Grzegorz Raczak

Bio: Grzegorz Raczak is an academic researcher from Gdańsk Medical University. The author has contributed to research in topics: Implantable cardioverter-defibrillator & Heart rate. The author has an hindex of 6, co-authored 18 publications receiving 123 citations.

Arterial baroreflex modulation of heart rate in patients early after heart transplantation: lack of parasympathetic reinnervation.

Abstract: Background: Orthotopic heart transplantation results in cardiac denervation. The presence of cardiac parasympathetic reinnervation in humans has been widely debated based on the application of differing indirect measures of autonomic control. However no attempt has been made to analyse the reflex heart rate response to baroreceptor stimulation whose occurrence is generally considered a reliable marker of the ability to activate cardiac vagal reflexes. This study tested the hypothesis that the presence of donor heart RR interval lengthening following phenylephrine induced blood pressure increase would be an index of parasympathetic reinnervation. Methods Baroreflex sensitivity (BRS) was assessed in 30 patients (mean age 51 ± 12 years) 1–24 months after heart transplantation carried out by the standard Lower-Shumway technique. In 6 patients the recipient atrium rate response (P-P interval) to baroreceptor stimulation by phenylephrine was also simultaneously determined by transesophageal recording. Results None of the 30 patients showed prolongation of RR intervals in the donor heart. The average BRS value was −0.28 ± 0.54 ms/mmHg (range −1.3–0.7 ms/mmHg). In the 6 patients in whom BRS was obtained at both the recipient atrium (P-P) and donor heart (R-R) the changes were 7.6 ± 5.7 ms/mmHg and −0.38 ± 0.58 ms/mmHg respectively ( p = 0.02), thus confirming that the absent RR interval lengthening in the donor heart is the consequence of efferent vagal fiber interruption. Conclusions The absence of any RR interval prolongation following phenylephrine induced baroreceptor stimulation demonstrates that vagal efferent reinnervation of the donor heart does not occur up to 24 months in patients operated via the standard Lower-Shumway procedure. It is also suggested that analysis of baroreceptor reflexes is a more specific method in the examination of cardiac parasympathetic reinnervation.

Can two‐dimensional speckle tracking echocardiography be useful for left ventricular assessment in the early stages of hereditary haemochromatosis?

Abstract: BACKGROUND Hereditary haemochromatosis (HH) is a common inherited disease. Abnormally increased intestinal iron absorption and accelerated recycling of iron by macrophages lead to progressive body iron accumulation and the generation of oxidative stress. In the late stages, iron overload can lead to dysfunction of the left ventricle (LV). It is believed that two-dimensional speckle tracking echocardiography (2D STE) can evaluate LV dysfunction more accurately than conventional echocardiography. This accurate evaluation seems to be clinically important in the early stages of HH before substantial damage of the LV. Evaluation of this assessment was the purpose of this paper. METHODS We prospectively enrolled 24 patients with early diagnosed HH and without any history of cardiovascular diseases; 23 healthy age- and sex-matched volunteers constituted the control group. Standard echocardiographic parameters and LV rotation and strain parameters were assessed and compared between the groups. RESULTS All echocardiographic parameters were within normal ranges, and there were no differences between the groups. 2D STE revealed significantly worse basal and apical rotation, twist and torsion values in HH patients. The peak systolic longitudinal strain was decreased in HH patients, even though the LV ejection fraction (LVEF) was normal. There were weak correlations between the iron turnover and 2D STE parameters. CONCLUSIONS 2D STE seems to be more sensitive than traditional echocardiography for detecting LV abnormalities in HH patients who are diagnosed early. The results of this study may be clinically useful, but their relevance and therapeutic implications remain to be confirmed by further studies.

Infections of cardiac implantable electronic devices: Epidemiology, classification, treatment, and prognosis.

