QT dispersion in infants with apparent life-threatening events syndrome.

Apparent life-threatening event (ALTE) is a term used to define an event of unknown cause after an infant is found limp, cyanotic, bradycardic, and/or requires resuscitation. Eight to 15% of children with ALTE die of sudden infant death syndrome. Obstructive sleep apnea, bradycardia, gastroesophageal reflux, and laryngotracheal abnormalities are frequently associated with ALTE. Wide QT dispersion is associated with sudden death in heart failure and increased risk of ventricular fibrillation in acute myocardial infarction. Here, we assess QT dispersion in infants with ALTE and its correlation to clinical and electrocardiographic indices. The study included eighty nine infants (age 2.14 +/- 1.8 months, 46 males and 43 females) referred with ALTE to the pediatric emergency room and 18 controls (age 2.77 +/- 2.2 months) who underwent electrocardiogram assessment of QTmin, QTmax, QT dispersion (QT-D), and as well as QTmin, QTmax, and QT-D corrected for heart rate (QTcmin, QTcmax, QTC-D, respectively). All infants were referred at the usual diagnostic tests-the gastroesophageal reflux test, apnea monitoring, Holter ECG monitoring, electroencephalogram, and Doppler echocardiography. QT-D, QTc-D, and QTc-min were significantly greater in the ALTE group (p < 0.01). Greater QTc-D was found in males compared to females (p < 0.001). QT-D and QTc-D showed little or no correlation with age of infant or positivity of diagnostic tests. QTc has been found by multiple regression analysis to be the independent variable with the greatest impact on QTc-D (beta = -0.68, p < 0.001).

The impact of new immigrants from the former Soviet Union on the severity of coronary angiographic findings in a public hospital in Israel.

BACKGROUND: The arrival of 610,000 new immigrants to Israel from the former Soviet republics accounted for 58% of the population growth in the early 1990's. OBJECTIVE: To compare the coronary angiographic findings and risk factors between the new immigrants and local Jewish and Arab patients in this era of cost containment. METHODS AND RESULTS: A total of 550 consecutive patients--314 Jews, 95 new immigrants and 141 Arabs--were catheterized and analyzed during a 5 month period in 1995. Of this group 403 were males (73%). The mean age was 63.6 +/- 10.2 years among new immigrants, 62.4 +/- 9.4 among Jews, and 55.1 +/- 10.9 among Arabs (P < 0.05). Immigrants, including those under age 60, had the highest prevalence of multivessel disease (88.7%). Arabs had a high prevalence of single vessel disease (34.6%) and a low prevalence of multivessel (65.4%) and left main coronary disease (5.6%). Age, gender, risk factors and ethnic origin in descending order were determinants of the extent of coronary angiographic disease as revealed by multiple regression analysis. CONCLUSION: New immigrants had the most extensive angiographic coronary involvement, while Arab patients were younger and had less severe coronary artery disease. More intensive risk factor modification may have a major impact on disease progression particularly in the new immigrant subgroup.

Nocturnal ischemic events in patients with obstructive sleep apnea syndrome and ischemic heart disease: effects of continuous positive air pressure treatment.

OBJECTIVES: To investigate the occurrence of nocturnal ischemic events in patients with obstructive sleep apnea syndrome (OSAS) and ischemic heart disease (IHD). BACKGROUND: Although previous reports documented nocturnal cardiac ischemic events among OSAS patients, the exact association between obstructive apneas and ischemia is not yet clear. It is also not known what differentiates between patients showing nocturnal ischemia and those that do not. METHODS: Fifty-one sleep apnea patients (age 61.3+/-8.3) with IHD participated in the study (after withdrawal of beta-adrenergic blocking agents and anti-anginotic treatment). All patients underwent whole-night polysomnography including ambulatory blood pressure recordings (30 min interval) and continuous Holter monitoring during sleep. A control group of 17 OSAS patients free from IHD were also similarly studied. Fifteen of the 51 patients were also recorded under continuous positive airway pressure (CPAP). RESULTS: Nocturnal ST segment depression occurred in 10 patients (a total of 15 events, 182 min), of whom six also had morning ischemia (06-08 am). Five additional patients had only morning ischemia. No ischemic events occurred in the control group. Age, sleep efficiency, oxygen desaturation, IHD severity and nocturnal-double product (DP) values were the main variables that significantly differentiated between patients who had ischemic events during sleep and those who did not. Nocturnal ischemia predominantly occurred during the rebreathing phase of the obstructive apneas, and it is characterized by increased heart rate (HR) and DP values. Treatment with continuous positive airway pressure significantly ameliorated the nocturnal ST depression time from 78 min to 33 min (p<0.001) as well as the maximal DP values (14,137+/-2,827 vs. 12,083+/-2,933, p<0.001). CONCLUSIONS: Exacerbation of ischemic events during sleep in OSAS may be explained by the combination of increased myocardial oxygen consumption as indicated by increased DP values and decreased oxygen supply due to oxygen desaturation with peak hemodynamic changes during the rebreathing phase of the obstructive apnea. Treatment with CPAP ameliorated the nocturnal ischemia.

