Diving Deep into Arrhythmias: Unravelling the Impact of Underwater Environments on Premature Ventricular Complexes in Divers.

This review examines the relationship between the physiological demands of diving and premature ventricular complexes (PVCs) in divers. In the general population, some individuals have a greater tendency to experience PVCs, often without awareness or a clear understanding of the triggering factors. With the increasing availability and popularity of both scuba and apnoea diving, more people, including those with a predisposition to PVCs, are engaging in these activities. The underwater environment, with its unique stressors, may increase the risk of arrhythmogenic events, particularly PVCs. Here, we review the prevalence, pathophysiology, and aggravating factors of PVCs in divers, emphasising the need for a comprehensive cardiovascular assessment. Evidence suggests a higher prevalence of PVCs in divers compared with the general population, influenced by factors such as age, dive depth, gas bubbles, cold water immersion, pre-existing cardiovascular diseases, and lifestyle factors. The change in environment during diving could potentially trigger an increased frequency of PVCs, especially in individuals with a pre-existing tendency. We discuss diagnostic strategies, management approaches, and preventive measures for divers with PVCs, noting that although guidelines for athletes can be adapted, individual assessment is crucial. Significant knowledge gaps are identified, highlighting the need for future research to develop evidence-based guidelines and understand the long-term significance of PVCs in divers. This work aims to evaluate potential contributing factors to PVCs in divers and identify individuals who may be at higher risk of experiencing major adverse cardiovascular events (MACEs). This work aims to improve diver safety by promoting collaboration between cardiologists and diving medicine specialists and by identifying key areas for future investigation in this field. This work aims to improve the safety and well-being of divers by understanding the cardiovascular challenges they face, including pressure changes, cold water immersion, and hypoxia. We seek to elucidate the relationship between these challenges and the occurrence of PVCs. By synthesising current evidence, identifying knowledge gaps, and proposing preliminary recommendations, we aim to encourage collaboration between cardiologists and diving medicine specialists to optimise the screening, management, and risk stratification of PVCs in the diving population.

Optimized target delineation procedure for the radiosurgery treatment of ventricular tachycardia: observer-independent accuracy.

Background: Part of the current stereotactic arrythmia radioablation (STAR) workflow is transfer of findings from the electroanatomic mapping (EAM) to computed tomography (CT). Here, we analyzed inter- and intraobserver variation in a modified EAM-CT registration using automatic registration algorithms designed to yield higher robustness. Materials and methods: This work is based on data of 10 patients who had previously undergone STAR. Two observers participated in this study: (1) an electrophysiologist technician (cardiology) with substatial experience in EAM-CT merge, and (2) a clinical engineer (radiotherapy) with minimum experience with EAM-CT merge. EAM-CT merge consists of 3 main steps: segmentation of left ventricle from CT (CT LV), registration of the CT LV and EAM, clinical target volume (CTV) delineation from EAM specific points. Mean Hausdorff distance (MHD), Dice Similarity Coefficient (DSC) and absolute difference in Center of Gravity (CoG) were used to assess intra/interobserver variability. Results: Intraobserver variability: The mean DSC and MHD for 3 CT LVs altogether was 0.92 ± 0.01 and 1.49 ± 0.23 mm. The mean DSC and MHD for 3 CTVs altogether was 0,82 ± 0,06 and 0,71 ± 0,22 mm. Interobserver variability: Segmented CT LVs showed great similarity (mean DSC of 0,91 ± 0,01, MHD of 1,86 ± 0,47 mm). The mean DSC comparing CTVs from both observers was 0,81 ± 0,11 and MHD was 0,87 ± 0,45 mm. Conclusions: The high interobserver similarity of segmented LVs and delineated CTVs confirmed the robustness of the proposed method. Even an inexperienced user can perform a precise EAM-CT merge following workflow instructions.

Sarcopenia and adipose tissue evaluation by artificial intelligence predicts the overall survival after TAVI.

