Sudden cardiac death prevention in the era of novel heart failure medications

Sudden cardiac death (SCD) occurs unexpectedly and is usually a result of ventricular arrhythmia in patients with structural heart disease. The implantable cardioverter-defibrillator (ICD), with or without biventricular pacing, has been proven to be protective for heart failure patients with reduced ejection fraction of <35 % (HFrEF). This device therapy prevents SCD, with additional optimal medications, namely angiotensin-converting enzyme-inhibitors, angiotensin-II receptor-blockers, beta-blockers and mineralocorticoid receptor-antagonists. HFrEF patients present the majority of SCD incidents, as they are characterized by cardiac fibrosis, the main arrhythmogenic element. The introduction of angiotensin-receptor-neprilysin inhibitors, sodium-glucose co-transporter-2 inhibitors and guanylate-cyclase stimulators was associated with reduction of SCD. Additionally, clinical trials have evaluated the improved outcome of these new medications on left ventricular ejection fraction, arrhythmias and HFrEF. These beneficial effects could possibly lead to important changes in decision-making on ICD implantation for primary prevention in patients with HFrEF and reduce the need for device therapy. In this review, we highlight the pathophysiological mechanisms of the new drug agents, and evaluate the possible effect they could have on the role of device therapy as a primary prevention of SCD.

Induction of periodontitis and oral microbiome dysbiosis in a mouse model with heart failure with preserved ejection fraction results in worsening hypertension and diastolic dysfunction

Introduction

Heart Failure with Preserved Ejection Fraction (HFpEF) is characterized by increased inflammation and disruption of the nitric oxide (NO) pathway. Oral microbiota has an essential role in the generation of a large portion of the NO bioavailability pool in the human body. Periodontitis (PD) is a common inflammatory condition that contributes to the development of chronic low-grade inflammation, oral microbiota dysbiosis, and dysregulation of the NO hemostasis.

Purpose

In this study, we sought to investigate the direct effect of PD induction on HFpEF manifestation in a mouse model.

Methods

HFpEF was induced in 11-week-old C57/black male mice by high-fat diet and inhibition of NO synthase using L-NAME (Nω-nitro-l-arginine-methyl-ester) (a “2-hit-model”) for 10 weeks. PD was induced by oral infection with P. gingivalis. Diastolic function of the left ventricle (LV) was assessed by high-frequency echocardiography. Blood pressure (BP) was measured using CODA non-invasive tail-cuff system.

Results

Induction of PD resulted in a significantly impaired diastolic function demonstrated by more pronounced decrease in e' and increase in E/e' ratio compared to HFpEF without PD or control mice (E/e': 39.7±2.6 vs. 30.1±1.9 vs. 24.3±2.1 for PD-HFpEF [n=15], HFpEF [n=15], and controls [n=10], respectively, p&lt;0.001). While LV ejection fraction (EF) was similar, global longitudinal strain (GLS) was decreased in the HFpEF group and further decreased in the PD-HFpEF group compared to controls (p&lt;0.001). BP was elevated in the HFpEF mice and PD induction resulted in a more remarkable increase in BP (systolic BP: 124.7±3.3 vs. 112.7±3.8 vs. 94.8±2.2 mmHg, respectively, p&lt;0.001).

Conclusions

Induction of PD in a mouse model with HFpEF results in a more pronounced BP elevation and diastolic dysfunction compared to HFpEF without PD. Extensive molecular experiments are ongoing to explore the mechanisms responsible for the increased HFpEF severity in the setting of PD.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Israel Science Foundation

Atrial fibrillation in patients with high-risk acute myocardial infarction – the PARADISE-MI trial

Background

Atrial fibrillation or flutter (AFF) is common in both patients with myocardial infarction (MI) and those with heart failure (HF). However, its impact on the risk of adverse outcomes in MI complicated by either reduced LVEF and/or transient pulmonary congestion is less known.

Purpose

To assess the relationship between AFF and outcomes and whether AFF modified the treatment response to sacubitril/valsartan in the PARADISE-MI (Prospective ARNI versus ACEi trial to determine superiority in reducing HF events after MI) trial.

