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Biomedical subjects

R Frank

Publications and source records attributed to R Frank.

At least 19 recordsLinked to original sources
PubMed2006

[The best of arrhythmia in 2005].

In 2005, one of the major areas of interest in the field of electrophysiology remains ablation of atrial fibrillation (AF). Identification of specific atrial sites, likely playing a role in the perpetuation of this arrhythmia has taken part in the ablation technique refinement. An increase in the rate of asymptomatic AF following ablation has been reported this year, which underlined the need for long lasting ECG recordings to demonstrate ablation success. The role of ventricular programmed stimulation remained controversial in the management of Brugada syndrome. Nevertheless, in the report of the second consensus conference, result of ventricular programmed stimulation was still considered as important in the decision making process. The third form of short QT syndrome (SQT3) has been found to be caused by a mutation in the KCNJ2 gene, leading to an increase in the function of Ik1 channel. Right ventricular dilation seemed to be the most frequent echocardiography anomaly in patients with right ventricular dysplasia as defined by the criteria published in 1994. Ablation of frequent (>20% on Holter monitoring) ventricular premature beats has been shown to improve hemodynamics in patients with left ventricular dilation and impaired ejection fraction. Safety and efficacy of implantable cardioverter defibrillator (ICD) have been demonstrated in high risk patients with hypertrophic cardiomyopathy in a large clinical study. However, the use of high energy ICD and the systematic determination of the defibrillation threshold were recommended. Despite the presence of sophisticated algorithms to discriminate VT from SVT, high rates of inappropriate therapies were still reported in recent ICD studies.

Anti-Arrhythmia Agents↗
PubMed2006

[Survey into cardiac pacing in the Ile-de-France area for the year 2001: evaluation of indications].

UNLABELLED: A survey into the implantation of cardiac pacemakers during 2001 in the Ile-de-France area was carried out by the French National Insurance Medical Service in order to evaluate performance in all centres performing more than 10 primary implantations per year. METHODS AND RESULTS: In 2001, 12 centres out of a total of 49 performed less than 50 primary implantations per year, representing 5% of the total regional activity, which was estimated to be 6414 procedures. The remaining 95% of procedures were spread evenly among 8 high-throughput centres (> 200 primary implantations per year) and 29 medium-throughput centres (50 to 200 primary implantations per year). Indications for pacing were analysed retrospectively by a team of regulatory doctors on a sample of 2176 patients with reference to the ACC/AHA/NASPE guidelines. After examination of the medical records, the indication was ranked as being class I, II or Ill (absence of indication). A valid indication was lacking in 8.2% of cases. Sinus node dysfunction represented 74.6% of the non-indications, and this classification had the predictive factors of asymptomatic dysfunction, and treatment with anti-arrhythmic or bradycardic medication. The proportion of class III interventions was significantly lower in the high-throughput centres (5.8 vs 9.9%, p < 0.05). CONCLUSION: 8.2% of primary pacing procedures were not indicated and resulted principally from asymptomatic sinus node dysfunction.

Aged↗
PubMed2005

[Arrhythmogenic right ventricular dysplasia and sudden cardiac death].

ARVD manifests itself by a wide spectrum of clinical presentations from asymptomatic patients to a broad range of ventricular arrhythmia, extrasystoles, tachycardia, or sudden arrhythmic death which can be the first symptom. It is a major cause for sudden death in young people and sportsmen. In known ARVD the risk of sudden death is not easy to assess from the literature, as its natural history is modulated by the wide variety of antiarrhythmic therapies. Hemodynamically ill tolerated ventricular arrhythmia, left ventricular involvement, sports, a youger age below 35, and uncontrolled therapy seem to predict an adverse outcome for these patients. These data may be helpful to decide for an AICD.

Age Factors↗
PubMed2005

A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging.