Sarcopenia is a serious systemic disease that reduces overall survival. TAVI is selectively performed in patients with severe aortic stenosis who are not indicated for open cardiac surgery due to severe polymorbidity. Artificial intelligence-assisted body composition assessment from available CT scans appears to be a simple tool to stratify these patients into low and high risk based on future estimates of all-cause mortality. Within our study, the segmentation of preprocedural CT scans at the level of the lumbar third vertebra in patients undergoing TAVI was performed using a neural network (AutoMATiCA). The obtained parameters (area and density of skeletal muscles and intramuscular, visceral, and subcutaneous adipose tissue) were analyzed using Cox univariate and multivariable models for continuous and categorical variables to assess the relation of selected variables with all-cause mortality. 866 patients were included (median(interquartile range)): age 79.7 (74.9-83.3) years; BMI 28.9 (25.9-32.6) kg/m2. Survival analysis was performed on all automatically obtained parameters of muscle and fat density and area. Skeletal muscle index (SMI in cm2/m2), visceral (VAT in HU) and subcutaneous adipose tissue (SAT in HU) density predicted the all-cause mortality in patients after TAVI expressed as hazard ratio (HR) with 95% confidence interval (CI): SMI HR 0.986, 95% CI (0.975-0.996); VAT 1.015 (1.002-1.028) and SAT 1.014 (1.004-1.023), all p < 0.05. Automatic body composition assessment can estimate higher all-cause mortality risk in patients after TAVI, which may be useful in preoperative clinical reasoning and stratification of patients.

Efficacy and Safety of Stereotactic Radiotherapy in Patients With Recurrent Ventricular Tachycardias: The Czech Experience.

BACKGROUND: Stereotactic arrhythmia radiotherapy (STAR) has been proposed recently in patients with refractory ventricular tachycardia (VT). OBJECTIVES: The purpose of this study was to describe the efficacy and safety of STAR in the Czech Republic. METHODS: VT patients were recruited in 2 expert centers after at least 1 previously failed catheter ablation (CA). A precise strategy of target volume determination and CA was used in 17 patients treated from December 2018 until June 2022 (EFFICACY cohort). This group, together with an earlier series of 19 patients with less-defined treatment strategies, composed the SAFETY cohort (n = 36). A dose of 25 Gy was delivered. RESULTS: In the EFFICACY cohort, the burden of implantable cardioverter-defibrillator therapies decreased, and this drop reached significance for direct current shocks (1.9 ± 3.2 vs 0.1 ± 0.2 per month; P = 0.03). Eight patients (47%) underwent repeated CA for recurrences of VT during 13.7 ± 11.6 months. In the SAFETY cohort (32 procedures, follow-up >6 months), 8 patients (25%) presented with a progression of mitral valve regurgitation, and 3 (9%) required intervention (median follow-up of 33.5 months). Two cases of esophagitis (6%) were seen with 1 death caused by the esophago-pericardial fistula (3%). A total of 18 patients (50%) died during the median follow-up of 26.9 months. CONCLUSIONS: Although STAR may not be very effective in preventing VT recurrences after failed CA in an expert center, it can still modify the arrhythmogenic substrate, and when used with additional CA, reduce the number of implantable cardioverter-defibrillator shocks. Potentially serious sides effects require close follow-up.

Virtual Reality for Patient Education about Hypertension: A Randomized Pilot Study.

BACKGROUND: Hypertension challenges arise in part from poor adherence due to inadequate patient education. VR offers immersive learning to improve hypertension knowledge. OBJECTIVE: To compare VR education with traditional verbal education to improve hypertension knowledge. METHODS: In this randomised trial, 182 patients with hypertension were assigned to receive either traditional physician-led education (n = 88) or VR education (n = 94) with equivalent content. The VR group experienced a 3D video using Oculus Quest 2 headsets. Knowledge was assessed post-intervention using a 29-item questionnaire. The primary outcome was the objective score. Subjective satisfaction and responder characteristics were secondary outcomes. RESULTS: Median objective scores were significantly higher for VR (14, IQR 3) versus traditional education (10, IQR 5), p < 0.001, indicating superior hypertension knowledge acquisition with VR. Subjective satisfaction was high in both groups. Participants were categorized into low (first quartile) and medium-high (second to fourth quartiles) responders based on their scores. Low responders had a significantly higher prevalence of older women than medium-high responders (57% vs. 40% female, p = 0.024; 68 vs. 65 years), p = 0.036). CONCLUSIONS: VR outperforms traditional education. Tailoring to groups such as older women can optimise learning.

