A5070793135- Cardiac electrophysiology and arrhythmias
- ECG Monitoring and Analysis
- Heart Rate Variability and Autonomic Control
- Cardiac Arrhythmias and Treatments
- Cardiac pacing and defibrillation studies
- Atrial Fibrillation Management and Outcomes
- Non-Invasive Vital Sign Monitoring
- Cardiac Imaging and Diagnostics
- Receptor Mechanisms and Signaling
- Cardiomyopathy and Myosin Studies
- Cardiovascular Function and Risk Factors
- Cardiovascular Syncope and Autonomic Disorders
- Ion channel regulation and function
- Cardiovascular Effects of Exercise
- Heart rate and cardiovascular health
- Phonocardiography and Auscultation Techniques
- Blood Pressure and Hypertension Studies
- Acute Myocardial Infarction Research
- Heart Failure Treatment and Management
- Advanced MRI Techniques and Applications
- Computational Drug Discovery Methods
- Analog and Mixed-Signal Circuit Design
- Electrochemical Analysis and Applications
- Viral Infections and Immunology Research
- Blind Source Separation Techniques
Lung Institute
2016-2024
Imperial College London
2015-2024
University of London
2014-2016
St George's, University of London
2002-2013
San Diego Cardiac Center
2008-2012
St. Paul's Co-educational College
2008-2012
Freie Universität Berlin
2002-2006
Washington DC VA Medical Center
2006
Wilhelminen Hospital
2006
Justus-Liebig-Universität Gießen
2006
Recently, it was demonstrated that the QT-RR relationship pattern varies significantly among healthy individuals. We compared intra- and interindividual variations of relationship. Twenty-four-hour 12-lead digital electrocardiograms (ECGs; SEER MC, GE Marquette; 10-s ECG recorded every 30 s) were obtained at baseline after 24 h, 1 wk, mo in 75 subjects (42 women, 33 men, age 27.9 ± 9.6 vs. 26.8 7.5 yr, P = not significant). QT interval measured automatically each by six different algorithms,...
AimsTo investigate the combination of heart rate turbulence (HRT) and deceleration capacity (DC) as risk predictors in post-infarction patients with left ventricular ejection fraction (LVEF) > 30%.
The EUropean Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter-Defibrillators (EU-CERT-ICD), a prospective investigator-initiated, controlled cohort study, was conducted in 44 centres and 15 European countries. It aimed assess current clinical effectiveness primary prevention ICD therapy.We recruited 2327 patients with ischaemic cardiomyopathy (ICM) or dilated (DCM) guideline indications for prophylactic implantation. endpoint all-cause...
Heart rate variability (HRV) has now been investigated for a number of decades. Different investigations linked HRV to the autonomic nervous system (ANS). Among these links, two clearly distinct facets need be distinguished. Ongoing debate relates used as measure tone. Nevertheless, this is very different from present discussion which deals with an indicator responsiveness, i.e. usefulness assessing whether ANS responds provocations and can detect changes in influence. control sinus node...
Background — The aim of the present study was to assess prognostic value novel repolarization descriptors from 12-lead ECG in a large cohort US veterans. Methods and Results Male veterans (n=813) with cardiovascular disease had digital ECGs recorded at VA Medical Center, Washington, DC, between 1984 1991. patient series retrospectively compiled 1991; follow-up prospectively assessed until 2000. Novel variables characterizing T-wave loop were automatically analyzed. Of 772 patients...
QT Dispersion and Repolarization Heterogeneity. Introduction : dispersion (QTd, range of intervals in 12 ECG leads) is thought to reflect spatial heterogeneity ventricular refractoriness. However, QTd may be largely due projections the repolarization dipole rather than “nondipolar” signals. Methods Results: Seventy‐eight normal subjects (47 ± 16 years, 23 women), 68 hypertrophic cardiomyopathy patients (HCM; 38 15 years. 21 72 dilated (DCM; 48 29 81 survivors acute myocardial infarction...
The time lag of the QT interval adaptation to heart rate changes (QT/RR hysteresis) was studied in 40 healthy subjects (18 females; mean age, 30.4+/-8.1 yr) with 3 separate daytime (>13 h) 12-lead electrocardiograms (ECG) each subject. In recording, 330 individual 10-s ECG segments were measured, including 100 preceded by 2 min varying greater than +/-2 beats/min. Other a stable rate. variable rate, QT/RR hysteresis characterized lambda parameters exponential decay models. intrasubject SDs...