UNLABELLED: Laser Doppler perfusion imaging (LDI) is an established technique for early assessment of burn depth to help determine a course of treatment. Laser speckle perfusion imaging (LSPI) is an alternative laser based, non-invasive perfusion monitoring technique that offers rapid and high resolution images of tissue. We have evaluated the ability of the LSPI instrument in determining and monitoring burn scar perfusion over time and compared it with the LDI instrument as a standard. METHODS: Ten patients with hypertrophic burn scars (time since injury: 1-8 months) were recruited. Burn scars were scanned with both instruments (LSPI and LDI) monthly over a period of 11 months. Clinical grading of the burn scars was assessed on every scan date using the Vancouver burn scar scale. RESULTS: Comparison of the perfusion values determined by each instrument shows a strong positive correlation, r2=0.86 (n=63). Each instrument's output also correlated significantly with the clinical grading of the scar, indicating the expected decrease in perfusion as the clinical condition of the scars improved with time. SIGNIFICANCE: The new LSPI instrument compared favorably with the established LDI instrument, yielding similar results. The considerably faster scan time and higher resolution of the LSPI method provides a distinct clinical advantage, both in terms of patient comfort and for reliably matching perfusion characteristics to their associated anatomical features. The fast temporal response of the LSPI instrument could be used to monitor near real-time responses to mechanical or pharmacological interventions to study dynamic vascular changes to burn damaged tissues.

Adult↗
PubMed2005

[The best of arrhythmia in 2004].

As for the preceding years, important studies regarding several remaining clinical issues for electrophysiologists have been reported in 2004. Large randomized studies have underlined the need for an EP study in asymptomatic patients with overt ventricular preexcitation. In addition to a short antegrade refractory period, arrhythmia induction (atrial fibrillation or reciprocating tachycardia) argues for accessory pathway ablation. Although currently leading to fairly good results, atrial fibrillation ablation technique is still evolving. Encircling pulmonary vein and the surrounding atrial tissue seems to give better long term clinical results as compared to ostial pulmonary vein disconnection. Large series have confirmed that whatever cardiomyopathy etiology, prophylactic ICD implantation was associated with a reduction of sudden arrhythmic death during follow-up in patients with low ejection fraction. However, in order to save one patient more and more patients have to be implanted because of the increasing efficacy of pharmacological treatment for heart failure. Three clinical series of arrhythmogenic right ventricular dysplasia implanted with AICD have been published this year. The prognostic factors for the occurrence of severe ventricular arrhythmia are hemodynamically ill tolerated ventricular tachycardia, and VT induction during EP study. Management of patients with Brugada syndrome is still far from being well defined. Interestingly in a recent report, hydroquinidine has been found to reduce the incidence of ventricular arrhythmia in the follow-up as well as the rate of ventricular arrhythmia induction in the EP lab. Yet, prophylactic ICD implantation remains the treatment of choice in symptomatic and inducible patients.

Arrhythmias, Cardiac↗
PubMed2005

[Characterization of premature ventricular contraction initiating ventricular fibrillation].

UNLABELLED: The aim of this study is to characterize the electrocardiographic features of premature ventricular contractions (PVC) from different anatomical region that trigger ventricular fibrillation (VF). METHODS AND RESULTS: 36 consecutives patients (20 males, 42+/-14 yrs) undergoing VF ablation from 7 centres were studied (22 with idiopathic VF, 4 associated with a long QT syndrome, 3 with Brugada syndrome, 4 with ischaemic cardiomyopathy and 3 associated with other substrate). Mapping of these PVC showed 2 different origins, which were then confirmed by ablation: right ventricular outflow tract (RVOT) (22%) and peripheral Purkinje network (81%). One patient had PVC from both origins (Brugada). RVOT PVC were frequent but had triggered only 5+/-5 episodes of VF for 26+/-33 months. Purkinje PVC were more likely to be present during electrical storm with 18+/-28 episodes of VF for 33+/-45 months. Right Purkinje PVC have a left bundle branch block with superior axis morphology whereas left Purkinje ones have a right bundle branch block. The axis of activation showed variation from inferior to superior depending on the area of origin from the Purkinje network and the exit site to the myocardium. However Purkinje PVC were characterized by short QRS duration (126+/-18 vs 145+/-13ms for RVOT PVC; p=0.05). In addition the coupling interval was significantly shorter compared to RVOT PVC (292+/-45 vs 358+/-37ms respectively; p=0.005). CONCLUSION: PVC initiating VF demonstrate specific electrocardiographic features that facilitate determination of their origin. Ablation of these typical PVC is feasible in order to reduce ICD shock.

