Environmental tobacco smoke exposure in school children: parent report and urine cotinine measures

BACKGROUND: Environmental tobacco smoke (ETS) in the home continues to be a major health risk for children around the world. Measuring ETS is a central feature of clinical and epidemiological studies, with children's exposure often assessed through parental estimates. The authors examined the relationship between parent-reported estimates of children's exposure to ETS and children's urinary cotinine levels and evaluated the ETS exposure and its effect on respiratory health in children. METHODS: A total of 188 school children were included in the study. Parents were asked to complete a questionnaire about their smoking habits, their children's respiratory morbidity status and housing conditions. Urinary cotinine levels were measured in children. RESULTS: According to the responses, 72.3% of the children came from households with smokers, and 34.6% had daily exposure to ETS. When urine cotinine levels of >10 ng/mL were used as the yardstick of exposure, 76% of the children were identified as ETS exposed. No relation was detected between the symptoms of respiratory tract diseases and ETS exposure. To determine the amount of ETS exposure, the contribution of parental reports was low. CONCLUSION: To evaluate the level of ETS exposure of children, the parents' reports were not reliable. The addition of a biological measure results in a more informative estimate of ETS exposure in children.     

Electromagnetic Device‐Device Interaction between a New Generation Implantable Pacemaker and Left Ventricular Assist Device: Recognition and Potential Solutions

An electromagnetic interaction between St. Jude Medical Inc. (St. Paul, MN, USA) permanent pacemakers and HeartMate II left ventricular assist devices (LVADs) (Thoratec Inc., Pleasanton, CA, USA) has been reported before, but the problem was thought to be resolved in the St. Jude Medical's most recently released pacemaker platform. We report a case of interference between the HeartMate II LVAD and the most recently released St. Jude Medical pacemaker (model no. PM3210; Anthem) and review new developments to overcome the electromagnetic interference problem in this setting. (PACE 2010; 1–3)     

QT Duration and Dispersion in Patients with Anomalous Origins of Coronary Arteries

Background: Coronary artery anomalies have been reported to show various symptoms ranging from chest pain and dyspnea to cardio-respiratory arrest and sudden death. In this study, we attempted to assess the changes in QT interval duration and dispersion in anomalous origins of coronary arteries (AOCA).
Methods: Nineteen AOCA patients (mean age: 52 ± 11 years) and 30 healthy control subjects (mean age: 50 ± 12 years) were included in the study. Minimum and maximum corrected QT intervals, and corrected QT dispersion were calculated. The two groups were compared in terms of QT dispersion and QT duration.
Results: There was no difference between the two groups in terms of baseline demographic characteristics. Maximum corrected QT intervals (QTc max), minimum corrected QT intervals (QTc min), and corrected QT dispersion were higher in AOCA patients than controls (452 ± 38 vs 411 ± 25 ms [P = 0.0001], 402 ± 31 vs 383 ± 28 ms [P = 0.048], and 51 ± 30 vs 28 ± 12 ms [P = 0.001], respectively).
Conclusion: In the patients with anomalous origins of coronary arteries, QT dispersion that is an indicator of sudden cardiac death and arrhythmias frequency increased. QTc max, QTc min, and corrected QT dispersion are higher in patients with anomalous origin of the coronary artery than in control subjects.     

The Prognostic Value of Combined Fractional Flow Reserve and TIMI Frame Count Measurements in Patients with Stable Angina Pectoris and Acute Coronary Syndrome

Background: The aim of this study was to evaluate the prognostic value of different fractional flow reserve (FFR) cutoff values and corrected thrombolysis in myocardial infarction frame (TIMI) count (CTFC) measurements in a series of consecutive patients with moderate coronary lesions, including patients with unstable angina, myocardial infarction, and/or positive noninvasive functional test findings. Methods: We included 162 consecutive coronary patients in whom revascularization of a moderate coronary lesion was deferred based on a FFR value ≥0.75. Patients were divided according to the results of the intracoronary pressure and flow measurements into four groups: group A: 0.75 ≤ FFR ≤ 0.85 and CTFC > 28 (n=22), group B: 0.75 ≤ FFR ≤ 0.85 and CTFC ≤ 28 (n = 55), group C: 0.85 < FFR and CTFC > 28 (n = 19), and group D: 0.85 < FFR and CTFC ≤ 28 (n = 66). Adverse cardiac events and the presence of angina were evaluated at follow‐up. Results: At a mean follow‐up of 18 ± 10 months, cardiac event rate in patients with 0.75 ≤ FFR ≤ 0.85 and FFR > 0.85 were 22% and 9%, respectively (P = 0.026) and also, a trend was observed toward a higher cardiac event rate in case of an abnormal CTFC (CTFC > 28) compared to a normal CTFC (24% vs 12%, P = 0.066). Furthermore, a significantly higher cardiac event rate was observed when group A was compared to group D (31.8% vs 7.6%, respectively, P = 0.004). Conclusion: Patients with potential microvascular dysfunction and borderline FFR values should be interpreted with caution, and management strategies should be guided not only by pressure measurement, but also by possibly supplementary clinical risk stratification and noninvasive tests. (J Interven Cardiol 2010;23:421–428)     