Exercise-Induced Blood Pressure Dynamics: Insights from the General Population and the Athletic Cohort.

Blood pressure (BP) dynamics during graded exercise testing provide important insights into cardiovascular health, particularly in athletes. These measurements, taken during intense physical exertion, complement and often enhance our understanding beyond traditional resting BP measurements. Historically, the challenge has been to distinguish 'normal' from 'exaggerated' BP responses in the athletic environment. While basic guidelines have served their purpose, they may not fully account for the complex nature of BP responses in today's athletes, as illuminated by contemporary research. This review critically evaluates existing guidelines in the context of athletic performance and cardiovascular health. Through a rigorous analysis of the current literature, we highlight the multifaceted nature of exercise-induced BP fluctuations in athletes, emphasising the myriad determinants that influence these responses, from specific training regimens to inherent physiological nuances. Our aim is to advocate a tailored, athlete-centred approach to BP assessment during exercise. Such a paradigm shift is intended to set the stage for evidence-based guidelines to improve athletic training, performance and overall cardiovascular well-being.

Early ganglion stellate blockade as part of two-step treatment algorithm suppresses electrical storm and need for intubation.

BACKGROUND: For the treatment of patients with electrical storm (ES), we established a two-step algorithm comprising standard anti-arrhythmic measures and early ultrasound-guided stellate ganglion blockade (SGB). In this single-center study, we evaluated the short-term efficacy of the algorithm and tested the hypothesis that early SGB might prevent the need for intubations. METHODS: Overall, we analyzed data for 70 ES events in 59 patients requiring SGB (mean age 67.7 ± 12.4 years, 80% males, left ventricular ejection fraction 30.0% ± 9.1%), all with implantable cardioverter-defibrillators (ICDs). RESULTS: The mean time from ES onset to SGB was 13.2 ± 12.3 hours. Percentage and mean absolute reduction in shocks at 48 hours after SGB reached 86.8% (-6.3 shocks), and anti-tachycardiac pacing (ATP) declined by 65.9% (-51.1 ATPs; all P < 0.001). Patients with the highest sustained ventricular arrhythmia (VA) burden (shocks ≥10/48 h; ATPs 10-99/48 h and ≥100/48 h) experienced the highest percentage decrease in ICD therapy (shocks -99.1%; ATPs -92.1% and -100.0%, respectively). For clinical response by defined criteria and two outcome periods (1/no sustained VA ≤48 hours post SGB, and 2/no ICD shock or <3 ATPs/day from day 3 to discharge/catheter ablation/day 8), 75.7% and 76.1% experienced complete response, respectively. Catecholamine support, no/low-dose ß-blocker therapy, polymorphic/mixed-type VA, and baseline sinus rhythm versus atrial fibrillation were more frequent in patients with early arrhythmia recurrence. Temporary Horner's syndrome occurred in 67.1%, and no other adverse events were recorded. Intubation and general anesthesia during and after SGB were not needed. CONCLUSION: The presented two-step algorithm for treating ES proved efficacious and safe. The results support implementation of early SGB in routine ES management.

Inflammation and fibrosis characterize different stages of myocardial remodeling in patients after stereotactic body radiotherapy of ventricular myocardium for recurrent ventricular tachycardia.

