Morphometry and comparative histology of sinus and atrioventricular nodes in humans and pigs and their relevance in the prevention of nodal arrhythmias

In this study, we describe the morphometry of the sinus and atrioventricular nodes of 10 adult humans and 10 pig hearts. A computerized morphometric study has been carried out, where we determined the number of cells that compose the nodes as well as different parameters related to their shape and size.The sinus node in human and pig is a compact structure, whose shape is oblong. Their cells (nodal and transitional cells) are pale and located in the center and the periphery, respectively. The atrioventricular node has also a shape oblong. P cells are pale in both species, but in humans, they are smaller than cardiomyocytes. The T cells are small and pale in both species, identified by hematoxylin-eosin and desmin stains. We have observed through a morphometric profile that the structure of sinus and atrioventricular nodes of pigs and humans show few differences. Pigs can be used as models for hemodynamic applications and experimental studies that include atrial electrical conduction and, in this way, prevent the presentation of arrhythmias that can generate sudden deaths in humans and pigs.
Source: Research in Veterinary Science - Category: Veterinary Research Source Type: research

Related Links:

The human and dog have sinus arrhythmia; however, the beat-to-beat interval changes were hypothesized to be different. Geometric analyses (R-R interval tachograms, dynamic Poincaré plots) to examine rate changes on a beat-to-beat basis were analyzed along with time and frequency domain heart rate variability from 40 human and 130 canine 24-hour electrocardiographic recordings. Humans had bell-shaped beat-interval distributions, narrow interval bands across time with continuous interval change and linear changes in rate. In contrast, dogs had skewed nonsingular beat distributions, wide interval bands {despite faster ...
Source: Frontiers in Physiology - Category: Physiology Source Type: research
Background: Ascent to altitude increases the prevalence of arrhythmogenesis in low-altitude dwelling populations (Lowlanders). High altitude populations (i.e., Nepalese Sherpa) may have arrhythmias resistant adaptations that prevent arrhythmogenesis at altitude, though this has not been documented in other High altitude groups, including those diagnosed with chronic mountain sickness (CMS). We investigated whether healthy (CMS-) and CMS afflicted (CMS +) Andeans exhibit cardiac arrhythmias under acute apneic stress at altitude.Methods and Results: Electrocardiograms (lead II) were collected in CMS- (N = 9), CMS + (N = 8), ...
Source: Frontiers in Physiology - Category: Physiology Source Type: research
The device touted as the world's smallest pacemaker is now FDA approved for patients with AV block, a condition in which the electrical signals between the chambers of the heart are impaired. FDA approved the original Micra Transcatheter Pacing System in 2016 for patients with atrial fibrillation or other dangerous arrhythmias such as bradycardia-tachycardia syndrome. The Micra AV is identical in size and shape to the original device, but has several additional internal sensing algorithms which detect cardiac movement, allowing the device to adjust pacing in the ventricle to coordinate with the atrium, providin...
Source: MDDI - Category: Medical Devices Authors: Tags: Implants Source Type: news
By ANISH KOKA, MD Mr. Smith has a problem.  He can’t see.  Even this cardiologist knows why.  The not so subtle evidence lies in the cloudy lens in front of his pupils.  He is afflicted with cataracts that obstruct his vision to the point he can’t really do his job refurbishing antique furniture safely.  His other problem is that he hates doctors. He hasn’t had reason to see one for more than a decade.  He’s 68, takes no medications, smokes a pack of cigarettes a day, and is a master of one word answers. He’s in my office because he needs a medical eval...
Source: The Health Care Blog - Category: Consumer Health News Authors: Tags: Medical Practice Patients Physicians Anish Koka cardiology low-value testing Source Type: blogs
Conclusion: Regional electrophysiology and paths in the model match human action potentials, dynamic behavior, and cardiac activation sequences. Connected in closed loop with a pacing device in DDD mode, the model generates complex arrhythmia such as atrioventricular nodal reentry tachycardia. Such device-induced outcomes have been observed clinically and we can establish the key physiological features of the heart model that influence the device operation. Significance: These findings demonstrate how an abstract heart model can be used for device validation and to design personalized treatment.
Source: IEEE Transactions on Biomedical Engineering - Category: Biomedical Engineering Source Type: research
Atrial fibrillation and hypertension represent 2 of the most important national public health priorities. Atrial fibrillation is the most common sustained cardiac arrhythmia among adults, affecting up to 2% of the US population. The prevalence of atrial fibrillation is expected to increase 3-fold in the next 3 decades. Robust data have identified hypertension as an independent modifiable risk factor for atrial fibrillation and as the most common cardiovascular condition associated with it. Hypertension is present in up to 80% of individuals with atrial fibrillation. Fulfilling a fundamental principle of evidence-based medi...
Source: JAMA - Category: General Medicine Source Type: research
Atrial Fibrillation (AF) is a common arrhythmia with serious clinical sequelae, but despite its significance little is known about the genetic origins. Recently, the untranscribed 98% of the human genome has been increasingly implicated in important processes like cardiac organogenesis, physiology, and pathophysiology. Specifically, long non-coding RNAs (lncRNA) have been shown to interact with the transcriptome in various ways that alter gene expression. Previously, multiple lncRNAs have been identified in disease processes such as heart failure, coronary artery disease, diabetes, and more.
Source: Heart Rhythm - Category: Cardiology Authors: Source Type: research
Catheter ablation of accessory pathways (AP) in Ebstein ’s anomaly (EA) has a higher recurrence rate than in normal hearts. Anatomic features could account for suboptimal ablation outcomes.
Source: Heart Rhythm - Category: Cardiology Authors: Source Type: research
AbstractThe2015 HRS/EHRA/APHRS/SOLAECE Expert Consensus Statement on Optimal Implantable Cardioverter-Defibrillator Programming and Testing provided guidance on bradycardia programming, tachycardia detection, tachycardia therapy, and defibrillation testing for implantable cardioverter-defibrillator (ICD) patient treatment. The 32 recommendations represented the consensus opinion of the writing group, graded by Class of Recommendation and Level of Evidence. In addition, Appendix B provided manufacturer-specific translations of these recommendations into clinical practice consistent with the recommendations within the parent...
Source: Journal of Interventional Cardiac Electrophysiology - Category: Cardiology Source Type: research
BOSTON (CBS) — Marijuana use is growing in popularity and local doctors are sounding the alarm about the potential harms the drug could have on the heart. They say marijuana carries many of the same cardiovascular risks as smoking tobacco. Researchers at Brigham and Women’s Hospital say while more patients are curbing their use of cigarettes, there has been an acceleration in marijuana use that marijuana users are now exceeding cigarette smokers. And the effects of the drug on cardiovascular health are not fully understood. Some studies have linked marijuana use with stroke, arrhythmias, and other heart conditi...
Source: WBZ-TV - Breaking News, Weather and Sports for Boston, Worcester and New Hampshire - Category: Consumer Health News Authors: Tags: Boston News Health Healthwatch Seen On WBZ-TV Syndicated CBSN Boston Syndicated Local Dr. Mallika Marshall Marijuana Source Type: news
More News: Arrhythmia | Cardiology | Computers | Heart | Science | Study | Veterinary Research