Third-degree block [keywords]
- Conduction disorders in bradyasystolic out-of-hospital cardiac arrest. [JOURNAL ARTICLE]
- Resuscitation 2016 Jul 12.
Bradyasystolic heart rhythms are often recorded in out-of-hospital cardiac arrest (OHCA). Atrioventricular (AV) conduction disorders might lead to OHCA, but the prevalence of AV-conduction disorders and other bradyasystolic rhythms in OHCA is unknown. These patients might benefit from pre-hospital pacing. We aimed to determine the prevalence of different types of bradyasystolic heart rhythms in OHCA, including third degree AV-block, and document survival rates.We used data from the ARREST-registry of OHCA in the Netherlands. Patients with bradyasystolic OHCA in 2006-2012 were included. ECGs were classified according to the presence of P-waves and QRS complexes in five rhythm groups. Differences in survival to discharge in relation to resuscitation characteristics, rhythm and pacing were tested using Chi-Square test and multivariate regression analysis.We included 2333 patients with a bradyasystolic rhythm; 371 patients (16%) presented with a third degree AV-block. In total 45 patients (1.9%, 95%-CI 1.4-2.5%) survived. A third degree AV-block (adjusted OR 0.86, 95%-CI 0.38-1.96) or pacing (adjusted OR 0.89, 95%-CI 0.21-3.78) was not associated with survival. Pacing was initiated in 110 patients (4.7%), after a long delay (median 18.7min). The strongest association with survival was found for the presence of a bradycardia (vs. asystole) (adjusted OR 4.20, 95%-CI 1.79-9.83), bystander witnessed (OR 4.13, 95%-CI 1.45-11.8) and EMS witnessed collapse (OR 5.18, 95%-CI 2.77-9.67).In bradyasystolic OHCA, 16% of all patients present with third degree AV-block, but survival for these and other bradyasystolic patients remains poor. Pacing is seldom initiated, often delayed, and rarely beneficial.
- Left Bundle Branch Block and Complete Heart Block Complicating Inferior Myocardial Infarction. [CASE REPORTS]
- Ann Noninvasive Electrocardiol 2016 Jul 13.
Left bundle branch block following inferior myocardial infarction remains uncommon and scarcely reported in the literature. We describe a rare presentation of a 58-year-old male patient who developed left bundle branch block and third degree atrioventricular block after inferior myocardial infarction requiring permanent pacemaker placement. Pathophysiology, impact on mortality, and management options are discussed.
- Heart block following stage 1 palliation of hypoplastic left heart syndrome. [Journal Article]
- J Thorac Cardiovasc Surg 2016 Jul; 152(1):189-94.
Publicly available data from the Pediatric Heart Network's Single Ventricle Reconstruction Trial was analyzed to determine the prevalence, timing, risk factors for, and impact of second- and third-degree heart block (HB) on outcomes in patients who underwent stage 1 palliation (S1P) for hypoplastic left heart syndrome (HLHS).The presence and date of onset of post-S1P HB occurring within the first year of life, potential risk factors for HB, and factors known to predict poor outcomes after S1P were extracted. Multivariable logistic and Cox regression analyses were performed to identify risk factors for HB and to determine the effect of HB on 3-year transplantation-free survival.Among the 549 patients in the cohort, 33 (6%) developed HB after S1P. The median interval between S1P and HB was 8 days (interquartile range, 0-133 days). Regression analysis showed that tricuspid valve repair during S1P and obstruction of pulmonary venous drainage requiring pre-S1P intervention were independently associated with HB (adjusted odds ratio [aOR], 11.6, 95% confidence interval [CI] 3.3-40; P < .001 and aOR, 5.1; 95% CI, 1.3-20.6; P = .02, respectively). Transplantation-free survival at 3 years was lower for those with HB (39% vs 65%; P = .004). HB remained associated with transplantation-free survival after controlling for known risk factors (adjusted hazard ratio, 3.1; 95% CI, 1.9-5.0; P < .001). Nine children (27%) had a pacemaker implanted, and 7 of these children (78%) died or underwent heart transplantation.HB after S1P is rare but heralds a poor outcome. Careful monitoring of these patients is recommended given their significantly increased risks of death and heart transplantation.
- Electrophysiological Mechanisms of Bayés Syndrome: Insights from Clinical and Mouse Studies. [Journal Article, Review]
- Front Physiol 2016.:188.