Abstract Monitoring of QTc interval is mandated in different clinical conditions. Nevertheless, intra-subject variability intervals reduces the utility monitoring strategies. Since this partly related to QT heart rate correction, 10 corrections (Bazett, Fridericia, Dmitrienko, Framingham, Schlamowitz, Hodges, Ashman, Rautaharju, Sarma, and Rabkin) were applied 452,440 ECG measurements made 539 healthy volunteers (259 females, mean age 33.3 ± 8.4 years). For each correction formula, short...
A multiparametric heart rate variability analysis was performed to prove if combined (HRV) measures of different domains improve the result risk stratification in patients after myocardial infarction. In this study, standard time domain, frequency domain and non-linear dynamics HRV assessment were applied 572 survivors acute Three parameter sets each consisting 4 parameters compared with measurement global HRVi. Discriminant technique t-test separate high groups from survivors. The...
The potential effects of the dopamine agonist rotigotine on cardiac repolarization were studied in patients with Parkinson's disease, which affects electrocardiogram (ECG) quality. parallel-group trial was double-blind and placebo- positive (moxifloxacin 400 mg)-controlled. After two 24-h baseline ECGs, randomized to (n = 66) or placebo 64). Twenty four–hour ECGs recorded days 14/15, 21/22, 28/29, 35/36, 42/43 a regimen involving weekly dose escalations 4 mg/24 h (4 h–24 h). In 10-s 357,948)...
Data of a large clinical study were used to investigate how much are the QT/RR patterns in healthy subjects curved and whether these curvatures differ between women men. Daytime drug-free 12-lead Holter recordings repeated 4 times each 176 female male aged 32.7 ± 9.1 yr. In subjects, up 1,440 carefully verified QT interval measurements obtained with hysteresis-corrected RR intervals. Individual subject data fit following regression equation: = χ + (δ/γ)(1 - RR(γ)) ε, where (in s), is...
The study investigated healthy subjects to sex and race differences in QRS durations the dependency of on heart rates other physiologic correlates. duration its rate were evaluated 420 615 electrocardiograms obtained 523 including 111 females African origin, 130 Caucasian females, 125 males 129 males. distributions QRS/RR slopes at RR intervals 1 0.5 s compared between sex- race-defined subgroups. At high rates, was increased ∼35% all subjects, while others, shortened (no subgroups)....
The reason for sex differences in arrhythmic risk remains unclear. Heterogeneity of ventricular repolarization is directly linked to arrhythmogenesis; thus we investigated homogeneity and its circadian pattern men women. During 24-h Holter recordings 60 healthy subjects (27 males), a 12-lead electrocardiogram (ECG) was obtained every 30 s. RR QT intervals, and, after singular-value decomposition, two characteristics were calculated each ECG. Corrected (QTc) values using an individually...
OBJECTIVE--Normal electrocardiographic recordings were analysed to establish the influence of measurement different numbers leads on results formulas expressing QT dispersion and effects adjustment obtained from a subset an electrocardiogram approximate true complete electrocardiogram. SUBJECTS AND METHODS--Resting 12 lead electrocardiograms 27 healthy people investigated. In each lead, interval was measured with digitising board evaluated by three formulas: (A) difference between longest...
The costs of clinical investigations drug‐induced QT interval prolongation are mainly related to manual processing electrocardiographic (ECG) recordings. Potentially, however, these can be decreased by automatic ECG measurement. To investigate the improvements in measurement accuracy modern equipment, this study investigated “old” and “new” versions 12SL algorithm GE Healthcare (Milwaukee, WI, USA) compared results carefully validated reconciled measurements. investigation used two sets (A...
Regulatory authorities require new drugs to be investigated using a so-called "thorough QT/QTc study" identify compounds with potential of influencing cardiac repolarization in man. Presently drafted regulatory consensus requires these studies powered for the statistical detection QTc interval changes as small 5 ms. Since this translates into noticeable drug development burden, strategies need identified allowing size and thus cost thorough minimized. This study influence QT RR data quality...
<i>Background:</i> To examine the relationship between reduced heart rate variability (HRV) and cognitive function in middle-aged adults general population. <i>Methods:</i> HRV, both time frequency domains, functioning were measured twice 5,375 male female participants of UK Whitehall II study (mean ages = 55 61 years, respectively). Logistic regression was used to model associations HRV cognition [short-term verbal memory, reasoning (Alice Heim 4-I), vocabulary,...
Sex differences are known in several facets of cardiac electrophysiology, mostly concerning myocardial repolarisation. In this study, heart rate and variability (HRV) responses to postural provocations were compared 175 176 healthy females males, respectively (aged 33.1 ± 9.1 years). Two different provocative tests with position changes supine→sitting→standing→supine supine→standing→sitting→supine (15-min standing, 10-min other positions) performed up 4 times each subject. Heart spectral...