Methods

5656 patients enrolled in the PARADISE-MI trial were divided into 3 groups: no known AFF, history of AFF without AFF at enrolment, and AFF occurring with the index MI event. We assessed outcomes and the treatment response to sacubitril/valsartan in all groups. The primary outcome of the PARADISE-MI trial was death from cardiovascular (CV) causes or incident HF. The outcome analyses were adjusted for the number of risk augmenting factors, age, pulmonary congestion, percutaneous coronary intervention, LVEF and hypertension.

Results

259 patients (4.6%) had only a history of AFF, 525 patients (9.3%) had AFF associated with index MI. Patients with a history of AFF and AFF with index MI were older, with a higher rate of pulmonary congestion and hypertension, lower eGFR values but lower rates of diabetes, compared with those without AFF (Table 1). In unadjusted analyses, history of AFF and AFF with index MI were associated with a significant increase in the risk of the primary outcome (hazard ratio (HR): 1.76; 95% confidence interval (CI): 1.32–2.35 and HR 1.69, 95% CI 1.37–2.10, respectively), remaining significant after adjustment only in those with AFF with index MI (HR=1.40, 95% CI 1.12–1.74) (Fig. 1). This was primarily driven by an increase in the crude and adjusted risk of incident HF, both in those with a history of AFF and AFF with index MI (adjusted HR=1.56, 95% CI 1.10–2.22 and HR=1.55, 95% CI 1.18–2.03, respectively). An increase in the crude risk of CV death was present in patients with a history of AFF and AFF with index MI (HR=1.57, 95% CI 1.04–2.39 and HR=1.66, 95% CI 1.23–2.24, respectively), yet did not remain significant after adjustment. The risk of the composite outcome of death from coronary heart disease, non-fatal MI, hospitalisation for angina or coronary was not associated with either a history of AFF or AFF with index MI, in unadjusted or adjusted analyses (adjusted HR=0.83, 95% CI 0.57–1.19 and HR=1.00, 95% CI 0.78–1.29, respectively) (Fig. 1). Neither history of AFF nor AFF with index MI modified the treatment effect of sacubitril/valsartan (p&gt;0.05).

Conclusions

In this post-MI cohort, history of AFF and AFF occurring with the index MI event were associated with an increased risk of CV death or incident heart failure, primarily driven by an increased risk of incident HF. However, the risk of the composite coronary outcome was not associated with AFF status, compared to other studied outcomes.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The PARADISE-MI trial was funded by Novartis

Etiologies and predictors for cardiac implantable electronic device implantation in young patients hospitalized for complete atrioventricular block

Introduction

Information regarding the etiologies of complete atrioventricular block (CAVB) in young patients is scarce. We aimed to investigate the potential causes for non-iatrogenic CAVB in young patients, as well as to identify possible predictors for need of implantable cardioverter-defibrillator (ICD) or permanent pacemaker (PPM) implantation in young patients presenting with CAVB.

Methods

Using the National Inpatient Sample (NIS) database, we identified patients aged 18–60 hospitalized with CAVB in the US between 2015 (last quarter)-2019. Patients who had concurrent cardiac surgery or electrophysiological procedures were excluded. Baseline demographics, clinical characteristics, potential etiologies for CAVB as well as outcomes including the need for temporary cardiac pacing (TCP), ICD and PPM implantation were analyzed. Multivariable logistic regression models were used to identify predictors of ICD or PPM implantation in patients with unknown etiology.

Results and discussion

An estimated total of 56,385 patients aged 18–60 with CAVB and no concurrent surgical or EP interventions were identified. The mean (±SD) age was 49 (±10) years and 59% were males. Approximately 55% of patients had no identified cause for CAVB (Table 1). While 16% of patients received TCP, 32% and 6% of patients were eventually implanted with a PPM and ICD, respectively (Figure 1), In patients with CAVB of unknown etiology, advanced age and need for TCP emerged in multivariable analyses as independent predictors of the need for both PPM and ICD implantation. Female gender was identified as a predictor for PPM implantation but was associated with a lower chance of ICD implantation.

Conclusion

The majority of non-iatrogenic young CAVB patients had no identified etiology in a nationwide database and less than 40% of the patients received an implantable cardiac device. Better risk stratification and diagnostic algorithms are needed for this population of patients.

Funding Acknowledgement

Type of funding sources: None.

