Effects of preparticipating hypohydration on cardiac burden in recreational athletes.

The global temperature rise will have extensive consequences on our organ systems, but hypohydration caused by reduced water intake or increased water loss through sweating plays the most relevant role. Many studies have already demonstrated the association between hypohydration and impaired exercise performance, but data related to the cardiac burden of hypohydration are scarce. This study is a sub-investigation of our large, prospective, self-controlled trial on the effects of hypohydration on cardiopulmonary exercise capacity with previously published results. In the current sub-study, we analyzed the impact of hypohydration on cardiac burden in this cohort of fifty healthy, recreational athletes during cardiopulmonary exercise test.Therefore, each participant underwent cardiopulmonary exercise test with a standardized ramp protocol twice, once in hypohydrated state and once in euhydrated state as control, and the cardiac markers Troponin T, NT-pro-BNP and Chromogranin A were measured before and after the exercise test at each state. Mean age was 29.7 years and 34% of probands were female. Hypohydration led to a reduced body water, a significant decrease in oxygen uptake and lower levels of power output. Yet, Troponin T, NT-proBNP, Chromogranin A and lactate levels did not significantly differ between the two conditions.In this study cohort, decreased exercise capacity during hypohydration was more likely due to impaired cardiac output with diminished plasma volume rather than measurable cardiac stress from fluid deprivation. However, whether these data are generalizable to a diseased cohort is left unanswered and should be addressed in future randomized controlled trials.

Clinical practice of continuous rhythm monitoring after embolic stroke of undetermined source.

AIMS: Embolic stroke of undetermined source (ESUS) accounts for up to 20% of ischemic strokes annually. Undetected atrial fibrillation (AF) is one important potential underlying cause. For AF, oral anticoagulation has evolved as the most preferable means of secondary stroke prevention. To detect unrecognized paroxysmal AF, long-term ECG monitoring is required, and implantable cardiac monitors (ICM) appear most suitable. Yet, ICMs are particularly costly, implantation is invasive, and remote monitoring places a personnel burden on health care providers. Here, we use data from a large cohort of ESUS patients to systematically analyze the effort of ICM remote monitoring for AF diagnosis and the strain on health care providers. METHODS AND RESULTS: From a prospective, single-center, observational ESUS registry, we analyzed all ICM-equipped patients post-ESUS (n = 172) between January 1st, 2018, and December 31st, 2019. Through January 2nd, 2023, 48 patients (27.9%) were diagnosed with AF by ICM remote monitoring. During follow-up, a total of 29,180 remote monitoring episodes were transmitted, of which 17,742 were alarms for AF. A systematic estimation of workload revealed that on average, 20.3 trained physician workhours are required to diagnose one patient with AF. CONCLUSION: ICM remote monitoring is useful to diagnose AF in cohort of post-ESUS patients. However, the number of ICM alarms is high, even in a cohort at known high risk of AF and in whom AF detection is therapeutically consequential. Improved automated event classification, clear recommendations for ICM interrogation after AF diagnosis, and a careful patient selection for ICM monitoring are warranted.

Pacing Using Cardiac Implantable Electric Device During TAVR: 10-Year Experience of a High-Volume Center.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is an effective and safe therapy for severe aortic stenosis. Rapid or fast pacing is required for implantation, which can be performed via a pre-existing cardiac implantable electric device (CIED). However, safety data on CIEDs for pacing in TAVR are missing. OBJECTIVES: The aim of this study was to elucidate procedural safety and feasibility of internal pacing with a CIED in TAVR. METHODS: Patients undergoing TAVR with a CIED were included in this analysis. Baseline characteristics, procedural details, and complications according to Valve Academic Research Consortium 3 (VARC-3) criteria after TAVR were compared between both groups. RESULTS: A total of 486 patients were included. Pacing was performed using a CIED in 150 patients and a transient pacemaker in 336 patients. No differences in technical success according to VARC-3 criteria or procedure duration occurred between the groups. The usage of transient pacers for pacing was associated with a significantly higher bleeding rate (bleeding type ≥2 according to VARC-3-criteria; 2.0% vs 13.1%; P < 0.01). Furthermore, impairment of the CIED appeared in 2.3% of patients after TAVR only in the group in which pacing was performed by a transient pacer, leading to surgical revision of the CIED in 1.3% of all patients when transient pacemakers were used. CONCLUSIONS: Internal pacing using a CIED is safe and feasible without differences of procedural time and technical success and might reduce bleeding rates. Furthermore, pacing using a CIED circumvents the risk of lead dislocation. Our data provide an urgent call for the use of a CIED for pacing during a TAVR procedure in general.

