Why does the heart beat? The discovery of the electrical system of the heart

Why does the heart beat? This question--known as the myogenic versus neurogenic theory--dominated cardiac research in the 19th century. In 1839, Jan Evangelista Purkinje discovered gelatinous fibers in the ventricular subendocardium that he thought were muscular. Walter Gaskell, in 1886, demonstrated specialized muscle fibers joining the atria and ventricles that caused "block" when cut and found that the sinus venosus was the area of first excitation of the heart. By examining serial embryologic sections, Wilhelm His, Jr, showed that a connective tissue sheet became a bundle connecting the upper and lower cardiac chambers, the bundle of His. Sunao Tawara traced the atrioventricular (AV) bundle of His backward to find a compact node of fibers at the base of the atrial septum and forward where it connected with the bundles of cells discovered by Purkinje in 1839. Tawara concluded that this "AV connecting system" originated in the AV node, penetrated the septum as the His bundle, and then divided into left and right bundle branches that terminated in the Purkinje fibers. Martin Flack and Arthur Keith studied the conduction system of a mole and found a structure in the sinoauricular junction that histologically resembled the AV node. They felt that this was where "the dominating rhythm of the heart normally begins" and named it the sinoauricular node in 1907. The ECG of Einthoven soon brought a new understanding to the complex electrical system that makes the heart beat. In 2006 and 2007, we celebrate the 100th anniversaries of the publication of the exciting discovery of the AV and sinus nodes, truly landmarks in our understanding of cardiac structure and physiology.     

Genetics of inflammatory bowel disease: The beginning of the end or the end of the beginning?

Recent identification of the first susceptibility gene for Crohn's disease has led to increasing enthusiasm for the investigation and dissection of inflammatory bowel disease. In the future, identification of additional genes and careful correlation of the genetic background with clinical features of the disease will help to elucidate the causes and cure of inflammatory bowel disease. However, caution is still needed in the short term since our present knowledge has limited influence on clinical management. This review focuses on the genetic background of inflammatory bowel disease, the process of discovering the mutations of the NOD2/CARD15 gene in Crohn's disease patients, and the functional clues of the genetic variants of this gene in relation to clinical features.     

The first results of the “bevolkingsonderzoek” in the Zaanstreek region in The Netherlands

This short communication describes the results with respect to stage of colorectal cancer in people detected via screening and patients with clinical complaints.     

Acute pancreatitis at the beginning of the 21st century： The state of the art

Acute pancreatitis is an acute inflammatory disease of the pancreas which can lead to a systemic inflammatory response syndrome with significant morbidity and mortality in 20% of patients. Gallstones and alcohol consumption are the most frequent causes of pancreatitis in adults. The treatment of mild acute pancreatitis is conservative and supportive; however severe episodes characterized by necrosis of the pancreatic tissue may require surgical intervention. Advanced understanding of the pathology, and increased interest in assessment of disease severity are the cornerstones of future management strategies of this complex and heterogeneous disease in the 21st century.     

The treatment of the “untreatable” patient-revisited

The limits of medicine have not yet been reached. Numerous human illnesses initially thought to be incurable are reversible under unique and unpredictable individual circumstances.This paper, and the preceding companion publication,describes instances of the successful treatment of patients previously labeled as untreatable, including instances of severe ulcerative colitis and Crohn‘s disease.     

The pars tuberalis of the hypophysis: a modulator of the pars distalis?