Amyloidosis of the aortic valve in patients with degenerative and bicuspid aortic stenosis

Introduction

Aortic stenosis (AS) is a common valvular disease, resulting in substantial morbidity and mortality. In younger patients, AS may occur as part of the bicuspid aortic valve (BAV) syndrome. Transthyretin cardiac amyloidosis (ATTR-CA) is an infiltrative disorder caused by the extracellular deposition of insoluble amyloid-derived fibrils. Recent studies have shown the presence of ATTR-CA in 4%-29% of degenerative AS patients. We hypothesized that amyloidosis may be involved in valve injury leading to AS.

Material and methods

We studied the aortic valves of 124 patients who underwent surgical aortic valve replacement at our institution over the last decade, included in our cardiosurgical database. Valves from 86 degenerative AS patients were compared to a control group of 38 patients with BAV stenosis. Patients with pure aortic regurgitation, history of rheumatic disease, or severe renal disease were excluded. The slides were stained with Congo red, and Thioflavin S then examined with regular, fluorescence and polarized light microscopy.

Results

In the degenerative AS group, Congo red and Thioflavin S staining was positive in 63% of the valves and 37% negative. The bicuspid AS group showed 68% positive and 32% negative for the Congo Red and Thioflavin S stains.

Discussion and conclusion

Our results indicate the presence of valvular amyloidosis in patients with AS, whether due to degenerative or congenital etiologies. This corroborates several recent studies. Intriguingly, there was an equally positive Congo red and Thioflavin S signal in bicuspid aortic valves. We speculate that the positive staining in the BAV group may indicate an inflammatory process associated with valve pathology inducing the accumulation of amyloid, and thus may not be transthyretin, as we expect in the experimental group. Another explanation may be that amyloidosis may be an epiphenomenon of valve “wear and tear” and not related to the pathogenesis in either etiology. Specific TTR immunofluorescence is underway to elucidate this question.

Funding Acknowledgement

Type of funding sources: None.

Insights into diurnal variations of advanced hemodynamic parameters in ambulatory individuals enabled by a photoplethysmography-based wearable monitor

Background

Recent technological developments enable non-invasive monitoring of advanced hemodynamic parameters, allowing big data-driven insights on diurnal changes for the first time. This study aimed to describe the trends of multiple advanced cardiovascular parameters among ambulatory individuals using a medical grade wearable monitor.

Methods

Common and advanced cardio-respiratory parameters were monitored for 24 hours in ambulatory volunteers using a photoplethysmography-based wearable monitor. The multi vital ambulatory monitoring (MVAM) included stroke volume (SV), cardiac index (CI), systemic vascular resistance (SVR), blood oxygen saturation (SpO2), respiratory rate (RR), systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP), and heart rate (HR). Diurnal variations were evaluated among all participants, and analyses were stratified based on sex, age, and body-mass index (BMI).

Results

A total of 256 participants were included in the analysis. All measured parameters showed significant (p&lt;0.001) diurnal changes. Nighttime values were lower excluding RR and SVR, reaching the nadir at 5 am, and then increasing to a maximum at 10 am, plateauing, and then gradually declining from 7 to 8 pm. CI demonstrated a reduction of 0.6 L/min/m2 (20%), while SVR demonstrated the opposite trend and was higher during the night increasing by up to 212 dynes/sec/cm5 (16%). Females demonstrated higher HR and CI with lower SVR during daytime and nighttime. Obese participants (BMI &gt;30 kg/m2) had a higher SBP and DBP, and lower SV and CI. SVR was higher among the elderly.

Conclusions

Diurnal changes using MVAM corresponding with awake-sleep hours were noticed in the monitored parameters and differed between sex, age, and BMI groups. This suggests that wearable monitoring platforms could shed more light on hemodynamic changes in subgroups, and might help with future efforts to provide tailored personalized medicine and pre-symptomatic diagnosis and prevention.

Funding Acknowledgement

Type of funding sources: None.

Alterations in the gut microbiota composition in the obesity phenotype of heart failure with preserved ejection fraction

Introduction

Obesity is one of the most common phenotypes of heart failure with preserved ejection fraction (HFpEF). A growing body of evidence indicates that obesity is characterized by compositional alterations in the intestinal microbiota and its metabolites, collectively referred as dysbiosis.

