Radiation dose reduction in the setting of cryoballoon ablation for atrial fibrillation: the value of optimized fluoroscopy settings and intracardiac echocardiography.

Cryoballoon (CB) has proven to be very effective in the percutaneous treatment of atrial fibrillation (AF). CB ablation is still hampered by X-ray exposure and the doses applied are consistently higher if compared to radiofrequency ablation. All patients who underwent CB ablation between 2015 and 2020 were analysed. Intracardiac echography was consistently used for transeptal puncture. To demonstrate the differences in radiation exposure 3 groups of 50 consecutive patients were selected. In the first group (G1) 3D rotational angiography (3DRA) was used as an intraprocedural imaging method. In the second group (G2), traditional X-ray imaging was used and frame rates both for fluoro and cine modes of diascopy were lowered. In the third group (G3) only 2-3 frames per second were used, cine mode was abandoned and the grid was removed from the X-ray detector. A total of 150 patients were included (76% males, mean age 57.3 ± 11.5 years). A dramatic reduction of radiation dose was obtained from 9585 ± 5610 µGy/m2 in G1 to 2469 ± 2002 µGy/m2 in G2 and finally 227.1 ± 360 µGy/m2 in G3 (p < 0.0001). There was also a significant decrease of procedural and fluoroscopy times. No difference in major complications and midterm outcomes was found between the groups. By following a few relatively simple steps (omitting the pre-procedural imaging, removing grid from the X-ray detector and using very low frame rates) CB ablation could be performed with ultralow radiation exposure without compromising the safety of efficacy of the procedure.

A CROSS-SECTIONAL STUDY OF HEPATITIS B AND HEPATITIS C KNOWLEDGE AMONG DENTAL MEDICINE STUDENTS AT THE UNIVERSITY OF ZAGREB.

Dental health care workers, particularly dental medicine students (DMS), are at an increased risk of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. The aim of our study was to assess the level of knowledge on HBV and HCV, estimate needlestick injury (NSI) prevalence and reporting practice in DMS at the University of Zagreb, and analyze how enrolment in obligatory and supplemental courses affects knowledge and NSI reporting practice. The knowledge was assessed by our questionnaires based on the Centers for Disease Control general handouts. Additional information was collected to examine the prevalence and reporting practice of NSI. Data were analyzed by descriptive statistical analysis, independent-samples t-test, proportion analyses, and combined factor analyses of categorical and quantitative variables in SPSS and R. In total, 206 students participated in the survey. The overall level of HBV- and HCV-related knowledge was poor, with the mean scores of 61.90% and 51.35%, respectively. Moreover, students enrolled in the first year demonstrated significantly lower levels of knowledge in comparison with their older peers. Of all participants, 18.2% had sustained a NSI and the majority of them (78.95%) had never reported the injury. In conclusion, DMS have low levels of knowledge on important occupational pathogens and poor NSI reporting practice. Moreover, formal education in the current form has failed to significantly improve student competence and theoretical knowledge translates poorly into more conscientious injury reporting practice. We should look for a better way to increase student awareness and level of knowledge on this topic.

Differences in activated clotting time and total unfractionated heparin dose during pulmonary vein isolation in patients on different anticoagulation therapy.

BACKGROUND: Periprocedural pulmonary vein isolation (PVI) anticoagulation requires balancing between bleeding and thromboembolic risk. Intraprocedural anticoagulation is monitored by activated clotting time (ACT) with target value >300 s, and there are no guidelines specifying an initial unfractionated heparin (UFH) dose. METHODS: We aimed to assess differences in ACT values and UFH dosage during PVI in patients on different oral anticoagulants. We conducted an international, multi-center, registry-based study. Consecutive patients with atrial fibrillation (AF) undergoing PVI, on uninterrupted anticoagulation therapy, were analyzed. Before transseptal puncture, UFH bolus of 100 IU/kg was administered regardless of the anticoagulation drug. RESULTS: Total of 873 patients were included (median age 61 years, IQR 53-66; female 30%). There were 248, 248, 189, 188 patients on warfarin, dabigatran, rivaroxaban, and apixaban, respectively. Mean initial ACT was 257 ± 50 s, mean overall ACT 295 ± 45 s and total UFH dose 158 ± 60 IU/kg. Patients who were receiving warfarin and dabigatran compared to patients receiving rivaroxaban and apixaban had: (i) significantly higher initial ACT values (262 ± 57 and 270 ± 48 vs. 248 ± 42 and 241 ± 44 s, p < .001), (ii) significantly higher ACT throughout PVI (309 ± 46 and 306 ± 44 vs. 282 ± 37 and 272 ± 42 s, p < .001), and (iii) needed lower UFH dose during PVI (140 ± 39 and 157 ± 71 vs. 171 ± 52 and 172 ± 70 IU/kg). CONCLUSION: There are significant differences in ACT values and UFH dose during PVI in patients receiving different anticoagulants. Patients on warfarin and dabigatran had higher initial and overall ACT values and needed lower UFH dose to achieve adequate anticoagulation during PVI than patients on rivaroxaban and apixaban.