Bayés syndrome is an under-recognized clinical condition characterized by inter-atrial block (IAB). This is defined electrocardiographically as P-wave duration > 120 ms and can be categorized into first, second and third degree IAB. It can be caused by inflammatory conditions such as systemic sclerosis and rheumatoid arthritis, abnormal protein deposition in cardiac amyloidosis, or neoplastic processes invading the inter-atrial conduction system, such as primary cardiac lymphoma. It may arise transiently during volume overload, autonomic dysfunction or electrolyte disturbances from vomiting. In other patients without an obvious cause, the predisposing factors are diabetes mellitus, hypertensive heart disease, and hypercholesterolemia. IAB has a strong association with atrial arrhythmogenesis, left atrial enlargement (LAE), and electro-mechanical discordance, increasing the risk of cerebrovascular accidents as well as myocardial and mesenteric ischemia. The aim of this review article is to synthesize experimental evidence on the pathogenesis of IAB and its underlying molecular mechanisms. Current medical therapies include anti-fibrotic, anti-arrhythmic and anti-coagulation agents, whereas interventional options include atrial resynchronization therapy by single or multisite pacing. Future studies will be needed to elucidate the significance of the link between IAB and atrial tachyarrhythmias in patients with different underlying etiologies and optimize the management options in these populations.
- Differential Clinical Implications of High-Degree Atrioventricular Block Complicating ST-Segment Elevation Myocardial Infarction according to the Location of Infarction in the Era of Primary Percutaneous Coronary Intervention. [Journal Article]
- Korean Circ J 2016 May; 46(3):315-23.
The clinical implication of high-degree (second- and third-degree) atrioventricular block (HAVB) complicating ST-segment elevation myocardial infarction (STEMI) is ripe for investigation in this era of primary percutaneous coronary intervention (PCI). We sought to address the incidence, predictors and prognosis of HAVB according to the location of infarct in STEMI patients treated with primary PCI.A total of 16536 STEMI patients (anterior infarction: n=9354, inferior infarction: n=7692) treated with primary PCI were enrolled from a multicenter registry. We compared in-hospital mortality between patients with HAVB and those without HAVB with anterior or inferior infarction, separately. Multivariate analyses were performed to unearth predictors of HAVB and to identify whether HAVB is independently associated with in-hospital mortality.STEMI patients with HAVB showed higher in-hospital mortality than those without HAVB in both anterior (hazard ratio [HR]=9.821, 95% confidence interval [CI]: 4.946-19.503, p<0.001) and inferior infarction (HR=2.819, 95% CI: 2.076-3.827, p<0.001). In multivariate analyses, HAVB was associated with increased in-hospital mortality in anterior myocardial infarction (HR=19.264, 95% CI: 5.804-63.936, p<0.001). However, HAVB in inferior infarction was not an independent predictor of increased in-hospital mortality (HR=1.014, 95% CI: 0.547-1.985, p=0.901).In this era of primary PCI, the prognostic impact of HAVB is different according to the location of infarction. Because of recent improvements in reperfusion strategy, the negative prognostic impact of HAVB in inferior STEMI is no longer prominent.
- Interaction between Macrophages and Fibroblasts during Wound Healing of Burn Injuries in Rats. [JOURNAL ARTICLE]
- Kurume Med J 2016 May 25.
Analysis of the structural changes and cell-to-cell interactions occurring during wound healing of burn injuries is essential to elucidate the morphological characteristics of the reconstitution of tissue architecture. However, conventional approaches do not provide sufficient information with respect to cell-to-cell interactions during wound healing. The aim of this study was to evaluate the interaction between bone marrow-derived cells and resident stromal cells throughout the wound healing of burn injuries, using immunohistochemistry and focused ion beam/scanning electron microscope tomography. We induced third-degree burn injuries on the backs of Wistar rats with a heated cylindrical aluminum block (2.0 cm in diameter). At 7 and 14 days after the burn injuries, the burned skin was immunostained with anti-Iba1 and anti-HSP47 antibodies for visualization of bone marrow-derived cells/macrophages and resident stromal cells/fibroblasts, respectively. Normal skin tissue was used as a control. Double-staining immunohistochemistry revealed frequent contacts between macrophages and fibroblasts and a higher contact ratio in the 3 normal skin compared with burned skin, particularly in the areas of granuloma. Three-dimensional ultrastructural analysis with focused ion beam/scanning electron microscope tomography revealed that macrophages and fibroblasts were located closer together in the normal skin than in the burned skin, confirming the analysis by light microscopic observations and ultrastructural analysis from single sections. These results highlight the importance of contact between macrophages and fibroblasts in the maintenance of skin tissue structure and during wound healing.
- A case of reversible third-degree AV block due to Lyme carditis. [Journal Article]
- J Electrocardiol 2016 Jul-Aug; 49(4):519-21.
The most common manifestation of Lyme carditis is a varying degree of atrioventricular (AV) conduction block. This case describes a 45-year-old male with third-degree AV block due to Lyme carditis. Treatment with intravenous antibiotics resulted in complete normalization of AV conduction, thereby averting permanent pacemaker implantation.
