An analysis of electrocardiograms from a patient with spontaneous double irregular ventricular parasystole is presented. Irregularity in one of the two parasystoles was produced by intermittence based on rate-dependent (phase 3) entrance block, and in the other parasystole it was attributed to "supernormal" exist conduction. Critical analysis of electrocardiograms revealed that first degree blo...

The steepest rise of the action potential obtained by an ultramicroelectrode from the most superficial subepicardial muscle fiber in situ of the tortoise was compared with the intrinsic deflection of the unipolar direct electrocardiogram and the surface electrocardiogram obtained from approximately the same region. No specific point on the intrinsic deflection, such as the highest or lowest poi...

These electrocardiograms were taken on a 36 yearold man, with no known cardiac abnormality. The twelve-lead tracing, which shows sinus rhythm at rates between 53 and 60/min., has abnormal T waves in Vl V4. A s{rip, using lead V6, shows the interesting phenomenon of rate-dependent left bundle branch block (LBBB). Please. note in this strip that the first four sinus beats have normal QRS-T waves....

OBJECTIVE To evaluate the accuracy of pediatric cardiologists' interpretations of electrocardiograms (ECGs). STUDY DESIGN A series of 18 ECGs that represented conditions causing pediatric sudden cardiac death or normal hearts were interpreted by 53 members of the Western Society of Pediatric Cardiology. Gold-standard diagnoses and recommendations were determined by 2 electrophysiologists (100...

TWO ASPECTS of the electrocardiogram, rhythm and voltage, have proved to be of particular importance in the management of dogs with orthotopic cardiac homotransplants. Arrhythmias are frequent in the early postoperative course as the heart recovers from the anoxic insult and adjusts to the denervated state and again in the later stages of cardiac rejection. Changes in the electrocardiographic v...

As traumatic shock develops, cardiac output falls. There are several fairly well-established explanations for this. It is usually stated, however, that this diminishing output is due to phenomena arising outside of the heart and that the heart itself remains unimpaired until very late. We had hoped to obtain evidence that would, insofar as could be judged by electrocardiograms, give information...

Small discrete spikes appearing on the electrocardiogram (ECG) of a man with a pacemaker turned out to be fasciculation potentials picked up from leg muscles. To find out how common these spikes were all routine ECGs made in one month were reviewed. Spike potentials were found in six patients, and in each case they originated from somatic musculature. Spikes could nearly always be detected on E...

THE anticipated value of the preoperative electrocardiogram for the assessment of perioperative cardiac risk has changed over the past decades. Initial risk scores included preoperative electrocardiogram variables as a prognostic factor for the occurrence of perioperative cardiac events; in recent years, however, the value of a routine preoperative electrocardiogram has been questioned. The cur...