Use of figure of eight suture for groin closure with no heparin reversal in patients undergoing cryoballoon ablation for atrial fibrillation.

PURPOSE: We aimed to demonstrate the feasibility of figure of eight (FoE) suture for groin access closure in cryoballoon (CB) ablation and its impact on the lab workflow. METHODS: We retrospectively analyzed all patients who underwent CB ablation in our institution from June 2018. From June 2019, we have been consistently using FoE suture for hemostasis (FoE+ group), and before that conventional manual compression was utilized (FoE- group). Ablations were performed under uninterrupted oral anticoagulant strategy. Both femoral veins were punctured, and a single introducer was placed in each vein. In the FoE- group, after ablation, protamine was administered, and manual compression was applied. In the FoE+ group, the suture was placed in both groins without protamine administration and manual compression. All patients were in decubitus position until the next morning. RESULTS: A total of 190 consecutive patients (73.2% male, 59.7 ± 11.0 years old) were evaluated, 90 being in the FoE+ group. There was no difference in the mean procedure duration between two groups (72.7 ± 23.1 min vs 73.7 ± 27.1 min, p = 0.784). However, the total lab time was significantly longer in FoE- group (132.9 ± 35.3 min vs 109.9 ± 32.6 min, p < 0.0001). There was no difference in complication rates. No major vascular complications were found in our cohort. CONCLUSIONS: Utilization of FoE sutures for hemostasis seems to be a safe and effective after cryoballoon ablation. It abolishes the need for protamine administration which can cause serious adverse events. As manual compression is unrequired, EP lab workflow improves due to significantly shortened total lab time per patient.

Improved real-time recordings using the fourth-generation cryoballoon technology-detection of dual fascicle electrograms.

BACKGROUND: We aimed to analyze the rate of visualization of real-time (RT) recordings and dual fascicle electrograms in our first series of patients treated with the fourth-generation cryoballoon (CB) device. METHODS: All consecutive patients who underwent CB ablation using the fourth-generation technology were included in the analysis. In all procedures, we used a 28-mm CB placed via a single transseptal puncture guided by intracardiac ultrasound. A 20-mm octapolar intraluminal circular catheter was used for intracardiac recordings. A single 180-s freeze strategy was employed. RESULTS: A total of 129 patients (72.9% male, mean age 60.1 ± 10.9 years) were enrolled in the study. RT recordings were detected in 445 (86.2%) pulmonary veins (PVs). Specifically, RT recordings were visualized in 115 left superior PVs (89.2%), 107 left inferior PVs (82.9%), 118 right superior PVs (91.4%), and 105 right inferior PVs (81.3%). Dual fascicle electrograms could be observed only in patients in sinus rhythm, in 23 of 396 PVs (5.8%). They were most commonly observed in the left superior PV (8.1%), somewhat less in both inferior veins (6.1%), while this phenomenon was least frequent in the right superior PV (3.0%). CONCLUSIONS: By using the fourth-generation CB, we report a specific pattern of isolation represented by a sequential isolation of two apparently distinct PV fascicles during a single CB freeze delivery. This phenomenon occurred in 5.8% of PV ablations. Of note, the rate of visualization of RT isolation with this novel CB was very high and could be documented in 86.2% of PVs.

MANAGEMENT OF PATIENTS WITH CARDIAC IMPLANTABLE ELECTRONIC DEVICES UNDERGOING MAGNETIC RESONANCE IMAGING - PROPOSAL FOR UNIFIED HOSPITAL PROTOCOL: CROATIAN WORKING GROUP ON ARRHYTHMIAS AND CARDIAC PACING.

