Biomedical subjects

S Priori

Publications and source records attributed to S Priori.

8 recordsLinked to original sources

PubMed2001

Clinical implications for affected parents and siblings of probands with long-QT syndrome.

BACKGROUND: Whenever a proband is identified with long-QT syndrome (LQTS), his or her parents and siblings should be evaluated regarding the possibility of carrying the disorder. In the majority of cases, one of the proband's parents and one or more siblings are affected. The aim of this study was (1) to determine whether the clinical severity of LQTS in the proband is useful in identifying first-degree family members at high risk for cardiac events, and (2) to evaluate the clinical course of affected parents and siblings of LQTS probands. METHODS AND RESULTS: The clinical and ECG characteristics of 211 LQTS probands and 791 first-degree relatives (422 parents and 369 siblings) were studied to determine if the clinical profile of the proband is useful in determining the clinical severity of LQTS in affected parents and siblings. Affected female parents of an LQTS proband had a greater cumulative risk for a first cardiac event than affected male parents. The probability of a parent or sibling having a first cardiac event was not significantly influenced by the severity of the proband's clinical symptoms. Female sex and QT(c) duration were risk factors for cardiac events among affected parents, and QT(c) was the only risk factor for cardiac events in affected siblings. CONCLUSIONS: The severity profile of LQTS in a proband was not found to be useful in identifying the clinical severity of LQTS in affected first-degree relatives of the proband.

Adolescent↗

PubMed2001

Carbon monoxide cardiotoxicity.

Cardiac dysfunction including arrhythmias and myocardial ischemia have often been reported in carbon monoxide poisoning; scattered punctiform hemorrhages throughout the heart have been documented in autopsy samples. An appropriate diagnostic approach is crucial to assess carbon monoxide cardiac damage. This evaluation may be confounded by several factors, including the absence of overt symptoms and of specific ischemic changes in the electrocardiogram. In experimental studies, laboratory animals can develop cardiac changes similar to those seen in humans and therefore proved to be useful models to study the effects and the mechanisms of cardiac damage due to carbon monoxide. These investigations, as well as others performed in vitro, provide support for a direct action of carbon monoxide on the heart, in addition to systemic hypoxia produced by carboxyhemoglobin formation. This review focuses on the diagnostic aspects of carbon monoxide cardiotoxicity. Experimental results obtained in animals and in vitro models are also discussed.

Animals↗

PubMed2001

Cardiac damage in pediatric carbon monoxide poisoning.

BACKGROUND: Cardiovascular disorders including myocardial ischemia and heart failure have been described in both laboratory animals and humans following carbon monoxide poisoning. Carbon monoxide cardiotoxicity may be clinically occult and often remains undiagnosed because of the lack of overt symptoms and specific ischemic changes in the electrocardiogram. Routine myocardial necrosis markers have low diagnostic efficiency, particularly in patients with concomitant skeletal muscle necrosis or multiple organ failure complicating carbon monoxide poisoning. Carbon monoxide-induced cardiotoxicity has been investigated rarely in children. CASE REPORT: This paper describes carbon monoxide poisoning in a 12-year-old child who suffered from occult cardiac damage despite mild symptoms and low carboxy hemoglobin concentrations. Myocardial and mitral valve dysfunctions were observed, suggesting an ischemia-like syndrome. Cardiac damage was completely reversible within 1 month. CONCLUSION: This case report supports that a prolonged carbon monoxide exposure can cause cardiac damage in children even in the absence of specific symptoms, cerebral failure and high carboxyhemoglobin concentrations.

Carbon Monoxide Poisoning↗

PubMed2000

Spectrum of mutations in long-QT syndrome genes. KVLQT1, HERG, SCN5A, KCNE1, and KCNE2.

BACKGROUND: Long-QT Syndrome (LQTS) is a cardiovascular disorder characterized by prolongation of the QT interval on ECG and presence of syncope, seizures, and sudden death. Five genes have been implicated in Romano-Ward syndrome, the autosomal dominant form of LQTS: KVLQT1, HERG, SCN5A, KCNE1, and KCNE2. Mutations in KVLQT1 and KCNE1 also cause the Jervell and Lange-Nielsen syndrome, a form of LQTS associated with deafness, a phenotypic abnormality inherited in an autosomal recessive fashion. METHODS AND RESULTS: We used mutational analyses to screen a pool of 262 unrelated individuals with LQTS for mutations in the 5 defined genes. We identified 134 mutations in addition to the 43 that we previously reported. Eighty of the mutations were novel. The total number of mutations in this population is now 177 (68% of individuals). CONCLUSIONS: KVLQT1 (42%) and HERG (45%) accounted for 87% of identified mutations, and SCN5A (8%), KCNE1 (3%), and KCNE2 (2%) accounted for the other 13%. Missense mutations were most common (72%), followed by frameshift mutations (10%), in-frame deletions, and nonsense and splice-site mutations (5% to 7% each). Most mutations resided in intracellular (52%) and transmembrane (30%) domains; 12% were found in pore and 6% in extracellular segments. In most cases (78%), a mutation was found in a single family or an individual.

Adolescent↗

PubMed2000

Clinical and genetic variables associated with acute arousal and nonarousal-related cardiac events among subjects with long QT syndrome.