We performed a histological and immunohistochemical analysis of myocardia from 3 patients who underwent radiosurgery and died for various reasons 3 months to 9 months after radiotherapy. In Case 1 (death 3 months after radiotherapy) we observed a sharp transition between relatively intact and irradiated regions. In the myolytic foci, only scattered cardiomyocytes were left and the area was infiltrated by immune cells. Using immunohistochemistry we detected numerous inflammatory cells including CD68+/CD11c+ macrophages, CD4+ and CD8+ T-lymphocytes and some scattered CD20+ B-lymphocytes. Mast cells were diminished in contrast to viable myocardium. In Case 2 and Case 3 (death 6 and 9 months after radiotherapy, respectively) we found mostly fibrosis, infiltration by adipose tissue and foci of calcification. Inflammatory infiltrates were less pronounced. Our observations are in accordance with animal experimental studies and confirm a progress from myolysis to fibrosis. In addition, we demonstrate a role of pro-inflammatory macrophages in the earlier stages of myocardial remodeling after stereotactic radioablation for ventricular tachycardia.

Case Report: Repeated Stereotactic Radiotherapy of Recurrent Ventricular Tachycardia: Reasons, Feasibility, and Safety.

Stereotactic body radiotherapy (SBRT) has been reported as an attractive option for cases of failed catheter ablation of ventricular tachycardia (VT) in structural heart disease. However, even this strategy can fail for various reasons. For the first time, this case series describes three re-do cases of SBRT which were indicated for three different reasons. The purpose in the first case was the inaccuracy of the determination of the treatment volume by indirect comparison of the electroanatomical map and CT scan. A newly developed strategy of co-registration of both images allowed precise targeting of the substrate. In this case, the second treatment volume overlapped by 60% with the first one. The second reason for the re-do of SBRT was an unusual character of the substrate-large cardiac fibroma associated with different morphologies of VT from two locations around the tumor. The planned treatment volumes did not overlap. The third reason for repeated SBRT was the large intramural substrate in the setting of advanced heart failure. The first treatment volume targeted arrhythmias originating in the basal inferoseptal region, while the second SBRT was focused on adjacent basal septum without significant overlapping. Our observations suggested that SBRT for VT could be safely repeated in case of later arrhythmia recurrences (i.e., after at least 6 weeks). No acute toxicity was observed and in two cases, no side effects were observed during 32 and 22 months, respectively. To avoid re-do SBRT due to inaccurate targeting, the precise and reproducible strategy of substrate identification and co-registration with CT image should be used.

Radiation-Induced Changes in Ventricular Myocardium After Stereotactic Body Radiotherapy for Recurrent Ventricular Tachycardia.

Stereotactic body radiotherapy (SBRT) has been suggested as a promising therapeutic alternative in cases of failed catheter ablation for recurrent ventricular tachycardias (VTs) in patients with structural heart disease. This case series is the first postmortem immunohistochemical analysis of morphologic changes in the myocardium early and late after SBRT. The present findings are in line with experimental observations on apoptosis followed by fibrosis. This may explain why the effect of SBRT on VT is not predominantly immediate. Together with observation of early recurrences after SBRT for VT, these data suggest that this strategy may have rather delayed antiarrhythmic effects.

Chronic refractory angina pectoris treated by bilateral stereotactic radiosurgical stellate ganglion ablation: first-in-man case report.

BACKGROUND: Refractory angina pectoris (AP) significantly impairs quality of life in patients with chronic coronary syndrome. Several minimally invasive methods (coronary sinus reducer, cell therapy, laser or shockwave revascularization, and spinal cord stimulation) or non-invasive methods (external counterpulzation) have been studied. However, their routine clinical use has not been widely implemented. Surgical or endoscopic sympathectomy is feasible for permanently relieving angina, but is often contraindicated due to the extent of complications associated with it. Neuromodulation by anaesthetic blockade of the left-sided stellate ganglion (SG) has been shown to relieve angina for days or weeks. To provide a long-term anti-anginal effect, novel pharmacological (phenol-based) or radiofrequency ablation techniques have been individually used to permanently destroy sympathetic pathways. CASE SUMMARY: We describe a first-in-man use of stereotactic radiosurgical SG ablation using a linear accelerator (CyberKnife) in a heart failure patient after myocardial infarction with chronic refractory AP. Repeated anaesthetic SG blockade in this patient resulted in a significant, but only short-term, clinical improvement. The left, and subsequently the right, SG was ablated by targeted irradiation. During the 1-year follow-up, the patient remained without angina. We did not observe any clinically relevant early or late complications. Atrial fibrillation that developed 2 months after the second procedure was deemed to be associated with a natural progression of co-existing heart failure. DISCUSSION: We conclude that stereotactic radiosurgical SG ablation has the potential to become a minimally invasive and low-risk procedure to treat refractory angina patients. However, this procedure needs to be evaluated in larger patient populations.