Effect of Acute Altitude Exposure on Anaerobic Threshold Assessed by a Novel Electrocardiogram-Based Method.

Background: Acute altitude has a relevant impact on exercise physiology and performance. Therefore, the positive impact on the performance level is utilized as a training strategy in professional as well as recreational athletes. However, ventilatory thresholds (VTs) and lactate thresholds (LTs), as established performance measures, cannot be easily assessed at high altitudes. Therefore, a noninvasive, reliable, and cost-effective method is needed to facilitate and monitor training management at high altitudes. High Alt Med Biol. 25:94-99, 2024. Methods: In a cross-sectional setting, a total of 14 healthy recreational athletes performed a graded cycling exercise test at sea level (Munich, Germany: 512 m/949 mbar) and high altitude (Zugspitze: 2,650 m/715 mbar). Anaerobic thresholds (ATs) were assessed using a novel method based on beat-to-beat repolarization instability (dT) detected by Frank-lead electrocardiogram (ECG) monitoring. The ECG-based ATs (ATdT°) were compared to routine LTs assessed according to Dickhuth and Mader. Results: After acute altitude exposure, a decrease in AT was detected using a novel ECG-based method (ATdT°: 159.80 ± 52.21 W vs. 134.66 ± 34.91 W). AtdT° levels correlated significantly with LTDickhuth and LTMader, at baseline (rDickhuth/AtdT° = 0.979; p < 0.001) (rMader/AtdT° = 0.943; p < 0.001), and at high altitude (rDickhuth/AtdT° = 0.969; p < 0.001) (rMader/AtdT° = 0.942; p < 0.001). Conclusion: Assessment of ATdT is a reliable method to detect performance alterations at altitude. This novel method may facilitate the training management of athletes at high altitudes.

Impact of Preparticipation Hypohydration on Cognitive Performance and Concussion-like Symptoms in Recreational Athletes.

BACKGROUND: Sports-related concussion is a relevant risk of contact sports, with several million cases per year worldwide. Prompt identification is crucial to prevent complications and late effects but may be impeded by an overlap with dehydration-associated impairment of cognitive function. Researchers have extensively studied the effects of pronounced dehydration in endurance sports, especially in the heat. However, little is known about the effects of isolated and mild dehydration. METHODS: Healthy recreational athletes underwent a standardized fluid deprivation test. Hypohydration was assessed by bioelectrical impedance analysis (BIA) and laboratory testing of electrolytes and retention parameters. Participants underwent cardiopulmonary exercise testing (CPET) with a cycle ramp protocol. Each participant served as their own control undergoing CPET in a hypohydrated [HYH] and a euhydrated [EUH] state. Effects were assessed using a shortened version of Sport Concussion Assessment Tool 3 (SCAT3). RESULTS: Fluid deprivation caused a mild (2%) reduction in body water, resulting in a calculated body mass loss of 0.8% without alterations of electrolytes, serum-osmolality, or hematocrit. Athletes reported significantly more (1.8 ± 2.2 vs. 0.4 ± 0.7; p < 0.01) and more severe (4.4 ± 6.2 vs. 1.0 ± 1.9; p < 0.01) concussion-like symptoms in a hypohydrated state. Balance was worse in HYH by trend with a significant difference for tandem stance (1.1 ± 1.3 vs. 0.6 ± 1.1; p = 0.02). No relevant differences were presented for items of memory and concentration. CONCLUSIONS: Mild dehydration caused relevant alterations of concussion-like symptoms and balance in healthy recreational athletes in the absence of endurance exercise or heat. Further research is needed to clarify the real-life relevance of these findings and to strengthen the differential diagnosis of concussion.

