyroid disorders. Thyroid ultrasonography showed increased vascularity, while scintigraphy imaging showed diffuse, homogeneous, and increased uptake in both thyroid lobes. The combination of negative serology and the absence of a family history, along with a hyperfunctional state on imaging, likely suggests a rare presentation of sporadic, non-autoimmune, nonfamilial form of thyrotoxicosis. Following the initiation of anti-thyroid therapy, the CHB completely resolved without the need for further cardiological intervention. He achieved a complete clinical remission after a few months and is being planned for radioactive iodine therapy. Conclusion Most of the thyrotoxicosis-associated CHB reported in the literature was due to Graves’ disease or some forms of autoimmune thyrotoxicosis, with auto-antibodies and activated lymphocytes having a role in the pathogenesis of the CHB. CHB in association with a non-autoimmune, non-familial form of thyrotoxicosis is indeed rare, and as this case illustrates, it completely went into spontaneous sinus rhythm upon initiation of conventional anti-thyroid therapy. This rare presentation of CHB is believed to have a benign clinical course.
Thyrotoxicosis ; Heart Block

Human ; Craniocerebral Trauma ; Coronary Artery Disease ; Heart Block ; Heart Failure

The electrocardiographic analysis of heart blocks provides great opportunities for the discussion of mechanisms of electrical cardiac conduction, serving as “teachable moments” in medicine. Recognition of heart blocks can sometimes be a challenge as they can present in many forms, different severities and levels of blocks that present as varied patterns on electrocardiographic tracing. The ultimate key to correct diagnosis rests on adequate understanding of normal electrophysiology of the electrical system of the heart. While it is vital to recognize the pattern, we should always know and understand the physiology behind the pattern. This article presents a detailed analysis of a case of heart block which can easily be misinterpreted on first look. The case is featured not for its rarity but for the interesting concepts in cardiac electrophysiology that are highlighted. Navigation of the different elements of tracing can be an adventure and a great learning experience enjoyed by both students and experts.
Heart Block ; Electrocardiography

OBJECTIVE: To investigate the clinical manifestations and laboratory indicators of anti-Sjögren's-syndrome-related antigen A (SSA) antibody associated fetal cardiac disease. METHODS: Pregnant women hospitalized at Peking University People's Hospital from January 2013 to July 2023 were included. Eleven patients with anti-SSA antibody positive were eventually diagnosed with fetal cardiac di-sease. And patients with anti-SSA antibody positive without fetal cardiac disease were selected as controls. Clinical manifestations, laboratory indications and drug usage were compared between the two groups. RESULTS: Among these 11 patients, congenital heart block was confirmed in seven, which was the most common manifestations of fetal cardiac malformation. The proportion of the patients diagnosed with autoimmune disease before pregnancy in fetal cardiac malformation group was significantly lower than that in the control group (P=0.032), while most of the patients in the fetal cardiac malformation group received immune-related examinations for the first time because of this time's fetal cardiac diagnosis. While most of the patients in the control group received routine examinations because of autoimmune diseases diagnosed before pregnancy. During pregnancy, the white blood cell level [(9.29±2.58)×10⁹/L vs. (7.10±1.90×10⁹/L, t=3.052, P=0.004], erythrocyte sedimentation rate [(49.50 (48.00, 51.00) mm/h vs. 23.00 (15.00, 30.25) mm/h, Z=-2.251, P=0.024], IgA level [3.46 (2.30, 5.06) g/L vs. 2.13 (1.77, 2.77) g/L, Z=-2.181, P=0.029], and antinuclear antibody (ANA) titers [1∶320 (1∶160, 1∶320) vs. 1∶80 (1∶40, 1∶160), Z=-3.022, P=0.003] were significantly higher in fetal cardiac malformation group than in the control group. The proportion of positive anti-SSB antibody during pregnancy did not show a statistically significant difference between the two groups (37.5% vs. 7.7%, P=0.053). There was no significant difference in hydroxychloroquine dosage and initiation time between the two groups. The dosage of prednisone in the second and third trimesters was significantly higher in the cardiac malformation group than that in the control group, but there was no significant difference in the first trimester. CONCLUSION Fetal cardiac disease is rare in pregnant women with anti-SSA antibody. White blood cell, erythrocyte sedimentation rate, IgA, the titer of ANA positivity were higher in the fetal heart disease group during pregnancy. Since congenital heart block is difficult to reverse, its prevention and monitoring are more important than remedial treatment.
Humans ; Female ; Pregnancy ; Sjogren's Syndrome/complications* ; Autoimmune Diseases ; Heart Block/diagnosis* ; Autoantibodies ; Antibodies, Antinuclear ; Immunoglobulin A