For many years, magnetic resonance imaging (MRI) was contraindicated in patients with cardiac implantable electronic devices (CIED). Today, there is a growing amount of evidence that MRI can be performed safely in the majority of patients with CIEDs. Firstly, there are devices considered MRI conditional by manufacturers that are available on the market and secondly, there is clear evidence that even patients with MRI non-conditional devices can also undergo MRI safely. Protocols have been developed and recommendations from different cardiac and radiologic societies have been published in recent years. However, the majority of physicians are still reluctant to refer these patients to MRI. Therefore, this document is published as a joint statement of the Croatian Working Group on Arrhythmias and Cardiac Pacing and Department of Radiology, Sestre milosrdnice University Hospital Centre to guide and ease the management of patients with CIED undergoing MRI. Also, we propose a unified protocol and checklist that could be used in Croatian hospitals.

TWARMI pilot trial: The value and optimal criteria of microvolt T-wave alternans in the diagnosis of reversible myocardial ischemia in patients without structural cardiac disease.

AIMS: Microvolt T-wave alternans (MTWA) testing is a beat-to-beat fluctuation in the amplitude of T wave. We investigated whether: (a) MTWA can be new non-invasive tool for detection of reversible ischemia in patients with suspected CAD without structural heart disease, (b) MTWA can detect ischemia earlier and with greater test accuracy compared with exercise ECG ST-segment testing, and (c) threshold value of MTWA and heart rate at which the alternans is estimated can be different compared to standard values. METHODS: A total of 101 patients with suspected stable coronary disease, but without structural heart disease, were included. Echocardiography, exercise ECG test, MTWA with classical and modified threshold alternans values, and coronary angiography were performed. RESULTS: About 33.3% patients had a false-positive result on exercise ECG test. The sensitivity of exercise ECG ST-segment test in the detection of coronary artery disease was 97.8%, and the specificity was 42.5% (DOR 33.89). In a group of angiographically positive patients, standard MTWA accurately identified 60% of patients, while 40% had a false-negative result. About 91.8% patients with negative angiography result were accurately identified with 8.2% false positives. The sensitivity of MTWA was 59.61% and specificity 91.83%. Best ratio of sensitivity and specificity (86.53% and 95.91%, DOR 151.06) had modified criteria for positive MTWA (MTWA >1.5 µV at heart rate 115-125/min). CONCLUSIONS: This study showed that MTWA can be the new non-invasive tool for the detection of reversible ischemia in patients with suspected CAD without structural heart disease. Also, MTWA can detect ischemia earlier and with greater accuracy compared with exercise ECG testing.

Manual Intracardiac Electrogram Method Is Accurate Alternative to Echocardiography for Atrioventricular and Interventricular Optimization in Cardiac Resynchronization Therapy.

Some manufacturers do not provide automated intracardiac electrogram method (IEGM) systems for atrioventricular (AV) and interventricular (VV) delay optimization in cardiac resynchronization therapy (CRT). We aimed to evaluate the accuracy of manual IEGM method in 48 patients previously implanted with Medtronic Syncra CRT. All patients underwent standard device interrogation followed by CRT optimization by IEGM method and by echocardiography one month after implantation. The patient mean age was 60.7±11.8 years and there were 33 (68.8%) males. After CRT implantation, the left ventricular ejection fraction increased from 28.0±7.9% to 39.1±11.0% (p<0.001). Optimal aortic flow Velocity Time Integral (aVTI) was obtained when VV was set to 20-50 ms left ventricular pre-activation. There was a strong correlation between VV values determined by echocardiography and IEGM (R=0.823, p<0.001). We found no significant difference in AV, VV and aVTI values between echocardiography and IEGM method. However, IEGM was significantly less time-consuming than echocardiography [20 (10-28) vs. 40 (35-60) minutes, p<0.001]. Manual IEGM method may be good alternative to echocardiography and automated IEGM method. It also emphasizes the need for implementation of automated IEGM systems in as many CRT devices as possible.

[ATRIAL FIBRILLATION AND HEMODINAMICALY UNSTABLE WIDE QRS COMPLEX TACHYCARDIA ­ A case report].

Tachycardia is an arrhythmia characterized by heart rate > 100 / minute. According to the width of the QRS complex it can be divided into narrow QRS (< 120 ms) and wide QRS tachycardia (> 120 ms). Narrow QRS tachycardia is always supraventricular which means that its source is proximal to the bundle of His, while wide QRS tachycardia can be ventricular (source is in the ventricle, distal to the bundle of His) or supraventricular. The strategies for treating these two conditions are different so the correct diagnosis is prerequisite for optimal therapy. We present this case because the differential diagnosis of wide QRS tachycardia and therefore the treatment planning was particularly difficult due to concurrently present atrial fibrillation with hemodynamic compromise and an acute threat to the life of the patient.