Effects of contemporary hard- and software mapping and ablation features on acute and long-term success in premature ventricular complex ablation.

BACKGROUND: Current standards of ablation of premature ventricular complexes (PVC) combine modern hard- and software mapping and ablation features like multielectrode mapping catheters (MEC), contact force (CF) guided ablation catheters and pattern matching filters (PMF). Benefits of these individual tools were described for selected patients with PVC, but data on combination of these features in the real world setting is sparse. METHODS: Between 2015 and 2021 we retrospectively enrolled 172 consecutive patients undergoing PVC ablation in our center. The utilization of MEC, CF guided ablation catheters and PMF software was analyzed in terms of procedural data, acute and long-term success after 12 months. RESULTS: Acute ablation success was reached in 71% of patients (n = 118) with an overall recurrence rate of 34% after 12 months. PMF software was used in 130 patients (78%), MEC in 131 patients (79%) and ablation was guided using CF in 99 patients (60%). PMF significantly reduced procedural duration and time of radiofrequency application (RF, 150 vs. 185 min, p 0.04 and 325 vs. 556 min, p 0.01). CF enabled significantly shorter radiation time (7.9 vs. 12.3 min, p 0.01), whereas MEC did not influence procedural data. Acute and long-term outcomes were not affected by these modern mapping and ablation features, yet, multivariable regression analysis revealed an underlying cardiomyopathy and the respective focus as independent predictors for recurrence. CONCLUSION: Contemporary hard- and software mapping and ablation features could reduce procedural, radiation and RF time in PVC ablation. Furthermore, patient characteristics rather than technical factors alter outcome of this all-comer collective.

Impact of Preparticipating Hypohydration on Cardiopulmonary Exercise Capacity in Ambitious Recreational Athletes.

BACKGROUND: Heat induces a thermoregulatory strain that impairs cardiopulmonary exercise capacity. The aim of the current study is to elucidate the effect of isolated dehydration on cardiopulmonary exercise capacity in a model of preparticipating hypohydration. METHODS: Healthy recreational athletes underwent a standardised fluid deprivation test. Hypohydration was assessed by bioelectrical impedance analysis (BIA) and laboratory testing of electrolytes and retention parameters in the blood and urine. The participants underwent cardiopulmonary exercise testing (CPET) with a cycle ramp protocol. Each participant served as their own control undergoing CPET in a hypohydrated [HYH] and euhydrated [EUH] state. RESULTS: Fluid deprivation caused a mild (2%) but significant reduction of body water (38.6 [36.6; 40.7] vs. 39.4 [37.4; 41.5] %; p < 0.01) and an increase of urine osmolality (767 [694; 839] vs. 537 [445; 629] mosm/kg; p < 0.01). Hypohydration was without alterations of electrolytes, serum osmolality or hematocrit. The oxygen uptake was significantly lower after hypohydration (-4.8%; p = 0.02 at ventilatory threshold1; -2.0%; p < 0.01 at maximum power), with a corresponding decrease of minute ventilation (-4% at ventilatory threshold1; p = 0.01, -3.3% at maximum power; p < 0.01). The power output was lower in hypohydration (-6.8%; p < 0.01 at ventilatory threshold1; -2.2%; p = 0.01 at maximum power). CONCLUSION: Isolated hypohydration causes impairment of workload as well as peak oxygen uptake in recreational athletes. Our findings might indicate an important role of hypohydration in the heat-induced reduction of exercise capacity.

A patient with Takayasu arteritis presenting with malignant hypertension: a case report.