Abstract: The increasing number of implantation procedures of implantable cardiac electronic devices (ICEDs) leads to a substantial growth of a cohort of patients in whom complications of such a therapy occur. Infective complications are among the most severe ones, as they are often associated with poor prognosis. Depending on the criteria applied, the incidence of cardiac device infection (CDI) is estimated at 0.5-2.2%. Many risk factors of CDIs have been identified, among which the most important are numerous previous cardiac electrotherapy procedures and their complexity, and the lack of perioperative antibiotic prophylaxis. Appropriate diagnosis of a suspected CDI is of utmost importance, as well as the correct classification of the infection, which leads to adequate treatment. Management of a CDI should include complete removal of the implanted device. Additionally, empirical and then targeted antibiotic therapy should be instituted. The prognosis of CDI may, nonetheless, be unfavorable. Despite appropriate treatment, the total mortality rate of such complication is estimated to be as high as 35%.

Intensive exercise and its effect on the heart: Is more always better?

Abstract: Regular physical exercise is undoubtedly beneficial for humans. Since the 1950s, numerous prospective follow-up studies have assessed both all-cause and cardiovascular (CV) mortality in relation to levels of physical activity. The results have always been unambiguous. Both men and women who presented with higher levels of physical activity were found to have a reduced risk of death (by up to 50%). Noteworthy, those who maintain a physically active lifestyle but at the same time present with other risk factors for CV diseases (CVD; smoking, hyperlipidemia, hypertension, diabetes, obesity) appear to be at a lower risk of premature death than sedentary subjects without risk factors [1]. Physical activity reduces the incidence of hypertension, ischemic heart disease and CV events, type 2 diabetes, cancers (in particular colon and breast cancer) and osteoporosis [2]. Furthermore, when applied in the secondary prevention of CVD, regular physical exercise, regular physical exercise reduces all-cause mortality. Whether for health-related reasons or not, the number of people participating in sports activities is increasing and healthy lifestyle has indeed become fashionable in the last decade. In addition, extreme forms of endurance exercise such as marathon, triathlon and ironman triathlon have become increasingly popular among amateurs. Globally, the number of marathon runners increased by 13% in 2009–2014 and 0.5% of the United States population participated in at least one marathon [3, 4]. Amateur participation in these extreme sports is associated with the need for hours of training, often daily, and competitions are exhausting. Thus, a question arises whether in spite of undisputable health benefits connected with physical activity, such intensive forms of endurance sport still continue to be so, or if they can adversely affect the cardiovascular system. Is more always better?

Implantable cardioverter-defibrillators in patients with long QT syndrome: a multicentre study.

Abstract: Background: Implantable cardioverter-defibrillator (ICD) therapy has been proven effective in the prevention of sudden cardiac death, but data on outcomes of ICD therapy in the young and otherwise healthy patients with long QT syndrome (LQTS) are limited. Aim: We sought to collect data on appropriate and inappropriate ICD discharges, risk factors, and ICD-related complications. Methods: All LQTS patients implanted with an ICD in 14 centres were investigated. Demographic, clinical, and ICD therapy data were collected. Results: The study included 67 patients (88% female). Median age at ICD implantation was 31 years (12–77 years). ICD indication was based on resuscitated cardiac arrest in 46 patients, syncope in 18 patients, and malignant family history in three patients. During a median follow-up of 48 months, 39 (58%) patients received one or more ICD therapies. Time to first appropriate discharge was up to 55 months. Inappropriate therapies were triggered by fast sinus rhythm, atrial fibrillation, and T-wave oversensing. No predictors of inappropriate shocks were identified. Risk factors for appropriate ICD therapy were: (1) recurrent syncope despite b-blocker treatment before ICD implantation, (2) pacemaker therapy before ICD implantation, (3) single-chamber ICD, and (4) noncompliance to b-blockers. In 38 (57%) patients, at least one complication occurred. Conclusions: ICD therapy is effective in nearly half the patient population; however, the rates of early and late complica­tions are high. Although the number of unnecessary ICD shocks and reimplantation procedures may be lowered by modern programming and increased longevity of newer ICD generators, other adverse events are less likely to be reduced.

