ISSN: 2378-2951 Valentinuzzi and Arriascu. Int J Clin Cardiol 2020, 7:164 DOI: 10.23937/2378-2951/1410164 Volume 7 | Issue 1 International Journal of Open Access Clinical Cardiology REViEw ARticLE Electrical Cardioversion: A Review Max E Valentinuzzi, EE, PhD1,2* and Luis Aguinaga Arriascu, MD3 1Emeritus Professor, Universidad Nacional de Tucumán, Argentina Check for 2Emeritus Investigator of CONICET, Argentina updates 3Director of the Arrhythmias Service, Del Parque Clinic San Miguel de Tucumán, Argentina *Corresponding author: Max E Valentinuzzi, EE, PhD, Emeritus Professor, Universidad Nacional de Tucumán, Argentina; Emeritus Investigator of Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina flammatory disease. AF can affect people at any age Abbreviations but is rare in children and is more common in the el- ECG: Electrocardiogram; DC: Direct Current; AC: Alternat- derly population; it reaches about 0.5% of the world's ing Current; VF: Ventricular Fibrillation population. According to the Centers for Disease Con- trol and Prevention (CDC), of Atlanta, Georgia, USA, Introduction approximately 2% of people younger than 65-years- Atrial fibrillation (AF), not to be confused with old have AF, while about 9% ages 65 and older have it atrial flutter, is the term used to describe an irregu- (data as for Nov 26, 2018). lar or abnormal heart rate. While AF and atrial flutter The main objective of the present article is to his- are similar, AF has more serious health implications torically review the development and evolution of this such as an increased risk of having a stroke or a blood important cardiac arrhythmia along with delving into its clot (thrombosis). The resting heart rate of someone future possibilities. without AF is usually between 60 and 100 beats per minute but this number is usually over 100 in AF. It Definition is usually the result of an underlying condition such Electrical cardioversion is a process by which the as hypertension (high blood pressure) or having an heart is shocked to convert it from an irregular rhythm overactive thyroid but may develop for no known back into a normal sinus rhythm. The ECG illustration reason. In this circumstance, the person is said to above shows what the heart rhythm looks like before have lone atrial fibrillation. There is some debate and after cardioversion. For patients in persistent atri- about the definition of lone AF. The term has been al fibrillation, electrical cardioversion may be applied used to describe different characteristics. Some think early in the process. For other AF patients, electrical it should not be distinguished as a type of AF at all. cardioversion may not be tried until later, when medi- According to the American College of Cardiology and cation has stopped working. While electrical cardiover- the American Heart Association, the term is current- sion may be effective at converting the heart back into ly used for people with AF who have no history or normal sinus rhythm, it may require multiple tries. The echocardiographic evidence of cardiovascular or pul- word version means to turn one organ from one con- monary disease. Also included are those who do not dition into another [1]. Such concept is similar, say, to have heart disease or are 60 years of age or younger a given language version of a book first published else- and do not have any related conditions (heart fail- where in another language. ure, chronic obstructive pulmonary disease (COPD), diabetes, hyperthyroidism, acute infections, recent Origins cardiothoracic or abdominal surgery, and systemic in- A paper authored by two Russians researchers, Citation: Valentinuzzi ME, Arriascu LS (2020) Electrical Cardioversion: A Review. Int J Clin Cardiol 7:164. doi.org/10.23937/2378-2951/1410164 Accepted: January 21, 2020; Published: January 23, 2020 Copyright: © 2020 Valentinuzzi ME, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Valentinuzzi and Arriascu. Int J Clin Cardiol 2020, 7:164 • Page 1 of 6 • DOI: 10.23937/2378-2951/1410164 ISSN: 2378-2951 Vishnevskiĭ and Tsukerman, described electroshock fluid in the lungs, heart attack, stroke, or even death, therapy in some heart rhythm disorders. That was though that is very rare. Various studies have report- in 1966 [2]. Many years after, in 2009, cardioversion ed that cardioversion is over 90 percent effective in was updated by Cakulev, Efimov and Waldo [3]. Actu- converting to a normal sinus rhythm though some ally, Vishnevsky and Tsukerman performed the first people revert back into AF shortly thereafter. Success reported cardioversion of AF using a DC shock in Feb- has been shown to be enhanced when patients are on ruary 1959. The patient had had AF for 3 years and an antiarrhythmic drug beforehand, which helps pre- the restoration of normal sinus rhythm took place vent reversion. Success depends on the size of the left during mitral valve surgery. The same team