Background: Takayasu arteritis (TA) is a rare large-vessel vasculitis primarily affecting the aorta and its proximal branches. The manifestation of TA is variable, ranging from asymptomatic cases to severe organ dysfunction secondary to vascular damage, which often delays diagnosis. Case summary: Here, we present a 37-year-old male patient suffering from visual impairment and malignant hypertension. Emergency fundoscopy showed large left subretinal bleeding and bilateral signs of hypertensive retinopathy. Echocardiographic and magnetic resonance imaging showed mildly reduced left ventricular ejection fraction and signs of hypertensive cardiomyopathy. Evaluation for secondary causes of arterial hypertension did not reveal an underlying disease, and the patient was discharged with optimal medical therapy. He was re-admitted after 11 days with fever of unknown origin, fatigue, and elevated inflammatory markers. The diagnosis of TA was finally established using 18F-fluorodeoxyglucose positron emission computed tomography scan and sonography of carotid and subclavian arteries. Anti-inflammatory combination therapy for active, severe TA with ophthalmologic involvement was initiated using high-dose glucocorticoids and the tumour necrosis factor alpha inhibitor adalimumab to minimize drug-related risks. The patient was scheduled for multidisciplinary follow-up appointments, including specialist consultation in rheumatology, angiology, cardiology, diabetology, and ophthalmology. Discussion: This case highlights the diversity of initial symptoms, the challenges of TA diagnosis, and the importance of comprehensive evaluation for rare secondary causes of arterial hypertension. Individualized acute and long-term care necessitates multidisciplinary management of immunosuppressive therapy, secondary organ involvement, and concomitant diseases.

[Cardiac implantable electric devices in forensic medicine : Overview from the forensic and cardiology perspective]. / Aktive kardiale Implantate in der Rechtsmedizin : Übersicht aus rechtsmedizinischer und kardiologischer Perspektive.

In 2021, about 75,000 persons in Germany died unnaturally or due to unexplained reasons. As a consequence, there are difficulties in more precisely identifying the time, cause and circumstances of death. Nevertheless, clarification is crucial not only from the clinical perspective, but these data are of considerable importance in the context of investigative procedures as they can be used to answer numerous legally relevant questions. Cardiac implantable devices (CIED) are of vital importance in the treatment of cardiac arrhythmias. In 2020 about 100,000 patients underwent CIED implantation in Germany. Therefore, CIED are present in a relevant proportion of the deceased mentioned above. The valuable source of information represented by postmortal CIED interrogation has been shown in numerous studies. Nevertheless, postmortal CIED interrogation is not routinely performed in the context of forensic medical examinations for reasons of practicability. This article summarizes benefits and limitations of postmortal CIED interrogation from the perspective of forensic medicine and cardiology and gives a recommendation for realization.

Prevalence, management, and prediction of venous access site occlusion in patients undergoing lead revision surgery.

BACKGROUND: Implantable electronic cardiac devices (CIED) have emerged as an essential component in the treatment of cardiac arrhythmias and heart failure. Due to increased life expectancy, expanding indications and limited technical survival, an increasing number of revision procedures can be anticipated. Venous access site occlusion (VASO) is the main obstacle during revision surgery. In this retrospective study we evaluated the prevalence, predictive parameters and operative management of venous access site occlusion. METHODS AND RESULTS: Between 01/2016 and 12/2020 304 patients underwent lead revision surgery of transvenous CIED in our department. Prevalence of VASO was 25.7% (n = 78), one patient was symptomatic. Independent predicting clinical parameters were male sex (2.86 (1.39-5.87), p < 0.01) and lead age (1.11 (1.05-1.18), p < 0.01)). Revision surgery despite VASO was successful in 97.4% (n = 76) without prolongation of the total surgery time or higher complication rates. Yet, lead extraction was possible in 92% of patients with VASO vs. 98.2% of patients without VASO (p 0.01). CONCLUSION: VASO is a frequent condition in patients undergoing lead revision surgery, but successful revision is feasible in most cases without preceding lead extraction. However, the lower success rates of lead extractions may be prognostically relevant, especially for younger patients.

