A 55 year old man with history of palpitation was referred for electrophysiologic study. Baseline ECG, physical examination and transthoracic echocardiographic study were normal. Electrophysiologic study revealed normal AH and HV intervals. Pacing of right atrium with a cycle length of 300 msec showed 2:1 AV block. AH interval was 252 msec and the block was infra-his (Figure 1). With continual ...

OBJECTIVE To determine the contribution of electrophysiologic testing in the diagnosis and anatomical classification of myoclonus. METHODS Participants with a clinical diagnosis of myoclonus were prospectively recruited, each undergoing a videotaped clinical examination and battery of electrophysiologic tests. The diagnosis of myoclonus and its subtype was reviewed after 6 months in the conte...

DURING the past decade, there has been enormous interest in the use of invasive electrophysiologic testing to evaluate patients with cardiac arrhythmias and conduction disturbances. In this editorial, we present our views on the clinical value of this procedure, ever mindful of our own biases and the knowledge that many important issues in this rapidly expanding area of cardiology remain contro...

Adrenergic activation during electrophysiologic study could potentially alter the electrophysiologic properties of the arrhythmia substrate. However, the catecholamine response to ventricular tachycardia induction and termination during electrophysiologic testing has to date not been quantitated. Therefore, in 13 patients undergoing electrophysiologic study, arterial plasma norepinephrine and e...

Conventional electrophysiologic measurements such as nerve conduction velocity, compound action potential, and neuropathic symptom scores have been used to assess the severity of diabetic neuropathy and have been the major efficacy end points following pharmacologic intervention trials. Unfortunately, these measurements are not particularly sensitive and their reproducibility is, at best, good....

The present study. In this issue of the Journal (1) investigators from the University of Minnesota report the third in a series of studies focusing on the phenomenon of “neurally mediated snycope.” In the present study, six patients (Group I) who presented with “cardiovascular collapse apparently associated with cardiac asystole” underwent head-up tilt testing before and during infusion of isop...