Dilated inferior vena cava: a common echocardiographic finding in highly trained elite athletes.

Typical structural features of the athlete's heart as defined by echocardiography have been extensively described; however, information concerning extracardiac structures such as the inferior vena cava (IVC) is scarce. Fifty-eight top-level athletes and 30 healthy members of a matched control group underwent a complete Doppler echocardiographic study. IVC diameter was determined in the subxiphoid approach 10 to 20 mm away from its junction to the right atrium. Measures reflect the median values between maximal inspiratory and expiratory values. IVC respiratory collapsibility index was determined as well. IVC in athletes was 2.31 +/- 0.46 cm compared with 1.14 +/- 0.13 cm in the control group (P <.001). Swimmers had an IVC diameter of 2.66 +/- 0.48 cm compared with 2.17 +/- 0.41 cm in other athletes (P <.05). The IVC was normal (/=2.6 cm) in 24.1% of athletes. The collapsibility index was 58% +/- 6.4% in athletes compared with 70.2% +/- 4.9% in the control group (P <. 001). Correlation was found between IVC size and VO(2) max (r = 0.81, P <.001) and the right ventricle (r = 0.81, P <.001) and with collapsibility index (r = -0.57, P <.05). Multiple regression analysis showed the impact of VO(2) max, cardiac index, and right ventricular and left ventricular end-diastolic dimensions on IVC diameter. IVC dilatation probably represents adaptation of an extracardiac structure to chronic strenuous exercise in top-level, elite athletes.

Effects of low altitude on exercise performance in patients with congestive heart failure after healing of acute myocardial infarction.

Patients with chronic congestive heart failure (CHF) have impaired oxygen delivery to working muscles. The Dead Sea, the lowest site on earth, is distinguished by natural oxygen enrichment, low humidity, high barometric pressure, and temperature with increased bromide and magnesium concentrations in the inspired air. The aim of this study is to examine the effects of descent to the Dead Sea on patients with CHF. Twelve patients with CHF and 4 age-matched healthy controls underwent complete echocardiographic studies at rest as well as treadmill and metabolic stress tests, both in Haifa, 130 m above sea level and 3 days after descent to the Dead Sea, 402 m below sea level. Significant changes in parameters at the Dead Sea compared with Haifa included time on treadmill, which increased from 612+/-198 to 672+/-1 86 seconds (p <0.05); the Borg scale decreased by 1 to 2 grades (p <0.05); and oxygen saturation increased by 3% throughout exercise (p <0.05). Systolic blood pressure decreased by 9 mm Hg at rest (p <0.05) and increased by 14 mm Hg at peak exercise at the Dead Sea in patients with CHF (p <0.05). Cardiac output at rest increased by 300 ml/min (p <0.05). Maximum oxygen consumption (VO2max) increased by 126 ml/ min (p <0.05), and even more so in patients with more severe exercise-induced oxygen desaturations, which was associated with lower peak minute ventilation to CO2 production ratio (p <0.05). Thus, descent to the Dead Sea acutely improved exercise performance due to better oxygenation and loading conditions in patients with CHF.

Effect of low altitude (Dead Sea location) on exercise performance and wall motion in patients with coronary artery disease.

To evaluate the effects of low altitude on exercise performance and myocardial ischemia, 12 patients with coronary artery disease and 6 normal controls underwent ergometric and exercise echocardiography in Haifa, 130 m above sea level, and at the Dead Sea, 402 m below sea level. At the Dead Sea, exercise duration increased by 15% (p <0.05) in the patient and control groups and wall motion score index was improved in patients at rest and after exercise, indicating that descent to the Dead Sea in patients with coronary disease is safe, improves exercise performance, and decreases ischemia.

[Circadian fluctuations in the success and efficacy of streptokinase thrombolytic therapy in acute myocardial infarction].

This study was designed to assess possible diurnal fluctuations in the efficacy of thrombolysis with streptokinase. 156 consecutive patients treated with streptokinase during the period 1.1.95-1.7.96 were studied retrospectively. Success or failure of thrombolysis was determined according to the accepted clinical and angiographic criteria starting at midnight, 12 times at 2-hour intervals, then 8 times at 3-hour intervals, and then 6 times at 4-hour intervals. A definite peak for successful thrombolysis was found in the late afternoon and early evening hours. Between 16:00-20:00 PM, in 30.23% successful thrombolysis were observed, compared to 6.98% between 20:00-24:00 PM (p < 0.05) and in 10.53% between 00.00-04:00 AM (p < 0.05). Multiple regression analysis showed that the independent factor with the greatest impact on successful reperfusion was the actual time until thrombolysis (p = 0.037); then came the interval from pain onset to streptokinase administration (p = 0.020), while age and gender had much lesser impacts (p = 0.328 and 0.215, respectively), and individual risk factors even less. These findings may have several clinical implications: dose adjustment for the time of day may be required, with larger doses needed during morning hours, or preference for primary coronary angioplasty to avoid increase in bleeding complications due to higher doses of thrombolytic agents.