Purpose

We sought to investigate whether the obese phenotype of HFpEF is mediated by further alterations in the microbiota and whether gut dysbiosis fuels metabolic inflammation leading to progression of HFpEF.

Methods

HFpEF was induced in C57/black mice by high-fat diet and inhibition of NO synthesis (a “2-hit-model”) (Figure 1A). High-frequency echocardiography was performed to assess diastolic function. Blood pressure (BP) was measured using CODA non-invasive tail-cuff system. For human studies, patients with obese HFpEF as well as obese and non-obese healthy individuals were prospectively recruited. Gut microbial DNA was subjected to 16S ribosomal RNA gene sequencing, and the differences in abundance and composition of bacteria were defined both in humans and mice.

Results

In mice, the 2-hit model demonstrated significantly increased BP and impaired diastolic function in the obese HFpEF group (Figure 1B). Microbiome analysis showed significant differences in the gut microbial diversity and composition in the obese HFpEF compared to the non-HFpEF obese and chow-fed mice (Figure 1C). Similarly, human microbiome sequencing showed significant gut bacterial alterations in the diversity and composition of bacteria with more profound dysbiosis observed in the obese HFpEF patients compared to the obese and lean healthy individuals (Figure 1D).

Conclusions

We provide evidence in humans as well as in a murine animal model that the obese HFpEF phenotype is associated with more pronounced gut dysbiosis compared to the non-HFpEF obesity state. Further research will elucidate the causative link between gut dysbiosis and HFpEF manifestation and the mechanistic insights into the implication of gut microbiota in HFpEF progression.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Israel science foundation

Utilization and in-hospital complications associated with implantation of dual versus single chamber implantable cardioverter defibrillator for primary prevention of sudden cardiac death

Introduction

Multiple studies showed no clinical benefit in implantation of a dual compared to a single chamber implantable cardioverter defibrillator (dICD vs. sICD) for primary prevention of sudden cardiac death (SCD), in patients with no pacing indication. We aimed to investigate the extent of utilization and complications in sICD vs. dICD implantations in the US, using the National In-Patient Sample (NIS) database.

Methods

Using the NIS database, we identified patients who underwent an elective ICD implantation in the US between 2015 (last quarter)-2019. Patients who had concurrent conduction disorders or indication for atrial pacing were excluded. Baseline demographics, clinical characteristics, cardiomyopathy etiologies as well as outcomes including in-hospital complications, length of stay and mortality were collected. Multivariable logistic regression models were used to identify predictors of complications.

Results and discussion

An estimated total of 15940 patients, who underwent elective ICD implantation for primary prevention of SCD were identified, 8860 (55.6%) of them received a dICD. Forty percent of patients had ischemic cardiomyopathy. The mean age was 64 years and 66% were males. The complication rates documented in the dICD and sICD groups were 13% and 11%, respectively (p&lt;0.001),driven by increased rate of pneumothorax (4.8% vs 3.2%, p&lt;0.001) and lead dislodgement (3.6% vs 2.3%, p&lt;0.001, Table 1). Multivariate analysis confirmed adding an atrial lead as an independent risk factor for “any complication” during ICD implantation [OR 1.13 (1.02–1.25), p=0.022] as well as for pneumo/hemothorax [OR 1.21 (1.03–1.44), p=0.025] and lead dislodgement [OR 1.41 (1.16–1.72), p&lt;0.001].

Conclusion

Despite significant evidence for lack of clinical benefit in adding an atrial lead to a primary prevention ICD implantation, significant proportion of the patients in the US are implanted with a dICD. We show increased risk for complications for dICD compared with sICD implantation in the US in recent years, driven by higher incidence of pneumo/hemothorax and lead dislodgement.

Funding Acknowledgement

Type of funding sources: None.

Cardiac and other presentation and clinical outcomes of COVID-19 pandemic among different ethnic and religious populations in the city of Jerusalem

Background

The COVID-19 pandemic is an ongoing global pandemic. Jerusalem with its 919,400 inhabitants has a wide variety of populations, of which 62% are Jews (36% ultra-orthodox; 64% non-ultraorthodox) and 38% Arabs which were largely affected by the pandemic.

