Jacek Gajek

Development of porcine model of chronic tachycardia-induced cardiomyopathy

BACKGROUND There are few experimental models of heart failure (HF) in large animals, despite structural and functional similarities to human myocardium. We have developed a porcine model of chronic tachycardia-induced cardiomyopathy. METHODS Homogenous siblings of White Large breed swine (n=6) underwent continuous right ventricular (RV) pacing at 170 bpm; 2 subjects served as controls. In the course of RV pacing, animals developed a clinical picture of HF and were presented for euthanasia at subsequent stages: mild, moderate and end-stage HF. Left ventricle (LV) sections were analyzed histologically and relative ANP, BNP, phospholamban and sarcoplasmic reticulum calcium ATPase 2a transcript levels in LV were quantified by real time RT-PCR. RESULTS In the course of RV pacing, animals demonstrated reduced exercise capacity (time of running until being dyspnoeic: 6.6 ± 0.5 vs. 2.4 ± 1.4 min), LV dilatation (LVEDD: 4.9 ± 0.4 vs. 6.7 ± 0.4 cm), impaired LV systolic function (LVEF: 69 ± 8 vs. 32 ± 7 %), (all baseline vs. before euthanasia, all p<0.001). LV tissues from animals with moderate and end-stage HF demonstrated local foci of interstitial fibrosis, congestion, cardiomyocyte hypertrophy and atrophy, which was not detected in controls and mild HF animals. The up-regulation of ANP and BNP and a reduction in a ratio of sarcoplasmic reticulum calcium ATPase 2a and phospholamban in failing myocardium were observed as compared to controls. CONCLUSIONS In pigs, chronic RV pacing at relatively low rate can be used as an experimental model of HF, as it results in a gradual deterioration of exercise tolerance accompanied by myocardial remodeling confirmed at subcellular level.

Electrocardiographic characteristics of atrioventricular block induced by tilt testing

AIMS The electrocardiographic (ECG) characteristics of atrioventricular (AV) block during reflex syncope may be unique due to the presence of hypervagotonia. The aim of the present study was to define the ECG characteristics of the AV block induced by neurocardiogenic reflex provoked by tilt testing (TT). METHODS AND RESULTS A series of 31 patients with presumed vasovagal syncope and AV block provoked by TT was studied. The duration of PP and PR interval, AV block grade and type, concomitant arrhythmias, and timing of the AV block occurrence were assessed. The AV block occurred at TT termination in 26 patients, in the recovery in 4 patients, and in both periods in 1 patient. Atrioventricular block was preceded by sinus slowing, and sinus rhythm during AV block was slow and instable. Mobitz I, 2:1 second-degree AV block, and advanced second-degree AV block were recognized in 35.5, 48.4, and 67.8% of patients, respectively. Third-degree AV block was diagnosed in 41.9% of patients. Twenty-one patients had at least two AV block forms. The most prevalent concomitant arrhythmia was junctional escape rhythm (61.3%). CONCLUSION (i) The occurrence of the AV block during neurocardiogenic reaction induced by TT is always preceded by sinus rhythm slowing and usually by PR interval prolongation. (ii) The AV block provoked by TT usually occurs at TT termination, but may occur even in the recovery period in a supine position. Sometimes the AV block may be present both at TT termination and during the recovery period.

The influence of a tilt training programme on the renin-angiotensin-aldosterone system activity in patients with vasovagal syncope.

Objective — We assessed the influence of short-term and long-term tilt training on the activity of the renin-angiotensin-aldosterone system (RAAS) in vasovagal patients. Methods and results — Thirty-nine patients (28 F, 11 M) aged 39.7 ± 11.2 years with a history of vasovagal syncope and a positive head-up tilt test (HUT) were studied. Blood samples for plasma renin activity (PRA) and aldosterone (ALDO) concentration were drawn at the baseline, immediately after HUT and 10 min after HUT, during the diagnostic, the negative short-term (2-5 days) follow-up HUT and long-term (1-3 months) follow-up HUT.Tilt training was started after diagnostic HUT. In diagnostic HUT, PRA increased significantly immediately after HUT comparing to the baseline, during recovery the values did not change.ALDO concentration increased after HUT comparing to baseline and further increased during recovery. After short-term tilt training, PRA and ALDO concentrations did not significantly change compared to their corresponding values in diagnostic HUT.After long-term tilt training, PRA did not significantly change compared to the values in the diagnostic and short-term follow-up HUT.ALDO concentration also did not change significantly at the baseline and immediately after HUT, and 10 min after HUT ALDO concentration was significantly lower than after diagnostic HUT. Conclusions — Tilt training changes the response of RAAS to the prolonged orthostasis in vasovagal patients. The coupling between PRA and ALDO after diagnostic HUT has been found to be altered and the physiological relationship was restored after long-term tilt training.The beneficial effect of tilt training depends partially on changed RAAS activation.

