Systolic ventricular filling

The evidence of the ventricular myocardial band (VMB) has revealed unavoidable coherence and mutual coupling of form and function in the ventricular myocardium, making it possible to understand the principles governing electrical, mechanical and energetical events within the human heart. From the earliest Erasistratus' observations, principal mechanisms responsible for the ventricular filling have still remained obscured. Contemporary experimental and clinical investigations unequivocally support the attitude that only powerful suction force, developed by the normal ventricles, would be able to produce an efficient filling of the ventricular cavities. The true origin and the precise time frame for generating such force are still controversial. Elastic recoil and muscular contraction were the most commonly mentioned, but yet, still not clearly explained mechanisms involved in the ventricular suction. Classical concepts about timing of successive mechanical events during the cardiac cycle, also do not offer understandable insight into the mechanism of the ventricular filling. The net result is the current state of insufficient knowledge of systolic and particularly diastolic function of normal and diseased heart. Here we summarize experimental evidence and theoretical backgrounds, which could be useful in understanding the phenomenon of the ventricular filling. Anatomy of the VMB, and recent proofs for its segmental electrical and mechanical activation, undoubtedly indicates that ventricular filling is the consequence of an active muscular contraction. Contraction of the ascendent segment of the VMB, with simultaneous shortening and rectifying of its fibers, produces the paradoxical increase of the ventricular volume and lengthening of its long axis. Specific spatial arrangement of the ascendent segment fibers, their interaction with adjacent descendent segment fibers, elastic elements and intra-cavitary blood volume (hemoskeleton), explain the physical principles involved in this action. This contraction occurs during the last part of classical systole and the first part of diastole. Therefore, the most important part of ventricular diastole (i.e. the rapid filling phase), in which it receives >70% of the stroke volume, belongs to the active muscular contraction of the ascendent segment. We hope that these facts will give rise to new understanding of the principal mechanisms involved in normal and abnormal diastolic heart functio

Hyperhomocysteinemia in patients with pulmonary embolism

Investigation of hyperhomocysteinemia (HHcy) as an important risk factor for pulmonary thromboembolism (PTE), which represents a most dangerous consequence of a unique phenomenon of venous thromboembolism which still suffers from sometimes conflicting or inadequately clarified results. The role of homocysteine in the clinical manifestation of this life-threatening disease and its treatment (in which any further information may be decisive) requires detailed examination. The purpose of this study is to determine the differences in HHcy incidence and homocysteinemia levels between patients with PTE and healthy persons. The study enrolled 70 patients with PTE and 50 healthy persons. Homocysteine was measured using the HPLC method with fluorescent detection and HHcy was defined as homocysteinemia above 12 mu mol/L. Statistical analyses included chi-square and Mann Whitney U tests. The median homocysteinemia value was significantly higher (p=0.017) in the patients (12.10 mu mol/L) than in the controls (10.35 mu mol/L). The comparison of HHcy incidence between the patients (51.5%) and controls (30%) revealed a significant difference (p=0.021). In patients, homocysteinemia was significantly higher (p=0.002) in men (14.05 mu mol/L) than in women (10.01 mu mol/L) HHcy was present in 67.6% of men with PTE, which was significantly higher (p=0.006) than the incidence in women with PTE (33.3%). Healthy males had significantly higher (p=0.001) homocysteinemia (12.54 mu mol/L) than healthy females (9.4 mu mol/L). A significant difference (p=0.031) was observed between the incidences of HHcy in healthy males (44.0%) and healthy females (16.0%). We conclude that the incidence of hyperhomocysteinemia and homocysteinemia are significantly higher in all the patients compared with de healthy persons, as well as in both healthy males and males with PTE compared with healthy females and female patients. This indicates that HHcy findings in PE are likely to have a clinical importance

What Is the Heart? Anatomy, Function, Pathophysiology, and Misconceptions

Cardiac dynamics are traditionally linked to a left ventricle, right ventricle, and septum morphology, a topography that differs from the heart’s five-century-old anatomic description of containing a helix and circumferential wrap architectural configuration. Torrent Guasp’s helical ventricular myocardial band (HVMB) defines this anatomy and its structure, and explains why the heart’s six dynamic actions of narrowing, shortening, lengthening, widening, twisting, and uncoiling happen. The described structural findings will raise questions about deductions guiding “accepted cardiac mechanics”, and their functional aspects will challenge and overturn them. These suppositions include the LV, RV, and septum description, timing of mitral valve opening, isovolumic relaxation period, reasons for torsion/twisting, untwisting, reasons for longitudinal and circumferential strain, echocardiographic sub segmentation, resynchronization, RV function dynamics, diastolic dysfunction’s cause, and unrecognized septum impairment. Torrent Guasp’s revolutionary contributions may alter future understanding of the diagnosis and treatment of cardiac disease

Dabigatran - Metabolism, Pharmacologic Properties and Drug Interactions

Background: The superiority of dabigatran has been well proven in the standard dosing regimen in prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF) and extended venous thromboembolism (VTE) treatment. Dabigatran, an anticoagulant with a good safety profile, reduces intracranial bleeding in patients with atrial fibrillation and decreases major and clinically relevant non-major bleeding in acute VTE treatment. However, several important clinical issues are not fully covered by currently available directions with regard to dabigatran administration. The prominent one is reflected in the fact that dynamic impairment in renal function due to dehydratation may lead to haemorragic complications on the one hand, while on the other hand glomerular hyperfiltration may be a possible cause of dabigatran subdosing, hence reducing the drug's efficacy. Furthermore, limitations of the Cockcroft-Gault formula, considered a standard equation for assessing the renal function, may imply that other calculations are likely to obtain more accurate estimates of the kidney function in specific patient populations. Method and Conclusions: Although not routinely recommended, a possibility of monitoring dabigatran in special clinical settings adds to optimization of its dosage regimens, timely perioperative care and administration of urgently demanded thrombolytic therapy, therefore significantly improving this drug's safety profile. Despite the fact that dabigatran has fewer reported interactions with drugs, food constituents, and dietary supplements, certain interactions still remain, requiring considerable caution, notably in elderly, high bleeding risk patients, patients with decreased renal function and those on complex drug regimens. Additionally, upon approval of idarucizumab, an antidote to dabigatran solution, hitherto being a major safety concern, has been finally reached, which plays a vital role in life-threatening bleeding and emergency interventions and surgery