American heart journal
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American heart journal · Nov 1990
Noninvasive assessment of cardiac output in children using impedance cardiography.
This study evaluated the effect of intracardiac shunting on the accuracy of thoracic bioimpedance-derived cardiac output determinations. Twenty-six patients, ranging in age from 3 months to 17 years, underwent cardiac catheterization during which simultaneous Fick and impedance measurements of cardiac output were obtained. ⋯ In the right-to-left shunt group, the impedance derived cardiac output correlated with Fick pulmonary flow (r = 0.82), but the variability was unacceptably large. Although further study is needed, impedance cardiography appears to have validity as a methodology in pediatric critical care and cardiovascular health research.
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American heart journal · Jul 1990
Case ReportsCardiac abnormalities demonstrated postmortem in four cases of accidental electrocution and their potential significance relative to nonfatal electrical injuries of the heart.
Death from accidental electrocution is generally thought to be due to an arrhythmia, but little is known of the anatomic changes in the heart and almost nothing is known about the conduction system itself. We have studied the hearts of four men who died from electrical accidents and directed particular attention to the coronary arteries, conduction system, and neural structures of the heart. In every heart there was widespread focal necrosis involving all the myocardium and including the specialized tissue of the sinus and atrioventricular nodes. ⋯ Another heart had fatty deposition extensively present within and around the sinus and atrioventricular nodes. Thus numerous abnormalities specifically attributable to the electrocution help explain the pathogenesis of the electrical instability known to occur. But in three of the four hearts there were also chronic abnormalities favoring electrical instability but predating the electrocution.
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American heart journal · Jun 1990
ReviewECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance.
These findings permit the following conclusions on cardiac changes induced by high-performance sports and high levels of training. Sinus bradycardia and AV block can frequently be observed in athletes, but they do not require attention as long as they are asymptomatic or do not produce pauses exceeding 4 seconds. Persistent rather than transient second-degree AV block or Mobitz second- or third-degree AV block is an extremely unusual finding even in athletes and should be considered a sign of organic lesions until proved otherwise. ⋯ The cause of sudden cardiac death among athletes less than 40 years of age can be predominantely ascribed to congenital heart diseases (such as hypertrophic cardiomyopathy or coronary anomalies). In athletes more than 40 years of age and with increasing age, coronary heart disease is the most frequent autopsy finding. A corresponding risk stratification should take these partial dangers into account.
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American heart journal · May 1990
Relation of echocardiographic morphology of the mitral apparatus to mitral regurgitation in mitral valve prolapse: assessment by Doppler color flow imaging.
Few data exist regarding the relationship of valvular anatomy and coaptation to the presence of mitral regurgitation (MR) in patients with mitral valve prolapse (MVP). Therefore this study was undertaken to assess the ability of two-dimensional echocardiographic features of mitral valve morphology to predict the presence, direction, and magnitude of MR as assessed by color Doppler flow imaging. MR was present in 21 of 46 patients with MVP on two-dimensional echocardiography. ⋯ MR jet direction tended to be anterior to central with posterior leaflet prolapse and posterior or central with anterior leaflet prolapse (p = 0.02). Maximal jet area of MR tended to be larger in patients with compared with those without mitral annular dilatation (5.4 +/- 2.3 versus 2.1 +/- 1.9 cm2, p = 0.001), and in those with abnormal rather than normal leaflet thickness (4.5 +/- 2.7 versus 2.0 +/- 1.6 cm2, p = 0.009). Thus the presence, direction, and size of MR jets in MVP are related to structural abnormality of the mitral apparatus on echocardiography.
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American heart journal · Apr 1990
Comparative StudyPrognostic significance of complete atrioventricular block in patients with acute inferior myocardial infarction with and without right ventricular involvement.
Data were obtained and analyzed in 243 patients with acute inferior myocardial infarction who were admitted to the coronary care unit during the years 1987 and 1988. One hundred and ninety-eight patients had no signs of right ventricular involvement (group I), whereas 45 patients had inferior myocardial infarction with right ventricular infarction (group II). Patients were divided into groups depending on the presence or absence of complete atrioventricular block during hospital stay (groups Ia and IIa without block and groups Ib and IIb with block). ⋯ Patients with right ventricular infarction but without complete atrioventricular block (group IIa) had a mortality rate similar to that found in patients with inferior myocardial infarction and no atrioventricular block (group Ia): 14% versus 11% (p = NS). In patients with inferior myocardial infarction without right ventricular involvement (group I), complete atrioventricular block did not influence survival: 14% mortality rate in group Ib versus 11% mortality rate in group Ia (p = NS). The excessively high mortality rate in patients who have inferior myocardial infarction with right ventricular involvement and complete atrioventricular block could be the consequence of greater infarct size, but the synergistic influence of right ventricular infarction and complete atrioventricular block could be the other factor that influences outcome.