Biomedical subjects
Publications and source records attributed to I Ovsyshcher.
A one-month-old infant developed atypical ventricular tachycardia, complete right bundle branch black, and alternating 2:1 Osborn waves during spontaneous mild hypothermia; 10 h after rewarming, the electrocardiogram was normal.
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Explore the source record for details and available documents.
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A patient with a right atrial thrombus and recurrent pulmonary emboli secondary to permanent pacemaker insertion is described. Possible precipitating factors were damage to the subclavian vein, congestive heart failure, paroxysmal atrial fibrillation, and immobilization. Venography demonstrated a large atrial thrombus in the superior vena cava and right atrium. The patient was successfully treated with heparin and subsequently with warfarin and dipyridamole.
A 35-year-old man, with recent onset angina, developed recurrent episodes of syncope due to ventricular tachycardia. His coronary angiogram showed normal coronary arteries and myocardial bridging of the left anterior descending causing severe systolic milking effect. Extensive invasive and noninvasive investigations did not reveal cardiac pathology other than the myocardial bridging. Electrophysiologic studies, not previously reported in myocardial bridging, demonstrated inducible sustained ventricular tachycardia at a rate of 280 beats/min. The possible relationship between the arrhythmia and the myocardial bridge is suggested. Combined medical treatment with amiodarone and diltiazem proved to be an effective alternative to surgical myotomy of the bridge.
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Systolic time intervals were measured in 147 healthy 13-19-year-old adolescents to derive regression equations for clinical use in this age group and to determine to what extent they differ from those of children and adults. Stepwise regression analysis showed that heart rate was the only variable consistently and significantly related to electromechanical systole (QS2), left ventricular ejection time (LVET) and preejection period (PEP). None of the other variables tested (age, height, weight, body surface area, blood pressure, hemoglobin, hematocrit and serum electrolytes), when used alone, were relevant variables in relation to QS2, LVET or PEP. The PEP/LVET ratio in adolescents was essentially independent of heart rate, as in children and adults. The regression lines for QS2, LVET and PEP in adolescents fall between those for children and adults, indicating that there is a distinct tendency toward lengthening of all the systolic time intervals with age, independent of changes in heart rate. The PEP lengthens proportionately more than the LVET, resulting in a progressive increase in the mean PEP/LVET ratio from childhood (0.30) to adolescence (0.32) and to adulthood (0.345). The precise hemodynamic factors underlying these changes with increasing age remain to be determined.
A significant error may be introduced in intervals measured from the onset of the QRS if an electrocardiographic lead that does not record the earliest deflection is used. To ascertain to what extent the commonly used leads can be relied on to show the earliest QRS onset, 100 normal subjects and 219 patients with heart disease were studied by means of simultaneous recording of three leads: a right precordial lead chosen to show an rS configuration, lead II, and another limb lead chosen to show a qR configuration. Lead II most frequently showed a delayed QRS onset--in 34% of normal subjects and 36% of the patients. In the other limb lead the initial QRS deflection was delayed in 24% of the normal subjects and 23% of the patients. The QRS onset in the right precordial lead was never delayed in the normal subjects; however, it was delayed in this lead in 6% of the patients. The delays in each of the leads ranged from 5-20 msec. We conclude that while a right precordial lead is by far the most reliable single lead that can be used for interval measurements, simultaneous recording of a right precordial lead and a limb lead assures that recording of the earliest QRS onset in all cases.
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Systolic time intervals were measured in 253 normal children, with careful attention to precise recording and measuring techniques, to derive regression equations which could be used as reliable standards for clinical assessment of left ventricular performance in this age group. Using stepwise regression analysis, a highly significant correlation was found for electromechanical systole (QS2) and for left ventricular ejection time (LVET) with heart rate alone in both males and females, and age was not found to be a relevant variable. Similarly, for the preejection period (PEP) in males, heart rate was the only relevant variable. PEP in females showed a small but significant influence of age in addition to heart rate; in practice, this small influence can be neglected. Regression equations relating each of the systolic time intervals to heart rate alone were therefore derived for clinical use. The PEP/LVET ratio was found to be only weakly correlated with heart rate in males and with age in females, and in practice can be considered to be independent of these variables. The mean value of the PEP/LVET ratio and its standard deviation (0.30 +/- 0.04) can therefore be used for all children. We found that satisfactory recording of systolic time intervals can be obtained with little difficulty in almost all children using the techniques described. The method is therefore practical for clinical use in children, as it is in adults, and the normal standards derived in this study can serve as a reliable basis for its application.
Although the precise mechanism of the cardiovascular effects in man evoked by the venom of the yellow scorpion has yet to be completely elucidated, previous studies indicate that excessive adrenergic activity is present in many of the cases. This report describes two patients in whom yellow scorpion sting was followed by bradyarrhythmia with varying degrees of atrioventricular block which promptly regressed after the administration of atropine; this is consistent with a direct parasympathomimetic effect of the venom or with a central effect producing increased vagal tone. It is suggested that the cardiovascular actions of the venom may represent a wide spectrum of effects on the autonomic nervous system, ranging from the predominantly sympathomimetic to the predominantly parasympathomimetic.
Muscular obstruction to right ventricular outflow is usually at the infundibular level, but, less commonly, it can occur within the body of the ventricle due to an anomalous muscle bundle. This lesion is almost always associated with a ventricular septal defect or other cardiac lesions, and is usually discovered in infancy or childhood. Two asymptomatic adults with severe obstruction due to right ventricular muscular band as an isolated lesion are presented. The lesion can be tentatively diagnosed on clinical grounds and confirmed by angiocardiography. The advisability of surgical correction in the asymptomatic adult with such an isolated lesion is uncertain.
One hundred consecutive patients who underwent i.v. pyelography had ECG performed before, immediately following and 5 min after the injection. ECG changes appeared in 15 patients and were considered to be major in five of them. The incidence of ECG changes was significantly higher in patients with abnormal ECG prior to pyelography. The average age of the patients who developed changes was higher than that of patients in whom no ECG changes were observed. There was no significant difference in the incidence of ECG changes after standard and infusion pyelography.