Clinical relevance of syncope and presyncope induced by tilt testing.

Objective — The authors investigated the relation between presyncope and syncope induced by tilt testing (HUTT) and demographics, medical history and HUTT data.The demographics, syncopal burden, data regarding the spontaneous syncope and reproduction of symptoms during HUTT were compared among patients with induced syncope and presyncope. The study group consisted of 574 patients (371 women, 203 men), aged 43.7 ± 18.5 years. Methods and results — Patients with syncope induced by HUTT (418 patients, 63.9% women) had a higher number of syncopal episodes in their medical history. Stepwise logistic regression revealed that syncope provocation was independently related to the cardiodepressive type of neuro-cardiogenic reaction (OR 7.8, CI 4.2-14.4, P < 0.001), NTG use (OR 1.7, CI: 1.0-2.7, P < 0.05), the reproduction of the symptoms during HUTT (OR 2.0, CI: 1.3-3.1, P < 0.01) and the higher number of syncopal episodes (OR 2.0, CI: 1.3-3.0, P < 0.01). In patients with positive HUTT during a passive phase it was related to the cardiodepressive type of reaction (OR 26.5, CI: 5.9-118.5, P < 0.001). In the group with positive HUTT after NTG syncope was related to the cardiodepressive type (OR 5.7, CI: 2.9-11.2, P < 0.001), vasovagal history (OR 2.0, CI: 1.2-3.3, P < 0.01), reproduction of the spontaneous symptoms (OR 1.9, CI: 1.1-3.1, P < 0.05) and higher number of syncopal episodes (OR 2.1, CI: 1.3-3.3, P < 0.01). Conclusions — Syncope is more frequently a HUTT outcome than presyncope.The provocation of syncope in the passive phase of HUTT depends only on the cardiodepressive type of neuro-cardiogenic reaction. The induction of presyncope after nitroglycerin provocation is related to the possibility of a false positive reaction.

Influence of tilt training on activation of the autonomic nervous system in patients with vasovagal syncope.

Objective — Tilt training is a new treatment for vasovagal syncope. Its therapeutic efficacy is thought to be the result of the desensitization of cardiopulmonary receptors, but it could be the influence of the tilt training on the activation of the autonomic nervous system as well. Methods and results — The study group consisted of 24 vasovagal patients (17 women and 7 men) aged 32.5 ± 11.8 years.The diagnostic head-up tilt test was performed according to the Italian protocol with nitroglycerin if necessary. The monitoring head-up tilt test was performed according to the Westminster protocol without provocation, after 1 to 3 months of tilt training. Holter ECG recordings for HRV parameters (time and frequency domain) were obtained from selected 2-min intervals before, during and after the diagnostic and monitoring tilt test. The diagnostic test was positive in the passive phase in 6 and after provocation in 18 patients. During the training period no syncope occurred.Analysing the HRV parameters we demonstrated the following findings: 1. mRR decreases immediately after assumption of a vertical position in both tests (diagnostic and monitoring) but in the diagnostic test its further decrease occurs earlier than in the monitoring test; 2. the absolute power of the HF component is greater in the early phase of tilt after tilt training than in the corresponding period in the diagnostic test. Conclusions — After a longer period of tilt training the activation of the sympathetic nervous system in response to the erect position is diminished.

The risk for syncope and presyncope during surgery in surgeons and nurses.

Background:  Surgeons and nurses are exposed to orthostatic stress.

