Antiarrhythmic drugs: mechanisms of action, clinical effects, indications for use

The lecture is devoted to one of the most difficult problems of modern cardiology – the use of antiarrhythmic therapy in clinical practice. The basic mechanisms of arrhythmias, aspects of their onset, maintenance and termination are briefly described. The current evidence on the electrophysiological mechanisms of cardiac arrhythmias – re-entry, abnormal impulse formation, and trigger activity – is presented. The article contains information about the remodeling of ion channels properties. The Sicilian gambit is analyzed, in which the mechanisms of arrhythmias are compared to the mechanisms of anti-arrhythmic action of drugs. Classification of anti-arrhythmic drugs, their mechanisms of action, indications and contraindications, side effects, and interaction with other drugs are presented.

Simulation on Spacecraft Formation Flight and Formation Reconfiguration

Spacecraft formation flight refers to two or more spacecraft according to a certain formation or arrangement of flight, it has important application value for deep spatial exploration, spatial science experiment, ground investigation and military and so. This paper studies the spacecraft formation flight design and formation reconfiguration based on STK. Firstly, the Clohessy-Wiltshire (CW) equation is used to describe the relative motion of the near-circular orbit and deduce the relative orbital dynamics model. Then, based on the dynamic method of the CW equation, the spatial circular formation is designed and the STK is applied to simulate it. Finally, based on the above formation, a simple multi-impulse formation reconfiguration is performed and the simulation test is verified by STK. The simulation results show that the absolute error of orbital elements of the spacecraft is calculated by the relative orbital dynamics model is less than 10-5, and the expected formation can be completed under the condition of two-body environment, and the feasibility of simple multi-pulse formation reconfiguration is proved successfully.

A Case of suspected Sick Sinus Syndrome due to combined Beta-blocker and Calcium Channel Blocker Therapy: Anesthesia Management

ABSTRACT Sick sinus syndrome (SSS) is a generalized abnormality of cardiac impulse formation. Abnormalities encompassed by this syndrome may include inappropriate sinus bradycardia, sinus arrest, bradyarrhythmias, or tachyarrhythmias. We present a case of a 54-year-old hypertensive male posted for L4–L5 decompression, whom we suspected to develop SSS due to overdose of combined beta-blocker (BB) and calcium channel blocker (CCB) therapy. How to cite this article Gala AA, Dalvi NP, Gvalani SK, Mahajan S. A Case of suspected Sick Sinus Syndrome due to combined Beta-blocker and Calcium Channel Blocker Therapy: Anesthesia Management. Res Inno in Anesth 2017;2(2):68-70.

Arrhythmias and Syncope

Cardiac arrhythmias are due to disorders of impulse propagation (reentry) or impulse formation (abnormal automaticity or triggered activity). Reentry is the most common mechanism of arrhythmia and is further classified as macroreentrant or microreentrant. Macroreentrant arrhythmias have a discrete, definable circuit such as atrioventricular (AV) reentrant tachycardia (sustained over AV nodal, ventricular, accessory pathway, and ventricular tissue) or ventricular tachycardia (sustained around an area of myocardial scar or infarcted tissue). Microreentry occurs within a circuit that is too small to be mapped and thus appears to arise from a single point in the myocardium.

Generation of Mechanical Waves in Metals under the High Power Ion Beam Irradiation

The system model «high power ion beam – metal» is suggested. Regularities of impulse formation of mechanical load in the volume of metal target subjected to the action of ion beams of different component composition in the range of power density 107...1010 W/cm2 have been considered. The influence of generation mechanisms on the profile and amplitude-to-time parameters of shock-wave excitation is studied.