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Biomedical subjects

S Rogel

Publications and source records attributed to S Rogel.

At least 37 records · Page 2Linked to original sources
PubMed1976

Diagnostic and therapeutic assessment by telephone electrocardiographic monitoring of ambulatory patients.

The electrocardiograms of ambulatory patients have been monitored over the telephone by staff of the intensive cardiac care unit using equipment in the unit. Telephone monitoring is a useful way of diagnosing transient symptomatic arrhythmias and a reliable aid in supervising the patient's rhythm at the beginning or end of treatment. The doctor has direct contact with the patient at the time of his symptoms so that he can reassure or instruct him. This system costs relatively little in manpower and equipment and permits relatively long periods of follow-up. It is effective, however, only in symptomatic cases in which the rate or rhythm disturbances last long enough to be transmitted. Also important are the negative findings when the patient complains of symptoms and abnormal findings during routine telephone transmissions. Accurate detection of transient ischaemic changes seems to be less reliable, and further technical improvements are required.

Adult↗
PubMed1976

Ventricular rhythms in acute myocardial infarction.

Ectopic ventricular activity in acute myocardial infarction is considered to be benign if it is slow and regular (accelerated idioventricular rhythm), but ominous when rapid (ventricular tachycardia). However, it has been observed in an increasing number of reports that these two types may coexist in the same patient, altering thereby the clinical significance of both. In the present study electrocardiograms were analyzed of 55 patients hospitalized for acute myocardial infarction, in whom idioventricular rhythm occurred. It was found that three major types of ventricular rhythms could be identified: a regular-stable rhythm, an irregularunstable one, and a third variant which was a combination of these two types. The stable ventricular rhythm was self limited and harmless. The unstable and combined types which were characterized by random coupling times and varying interbeat intervals, were frequently associated with re-entrant beats and fast ventricular rates and therefore a potentially ominous prognosis. It is suggested that the Ca++ dependent slow diastolic depolarization may be the mechanism responsible for the unstable ventricular rhythm, and the reasons for this assumption are discussed. A therapeutic approach based on the above considerations is described.

Acute Disease↗
PubMed1975

Heart rate and myocardial substrate preference during normal and hypoxic perfusion of the heart in vivo.

Selective utilization of carbohydrates and FFA by the heart was studied on the open-chest dog preparation. The heart was paced at frequencies from 120-240/min, and arterial and coronary venous blood samples were taken at these frequencies both during normal ventilation and hypoxia (arterial PO2 similar to 55 mmHg). The concentrations of glucose, lactate, pyruvate, and FFA were determined, and substrate utilization was calculated from these values and coronary blood flow. It was found that increased heart rate, particularly during hypoxia, increased utilization of both glucose and FFA. However, the relative amount of the energy produced from glucose utilization was minimal during hypoxia and most glucose underwent glycolysis only. Thus, whereas in control conditions of the relation between carbohydrate and FFA was about 60% to 40% during hyposia and high frequency the relation was reversed and almost 90% of all energy produced was supplied by FFA.

Animals↗
PubMed1975

Coronary venous flow and O2 saturation during transitional phases between various cardiac rates.

The instantaneous and continuous interrelationship between coronary blood flow and coronary venous O2 saturation was determined during transient periods following abrupt rate change in the electrically paced canine heart. Through a catheter in the coronary sinus, O2 saturation was continuously monitored using a fibreoptics technique, and venous flow was measured with an electromagnetic flowmeter. Various patterns of change in flow and O2 saturation were observed depending both on the absolute values of the cardiac rates as well as on the relative difference between them during changes from one rate to another. Whereas elevation of coronary flow was monophasic when the magnitude of heart rate change was below 75 beats per minute, a drop in flow was observed preceeding its elevation when the difference was greater. At high rates further increase in rate caused either no alteration or led to a monophasic drop in flow during the transitional period. Changes in O2 saturation were observed only when heart rate difference exceeded 60 beats per minute. Between 60-90 beats per minute O2 saturation remained steady except during the transient rate elevation, ending in a lower steady state O2 saturation. The results indicate that both O2 saturation and coronary flow change with heart rate initially because of mechanical consequence of the increased rate on the myocardium, and later according to its new metabolic needs also manifested by changed O2 extraction.

Animals↗