Bundle of His ; Bundle-Branch Block/therapy* ; Cardiac Pacing, Artificial ; Electrocardiography ; Heart Conduction System ; Heart Failure/therapy* ; Humans

Autoantibodies ; Heart Block/prevention & control* ; Humans

heart rate, end-tidal carbon dioxide, end-tidal sevoflurane and intraoperative infusion rates during surgery were calculated. Presence of intra-operative and post-operative bradycardia, tachycardia, hypotension, hypertension, hypothermia, hyperthermia was recorded. Time to endotracheal extubation, intraoperative occurrence of atrioventricular block, postoperative presence of agitation, seizures, use of labetalol and dexmedetomidine infusion were also recorded. Data from the two groups were compared with Fisher's exact test and unpaired t tests with Welch's correction. Odds ratio (OR) and 95% confidence interval (CI) were calculated for categorical variables. Intra-operatively, MAP was lower in Sevo-Op [85 (± 6.54) vs. 97.69 (± 7.8) mmHg, p = 0.0009]. Time to extubation was longer in Sevo-Dex [37.69 (10–70) vs. 19.63 (10–25), p = 0.0033]. No differences were found for the other intra-operative and post-operative variables investigated. Post-operative hypertension and agitation were the most common complications (11 and 12 out of 21 animals, respectively). These results suggest that the infusion of dexmedetomidine provides similar intra-operative conditions and post-operative course to a short acting opioid infusion during sevoflurane anesthesia in dogs undergoing elective rostrotentorial or transfrontal intracranial surgery.]]>
Airway Extubation ; Anesthesia ; Animals ; Arterial Pressure ; Atrioventricular Block ; Bradycardia ; Brain Neoplasms ; Carbon Dioxide ; Dexmedetomidine ; Dihydroergotamine ; Dogs ; Fever ; Heart Rate ; Hypertension ; Hypotension ; Hypothermia ; Labetalol ; Neurosurgery ; Observational Study ; Odds Ratio ; Retrospective Studies ; Seizures ; Tachycardia

Sarcoidosis is a multisystem granulomatous disorder of unknown etiology. The annual incidence of systemic sarcoidosis is estimated at 10–20 per 100,000 individuals. Owing to the recent advances in imaging modalities, cardiac sarcoidosis (CS) is diagnosed more frequently. The triad of CS includes conduction abnormality, ventricular tachycardia, and heart failure. Atrial and ventricular arrhythmias are caused by either inflammation or scar formation. Inflammation should be treated with immunosuppression and antiarrhythmic agents and scar formation should be treated with antiarrhythmics and/or ablation, in addition to implantable cardioverter defibrillator (ICD) implantation, if necessary. Ablation can provide a good outcome, but it might require bipolar ablation if the critical portion is located mid-myocardium. Late recurrence might be caused by reactivation of sarcoidosis, which would need to be evaluated by positron emission tomography-computed tomography imaging. Risk of sudden cardiac death (SCD) in patients with advanced atrioventricular block is not low, and ICD implantation could be considered instead of a pacemaker. For risk stratification for SCD, late gadolinium enhancement by cardiac magnetic resonance imaging or program stimulation is often used.
Arrhythmias, Cardiac ; Atrioventricular Block ; Catheter Ablation ; Cicatrix ; Death, Sudden, Cardiac ; Defibrillators ; Defibrillators, Implantable ; Electrons ; Gadolinium ; Heart Failure ; Humans ; Immunosuppression ; Incidence ; Inflammation ; Magnetic Resonance Imaging ; Recurrence ; Sarcoidosis ; Tachycardia, Ventricular