Use of autonomic nervous system neurotransmitters inhibition and atrial parasympathetic fibers ablation for the treatment of atrial arrhythmias and to preserve drug effects

Abstract: Atrial arrhythmias, a major contributor to cardiovascular morbidity, are believed to be influenced by autonomic nervous system tone. The main purpose of this invention was to highlight new findings that have emerged in the study of effects of autonomic nervous system tone on atrial arrhythmias, and its interaction with class III antiarrhythmic drug effects. This invention evaluates the significance of sympathetic and parasympathetic activation by determining the effects of autonomic nervous system using a vagal and stellar ganglions stimulation, and by using autonomic nervous system neurotransmitters infusion (norepinephrine, acetylcholine). This invention evaluates the autonomic nervous system effects on the atrial effective refractory period duration and dispersion, atrial conduction velocity, atrial wavelength duration, excitable gap duration during a stable circuit (such atrial flutter circuit around an anatomical obstacle), and on the susceptibility of occurrence (initiation, maintenance and termination) of atrial re-entrant arrhythmias in canine. This invention also evaluates whether autonomic nervous system activation effects via a local neurotransimitters infusion into the right atria can alter those of class III antiarrhythmic drug, sotalol, during a sustained right atrial flutter. This invention represents an emergent need to set-up and develop a new class of anti-cholinergic drug therapy for the treatment of atrial arrhythmias and to combine this new anti-cholinergic class to antiarrhythmic drugs. Furthermore, this invention also highlights the importance of a local application of parasympathetic neurotransmitters/blockers and a catheter ablation of the area of right atrium with the highest density of parasympathetic fibers innervation. This may significantly reduce the occurrence of atrial arrhythmias and may preserve the antiarrhythmic effects of any drugs used for the treatment of atrial re-entrant arrhythmias.

"Cardioneuroablation"--new treatment for neurocardiogenic syncope, functional AV block and sinus dysfunction using catheter RF-ablation

Abstract: Cardiac neuroablation is a new technique for management of patients with dominantly adverse parasympathetic autonomic influence. The technique is based on radiofrequency (RF) ablation of autonomic connections in the three main ganglia around the heart. Their connections are identified by Fast-Fourier Transforms (FFTs) of endocardial signals: sites of autonomic nervous connections show fractionated signals with FFTs shifted to the right. In contrast, normal myocardium without these connections does not show these features. RF-ablation is thought to inflict permanent damage on the parasympathetic autonomic influence because its cells are adjacent to the heart whereas sympathetic cells are remote. Twenty-one patients with a mean age of 48 years, neurally mediated reflex syncope in six, functional high grade atrioventricular block in seven and sinus node dysfunction in 13 (there is overlap between the second and third groups) were treated. Follow-up for a mean of 9.2 months demonstrated success in all cases with relief of symptoms. No complications occurred.

Acc/aha/hrs 发布新版成人室上性心动过速指南

Abstract: 美国心脏病学院（ACC）、美国心脏协会（AHA）、美国心律学会（HRS）专家工作组历时1年，于近期联合发布了新版成人室上性心动过速（SVT）指南，全文于2015年9月23日全文刊登在Circulation、Journal of the American College of Cardiology和Heart Rhythm Journal三大重要杂志上。

Common syndromes of orthostatic intolerance.

Abstract: The autonomic nervous system, adequate blood volume, and intact skeletal and respiratory muscle pumps are essential components for rapid cardiovascular adjustments to upright posture (orthostasis). Patients lacking sufficient blood volume or having defective sympathetic adrenergic vasoconstriction develop orthostatic hypotension (OH), prohibiting effective upright activities. OH is one form of orthostatic intolerance (OI) defined by signs, such as hypotension, and symptoms, such as lightheadedness, that occur when upright and are relieved by recumbence. Mild OI is commonly experienced during intercurrent illnesses and when standing up rapidly. The latter is denoted “initial OH” and represents a normal cardiovascular adjustment to the blood volume shifts during standing. Some people experience episodic acute OI, such as postural vasovagal syncope (fainting), or chronic OI, such as postural tachycardia syndrome, which can significantly reduce quality of life. The lifetime incidence of ≥1 fainting episodes is ∼40%. For the most part, these episodes are benign and self-limited, although frequent syncope episodes can be debilitating, and injury may occur from sudden falls. In this article, mechanisms for OI having components of adrenergic hypofunction, adrenergic hyperfunction, hyperpnea, and regional blood volume redistribution are discussed. Therapeutic strategies to cope with OI are proposed.