Real-time measurement of ICD lead motion during stereotactic body radiotherapy of ventricular tachycardia.

BACKGROUND: Here we aimed to evaluate the respiratory and cardiac-induced motion of a ICD lead used as surrogate in the heart during stereotactic body radiotherapy (SBRT) of ventricular tachycardia (VT). Data provides insight regarding motion and motion variations during treatment. MATERIALS AND METHODS: We analyzed the log files of surrogate motion during SBRT of ventricular tachycardia performed in 20 patients. Evaluated parameters included the ICD lead motion amplitudes; intrafraction amplitude variability; correlation error between the ICD lead and external markers; and margin expansion in the superior-inferior (SI), latero-lateral (LL), and anterior-posterior (AP) directions to cover 90% or 95% of all amplitudes. RESULTS: In the SI, LL, and AP directions, respectively, the mean motion amplitudes were 5.0 ± 2.6, 3.4. ± 1.9, and 3.1 ± 1.6 mm. The mean intrafraction amplitude variability was 2.6 ± 0.9, 1.9 ± 1.3, and 1.6 ± 0.8 mm in the SI, LL, and AP directions, respectively. The margins required to cover 95% of ICD lead motion amplitudes were 9.5, 6.7, and 5.5 mm in the SI, LL, and AP directions, respectively. The mean correlation error was 2.2 ± 0.9 mm. CONCLUSIONS: Data from online tracking indicated motion irregularities and correlation errors, necessitating an increased CTV-PTV margin of 3 mm. In 35% of cases, the motion variability exceeded 3 mm in one or more directions. We recommend verifying the correlation between CTV and surrogate individually for every patient, especially for targets with posterobasal localization where we observed the highest difference between the lead and CTV motion.

Stereotactic radiosurgery for ablation of ventricular tachycardia.

AIMS: Stereotactic body radiotherapy (SBRT) for ventricular tachycardias (VTs) could be an option after failed catheter ablation. In this study, we analysed the long-term efficacy and toxicity of SBRT applied as a bail-out procedure. METHODS AND RESULTS: Patients with structural heart disease and unsuccessful catheter ablations for VTs underwent SBRT. The planning target volume (PTV) was accurately delineated using exported 3D electroanatomical maps with the delineated critical part of re-entry circuits. This was defined by detailed electroanatomic mapping and by pacing manoeuvres during the procedure. Using the implantable cardioverter-defibrillator lead as a surrogate contrast marker for respiratory movement compensation, 25 Gy was delivered to the PTV using CyberKnife. We evaluated occurrences of sustained VT, electrical storm, antitachycardia pacing, and shock; time to death; and radiation-induced events. From 2014 until March 2017, 10 patients underwent radiosurgical ablation (mean PTV, 22.15 mL; treatment duration, 68 min). After radiosurgery, four patients experienced nausea and one patient presented gradual progression of mitral regurgitation. During the follow-up (median 28 months), VT burden was reduced by 87.5% compared with baseline (P = 0.012) and three patients suffered non-arrhythmic deaths. After the blanking period, VT recurred in eight of 10 patients. The mean time to first antitachycardia pacing and shock were 6.5 and 21 months, respectively. CONCLUSION: Stereotactic body radiotherapy appears to show long-term safety and effectiveness for VT ablation in structural heart disease inaccessible to catheter ablation. We report one possible radiation-related toxicity and promising overall survival, warranting evaluation in a prospective multicentre clinical trial.

Results of complex left atrial ablation of long-lasting persistent atrial fibrillation.