Circadian fluctuations in the efficacy of thrombolysis with streptokinase.

This study was designed to investigate possible diurnal fluctuations in the efficacy of thrombolysis with streptokinase and whether they follow the circadian periodicity which has already been well documented for the time of onset of acute myocardial infarction, transient myocardial ischaemia, sudden cardiac death, thrombotic stroke, and for the efficacy of thrombolysis with tissue-type plasminogen and urokinase. A total of 156 consecutive patients treated with streptokinase were studied retrospectively; success or failure of thrombolysis was determined according to accepted clinical and angiographic criteria. A definite time peak for successful thrombolysis could be detected at the late afternoon and early evening hours; between 16.00 and 20.00 h, 30.2% of all successful thrombolysis cases were observed compared with 7.0% between 20.00 and 24.00 (p < 0.05) or 10.5% between 00.00 and 04.00 (p < 0.05). Between 16.00 and 20.00 h, 75.8% of treated patients had successful thrombolysis compared to 15.2% of failed treatments and 9% equivocal results (p < 0.001). Multiple regression analysis showed that the independent factor with the major impact on successful reperfusion was the actual time of thrombolysis (p = 0.037), followed by the time delay from pain onset to streptokinase administration (p = 0.020), while age and gender had much lesser impact (p = 0.328 and 0.215, respectively) and the individual risk factors even less. These findings may have several clinical implications; dose adjustment for the time of day may be required, with higher doses during morning hours, or preference for primary coronary angioplasty in order to avoid the increase in bleeding complications related to higher doses of thrombolytic agents.

Fetal cardiac measurements derived by transvaginal and transabdominal cross-sectional echocardiography from 14 weeks of gestation to term.

OBJECTIVE: Most of the routine ultrasound screening in our institution consists of early transvaginal examinations at 14-17 weeks. Complete fetal echocardiography is performed in every case. However, normal values for most fetal cardiac structures at this stage of gestation are not available. Our aim was to construct normal ranges for fetal cardiac structures, derived from cross-sectional echocardiography, at 14-40 weeks of gestation. DESIGN: A prospective study was performed. The study group consisted of 637 pregnant women referred for a routine sonographic examination. Women with abnormal prenatal or postnatal outcome were not included in the study. Transvaginal examinations were used for 14-17 weeks of gestation. More advanced pregnancies were examined transabdominally. RESULTS: We constructed normal ranges for the left and right end-diastolic transverse ventricular diameters (n = 637), left/right ventricular ratio (n = 637), aortic root diameter (n = 637), pulmonary artery diameter (n = 637), aortic/pulmonary ratio (n = 490), left and right transverse atrial diameters (n = 201) and left/right atrial ratio (n = 201). CONCLUSIONS: The results provide the examiner with normal ranges for fetal cardiac structures for the early transvaginal examination. The continuity of all curves from 14 to 40 weeks of gestation allows follow-up of any specific fetus to term.

The effects of isometric stress on left ventricular filling in athletes with isometric or isotonic training compared to hypertensive and normal controls.

Hypertrophy of the left ventricle may be associated with altered left ventricular filling dynamics. To test whether isometric and isotonic training affect left ventricular filling differently at rest and during isometric stress, 38 males, 13 long distance runners, eight weight-lifters, eight hypertensive patients and nine age-matched healthy male controls with a mean age of 30 +/- 7 years, were studied before and after 90 s of 50% maximal handgrip force. Left ventricular Doppler filling parameters were compared in the four groups while they were resting and during isometric stress testing, and the results assessed in relation to left ventricular mass index and wall stress. All subjects had normal resting filling patterns except for hypertensive patients, and peak meridional wall stress was low in both athletic groups at rest. Weight-lifters had a hypertensive response during isometric stress testing, associated with a reduction in peak E velocity and a marked increase in peak A velocity, resembling the filling pattern in hypertensive subjects. In runners the filling pattern remained normal. Thus, while the resting left ventricular pattern was normal in all athletes, isometric stress testing was associated with a hypertensive filling pattern only in weight-lifters compared to normal filling in runners.

[The clinical aspects of thrombolytic therapy with streptokinase in myocardial infarct]. / Klinicheskie aspekty tromboliticheskoi terapii streptokinazoi pri infarkte miokarda.

We analyzed retrospectively 130 case histories of patients treated with streptokinase for acute MI in our cardiological department. The patients were subdivided into three groups according to the expected success of thrombolysis: successful-50.8% (66 pts), probably successful-19.2% (25 pts) and unsuccessful-30% (39 pts). There was neither difference in age, sex, MI location, nor in risk factor prevalence between the groups. Two factors were found to have a significant impact on thrombolysis success: time lag between onset of pain and treatment (streptokinase) initiation (the shorter this period was the better were the results, p = 0.002) and the time of day when the treatment was initiated, i.e. a circadian influence. The response to the treatment was observed much more frequently during evening hours (55.6% versus 18.5%, p = 0.001). It is concluded that there are circadian variations in the response to streptokinase therapy which are related most probably to circadian variations in the fibrinolytic system activity.