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Biomedical subjects

B Luderitz

Publications and source records attributed to B Luderitz.

5 recordsLinked to original sources
PubMed2000

The impairment of health-related quality of life in patients with intermittent atrial fibrillation: implications for the assessment of investigational therapy.

OBJECTIVES: We sought to assess the impact of intermittent atrial fibrillation (AF) on health-related quality of life (QoL). BACKGROUND: Intermittent AF is a common condition with little data on health-related QoL questionnaires to guide investigational therapies. METHODS: Outpatients from four centers, with documented AF (n = 152), completed validated QoL questionnaires (Medical Outcomes Study Short Form 36 [SF-36], Specific Activity, Symptom Checklist, Illness Intrusiveness and University of Toronto AF Severity Scales). Comparison groups were made up of healthy individuals (n = 47) and four cardiac control groups: published (n = 78) and created for study (n = 69) percutaneous transluminal coronary angioplasty (PTCA); published heart failure (n = 216) and published postmyocardial infarction (MI) (n = 107). RESULTS: Across all domains of the SF-36, AF patients reported substantially worse QoL than healthy controls (1.3 to 2.0 standard deviation units), with scores of 24%, 23%, 16% and 30% lower than healthy individuals on measures of physical and social functioning, mental and general health, respectively (all p < 0.001). Patients with AF were either significantly worse (p < 0.05, published controls) or as impaired (study controls) as either PTCA or post-MI patients on all domains of the SF-36 and the same as heart failure controls on SF-36 psychological subscales. Patients with AF were as impaired or worse than study PTCA controls on measures of illness intrusiveness, activity limitations and symptoms. Associations between objective disease indexes and subjective QoL measures had poor correlations and accounted for <6% of the total variability in QoL scores. CONCLUSIONS: Quality of life is as impaired in patients with intermittent AF as in patients with significant structural heart disease. Patients' perception of QoL is not dependent on the objective measures of disease severity that are usually employed.

Anti-Arrhythmia Agents↗
PubMed1995

Paraprosthetic regurgitation in aortic prostheses: determination of the hemodynamic significance by pulsed Doppler examination of the subclavian artery flow.

Paraprosthetic leaks in aortic prostheses may cause significant aortic regurgitation. Color flow Doppler echocardiography is the method of choice for detecting paraprosthetic leaks, but quantitation of regurgitation is limited by this method. This study investigated the value of pulsed Doppler of the left subclavian artery flow for assessing the hemodynamic significance of paraprosthetic regurgitation in aortic prostheses in 32 patients with, and in 77 control subjects without paraprosthetic leaks. Paraprosthetic leaks were either detected by transthoracic or transesophageal color flow echocardiography. The hemodynamic significance of paraprosthetic regurgitation was determined by means of a dichotomous angiographic classification - significant versus insignificant regurgitation. Pulsed Doppler was performed to measure the maximal diastolic and systolic velocities, and diastolic and systolic velocity-time-integrals (VTI) and their ratios in the subclavian artery flow. The accuracy of these parameters for differentiating significant versus insignificant regurgitation was assessed. Angiography revealed 13 significant and 19 insignificant forms of aortic regurgitation. In all patients, examination of the subclavian artery was feasible by pulsed Doppler. The highest correlation between Doppler derived parameters and regurgitation was calculated for the ratios of diastolic and systolic VTI (r = 0.84), diastolic VTI (r = 0.82) and ratio of diastolic and systolic velocities (r = 0.80). An increase of the ratio of diastolic and systolic VTI (> 45%) and ratio of diastolic to systolic velocity (> 0.4), and increased diastolic VTI (> 60 cm) in the subclavian artery velocity profile identified significant paraprosthetic regurgitation with a sensitivity of 94%, 75% and 87%, and specificity of 87%, 80% and 87%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1983

Acceleration of sinus rhythm during slow-rate atrial pacing.

We evaluated the effects of slow-rate atrial pacing on impulse formation of the sinus node in 13 isolated rabbit right atria using the microelectrode technique. After the spread of activation was mapped to determine true sinoatrial conduction time (SACT) (38 +/- 16 msec [+/- SD]), the atrium was paced for eight beats at constant intervals slightly shorter than spontaneous cycle length in steps of 10 msec. In all preparations, slow-rate atrial pacing failed to capture the pacemaker center, but shortened action potential duration because of electrotonic interaction between atrium and sinus node. The resulting acceleration of impulse formation of dominant fibers ceased instantaneously when atrial pacing was terminated. Estimation of SACT by constant pacing 5 beats/min faster than sinus rhythm seriously underestimated the true values (p less than 0.05), because sinus node acceleration prevented capture of dominant pacemaker fibers in 10 of 13 preparations. At pacing rates 10 beats/min faster than sinus rhythm, capture did not occur in eight of 13 experiments; at pacing rates 20 beats/min faster, the pacemaker center was captured in all preparations. This study describes sinus node acceleration as a consistent and hitherto unknown finding during slow-rate stimulation of the atrium. This phenomenon accounts for the failure of the constant atrial pacing technique to determine SACT accurately in man.

Action Potentials↗