Review: Sex-related differences in the treatment of cardiac arrhythmia.

Cardiac arrhythmias are a common and potentially serious cardiovascular disorders that affect both men and women. However, there is evidence to suggest that there may be sex-related differences in the prevalence, clinical presentation, and management of cardiac arrhythmias. Hormonal and cellular factors may play a role in these sex-specific differences. In addition, there are differences in the types of arrhythmias that men and women experience, with men more likely to experience ventricular arrhythmias and women more likely to experience supraventricular arrhythmias. The management of cardiac arrhythmias also differs between men and women. For example, some studies have found that women are less likely to receive appropriate treatment for arrhythmias and are more likely to have adverse outcomes following treatment. Despite these sex-related differences, the majority of research on cardiac arrhythmias has been conducted in men, and there is a need for more research to specifically examine the differences between men and women. This is especially important given that the prevalence of cardiac arrhythmia is increasing, and it is essential to understand how to effectively diagnose and treat these conditions in both men and women. In this review, we examine the current understanding of sex-related differences in cardiac arrhythmias. We also review the available data on sex-specific management strategies for cardiac arrhythmias and highlight areas of future research.

Evaluation of a Standardized Training and Adherence Surveillance Programme to Overcome Quality-of-Life Impairments and Enhance Compliance in Patients Treated with Wearable Cardioverter Defibrillator.

Background: Treatment with wearable cardioverter defibrillators (WCD) is a non-invasive, transient therapy option for prevention of sudden cardiac death (SCD) in patients with temporary contraindications for implantation of a permanent cardioverter defibrillator. Due to the constant risk of fatal arrhythmias, compliance is the fundamental requirement for effectiveness of a WCD, but this might be hindered by the poor quality-of-life (QoL) during WCD therapy. In this retrospective single-center study, we examined if a standardized WCD training and adherence surveillance programme could enhance compliance and QoL. Methods: All patients with a prescription for WCD treatment from January 2017 to August 2019 were included and received a standardized WCD training programme. QoL was validated using the modified EQ-5D-3L questionnaire. The findings were compared to a historical, previously published, retrospective cohort from our center (WCD prescription period 03/2012-02/2016), not receiving the additional training programme. Endpoints comprised therapy adherence, arrhythmic episodes, and dimensions of QoL. Results: Ninety-two patients underwent WCD treatment in the study cohort for a median of 49 days. Median daily wear time was enhanced in the study cohort (historical cohort vs study cohort 21.9 vs 23.3 hours/per day, p<0.01) and artefact alarms occurred less frequently (67.9% vs 48.9%, p 0.01). Major restrictions in QoL in the study cohort were found in mobility (48%), daily routine (44%), and sleep (49%), but the dimensions pain (36% vs 4%, p<0.01), mental health (43% vs 29%, p 0.03), and restrictions in daily routine (48% vs 30%, p 0.04) improved. Conclusion: A standardized training and adherence surveillance programme might have beneficial effects on compliance and QoL. As these findings are essential for therapy success, they might potentially lead to a reduction in arrhythmic deaths in upcoming WCD trials.

Impairment of Quality of Life in Patients with Implanted Subcutaneous Cardioverter Defibrillator (S-ICD) Compared to Implanted Transvenous Cardioverter Defibrillator Therapy.

