Israel Medical Association Journal

Background: The QT interval reflects the total duration of ventricular myocardial repolarization. Its prolongation is associated with increased risk of polymorphic ventricular tachycardia, or torsade de pointes, which can be fatal.

Objectives: To assess the prevalence of both prolonged and short QT interval in patients admitted to an acute geriatric ward.

Methods: This retrospective study included the records over 6 months of all patients hospitalized in an acute geriatric ward. Excluded were patients with pacemaker, bundle branch block and slow or rapid atrial fibrillation. The standard 12 lead electrocardiogram of each patient was used for the QT interval evaluation.

Results: We screened the files of 422 patients. QTc prolongation based on the mean of 12 ECG leads was detected in 115 patients (27%). Based on lead L2 only, QTc was prolonged in 136 (32%). Associated factors with QT prolongation were congestive heart failure and use of hypnotics. Short QT was found in 30 patients (7.1%) in lead L2 and in 19 (4.5%) by the mean 12 leads. Short QT was related to a higher heart rate, chronic atrial fibrillation and schizophrenia.

Conclusions: Our study detected QT segment disturbances in a considerable number of elderly patients admitted acutely to hospital. Further studies should confirm these results and clinicians should consider a close QT interval follow-up in predisposed patients.
 

Background: High levels of plasma homocysteine constitute a risk for cardiovascular disease. Physical activity, known to reduce CVD[1] risk, has been related to levels of Hcy[2]. Recently, higher Hcy was shown to be associated with lower cardiovascular fitness in women but not in men.

Objectives: To further explore the relationship between cardiorespiratory fitness and plasma total homocysteine levels in a large cohort of adult males and females.

Methods: This cross-sectional study included 2576 fitness and Hcy examinations in adults (62% males) aged 30–59 years, randomly drawn from a population undergoing a periodic health examination in the Sheba Medical Center's Executive Screening Survey. Blood tests were collected for tHcy[3] and a sub-maximal exercise test was performed to estimate cardiorespiratory fitness. Information on CVD/CVD risk factors (coronary heart disease, cerebrovascular accident, diabetes, hypertension or dyslipidemia) was self-reported.

Results: Mean tHcy plasma levels were 14.4 ± 7.7 and 10.2 ± 3.0 µmol/ml, and mean maximal oxygen uptake 36.5 ± 11.7 and 29 2 ± 9.5 ml/kg/min for males and females, respectively. A multiple regression analysis, adjusting for age, body mass index and CVD/CVD risk factors, showed no association between cardiorespiratory fitness and level of tHcy in males (P = 0.09) or in females (P = 0.62).

Conclusions: In this sample no relationship was found between level of cardiorespiratory fitness and plasma tHcy in men or women. The inconsistency of findings and the small number of studies warrant further research of the association between cardiorespiratory fitness and tHcy, an association that may have clinical implications for the modifications of cardiovascular risk factors.

Background: Long QT syndrome is an inherited cardiac disease, associated with malignant arrhythmias and sudden cardiac death.

Objectives: To map and identify the gene responsible for LQTS[1] in an Israeli family.

Methods: A large family was screened for LQTS after one of them was successfully resuscitated from ventricular fibrillation. The DNA was examined for suspicious loci by whole genome screening and the coding region of the LQT2 gene was sequenced.

Results: Nine family members, 6 males and 3 females, age (median and interquartile range) 26 years (13, 46), who were characterized by a unique T wave pattern were diagnosed as carrying the mutant gene. The LQTS-causing gene was mapped to chromosome 7 with the A614V mutation. All of the affected members in the family were correctly identified by electrocardiogram. Corrected QT duration was inversely associated with age in the affected family members and decreased with age.
Conclusions: Careful inspection of the ECG can correctly identify LQTS in some families. Genetic analysis is needed to confirm the diagnosis and enable the correct therapy in this disease

Background: Heart rate variability is a sensitive marker of cardiac sympathetic activity.

Objectives: To determine whether long-term hyperthyroidism induced by thyroxine suppressive therapy affects HRV[1].

Methods: Nineteen patients treated with suppressive doses of thyroxin for thyroid cancer and 19 age-matched controls were enrolled. Thyroid function tests and 1 minute HRV were performed on all subjects and the results were compared between the groups. The 1 minute HRV was analyzed during deep breathing and defined as the difference in beats/minute between the shortest and the longest heart rate interval measured by eletrocardiographic recording during six cycles of deep breathing.

Results:  One minute HRV during deep breathing was significantly lower among thyroxine-treated patients compared to healthy controls (25.6 ± 10.5 vs. 34.3 ± 12.6 beats/min, P < 0.05). There were no significant differences in mean, maximal and minimal heart rate between the groups

Conclusions: Thyroxine therapy administered for epithelial thyroid cancer resulted in subclinical hyperthyroidism and significantly decreased HRV due to autonomic dysfunction rather than basic elevated heart rate.

Background: Polymorphonuclear leukocyte priming and low grade inflammation are related to severity of kidney disease. Erythropoietin-receptor is present on PMNLs[1].

Objectives: To evaluate the effect of 20 weeks of EPO[2]-alpha treatment on PMNL characteristics in relation to the rate of kidney function deterioration in patients with chronic kidney disease.

Methods: Forty anemic chronic kidney disease patients, stage 4-5, were assigned to EPO and non-EPO treatment for 20 weeks. A group of 20 healthy controls was also studied. PMNL priming and PMNL-derived low grade inflammation were estimated, in vivo and ex vivo, before and after EPO treatment: The rate of superoxide release, white blood cells and PMNL counts, serum alkaline phosphatase and PMNL viability were measured. EPO-receptor on PMNLs was assayed by flow cytometry. The effect of 20 weeks of EPO treatment on kidney function was related to the estimated glomerular filtration rate.

Results: EPO treatment attenuated superoxide release ex vivo and in vivo and promoted PMNL survival ex vivo. Decreased low grade inflammation was reflected by reduced WBC[3] and PMNL counts and ALP[4] activity following treatment. EPO retarded the deterioration in GFR[5]. The percent of PMNLs expressing EPO-R[6] was higher before EPO treatment and correlated positively with the rate of superoxide release. After 20 weeks of EPO treatment the percent of PMNLs expressing EPO-R was down-regulated.

Conclusions: These non-erythropoietic properties of EPO are mediated by EPO-R on PMNLs, not related to the anemia correction. A new renal protection effect of EPO via attenuation of PMNL priming that decreases systemic low grade inflammation and oxidative stress is suggested.