PURPOSE: The aim of the study was to identify variables associated with successful long-term maintenance of sinus rhythm (SR) after a single ablation of long-lasting persistent atrial fibrillation (AF). METHODS: Complex left atrial (LA) ablation was performed in 100 patients. Restoration of SR by ablation was the desired procedure endpoint. RESULTS: SR was restored by ablation in 38 patients during the first procedure. Following one ablation, 50 patients remained in SR for 31 +/- 14 months. SR maintenance was associated with shorter duration of the persistent AF (median 14 vs. 22 months; P = 0.05), lower proportion of the LA points exhibiting voltage <0.2 mV (median 20% vs. 33%; P = 0.006), and higher proportion of LA points showing voltage >1 mV (median 15% vs. 11%; P = 0.02). CONCLUSION: Among clinical variables, shorter duration of persistent AF and higher voltage recorded around the LA predicted long-term maintenance of SR after single ablation.

Termination of long-lasting persistent versus short-lasting persistent and paroxysmal atrial fibrillation by ablation.

BACKGROUND: Left atrial (LA) structures for the maintenance of different atrial fibrillation (AF) forms are not uniform. The incidence, electrophysiological patterns, and LA sites of sinus rhythm (SR) restoration during ablation of different AF forms were evaluated. METHODS: One hundred patients with long-lasting persistent AF were retrospectively compared to 35 patients with short-lasting persistent AF and 59 patients with a sustained episode of paroxysmal AF. All patients underwent a first ablation using a stepwise ablation approach with the endpoint of SR restoration by ablation. RESULTS: SR was restored in 38%, 83%, and 97% of patients with long-lasting persistent, short-lasting persistent, and paroxysmal AF, respectively (P <0.001 for long-lasting persistent vs paroxysmal AF; P = 0.02 for long-lasting persistent vs short-lasting persistent AF). When modes and sites of SR restoration were evaluated among the patients with long-lasting persistent, short-lasting persistent, and paroxysmal AF, SR was restored via conversion into LA tachycardia in 79%, 52%, and 4% of patients (P <0.001 for long-lasting persistent vs paroxysmal AF); by the pulmonary vein encircling in 8%, 24%, and 93% patients (P <0.001 for long-lasting persistent vs paroxysmal AF); and by ablation at the LA anterior wall or inside the coronary sinus in 66%, 45%, and 2% patients (P <0.001 for long-lasting persistent and paroxysmal AF). During the 31 +/- 14 month follow-up since the first ablation, of the 50 patients with long-term SR maintenance (38 patients free of class I or III antiarrhythmic drugs), SR was restored by ablation in 29 (58%) patients versus nine (18%) patients out of 50 patients with unsuccessful clinical outcome (P = 0.009). CONCLUSION: Ablation of long-lasting persistent AF was characterized by more frequent failure to restore SR, and predominant conversion into LA tachycardia prior to SR restoration, and SR restoration by ablation outside the LA posterior wall. SR restoration by ablation was associated with better clinical outcome in these patients.

Pulmonary vein isolation using segmental versus electroanatomical circumferential ablation for paroxysmal atrial fibrillation: over 3-year results of a prospective randomized study.

PURPOSE: We tested the hypothesis that electroanatomic pulmonary vein (PV) antra encircling for the PV isolation will improve the outcome in treatment of paroxysmal atrial fibrillation (PAF), compared with segmental PV isolation. METHODS: Fifty-four patients underwent segmental PV isolation (group 1) and 56 patients circumferential PV isolation (group 2) for symptomatic PAF in a randomized study. RESULTS: Following single ablation procedure, at the 48 +/- 8 month follow-up, 30 (56%) and 32 (57%) patients in groups 1 and 2 remained free of arrhythmia (P = 0.41). After repeat ablation, 43 (80%) and 45 (80%) patients in groups 1 and 2 were free of arrhythmia without antiarrhythmic drugs (AADs); 48 (89%) and 51 (91%) patients in groups 1 and 2 did not have arrhythmia recurrences without or with AADs. CONCLUSION: This study demonstrates no advantage in long-term arrhythmia-free clinical outcome after circumferential PV isolation in patients with frequent PAF.