Adult↗
PubMed2004

Los Años de la Crisis: an examination of change in differential infant mortality risk within Mexico.

The main aim of the present analysis is to test the possibility that the period of economic hardship characterizing Mexico over the decade 1986-1996 has negatively influenced infant health outcomes. Data on births from two installments of the Encuesta Nacional de la Dinámica Demográfica, a nationally representative demographic survey, are used to determine whether a reduction in mortality differentials has paralleled the overall drop in the national infant mortality rate. The findings indicate that the decrease observed in the overall infant mortality rate has been matched by decreases in several disparities at the same time that it has been marred by increases in others. The data support the possibility that where you live has become an increasingly salient factor in determining the odds of infant mortality. High parity, low education and unemployment status have also become more salient factors in predicting post neonatal infant mortality risk in the more recent period as compared to the earlier period. As Mexico's infant mortality rate begins to stabilize in the near future, this research highlights the need to re-focus our research efforts on the causes and consequences of differential mortality trends.

Adult↗
PubMed2004

Parallel hash-based EST clustering algorithm for gene sequencing.

EST clustering is a simple, yet effective method to discover all the genes present in a variety of species. Although using ESTs is a cost-effective approach in gene discovery, the amount of data, and hence the computational resources required, make it a very challenging problem. Time and storage requirements for EST clustering problems are prohibitively expensive. Existing tools have quadratic time complexity resulting from all against all sequence comparisons. With the rapid growth of EST data we need better and faster clustering tools. In this paper, we present HECT (Hash based EST Clustering Tool), a novel time- and memory-efficient algorithm for EST clustering. We report that HECT can cluster a 10,000 Human EST dataset (which is also used in benchmarking d2_cluster), in 207 minutes on a 1 GHz Pentium III processor which is 36 times faster than the original d2_cluster algorithm. A parallel version of HECT (PECT) is also developed and used to cluster 269,035 soybean EST sequences on IA-32 Linux cluster at National Center for Supercomputing Applications at UIUC. The parallel algorithm exhibited excellent speedup over its sequential counterpart and its memory requirements are almost negligible making it suitable to run virtually on any data size. The performance of the proposed clustering algorithms is compared against other known clustering techniques and results are reported in the paper.

Algorithms↗
PubMed2004

[Are patients of Asian medicine active consumers?].

BACKGROUND: The hypothesis that heterodox patients are active consumers. OBJECTIVE: What are the decisional criteria that lead patients to Asian medicine? Do they want to be involved in therapeutic decision-making? Are they well informed about diverse therapeutic options? METHODS: Semistructured interviews with 26 patients using Ayurveda or acupuncture. RESULTS: Active consumerism among the patients is limited to processes before the beginning of the treatment. They collect little information about the concepts of Asian medicine. They also tend to welcome a rather paternalistic therapeutic relationship in which medical decision-making is centered around the physician. CONCLUSION: As only two of the 26 interviewed patients conform to the notion of active consumerism, we argue that the majority of patients engages in practices of passive consumerism.

Acupuncture↗
PubMed2004

Trofosfamide in the palliative treatment of cancer: a review of the literature.

Trofosfamide is an alkylating agent that is derived from the oxazaphoshorines. It has found application in a broad spectrum of malignancies in the last three decades. The main indications for application were in the palliative situation and as maintenance therapy. Good results were reported from the treatment of non-Hodgkin's lymphomas and soft tissue sarcomas. A lot of small studies and casuistic contributions are available giving treatment results of several solid carcinomas (malignant gliomas, ovarian, lung and prostate cancer, and others). Due to its oral formulation and good tolerability trofosfamide is an attractive candidate for the palliative situation because treatment on an outpatient basis is possible. However, there is still a lack of randomized clinical studies with trofosfamide. Thus, evidence-based conclusions on the therapeutic value of the drug cannot be drawn. In the future, phase III trials should be undertaken.

