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Stab wounds to the heart can present without clinical evidence of injury. Echocardiography has been advocated as an alternative to subxyphoid exploration in these cases. We present a case in which two serial echocardiography exams missed a diagnosis. Electrocardiographic changes and elevation of serial troponin I levels suggested the diagnosis, which was confirmed by thoracoscopy. Repair was facilitated by use of adenosine cardiac standstill.

SummaryA hyperkalemia and cardiac standstill resulting in 100%percnt; mortality was induced within 20 minutes after the administration of 2 ml of a 50%percnt; glucose solution into the stomachs of adrenalectomized rats. Pretreatment with epinephrine 60 minutes before the administration of the glucose solution protected the adrenalectomized rats. Pretreat-ment with lipo-adrenal extract 120 minutes before giving the glucose solution did not protect the adrenalectomized rats. The admission of the glucose solution to demedullated rats with functional adrenal cortices resulted in a 50%percnt; mortality. The difference in mortality of the adrenalectomized and demedullated rats was ascribed to the initial relatively “low” plasma potassium concentration of the latter group. Epinephrine pretreatment protected the demedullated group too. These data are discussed as indicating that epinephrine protected the experimental groups of rats by inducing a lower than “normal” plasma potassium concentration and “blocking” a ...

Conclusion1. Parahydiroxyphenylisopropylamine, when adminnstered by niouth, is effective in the prevention of cardiac arrest. 2. This substance is more active than ephedrine on induced cardiac arrest. 3. When administered in a dosage effective in preventing cardiac staiidstill, parahydroxyphenylisopropylamine does not produce a central nervous stimulation with resultant unpleasant side effects.

In the normal heart several centers of rhythm formation are potentially active, but the sinus node, which generates the impulse most rapidly, sets the pace of the heart. Observations on experimental animals indicate that there is considerable variation in the rhythmic efficiency of other portions of the heart. Cohn, Kessel and Mason,1 after removing the sinus node in dogs, found a transitory quiescence of the heart varying from 4 seconds to 3 minutes, the interval being less than 30 seconds in most instances. The period of the quiescence was interpreted as representing the time required for some other portion of the heart to take on the pacemaking function. Rothberger and Winterberg2 demonstrated in dogs that depression of the sinus node by stimulation of the right vagus nerve usually resulted in cardiac standstill. After eliminating the sinus node by vagus stimulation these observers studied the influence of various procedures in inducing new centers of impulse initiation. Thus they found that upon stimu...

Hoffa and Ludwig1 demonstrated that electrical stimulation of the mammalian heart led to ventricular fibrillation and death. Prevost and Battelli2 studied the effect of electric currents on the heart and reported that a brief countershock of sufficient strength applied directly to the heart through an electrode placed on the ventricles would produce a brief period of complete cardiac standstill from which coordinated ventricular beats might be resumed. Cardiac massage was found necessary preceding the countershock when the ventricular fibrillation had existed longer than 15 seconds. Hooker, Kouwenhoven and Langworthy3 found that currents of 0.4 amperes and less applied directly through the heart cause ventricular fibrillation, while currents of 0.8 amperes and over will stop the fibrillation. They advised the central carotid injection of calcium chloride and adrenaline after countershock as an aid in restoring a vigorous beat. Wiggers4 emphasized the importance of cardiac massage preceding the electric sh...