Permanent His bundle pacing — An optimal treatment method in heart failure patients with AF and narrow QRS

Article history: Received 28 March 2016 Accepted 3 April 2016 Available online 8 April 2016 complexes the cardiac resynchronisation contributes to hemodynamic, echocardiographic and clinical improvement [3]. There are very scarce data dealing with the problem of an outcome of resynchronisation in narrow and broad QRS patients. Only one small study by Lustgarten et al. has addressed this problem and only in a subset of studied patients. The smart idea of their study was to implant CHF and LBBB

The Choice of Surgical Specialization by Medical Students and Their Syncopal History

Background The aim of the study was to assess whether medical students’ fainting outside the university or while witnessing surgical procedures and/or autopsies influenced their choice of a specialization. Materials and Methods The study group consisted of 605 medical students (from fourth to sixth year of study) from five medical universities in Poland (325 women, 212 men and 8 responders of an unspecified gender). The median age of subjects studied was 23 years, and the interquartile range was 23–24 years. The students at each university were chosen randomly by the author who worked there and had contact with them. An anonymous questionnaire was developed to gather information regarding demographics, the specialization which each student wanted to choose, the syncope occurrence in the medical history, the syncope and presyncope occurrence during surgery and autopsy as well as the syncopal events’ characteristics. Results The group of 15% of women and 30% of men declared to have pursued the surgical specialization (P<0.001), 29% of women and 56% of men declared the intention to pursue an invasive specialization (P<0.001). As many as 36.0% of women studied and 13.1% of men studied reported syncopal spells outside university (P<0.001). Only 41 students (6.8%) reported that syncope or presyncope in any studied circumstances had an impact on their specialization choice. The multivariate analysis showed that the choice of surgical specialization is related to the male gender and the absence of syncopal spells outside the university. Conclusions Syncopal and presyncopal spells may affect the professional choices of the medical students. The male gender and a lack of syncope occurrence outside operating room are related to the choice of surgical specialization.

Cardiac arrest due to left circumflex coronary artery embolism as a complication of subtherapeutic oral anticoagulation in a patient with mitral and aortic mechanical valve prostheses.

We report a case of a 65-year-old female patient after replacement of aortic and mitral valve with mechanical prostheses and implantation of a pacemaker hospitalized in our clinic due to acute coronary syndrome complicated with cardiac arrest due to ventricular fibrillation. The electrocardiogram performed on admission showed signs of myocardial infarction with concomitant ventricular pacing. After successful resuscitation the coronary angiography was performed, which showed occlusion of the left circumflex artery (LCx) by thrombus. On the basis of intravascular ultrasound imaging the presence of vulnerable plaque, parietal thrombus and dissection of LCx were excluded. It suggested that occlusion of the LCx resulted from its embolism by left-sided heart thrombus due to subtherapeutic oral anticoagulation. In this case suboptimal anticoagulation was partially iatrogenic. Two weeks before the patient had been given vitamin K intravenously due to indeterminable international normalized ratio (INR) level, which caused transient resistance to oral anticoagulants. This case report illustrates tragic difficulties in the treatment with vitamin K antagonists, which concern as many as 2/3 of anticoagulated patients. These troubles contributed to the search for new, more efficient and safer anticoagulants. There are two classes of new oral anticoagulant drugs, which do not require monitoring of coagulation: direct thrombin inhibitors (e.g. dabigatran) and factor Xa inhibitors (e.g. rivaroxaban). In spite of their proven efficacy in the prevention of ischaemic stroke related to atrial fibrillation and prevention or treatment of deep vein thrombosis and pulmonary embolism, the use of new oral anticoagulants for the treatment of patients with mechanical valve prostheses needs further research.

The clinical relevance of the duration of loss of consciousness provoked by tilt testing.

Objective — The authors assessed the relationships between the duration of loss of consciousness (dLOC) during tilt testing-induced syncope (TTS) and demographics, medical history as well as tilt testing results. Previous research focused on the relevance of the type of neurocardiogenic reaction during TTS. The importance of dLOC has not been assessed so far. The study was carried out in 274 patients with suspected neurally mediated syncope and total loss of consciousness during tilt testing. Results — The syncope burden, demographics, and data regarding spontaneous syncope or TTS were compared between group 1 with dLOC ≥ 47 seconds and group 2 with dLOC < 47 seconds. Medical history revealed that patients in group 1 had more syncopal spells, more frequent syncope-related traumatic injuries, urine incontinence, jerking movements and typical vasovagal history than in group 2. Moreover, group 1 patients had more frequently a cardioinhibitory type of reaction and a shorter active phase duration. In addition, they manifested more frequent accompanying cerebral hypoperfusion signs and reproduction of symptoms during TTS than patients in group 2. Conclusions — The loss of consciousness during tilt testing-induced syncope differs in terms of duration among patients with neurally mediated syncope.The dLOC during TTS is associated with medical history and tilt-testing data which confirm the vasovagal aetiology of spontaneous events. The longer dLOC suggests deeper cerebral haemodynamic disturbances during either spontaneous or provoked syncope.