report- atrium as well as how long the patient has been in AF. ed the first successful transthoracic cardioversion of Patients with a very large left atrium, greater than 5 atrial arrhythmias in 20 patients using DC cardiover- cm, or who have been in constant AF for a year or two, sion in 1960. In 1970, Gurvich introduced the first may find that electrical cardioversion is not effective. biphasic transthoracic defibrillator, which became Following a successful electrical cardioversion, the standard in Soviet medical practice from that time, goal is to maintain a normal sinus rhythm, which only preceding Western analogs by at least 2 decades [4]. happens with about 20-30 percent of patients within the first year if they are not on antiarrhythmic drugs. AF and Atrial Remodeling Overall, the likelihood of reversion into atrial fibrilla- Three forms of atrial remodeling during a progres- tion is quite high, regardless of whether the patient sion of atrial fibrillation (AF) have been described: is on rhythm control drugs. Several patients have Electrical, contractile and structural. Electrical re- mentioned that their electrical cardioversions were modeling is a consequence of high atrial rates and not successful in converting them to a normal sinus includes shortening of the refractory period of atrial rhythm or in maintaining it. We know that AF patients myocytes and slowing of atrial conduction velocity. with untreated sleep apnea are more likely to revert Structural remodeling is characterized both by chang- back than AF patients without sleep apnea. We recall es in atrial myocytes in the interstitium and by chang- a patient, close relative of one of us, who in the early es in extracellular matrix composition and deposition 1960's lived for about 20 years with the arrhythmia. of fibrotic tissue. Changes at the level of atrial my- Cardioversion was then unknown in Argentina. ocytes include the loss of contractile structures and expression of fetal-like proteins, and accumulation of Interesting Sad Learning Experience glycogen in the atrial interstitium. The behavior of the human being is often decep- To avoid having blood clots break free during the tive. As part of a trip to further international coop- electrical discharge, it is of paramount importance eration in medical research, in 1958, the well-known that the patient takes an anticoagulant for one to two and influential senator Hubert H. Humphrey [5] visit- months before the procedure. Most likely, the patient ed Moscow. Humphrey saw the Research Laboratory is recommended not to have anything by mouth after of General Reanimatology (Resuscitation), where he midnight the night before. On arrival to the operating met its director, Dr. Vladimir Negovsky [6], and the room, the patient will be fitted with an IV for receiv- laboratory's leading defibrillation researcher, Dr. ing medications and fluids and connected to monitors. Naum Gurvich (1905-1981) [7]. There, Humphrey saw Once the patient is anesthetized, a defibrillator/car- experiments on the reversibility of death in animals dioverter/pacemaker equipment will deliver a heart through massive electric shocks. On return to the jolt of energy through paddles or ECG-type patches USA, he reported publically on such experiments and placed, say, on the front and back of the chest. This urged the development of programs through the Na- electric shock should restore the normal heart rhythm, tional Institutes of Health on the physiology of death and may take several tries. If external cardioversion and resuscitation. Nevertheless, the work behind the fails, then internal cardioversion may be done and in- Iron Curtain remained virtually unrecognized in the volves delivering the discharge through catheters in- West. side the heart. Once the patient wakes up, he/she can Work in the Western World After 1950 go home, but will need someone to drive him/her. For a few days following the procedure, the chest is tender In 1956, Paul Zoll [8] of Beth Israel Hospital and or the skin may have red patches. After the electrical Harvard Medical School in Boston, MA, demonstrat- cardioversion, antiarrhythmic drugs, and/or rhythm ed successful closed-chest defibrillation in humans, control medication may be administered. Besides, the again using an AC shock. Not long after, in 1960, anticoagulant medication must continue according to working at Lariboisiere Hospital in Paris, France, an medical advice. electrical engineer and physician, Fred Zacouto [9], completed the design of the first external automatic Risks and Success Rates for Cardioversion defibrillator/pacer. He had invented it in March 1953 Electrical cardioversion risks include skin burns, and filed the related patent in July 1953 in Paris [10]. Valentinuzzi and Arriascu. Int J Clin Cardiol 2020, 7:164 • Page 2 of 6 • DOI: 10.23937/2378-2951/1410164 ISSN: 2378-2951 successfully terminate an arrhythmia other than VF.