Objectives

The aim of our study was to understand the different presentations, course and clinical outcomes in these different ethnical and cultural groups in Jerusalem in the COVID-19 pandemic.

Methods

We performed a cohort study of all COVID-19 patients admitted between March 9 - July 16, 2020 to the two university medical centers in Jerusalem. Demographic data, presenting symptoms, comorbid conditions, medications, physical examination, laboratory and imaging data as well as outcome at 30-day were systematically recorded. Patients were divided according to their religion and ethnicity into 3 main groups: 1) Ultra-Orthodox Jews; 2) other (non-Ultra-Orthodox) Jews and 3) Arabs.

Results

Six hundred and two patients comprised the study population. Of them the 361 (60%) were Ultra-Orthodox Jews; 166 (27.5%) non-Ultra-Orthodox Jews and 75 (12.5%) Arabs. The Arab patients were younger than the Ultra-Orthodox Jews and the non-Ultra-Orthodox Jews (51±18 year-old vs. 57±21 and 59±19, respectively, p&lt;0.01), but suffered from significantly more co-morbidities. Fever, cough, dyspnea and fatigue, were more prominent, as presenting symptoms, in the Jewish patients as compared with the Arab patients. Moreover, hemodynamic shock, ischemic ECG changes and pathological chest x-ray were all more frequent in the Ultra-Orthodox patients as compared the other groups of patients. Being an Ultra-Orthodox was independently associated with significantly higher rate of Major Adverse Cardiovascular Events (MACE) [OR=1.96; 95% CI (1.03–3.71), p&lt;0.05]. Age was the only independent risk factor associated with increased mortality rate [OR=1.10; 95% CI (1.07–1.13), p&lt;0.001].

Conclusions

The COVID-19 first phase in Jerusalem, affected different ethnical and cultural groups differently, with the Ultra-Orthodox Jews mostly affected by admission rates, presenting symptoms clinical course and MACE (Acute coronary syndrome, shock, cerebrovascular event or venous thromboembolism). It is conceivable that vulnerable populations need special attention and health planning in time of pandemic, to prevent rapid distribution and severe morbidity.

Funding Acknowledgement

Type of funding sources: None.

Utilization and complications of catheter ablation for ventricular arrhythmias in patients with mechanical valves

Background

Catheter ablation (CA) for ventricular arrhythmias (VAs) is increasingly utilized in the recent years. Ablation for VAs in patients with mechanical valves (MVs), can be challenging due to the chronic anticoagulation therapy, limitations in accessing the cardiac chambers, the risk for entrapment of mapping or ablation catheters between the leaflets of MVs and more.

Purpose

To investigate the nationwide trends in utilization and complications of CA for VAs in patients with prior MVs.

Methods

We drew data from the US National Inpatient Sample database to identify cases of VA ablations, including premature ventricular contraction (PVC) and ventricular tachycardia (VT) ablations, in patients with MVs between 2003 and 2015. Sociodemographic and clinical data were collected, and incidence of catheter ablation complications, mortality, and length of stay were analyzed. We compared the outcomes to a propensity matched cohort of patients without prior valve surgery.

Results

The study population included a weighted total of 647 CA cases in patients with prior MVs. The annual number of ablations almost doubled, from 34 ablations on average during the “early years” (2003–2008) to 64 annual ablation procedures on average during the “late years” (2009–2015) of the study (p=0.001). Length of stay at the hospital did not differ significantly between patients with MVs and 649 matched patients without prior MVs (5.4±0.4, 4.7±0.3 days respectively, p=0.12). The incidence of complications was higher among patients with and without MVs (12.6% vs. 7.5% respectively, p=0.14), however, not reaching statistical significance. Moreover, the data revealed a trend toward higher mortality among patients with MVs undergoing CA compared to matched control patients without MVs (3.7% vs. 0.7% respectively, p=0.087).

Conclusion

The utilization of catheter ablations for ventricular arrhythmias in patients with mechanical valves increased substantially over the years. The data show a trend towards increased incidence of morality and complications in the study population, requiring further investigation in larger population cohort.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Padeh Medical Center Research Fund

Personalising docetaxel and G-CSF schedules in cancer patients by a clinically validated computational model

Background:

This study was aimed to develop a new method for personalising chemotherapeutic and granulocyte colony-stimulating factor (G-CSF) combined schedules, and use it for suggesting efficacious chemotherapy with reduced neutropenia.