[The first case of radiofrequent ablation of ventricular tachycardia in a patient with ischemic cardiomyopathy in our country]. / Prvi slucaj radiofrekventne ablacije ventrikularne tahikardije kod bolesnika s ishemijskom kardiomiopatijom u nasoj zemlji.

Ablation of ventricular tachycardia in patients with ischemic cardiomyopathy is more complicated and more difficult than ablation of most supraventricular tachycardias. Arrhythmogenic substrate is complex and its localisation is often unclear. Because of the tachycardia characteristics, more precise mapping methods often can't be utilised. Also, patients are usually seriously ill with decreased systolic function, heart failure, ischemia and various comorbidities where tachycardia induction and ablation procedure may facilitate abrupt hemodynamic disturbance. Uninducibility of the clinical tachycardia can be achieved in 65-95% of patients, but tachycardia recurs in 20-44% of patients. Serious complications were noted in 8% of patients with lethal outcome in 2.7% of patients. Decision about therapeutic strategy should be made individually according to potential risk and procedure benefit. This paper presents the first case of the successful ablation of ventricular tachycardia in a patient with ischemic cardiomyopathy in our country.

Morbidly obese are ghrelin and leptin hyporesponders with lesser intragastric balloon treatment efficiency : ghrelin and leptin changes in relation to obesity treatment.

BACKGROUND: Ghrelin and leptin recently emerged as the most influential neuroendocrine factors in the pathophysiology of obesity. The said peptides act in reciprocity and are responsible for regulation of appetite and energy metabolism. Intragastric balloons acquired worldwide popularity for obesity treatment. However, the roles of ghrelin and leptin in intragastric balloon treatment were still not systematically studied. METHODS: A prospective single-center study included 43 Caucasians treated with BioEnterics intragastric balloon, with age range of 18-60, and divided to non-morbid (body mass index cutoff 40 kg/m(2)) or morbid type of obesity, with 12 months follow-up. Serum hormonal samples were taken from fasting patients and kept frozen until analyses. RESULTS: Significant differences were observed in anthropometrics and there were no differences between genders or comorbidities. The baseline weight for non-morbid vs. morbid was 104 kg (90-135) vs. 128.5 kg (104-197). Weight loss was statistically different between the studied groups during the study course with a median control weight at 6 months of 92 kg (72-121) vs. 107 kg (84-163), p < 0.001. Treatment was successful for 18 (94.7%) vs. 16 (66.7%) patients, p = 0.026. Ghrelin varied from 333.3 to 3,416.8 pg/ml and leptin from 1.7 to 61.2 ng/ml, with a statistically significant time-dependent relationship. A significant difference (p = 0.04) with emphasized ghrelin peak was found in the 3rd month of treatment for non-morbidly obese subjects. CONCLUSIONS: The importance of ghrelin and leptin in treatment-induced changes was reaffirmed. Ghrelin hyper-response in non-morbidly obese subjects characterized greater short-term treatment efficiency and landmarked an inclination to weight regain. The results suggest a potential pattern of individualization between obese patients according to body mass index towards intragastric balloon or bariatric surgery. Further studies are needed in order to get better insights in the pathophysiologic mechanisms of obesity.

First report of connexin 43-positive gastrointestinal stromal tumor (GIST).

Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms most frequently found in the stomach and presenting without symptoms or with unspecific ones such as hemorrhage and abdominal pain. The malignant potential of GIST is variable and there are several prognostic indexes for treatment and follow up. The superior diagnostic method is endoscopic ultrasound combined with fine needle aspiration biopsy (EUS-FNA) immunocytochemistry. Surgery is the preferable treatment option, while recurrent or advanced disease is best managed with thyrosine kinase inhibitors. We report a case of a 20-year-old man that presented with gastrointestinal bleeding and anemia. Upper gastrointestinal endoscopy detected a submucosal lesion and computerized tomography revealed a node near the liver. EUS-FNA immunocytochemistry found CD-117 positive cells suggestive of GIST and the patient was operated on. The diagnosis was confirmed by histopathology with immunostaining. Prognostic assessment was done according to tumor size and Ki-67 index with mitosis count on microscopy. Many studies have shown that tumors demonstrate an abnormal number, structure and occurrence of connexin proteins with altered connexin-mediated intercellular communication. Since a great deal of gastroenterological tumors express connexin 43, our aim was to find out whether it was present in GIST. Immunohistochemically, the tumor was positive for connexin 43, which was not previously described as typical. The early postoperative course was uneventful, free from complications. At three-year postoperative follow-up, the patient was subjectively well and without clinical signs of disease recurrence.