Background: The subcutaneous cardioverter defibrillator (S-ICD) has been shown to be a viable alternative to transvenous ICDs (TV-ICD) in all patients at risk of sudden cardiac death (SCD) but without pacing indication. Aim: The aim of this study was to examine the impact of therapy with current S-ICD devices on quality of life (QoL) in comparison to patients with TV-ICD devices. Methods: In our single-centre study, 52 consecutive patients with S-ICD and 52 matched patients with TV-ICD were analysed. QoL has been assessed by a standardized questionnaire (EQ-5D-3L, modified). Additionally, clinical baseline and follow-up data were evaluated. Results: Two-thirds of the total study population reported restrictions in daily routine compared to their life before ICD implantation. A total of 27.7% of S-ICD patients stated to expect an improvement of QoL by deactivation or explantation of their defibrillator compared to only 6.4% of patients with TV-ICD (p=0.006), which was mainly caused by discomfort and pain from the S-ICD pocket (relevant discomfort and pain in 32.6% vs 11.5%; p<0.01). Limitations: Main limitation of the study is that quality of life was assessed for one single time point only and time since implantation differed significantly between S-ICD and TV-ICD. Furthermore our collective is younger, and, due to the high proportion of patients without cardiomyopathy, the mean EF is better than usual ICD collective. The absence of heart failure in about the half of our patients might have relevant impact on our QoL analysis. Conclusion: A relevant proportion of S-ICD patients expects an improvement of QoL by explantation of the device. Of note, this impression was not driven by the fear of receiving shocks but mainly by discomfort and pain caused by the pulse generator.

Determination of time of death by blinded post-mortem interrogation of cardiac implantable electrical devices.

Postmortal interrogation of cardiac implantable electrical devices (CIED) may contribute to the determination of time of death in forensic medicine. Recent studies aimed to improve estimation of time of death by combining findings from autopsy, CIED interrogation and patients´ medical history. CIED from deceased undergoing forensic autopsy were included, if time of death remained unclear after forensic assessment. CIED explanted from deceased with known time of death were analysed as a control cohort. CIED were sent to our device interrogation lab and underwent analysis blinded for autopsy findings, medical history and police reports. The accuracy of time of death determination and the accuracy of time of death in the control cohort served as primary outcome. A total of 87 CIED were analysed. The determination of time of death was possible in 54 CIED (62%, CI 52-72%). The accuracy of the estimated time of death was 92.3% in the control cohort. Certain CIED type and manufacturers were associated with more successful determination. Blinded postmortal analysis enables a valid determination of the time of death in the majority of CIED. Analysis of explanted CIED in a cardiological core lab is feasible and should be implemented in forensic medicine.

Single-center experience of ultra-high-density mapping guided catheter ablation of focal atrial tachycardia.

INTRODUCTION: Catheter ablation is the treatment of choice for recurrent focal atrial tachycardia (FAT) as medical therapy is limited. Routinely, a three-dimensional mapping system is used. Whether or not optimized signal detection does improve ablation success rates has not yet been investigated. This retrospective cohort study compared ablation procedures using an ultra-high-density mapping system (UHDM, Rhythmia, Boston Scientific) with improved signal detection and automatic annotation with procedures using a conventional electroanatomic mapping system (CEAM, Biosense Webster, CARTO). METHODS: All patients undergoing ablation for FAT using UHDM or CEAM from April 2015 to August 2018 were included. Endpoints comprised procedural parameters, acute success as well as freedom from arrhythmia 12 months after ablation. RESULTS: A total of 70 patients underwent ablation (48 with UHDM, 22 with CEAM). No significant differences were noted for parameters like procedural and radiation duration, area dose, and RF applications. Acute success was significantly higher in the UHDM cohort (89.6% vs. 68.2%, p = .03). Nevertheless, arrhythmia freedom 12 months after ablation was almost identical (56.8% vs. 60%, p = .87), as more patients with acute success of ablation presented with a relapse during follow-up (35.0 vs. 7.7%, p = .05). CONCLUSION: Acute success rate of FAT ablation might be improved by UHDM, without an adverse effect on procedural parameters. Nevertheless, further research is needed to understand the underlying mechanism for increased recurrence rates after acute successful ablation.

Permanent pacemaker dependency in patients with new left bundle branch block and new first degree atrioventricular block after transcatheter aortic valve implantation.

