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

Central venous catheter (CVC) placement is an operation which can establish a fast, safe, and effective deep venous access to rescue patients under critical conditions, especially for those receiving hemodialysis. It is a simple operation with almost no complications, but different complications have been still reported, such as bleeding, infection, embolism, low blood flow, and cardiac arrhythmias. In this case, the patient with preexisting left bundle branch block suffered right bundle branch block, leading to complete heart block during CVC placement. When the patient developed complete heart block, we immediately treated him with isoproterenol, and the surgery was terminated as soon as possible. The patient gradually recovered the sinus rhythm after the treatment. This complication is rare but severe, and clinicians should recognize the risks and take strategies as early as possible. We think the cause of complete heart block in this patient may be related to mechanical trauma to the right ventricle by the guide wire or catheter insertion. Therefore, CVC placement should be performed with more caution, and the guide wire and catheter tip should be inserted less than 18 cm deep.
Arrhythmias, Cardiac ; Catheterization, Central Venous ; Central Venous Catheters ; Heart Block ; Humans ; Male ; Renal Dialysis

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

BACKGROUND AND OBJECTIVES: Conflicting data exist regarding the prognostic implication of ventricular conduction disturbance pattern in patients with heart failure (HF). This study investigated the prognostic impact of ventricular conduction pattern in hospitalized patients with acute HF. METHODS: Data from the Korean Acute Heart Failure registry were used. Patients were categorized into four groups: narrow QRS (<120 ms), right bundle branch block (RBBB), left bundle branch block (LBBB), and nonspecific intraventricular conduction delay (NICD). The NICD was defined as prolonged QRS (≥120 ms) without typical features of LBBB or RBBB. The primary endpoint was the composite of all-cause mortality or rehospitalization for HF aggravation within 1 year after discharge. RESULTS: This study included 5,157 patients. The primary endpoint occurred in 39.7% of study population. The LBBB group showed the highest incidence of primary endpoint followed by NICD, RBBB, and narrow QRS groups (52.5% vs. 49.7% vs. 44.4% vs. 37.5%, p<0.001). In a multivariable Cox-proportional hazards regression analysis, LBBB and NICD were associated with 39% and 28% increased risk for primary endpoint (LBBB hazard ratio [HR], 1.392; 95% confidence interval [CI], 1.152–1.681; NICD HR, 1.278; 95% CI, 1.074–1.520) compared with narrow QRS group. The HR of RBBB for the primary endpoint was 1.103 (95% CI, 0.915–1.329). CONCLUSIONS: LBBB and NICD were independently associated with an increased risk of 1-year adverse event in hospitalized patients with HF, whereas the prognostic impacts of RBBB were limited. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01389843
Bundle-Branch Block ; Heart Failure ; Heart ; Humans ; Incidence ; Mortality ; Prognosis

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

A 38-year-old female patient had bradycardia in the preoperative electrocardiogram (ECG), and she showed severe bradycardia, with the heart rate (HR) under 40 beats per minute (bpm) even after arrival in the operating room. Immediately after endotracheal intubation, ventricular tachycardia with HR over 200 bpm occurred, but it disappeared voluntarily. The surgery was postponed for additional cardiac evaluation because of the persistent severe bradycardia. On postanesthesia day 2, complete atrioventricular (AV) block appeared. We expected spontaneous recovery over 2 weeks, but the complete AV block persisted. A permanent pacemaker was eventually inserted, and the patient was discharged without other complications on day 4 after insertion of the pacemaker. We report this case because complete AV block has commonly occurred in patients with risk factors such as first AV block, secondary AV block, or bundle branch block, but complete AV block has occurred despite the absence of arrhythmia in this patient.
Adult ; Anesthesia, General ; Arrhythmias, Cardiac ; Atrioventricular Block ; Bradycardia ; Bundle-Branch Block ; Electrocardiography ; Female ; Heart Rate ; Humans ; Intubation, Intratracheal ; Operating Rooms ; Risk Factors ; Tachycardia, Ventricular