תוצאת חיפוש

Circadian Fluctuations in Efficacy of Streptokinase Thrombolysis

E. Goldhammer, L.Kharash, E.G. Abinader

Cardiology Dept., Bnei-Zion Medical Center and Technion Faculty of Medicine, Haifa

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.

Diagnosis of Cerebral Embolism by Transesophageal Echocardiography

A. Mahagney, D. Sharif, B. Weller, E. Abineder, B. Sharf

Depts. of Neurology and Cardiology, Bnai Zion Hospital, Haifa

Cerebrovascular events have high mortality and morbidity, especially in the elderly. Ischemia is the main cause and 30% of the ischemic events are embolic and of cardiac origin. The clinical picture is not always typical of the type of stroke, but diagnosis of the mechanism of the event determines treatment. Transesophageal echocardiography (TEE) is a sensitive procedure more appropriate for diagnosing emboli of cardiac origin than transthoracic echocardiography (TTE). We therefor compared TEE and TTE in the determination of the source of emboli in 65 patients with ischemic stroke but without significant atherosclerotic changes in their carotid arteries, and compared these findings with those in 50 patients without stroke. 68% of the patients had potential sources of emboli according to TEE, compared to only 15% according to TTE. In the control group only 24% had potential sources of emboli by TEE. The findings were: clots in the left atrium, severe aortic atheroma, patent foramen ovale with paradoxical shunt, spontaneous echocardiography contrast, vegetations and mitral valve prolapse. The study showed that TEE is better than TTE in detecting the etiology of embolic stroke in those with normal carotid arteries, thus determining appropriate management.

Circadian Fluctuations of the Signal-Averaged ECG

Ehud Goldhammer, Edward Abinader

Cardiology Dept., Bnei-Zion Medical Center and Bruce Rappaport Faculty of Medicine, The Technion, Haifa

Circadian periodicity for the time of onset of acute myocardial infarction has been shown; the early morning peak of infarction coincides with the onset of other related phenomena, including sudden cardiac death, ventricular arrhythmias, thrombotic stroke, etc. Late potentials detected by the signal-averaged ECG are considered to be independent markers of vulnerability to ventricular arrhythmias. The signal-averaged ECG enables the amplifying and recording of small bioelectric signals of cardiac origin, while eliminating extraneous electrical "noise." To determine whether late potentials are themselves subject to circadian influence, 31 patients (age range 41-79) who had had an old or recent myocardial infarction underwent late potential assessment by the signal-averaged ECG. 4 indices were studied: duration of late LPD potentials (LPD), total QRS duration (TQRS), and root mean square voltage of the last 40 msec, and of the last 50 msec (RMS 40 and RMS 50). These indices were assessed 3 times, during the early morning hours, at noon and during the evening. Morning LPD differed significantly from noon and evening LPD and the morning RMS 40 similarly differed from noon and evening values. TQRS and RMS 50, even though remaining in the normal range, also showed a tendency to abnormal values during morning hours. These findings could possibly be related to the early morning incidence peaks of severe ventricular arrhythmia and sudden cardiac death, since abnormal late potentials constitute the physiopathological basis for certain ventricular arrhythmias.