Stimulant Drugs of Abuse and Cardiac Arrhythmias

Nonmedical use of prescription and nonprescription drugs is a worldwide epidemic, rapidly growing in magnitude with deaths because of overdose and chronic use. A vast majority of these drugs are stimulants that have various effects on the cardiovascular system including the cardiac rhythm. Drugs, like cocaine and methamphetamine, have measured effects on the conduction system and through several direct and indirect pathways, utilizing multiple second messenger systems, change the structural and electrical substrate of the heart, thereby promoting cardiac dysrhythmias. Substituted amphetamines and cocaine affect the expression and activation kinetics of multiple ion channels and calcium signaling proteins resulting in EKG changes, and atrial and ventricular brady and tachyarrhythmias. Preexisting conditions cause substrate changes in the heart, which decrease the threshold for such drug-induced cardiac arrhythmias. The treatment of cardiac arrhythmias in patients who take drugs of abuse may be specialized and will require an understanding of the unique underlying mechanisms and necessitates a multidisciplinary approach. The use of primary or secondary prevention defibrillators in drug abusers with chronic systolic heart failure is both sensitive and controversial. This review provides a broad overview of cardiac arrhythmias associated with stimulant substance abuse and their management.

Predictive value of electrophysiological study for risk stratification of ventricular tachyarrhythmias in patients with non-ischemic cardiomyopathy and chronic systolic heart failure

A systematic review and meta-analysis of studies providing information on the use of intracardiac electrophysiological study (EPS) to stratify the risk of ventricular tachyarrhythmia (VT) in patients with non-ischemic chronic heart failure with low left ventricle ejection fraction (HFrEF). Relevant publications were searched until 20.01.2021 by two independent researchers in major search engines, electronic archives of clinical research, and open access preservatives repository. The end point considered was an episode of sudden cardiac death or sustained paroxysm of VT, or an appropriate electrotherapy of an implanted cardiac defibrillator. Ten clinical trials with 608 relevant patients (mean age: 51.5 ± 12 years; mean left ventricle EF: 26.8±8.5%, NYHA class: I - 17.7%; II - 33.7%; III - 35.9%, IV - 12.7%) were selected. The end point was registered in 92 patients (15.1%): in 47 patients (43.9%) with previously induced VT during EPS and in 45 patients (8.9%) without VT. The diagnostic odds ratio was 5.57 (2.27-13.63). The combined sensitivity and specificity of the EPS were 42% (26-61%) and 88% (83-92%) respectively. The results indicate the potential of EPS to stratify the arrhythmic risk in patients with non-ischemic HFrEF.

FALLS IN PATIENTS WITH CHRONIC SYSTOLIC HEART FAILURE 65 AND MORE YEARS OLD

В настоящее время значительно увеличилось число больных пожилого и старческого возраста с систолической ХСН. В этой категории пациентов существенное значение для прогноза и качества жизни могут играть гериатрические синдромы. Синдром падений является одним из ведущих гериатрических синдромов, способных влиять на качество жизни и прогноз у больных с данной патологией. Целью нашей работы явилось изучение распространенности синдрома падений у пациентов 65 лет и старше с систолической ХСН и выявление у них предикторов развития падений. Основную группу ( n =240) составили пациенты 65 лет и старше с ХСН с ФВ<50 %; контрольную ( n =200) - больные с сердечно-сосудистыми заболеваниями того же возраста без признаков ХСН и при отсутствии снижения ФВ и значимой клапанной патологии. В основной группе выявлено достоверно большее число пациентов, страдающих падениями и эквивалентами падений. Доказана высокая предсказательная роль теста стояния на одной ноге в данной группе пациентов; выявлено достоверное снижение времени стояния на одной ноге при сравнении с больными контрольной группы. Снижение ФВ<50 % повышает риск падений в 1,56 раза ( p =0,022), но при этом не определяется достоверной корреляции значения ФВ и риска падений. Риски падений достоверно коррелируют со степенью гипертрофии ЛЖ, выраженностью нарушений диастолической функции у пациентов 65 лет и старше с систолической ХСН. Today we can see a rapidly growing number of patients with systolic heart failure (HF) 65 and over years old. Geriatric conditions may play an important role in such patients. Falls are one of geriatric syndromes, which can influence in prognosis and quality of life in patients with chronic systolic heart failure. Aim of our research was to appreciate prevalence of falls in patients with systolic HF 65 and over years old, identify fall predictors in this group of patients. Patients with chronic HF 65 and over years old with depressed ejection fraction (EF less than 50 %) were included in the main group ( n =240). Control group ( n =200) was composed by patient with cardiac diseases but with no evidences of congestive HF, without EF decline and with no significant valve dysfunctions. Patients were asked about falls and fall equivalents. Risk of falls was also validated by 1 leg balance test. Falls and fall equivalents were more frequent in the main group of patients ( p =0,022). High predictive value of 1-leg balance test for such patients was validated. Time of 1-leg balance test was significantly lower in the main group of patients. Significant relations were observed between falls, fall equivalents and echocardiographic parameters. Depression of EF increase risk of fall in 1,56 times ( p =0,022) but with no correlation between EF and falling risk. Falls are significantly related with left ventricular hypertrophy and diastolic dysfunction in patients with chronic systolic heart failure 65 years old and older.

The evolution of cardiac resynchronization therapy and an introduction to conduction system pacing: a conceptual review

In chronic systolic heart failure and conduction system disease, cardiac resynchronization therapy (CRT) is the only known non-pharmacologic heart failure therapy that improves cardiac function, functional capacity, and survival while decreasing cardiac workload and hospitalization rates. While conventional bi-ventricular pacing has been shown to benefit patients with heart failure and conduction system disease, there are limitations to its therapeutic success, resulting in widely variable clinical response. Limitations of conventional CRT evolve around myocardial scar, fibrosis, and inability to effectively simulate diseased tissue. Studies have shown endocardial stimulation in closer proximity to the specialized conduction system is more effective when compared with epicardial stimulation. Several observational and acute haemodynamic studies have demonstrated improved electrical resynchronization and echocardiographic response with conduction system pacing (CSP). Our objective is to provide a systematic review of the evolution of CRT, and an introduction to CSP as an intriguing, though experimental physiologic alternative to conventional CRT.