Anterior Mitral Valve Length is Associated with Ventricular Tachycardia in Patients with Classical Mitral Valve Prolapse

Background: The aim of this study was to investigate the electrocardiographic and echocardiographic predictors of ventricular tachycardia (VT) in patients with classical mitral valve prolapse (MVP). Methods: Thirty patients (nine men and 21 women; mean age, 41.5 ± 15 years) in sinus rhythm with mitral valve prolapse who had VT in 24‐hour Holter analysis and 30 patients with MVP without VT (eight men and 22 women; mean age, 43 ± 16 years) were included in this study. Transthoracic echocardiography, QT analyses from 12‐lead electrocardiography, and 24‐hour Holter electrocardiogram recordings were performed. Results: Mitral posterior leaflet thickness (0.48 ± 0.03 cm vs 0.43 ± 0,08 cm, P = 0.025), mitral anterior leaflet length (3.2 ± 0.24 cm vs 2.9 ± 0.36, P < 0.001), mitral posterior leaflet length (2.2 ± 0.3 cm vs 1.9 ± 0.35 cm, P = 0.01), left atrium anteroposterior diameter (4.2 ± 0.8 cm vs 3.5 ± 0.5 cm, P = 0.001), and mitral annulus circumference (15.7 ± 1.3 cm vs 14.6 ± 1.6 cm, P = 0.004) were increased significantly in MVP cases with VT. No significant difference was found between the cases with and without VT in terms of frequency‐ and time‐domain analysis. QT dispersion (72 ± 18 ms vs 55 ± 15 ms, P = 0.0002) and corrected QT dispersion (QTcD) (76 ± 18 ms vs 55 ± 15 ms, P = 0.0002) were significantly increased in cases with VT compared with those without VT. Based on logistic regression analysis for MVP cases, in the case of VT, an enhancement in QTcD (P = 0.01) and the mitral anterior leaflet length (P = 0.003) were the independent predictors of VT. Conclusion: Mitral anterior leaflet length and enhanced QTcD are closely related with VT in patients with classical MVP. (PACE 2010; 33:1224–1230)     

Heart Rate Recovery and Chronotropic Incompetence in Patients with Subclinical Hypothyroidism

Background: Heart rate recovery (HRR) and chronotropic incompetence (CI) in patients with subclinical hypothyroidism (SCH) has not been explored previously. The aim of the present study was to evaluate the HRR and CI in patients with SCH.
Methods: Twenty-five patients (11 men, 14 women with a mean age of 36 ± 10 years) who were diagnosed SCH determined by an increased serum thyrothrophine (TSH) concentration (>4.0 ng/mL) and the normal free triiodothyronine (fT3) and free thyroxin (fT4) levels, were included in the study. The control group of healthy individuals with normal TSH (12 males, 15 females) with a mean age of 36 ± 3 years was also included. Two groups were well matched for age, sex, and body mass index. Medical history, physical examination, electrocardiogram, treadmill exercise testing, and chest radiogram were performed for all participants.
Results: The characteristics of SCH patients and control cases were similar with regard to age, sex, and BMI except for TSH levels. Serum TSH levels were significantly higher in SCH patients than the controls (P < 0.001). No significant differences were observed in the changes of heart rate (HR), exercise tolerance (metabolic equivalents) , or systolic and diastolic blood pressures at rest or during exercise between the groups, whereas HRR and CI were significantly lower during exercise testing in the SCH patients compared to controls (P < 0.003; P < 0.03, respectively).
Conclusion: The results of the present study demonstrated that SCH can cause impaired cardiovascular autonomic function and attenuated HR response to exercise. (PACE 2010; 2–5)