BACKGROUND: Although device-based optimization has been developed to overcome the limitations of conventional optimization methods in cardiac resynchronization therapy (CRT), few real-world data supports the results of clinical trials that showed the efficacy of automatic optimization algorithms. We investigated whether CRT using the adaptive CRT algorithm is comparable to non-adaptive biventricular (BiV) pacing optimized with electrocardiogram or echocardiography-based methods. METHODS: Consecutive 155 CRT patients were categorized into 3 groups according to the optimization methods: non-adaptive BiV (n = 129), adaptive BiV (n = 11), and adaptive left ventricular (LV) pacing (n = 15) groups. Additionally, a subgroup of patients (n = 59) with normal PR interval and left bundle branch block (LBBB) was selected from the non-adaptive BiV group. The primary outcomes included cardiac death, heart transplantation, LV assist device implantation, and heart failure admission. Secondary outcomes were electromechanical reverse remodeling and responder rates at 6 months after CRT. RESULTS: During a median 27.5-month follow-up, there was no significant difference in primary outcomes among the 3 groups. However, there was a trend toward better outcomes in the adaptive LV group compared to the other groups. In a more rigorous comparisons among the patients with normal PR interval and LBBB, similar patterns were still observed. CONCLUSION: In our first Asian-Pacific real-world data, automated dynamic CRT optimization showed comparable efficacy to conventional methods regarding clinical outcomes and electromechanical remodeling.
Bundle-Branch Block ; Cardiac Resynchronization Therapy ; Death ; Electrocardiography ; Follow-Up Studies ; Heart Failure ; Heart Transplantation ; Humans ; Immunodeficiency Virus, Bovine

PURPOSE: We aimed to examine associations between right bundle branch block (RBBB) following heart transplantation (HT) and graft rejection. MATERIALS AND METHODS: We investigated 51 patients who underwent endomyocardial biopsies, electrocardiogram, right-side cardiac catheterization, and echocardiography at 1 month and 1 year after HT. We classified patients into four groups according to the development of RBBB, based on electrocardiogram at 1 month and 1 year: 1) sustained RBBB, 2) disappeared RBBB, 3) newly developed RBBB, and 4) sustained non-RBBB. The RBBB was defined as an RSR' pattern in V1 with a QRS duration ≥100 ms on electrocardiogram. RESULTS: The newly developed RBBB group (n=13, 25.5%) had a higher rate of new onset graft rejection (from grade 0 to grade ≥1R, 30.8% vs. 10.0% vs. 21.4%, p=0.042) at 1 year, compared with sustained RBBB (n=10, 19.6%) and sustained non-RBBB group (n=28, 54.9%). In contrast, the incidence of resolved graft rejection (from grade ≥1R to grade 0) was higher in the sustained RBBB group than the newly developed RBBB and sustained non-RBBB groups (70.0% vs. 7.7% vs. 25.0%, p=0.042). Left atrial volume index was significantly higher in the newly developed RBBB group than the sustained RBBB and sustained non-RBBB groups (60.6±25.9 mL/m2 vs. 36.0±11.0 mL/m2 vs. 38.4±18.1 mL/m2, p=0.003). CONCLUSION: Close monitoring for new development of RBBB at 1 year after HT, which was associated with a higher incidence of new onset graft rejection, may be helpful to identify high risk patients for graft rejection.
Biopsy ; Bundle-Branch Block ; Cardiac Catheterization ; Cardiac Catheters ; Echocardiography ; Electrocardiography ; Graft Rejection ; Heart Transplantation ; Heart ; Humans ; Incidence ; Transplants