In patients with the long QT syndrome (LQTS), the occurrence of cardiac events (syncope or cardiac arrest) is frequently associated with acute arousal caused by exercise, swimming, emotion, or noise. However, cardiac events may also occur during sleep or with ordinary daily activities. The purpose of this study was to determine whether there are differential clinical, electrocardiographic, and genetic features among LQTS patients who experienced cardiac events with and without acute arousal. We identified 1,325 patients with cardiac events from the International LQTS Registry. Based on the precipitating conditions of the first event, 427 patients were classified as arousal, 345 as nonarousal, and the remaining 553 were unknown (not classifiable). Gene linkage was known in 78 of the 772 patients with classifiable first events. The age at first cardiac event was significantly younger in the arousal than the nonarousal group (11.7 vs. 15.5 years, respectively; p<0.001). The arousal-type patients had a higher rate of subsequent cardiac events during follow-up after the index event than the nonarousal-type patients (p = 0.02). Arousal-related cardiac events occurred in 85% of LQT1, 67% of LQT2, and 33% of LQT3 patients (p = 0.008). This study provides evidence that the genotype is an important determinant of the LQTS phenotype in terms of arousal and nonarousal-related cardiac events.

Acute Disease↗

PubMed1993

High permittivity patch radiator for single and multi-element hyperthermia applicators.

This paper describes a compact, low-profile patch radiator which is the base element for efficient, small-size applicators suitable for superficial hyperthermia. The design criteria and the technological processes involved are presented. The electromagnetic characteristics of the patch element are outlined, and possible application of the radiator are discussed.

Ceramics↗

PubMed1985

Lack of correlation between occlusion and reperfusion arrhythmias in the cat.

Recently it has been stated that in dogs absence of arrhythmias during coronary artery occlusion identifies a subgroup at almost no risk for developing ventricular fibrillation (VF) during reperfusion. A potential implication would be that prevention of ischemic arrhythmias may also prevent the most severe reperfusion arrhythmias. This concept is at variance with available clinical evidence. In order to reexamine this problem the left anterior descending coronary artery was occluded for 20 minutes in 41 anesthetized cats; the incidence and type of arrhythmias during occlusion and during the first minute of reperfusion were analyzed. Five animals had VF during occlusion and were not resuscitated. Twenty animals had ischemic arrhythmias, and among them the incidence of reperfusion VF was 50%. Sixteen animals did not have ischemic arrhythmias, but they did have a very similar incidence of reperfusion VF (44%). Thus, in this feline preparation, absence of ischemic arrhythmias did not help to predict a favorable outcome at the moment of reperfusion. This disparity with previous studies does not depend on the protocol used, but it may be partly due to species difference. These results demonstrate a lack of correlation between reperfusion VF and ischemic arrhythmias and provide further support for the concept of different mechanisms involved in occlusion and reperfusion arrhythmias.

Animals↗

PubMed1985

[Evaluation of flecainide in the therapy of chronic ventricular arrhythmia using the acute oral load method].

The efficacy of the new class Ic anti-arrhythmic (aa) drug, Flecainide, has been evaluated in patients (pts) affected by frequent and/or severe chronic ventricular arrhythmias (VA), as assessed by 24 hours Holter monitoring and maximal exercise stress testing. The protocol consisted in a preliminary screening with multiple aa drugs (average 6.0 per pt) using the acute oral drug testing. The most effective drug was then given for 72 hours and 24 hours Holter monitoring and exercise stress testing repeated; if the efficacy was confirmed, chronic treatment was initiated and control visits were repeated after 3, 6 and 12 months. The study population consisted of 27 pts; 22 (81%) were in Lown class 4A (18%) or 4B (63%). Eight pts (30%) had a previous (greater than 1 year) myocardial infarction, while in 14 (52%) no evidence of cardiac disease was found. During acute oral drug testing a positive response (reduction of PVC's greater than 90% and abolition of grades 4A and 4B) was obtained with Flecainide, 200 mg, in 20 pts (74%). In 6 pts (22%) no effect was observed, while a possible proarrhythmic effect was observed in 1 pt (4%). Eighteen pts entered the second phase of the study with an average dose of Flecainide of 175 mg b.i.d. In 83% of the pts there was a positive concordance between the acute oral testing and the 72 hours treatment, as in 15 out of 18 pts grades 4A and 4B were totally abolished and the mean frequency of PVC's was reduced by 99%. In 3 pts (17%) no response was observed. Flecainide increased significantly PR (37 msec), QRS (20 msec) and QTc (28 msec). The plasma levels attained with chronic therapy (846 ng/ml) were higher than those achieved with the acute oral testing (372 ng/ml). Mild side effects (dizziness, tremor and headache) were observed in 33% of the pts and were all eliminated by a 100 mg reduction in Flecainide dose. Fifteen pts entered the third phase (long term treatment): in this group there was a 93.3% correlation with phase two, as in 14 out of 15 pts there was a complete abolition of grade 4B arrhythmias, a 98.8% reduction of couplets and a reduction in the number of PVC's greater than 85%. This study shows that Flecainide is a quite powerful aa drug with modest side effects. Its efficacy against chronic VA is high, also when compared to the most effective and available aa drugs.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