Antineoplastic Agents↗
PubMed2004

[Arrhythmogenic right ventricular dysplasia].

Congestive cardiac failure could be as important as cardiac arrhythmias in the natural history of arrhythmogenic right ventricular dysplasia. This can be related to the progressive replacement of myocardium by fat and fibrosis of the right ventricle. The left ventricle may also be involved by the same disease process. Moreover, inflammation can be superimposed on ARVD, resulting in a wide spectrum of clinical presentation which can mimick idiopathic dilated cardiomyopathy. Right ventricular cardiac failure has been controlled by anterior dynamic cardiomyoplasty.

Arrhythmogenic Right Ventricular Dysplasia↗
PubMed2003

[Wolff-Parkinson-White syndrome in the child. A case report with associated atrial fibrillation].

UNLABELLED: In children, Wolff-Parkinson-White (WPW) syndrome is often revealed by reentrant tachycardia episodes. Rarely, this syndrome can be the cause of syncope or of sudden death, resulting from rapid conduction of atrial fibrillation to the ventricles through the accessory pathway. CASE REPORT: The authors report the case of a child, who had a WPW syndrome diagnosed after birth because of a supraventricular tachycardia and who was later asymptomatic. At ten years of age, he was admitted because of palpitations due to atrial fibrillation and rapid conduction through the accessory pathway. CONCLUSION: In a child with WPW syndrome, tachycardia with wide and irregular QRS complexes should evoke the involvement of atrial fibrillation, with rapid conduction to the ventricle. Drugs blocking conduction through the atrio-ventricular node are contra-indicated and the condition is an indication for radiofrequency ablation.

Atrial Fibrillation↗
PubMed2003

[Effects of 50 to 60 Hz and of 20 to 50 kHz magnetic fields on the operation of implanted cardiac pacemakers].

UNLABELLED: The effect of 50 Hz and 60 Hz (frequencies of current distribution) and 20 kHz to 50 kHz (frequencies of induction cooktop) magnetic interference on implanted pacemakers have been assessed with the present generation of device technology. Sixty patients implanted in 1998 and 1999 with dual chamber pacemakers from 9 different manufacturers were monitored with telemetry while passing through, and standing between a system of two coils. They generated a 50 Hz or a 60 Hz magnetic field at 50 microT. Then, patients used a cooktop at different power. The recordings were made with the standard setting of "medically correct" sensing parameters chosen for the patients. Then pacemakers were reprogrammed to the unipolar mode, with the highest atrial (A) and ventricular (V) sensitivity that did not induce muscular inhibition while moving. Between each exposure (50 Hz, 60 Hz or 20 kHz to 50 kHz), the pacemaker programmation was controlled. At the end of the tests, pacemakers will be reprogrammed with the standard setting. The medical observer being blind to the existence or not of the magnetic field. No pacemaker was influenced by the vicinity of the magnetic field at medically correct settings. At unipolar high sensitivity, no inhibition nor reprogramming was observed. Transient reversion to interference mode was observed in 6 cases, 3 transient acceleration due to atrial detection of the interference, and one T wave detection by the ventricular lead. All were observed with the 60 Hz, and only 3 with the 50 Hz magnetic field. One device (Biotronik) shifted out of its special program (hysteresis research) during the tests with the induction cooktop, but it maintained its standard program, and the event could not be repeated despite further testing. CONCLUSION: Actual pacemakers do not present any electromagnetic interference with 50 Hz and 60 Hz or induction cooktop frequency working. They are insensitive with medically correct settings. Unusual high sensitivity leads only to noise reversion mode, or transient ventricular tracking.

Dose-Response Relationship, Radiation↗
PubMed2003

[Cardiac Pacemakers, implantable defibrillators and IRM].

The IRM is formally contraindicated to the pacemaker and cardiac defibrillator wearers because of the risk of inhibition or inappropriate stimulations during the examination. However if the examination is essential, suitable programming of the apparatus and a constant monitoring of the heartbeat rate by a qualified doctor in cardiac stimulation must make it possible to avoid any accident.

Defibrillators, Implantable↗