Methods:

Clinical data from 38 docetaxel (Doc)-treated metastatic breast cancer patients were employed for validating a new pharmacokinetic/pharmacodynamics model for Doc, combined with a mathematical model for granulopoiesis. An optimisation procedure was constructed and used for selecting improved treatment schedules.

Results:

The combined model accurately predicted observed nadir timing (r=0.99), grade 3 or 4 neutropenia (86% success) and neutrophil counts over time in individual patients (r=0.63), and showed robustness to CYP3A-induced variability in Doc clearance. For average patients, the predicted optimal support for the standard chemotherapy regimen, Doc 100 μg m⁻² tri-weekly, is G-CSF, 300 μg, Q1D × 3, starting day 7 post-Doc. This regimen largely moderates chemotherapy-induced neutrophil nadir and neutropenia duration. The more intensive Doc dose, 150 mg m⁻², is optimally supported by the slightly less cost-effective G-CSF 300 μg, Q1D × 4, 5 days post-Doc. The latter regimen is optimal for borderline patients (2000 neutrophils per μl) under Doc, 100–150 mg m⁻² tri-weekly.

Conclusions:

The new computational method can serve for tailoring efficacious cytotoxic and supportive treatments, minimising side effects to individual patients. Prospective clinical validation is warranted.

Effect of different sprint training regimes on the oxygen delivery-extraction in elite sprinters

AIM

The effects of sprint training regimes of varying distance schedules on the oxygen delivery-extraction relationship were investigated in 15 young (22+/-1 years) healthy males national-level sprinters.

METHODS

During one session subjects performed four sprints, in a schedule of increasing distance order (100, 200, 300 and 400 m), and during the other session, in a schedule of decreasing distance order (400, 300, 200, and 100 m). All sprint bouts were performed on a treadmill at a speed of 22 km/h-1, which corresponds to 85% of subjects' maximal speeds. The order of the running sequences during sessions was balanced over subjects.

RESULTS

During both sprint schedules, all variables except for oxygen extraction in the incremented training regime, increased significantly from rest to exercise. Training regimes were not different with regard to cardiac output and absolute oxygen uptake. However, the decreasing compared to the increasing scheme was characterized by significantly (P<0.05) higher mean values of heart rate (194.5+/-4.1 185.2+/-5.7 beats/min-1, respectively), oxygen extraction (54.3+/-3.8 and 47.1+/-3.4 mL/L-1, respectively) and lactate (10.6+/-0.5 and 9.2+/-0.7 mmol/L-1, respectively), while stroke volume was significantly (P<0.05) lower (100.4+/-4.5 and 109.7+/-4.4 mL, respectively).

CONCLUSION

The present study indicates that in sprinters performing a similar distance at the same speed, but under different training regimes interplay exists between oxygen delivery and extraction, suggesting a link between the type of training scheme and physiological cardiovascular and skeletal muscle metabolic adaptations. This may explain the absence of differences between the conditions in absolute oxygen uptake and peak power output.

Acute incremental exercise to maximal performance does not cause alterations in serum oxidant levels of healthy young individuals

AIM

This study was designed to analyze serum oxidative stress (OS) levels in healthy young individuals performing a routine maximal aerobic exercise and to evaluate the correlation between OS levels and physiological parameters.

METHODS

Serum OS levels were studied by thermochemiluminescence (TCL) parameters at rest and following maximal aerobic exercise in 85 healthy young subjects. Levels were measured by a real time on line TCL assay (higher TCL-Ratio and TCL-H3 = lower OS level).

RESULTS

Aerobic capacity had no effect on baseline OS levels. Post-exercise OS levels correlated with maximal oxygen uptake (V.O(2max)) (P<0.005), delta V.O(2) (V.O(2max)- V.O(2)rest) (P<0.005), anaerobic threshold (VTH) (P<0.01), and total oxygen uptake (especially O(2) after VTH), (P<0.005). TCL-Ratio was related to total running time (P<0.01), as well. Post-exercise OS levels for the whole study group did not vary from baseline values. However, individuals with higher fitness level (V.O(2max) >percentile 60) had significantly lower values of TCL-H3 (P=0.04) and tended to have lower TCL-Ratio, indicating they had elevated OS levels. In a multivariate analysis OS level was most affected by V.O(2) after VTH (anaerobic phase of the test) (P=0.003; adjusted odds ratio of 3.41, 95% confidence interval: 1.55-7.48).