The pineal hormone melatonin is known to influence circadian systems. Melatonin is also ascribed to mediate photoperiodic effects on the regulation of the hypothalamo-hypophyseal-gonadal axis. Other endocrine actions, especially a thyrotropic influence, have been postulated. Site and mechanism of action of melatonin, however, are still matters of speculation. In search of a functional cascade of (i) photoperiodic stimuli, (ii) their hormonal messenger melatonin, and (iii) endocrine targets, the pars tuberalis has gained a key position. The recent discovery and characterization of melatonin receptors located in the pars tuberalis of several species support such a functional significance. Earlier results point to a functional connection of the pars tuberalis with the pineal gland: the pars tuberalis is known for a pattern of differentiation distinctly different from other parts of the adenohypophysis. It contains a specific cell population with a morphology typical of peptide secreting cells. Like the hypothalamic nerve endings of the median eminence, they are in close contact with the primary plexus of the portal system. In contrast to secretory cells of the pars distalis, the specific cells of the pars tuberalis do not respond with morphological alterations to functional changes of peripheral endocrine glands. Yet, photoperiodic stimuli obviously influence morphology and functional activity of the pars tuberalis-specific cells. Investigations during recent years have led to the tentative conclusion that the pars tuberalis represents the hypophysial "receptor" for melatonin as the chemical messenger of photoperiodic stimuli. Depending on melatonin secretion pattern and melatonin receptivity, the pars tuberalis seems to modulate at least gonadotropic and thyrotropic activity of the pars distalis via a peptide hormone distributed in the pars distalis by the portal plexus.(ABSTRACT TRUNCATED AT 250 WORDS)     

The influence of the technology on the success of the treatment of paroxysmal atrial fibrillation—single center experience

IntroductionPulmonary vein isolation (PVI) is considered to be a cornerstone of invasive therapy of paroxysmal atrial fibrillation (PAF). However, numerous technologies appeared on the market during last 10 years and besides typical “point-by-point” ablation, other “single-burn” technologies or remote navigation emerged.GoalThe aim of this article is to summarize single center experience with PVI using different technologies.Methods and resultsThe study was conducted in partially retrospective and mainly prospective manner. Consecutive cohorts of patients with PAF were followed after their index procedure using four different systems (CARTO XP, pulmonary vein ablation catheter (PVAC), CARTO3 and Sensei robotic system). After 3 month blanking period, repeated 7 day-Holters were carried out every 3 months following the index procedure, which consisted of catheter-based radiofrequency PVI. Documented episodes of AF lasting >60 s on any of these 7-day Holters were considered a failure of treatment. Using of the PVAC technology was associated with the shortest procedure duration when compared to any other system (p<0.0001 for all) and significant shortening of fluoroscopic time when compared to CARTO XP (p<0.0001). Using of novel CARTO3 mapping system or robotic navigation led to significant decrease of procedural time when compared to older 3D mapping system (p<0.0001). Arrhythmia free survival at 12 months following the index procedure was 65.8%, 68.7%, 75% and 76.1% when using CARTO XP, PVAC, CARTO3 and robotic navigation, respectively. Using of either CARTO3 or robotic navigation system led to significant improvement of AF-free survival (log rank p<0.01). One major vascular complication was recorded in the robotic group of patients while none in other groups. No minor or major late complications (beyond 30 days following the index procedure) were noted in any of the groups.ConclusionsNovel technologies bring significantly better results in terms of arrhythmia recurrence and allow for shorter procedure duration and lower radiation burden both for patients and the operating physicians.     

The Evaluation of the Safety and Efficacy of Transradial Coronary Procedures

Objectives To evaluate the safety and efficacy of transradial coronary procedures (TRCP). Methods The data of 83 cases who accepted transradial coronary angiography (CAG) and transradial percutaneous coronary intervention (PCI) in our department were summarized. The success rates, proximal coronary complications, peripheral vascular complications, severe vagal reflex, mean operation time (MOT), mean recumbent time (MRT), mean hospital-staying time (MHT) were analyzed. The data were compared with that of 420 cases of transfemoral coronary procedures (TFCP) in the same period. Results Success rates and proximal coronary complications were similar in both groups. Severe vagal reflexes were less in TRCP group than in TFCP group. MOT was longer in TRCP group. MRT and MHT were shorter in TRCP group. 12( 14.5%) radial artery spasm, 3(3.6%) radial artery obstruction, 1 sudden respiratory arrest caused by jugular hematoma were observed in TRCP group. Conclusions The efficacy and safety of TRCP are definite. TRCP is more economical. For the purpose of properly evaluate the peripheral vascular complications of TRCP, it is necessary to pay special attention to radial artery occlusion, radial artery stenosis, and jugular hematoma.     

The role of hypergastrinemia in the pathogenesis of intussusception in infants

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