- Incidence and characteristics of heart block after heart surgery in pediatric patients: A multicenter study. [Journal Article]
- J Thorac Cardiovasc Surg 2016 Jul; 152(1):197-202.
Advanced second- or third-degree heart block has been reported with variable incidence after surgery for congenital heart disease in children. We report the incidence of heart block requiring a pacemaker and describe the risk factors for this complication in a large multicenter study.We performed a retrospective cohort study, using the Pediatric Health Information System database from 45 hospitals in the United States, for all children aged 18 years, discharged between January 1, 2004, and December 31, 2013, who underwent open surgery for congenital heart disease. Patients who had heart block and placement of a pacemaker during the same hospitalization were identified. Demographic characteristics, procedure and diagnostic codes, length of stay, and mortality were analyzed. Univariable and multivariable analyses were performed.There were 101,006 surgeries performed. The median age of patients was 0.5 years (interquartile range, 26 days to 3.2 years), and 1% of patients (n = 990) had heart block and placement of a pacemaker. Surgeries associated with the highest incidences of heart block and placement of a pacemaker included the double switch operation (15.6%), tricuspid valve (7.8%) and mitral valve (7.4%) replacement, atrial switch with ventricular septal defect repair (6.4%), and Rastelli operation (4.8%). On multivariable analysis, after controlling for surgical complexity, other comorbidities, age at surgery, admission year, and clustering by institution, patients with heart block and placement of a pacemaker had higher odds of mortality (odds ratio, 1.67; 95% confidence interval, 1.24-2.26; P < .001).The incidence of postoperative heart block requiring permanent pacemaker placement immediately after congenital heart surgery is low (1%). However, these patients have higher mortality even after adjusting for heart surgery complexity.
- Continuous intraoperative monitoring of vagus and recurrent laryngeal nerve function in patients with advanced atrioventricular block. [Journal Article]
- Langenbecks Arch Surg 2016 Jun; 401(4):551-6.
Intraoperative neuromonitoring of recurrent laryngeal nerve function after stimulation of the vagus nerve has been embraced as a risk minimization tool in thyroid surgery to prevent recurrent laryngeal nerve injury. Because this technology is increasingly used in an elderly and sicker population, the present study was conducted to determine the safety of this method in patients with second- or third-degree atrioventricular block.This study aimed at evaluating the feasibility and safety of continuous intraoperative neuromonitoring (CIONM) in patients with second- or third-degree atrioventricular block.A total of six patients (12 nerves at risk), accounting for 0.3 % of all 1800 patients (3049 nerves at risk) who underwent thyroid surgery during the study period, were found to have second- or third-degree atrioventricular block. All these patients maintained normal systolic and diastolic blood pressures; heart rate; and peripheral arterial oxygen saturation before, during, and after CIONM. No clinically relevant changes in heart rate or blood pressure, cardiac arrhythmia, or other hemodynamically important events were noted despite careful monitoring of these patients. There was no interference between the biphasic waveform of the vocal muscle electromyogram and the spikes generated by the implanted cardiac pacemakers. Outcomes were uneventful with normal vocal fold and parathyroid gland function.Within the limitations of this series and considering experimental, animal, and human data, continuous IONM of the vagus nerve at ≤2 Hz seems to be reasonably safe. Additional research is warranted to confirm these results in larger groups of patients with advanced atrioventricular block.
- [The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing--Annual report 2014]. [English Abstract, Journal Article]
- G Ital Cardiol (Rome) 2016 Feb; 17(2):95-107.
The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2014 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers.The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards.PM Registry: data about 24 680 PM implantations were collected (19 480 first implant and 5200 replacements). The number of collaborating centers was 208. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 45.3% of first PM implants, sick sinus syndrome in 23.1%, atrial fibrillation plus bradycardia in 11.7%, other in 19.9%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (22.7% of first implants). Use of single-chamber PMs was reported in 26.9% of first implants, of dual-chamber PMs in 63.6%, of PMs with cardiac resynchronization therapy (CRT) in 1.7%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 7.8%. ICD Registry: data about 17 116 ICD implantations were collected (11 274 first implants and 5842 replacements). The number of collaborating centers was 424. Median age of treated patients was 71 years (62 quartile I; 77 quartile III). Primary prevention indication was reported in 72.3% of first implants, secondary prevention in 27.7% (cardiac arrest in 10.1%). A single-chamber ICD was used in 32.2% of first implants, dual-chamber in 37.1% and biventricular in 30.7%.The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a large use of prophylactic and biventricular ICD, reflecting a favorable adherence to trials and guidelines in clinical practice.