CONCLUSIONS

In conclusion, acute incremental exercise to maximal performance does not cause alterations in serum oxidant levels of healthy young individuals. In healthy individuals performing maximal aerobic exercise, OS levels correlate with maximal aerobic power.

Pitch discrimination: are professional musicians better than non-musicians?

Musicians are typically considered to exhibit exceptional auditory skills. Only few studies, however, have substantiated this in basic psychoacoustic tasks. The purpose of the present investigation was to expand our knowledge on basic auditory abilities of musicians compared to non-musicians. Specific goals were: (1) to compare frequency discrimination thresholds (difference limen for frequency [DLF]) of non-musical pure tones in controlled groups of professional musicians and non-musicians; (2) to relate DLF performance to musical background; and (3) to compare DLF thresholds obtained with two threshold estimation procedures: 2- and 3- interval forced choice procedures (2IFC and 3IFC). Subjects were 16 professional musicians and 14 non-musicians. DLFs were obtained for three frequencies (0.25, 1 and 1.5 kHz) using the 3IFC adaptive procedure, and for one frequency (1 kHz) also using the 2IFC. Three threshold estimates were obtained for each frequency, procedure and subject. The results of the present study support five major findings: (a) mean DLFs for musicians were approximately half the values of the non-musicians; (b) significant learning for both groups during the three threshold estimations; (c) classical musicians performed better than those with contemporary musical background; (d) performance was influenced by years of musical experience; and (e) both groups showed better DLF in a 2IFC paradigm compared to the 3IFC. These data highlight the importance of short-term training on an auditory task, auditory memory and factors related to musical background (such as musical genre and years of experience) on auditory performance.

The Hebrew vowel system: raw and normalized acoustic data

It is well known that different languages use different vowel systems in terms of variety and number. The Hebrew vowel system consists of five vowels /i, e, a, o, u/. The present research identified the acoustic features of the vowels produced by Hebrew speakers differing in age and sex. Ninety speakers (men, women, boys, and girls) were recorded. The vowels were presented in a nonword context that was placed in a meaningful Hebrew sentence. The data included measurements of F0, F1, F2, F3, F4, and vowel duration for the five different vowels produced by the four groups of participants. Conversion of the physical frequency measures of formants into a critical band (bark) scale was performed as well. The results indicated that the F2/F1 ratio is a distinctive feature of all five vowels, keeping with the findings of previous research in other languages. Nevertheless, the values of the F2/F1 ratios led to an overlap between different vowels produced by different groups of speakers. Applying the bark transformation as speaker normalization procedure succeeded in reducing speaker differences while increasing vowel differences.

A longitudinal investigation of speaking rate in preschool children who stutter

Both clinical and theoretical interest in stuttering as a disorder of speech motor control has led to numerous investigations of speaking rate in people who stutter. The majority of these studies, however, has been conducted with adult and school-age groups. Most studies of preschoolers have included older children. Despite the ongoing theoretical and clinical focus on speaking rate in young children who stutter and their parents, no longitudinal or cross-sectional studies have been conducted to answer questions about the possible developmental link between stuttering and the rate of speech, or about differences in rate development between preschool children who stutter and normally fluent children. This investigation compared changes in articulatory rate over a period of 2 years in subgroups of preschool-age children who stutter and normally fluent children. Within the group of stuttering children, comparisons also were made between those who exhibited persistent stuttering and those who eventually recovered without intervention. Furthermore, the study compared two metrics of articulatory rate. Spontaneous speech samples, collected longitudinally over a 2-year period, were analyzed acoustically to determine speaking rate measured in number of syllables and phones per second. Results indicated no differences among the 3 groups when articulation rate was measured in syllables per second. Using the phones per second measure, however, significant group differences were found when comparing the control group to the recovered and persistent groups.