Conduction disorders with need for permanent pacemaker (PPM) implantation remain frequent complications after transcatheter aortic valve implantation (TAVI). Up to 22% of PPM after TAVI are implanted for new onset left bundle branch block (LBBB) and atrioventricular block (AVB) I. However, clinical benefit and predictors of ventricular pacing in TAVI patients receiving PPM for this indication remain unclear. We retrospectively evaluated pacemaker interrogation data of patients who received a PPM post TAVI for new LBBB and new AVB I. The primary endpoint of this study was relevant ventricular pacing (ventricular pacing rate: Vp ≥ 1%) at the first outpatient pacemaker interrogation. Secondary endpoints were predictors for relevant ventricular pacing. At the first pacemaker interrogation (median follow up at 6.23 [2.8-14.8] months), median ventricular pacing frequency was 1.0% [0.1-17.8]. Out of 61 patients, 36 (59%) had Vp rates ≥ 1%. Patients with frequent ventricular pacing showed longer QRS duration (155 ms ± 17 ms vs. 144 ms ± 18 ms, p = 0.018) at the time of PPM implantation and were less likely treated with a balloon-expandable Edwards Sapiens Valve (39% vs. 12%, p = 0.040). Our findings suggest that the majority of patients with new LBBB and new AVB I after TAVI show relevant ventricular pacing rates at follow up. Further prospective studies are necessary to identify patients at higher risk of pacemaker dependency.

Effect of acute altitude exposure on ventilatory thresholds in recreational athletes.

PURPOSE: High altitude (HA) training is frequently used in endurance sports and recreational athletes increasingly participate in cross mountain competitions. At high altitude aerobic physiology changes profoundly. Ventilatory thresholds (VTs) are measures for endurance performance but the impact of exposure to acute altitude (AA) on VTs in recreational athletes has been insufficiently explored to date and most studies investigated effects under normobaric hypoxia. METHODS: In this cross-sectional study we investigated the effects of AA exposure at 2650 m/715 mbar on anerobic threshold (VT1) and respiratory compensation point (VT2) in a graded cycling test in 14 recreational athletes (4 female, 10 male) compared to baseline levels (521 m, 949 mbar). RESULTS: At VT1, a decline in power output (PO) from median 115.5 W to 105.0 W (median -12.3 %, p = 0.032; Wilcoxon test) during exposure to HA was observed. VO2/body weight and VO2/heart rate decreased markedly (- 9.5 %, p = 0.016; -10.5 %, p = 0.012). At VT2 we found a significant decline of PO from 184.5-170.5 W (-13.1 %, p = 0.0014), of VO2/body weight and of VO2/heart rate (-10.1 %, p = 0.0015; -8.7 %, p = 0.002) compared to baseline values. Absolute VO2 decreased (-9.5 %, p = 0.0014 and -10.1 %, p = 0.0002) while minute ventilation and heart rates remained unchanged at both thresholds. CONCLUSION: Our data allows a quantification of performance loss at HA in recreational athletes and demonstrates that VT-guided training intensities and workloads need to be adapted for training at HA.

Survival after left ventricular assist device implantation correlates with a novel device-based measure of heart rate variability: the heart rate score.

OBJECTIVES: The heart rate score (HRS) serves as a device-based measure of impaired heart rate variability and is an independent predictor of death in patients with heart failure and a cardiac implantable electrical device. However, no data are available for predicting death from the HRS in patients with end stage heart failure and a left ventricular assist device. METHODS: From November 2011 to July 2018, a total of 56 patients with a pre-existing cardiac implantable electrical device underwent left ventricular assist device implantation at our 2 study sites. The ventricular HRS was calculated retrospectively during the first cardiac implantable electrical device follow-up examination following the index hospitalization. Survival during follow-up was correlated with initial HRS. RESULTS: During the follow-up period, 46.4% of the patients (n = 26) died. The median follow-up period was 33.2 months. The median HRS after the index hospitalization was 41.1 ± 21.8%. More patients with an HRS >65% died compared to patients with an HRS <30% (76.9% vs 14.4%; P = 0.007). CONCLUSIONS: In our multicentre experience, survival of patients after an left ventricular assist device implant correlates with the HRS. After confirmation of our findings in a larger cohort, the effect of rate-responsive pacing will be within the scope of further investigation.