Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Oct 1991
Comparative Study Clinical Trial Controlled Clinical TrialPrehospital transcutaneous cardiac pacing for symptomatic bradycardia.
We studied patients with symptomatic bradycardia to determine the importance of presenting hemodynamic status and prehospital transcutaneous cardiac pacing (TCP) upon patient survival. Of 51 patients with witnessed cardiovascular decompensation and initial bradycardia, 27 (53%) received TCP. There were no significant differences between the paced patients and those without TCP for mean times from collapse until cardiopulmonary resuscitation, paramedic arrival and a paceable rhythm, or from paramedic arrival until a paceable rhythm. ⋯ No patient without a palpable pulse on paramedic arrival survived to leave the hospital. Of patients with a palpable pulse upon paramedic arrival, survival to hospital discharge was greater for the paced group (80% in paced vs 0% in nonpaced group; P = 0.024). TCP appears to be most beneficial in those patients with bradycardia who have a palpable pulse when first seen.
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Pacing Clin Electrophysiol · May 1991
Case ReportsMalignant ventricular tachycardia during propafenone treatment in a child with junctional automatic tachycardia: effectiveness of intravenous molar sodium lactate.
Propafenone may aggravate the preexisting arrhythmia or induce another one. Usually, such proarrhythmic effects occur in patients with spontaneous ventricular arrhythmias and/or coronary heart disease with poor left ventricular function. ⋯ The serum propafenone level obtained before MSL infusion was within the therapeutic range. Two hypothesis could explain the beneficial effects of MSL in our patient: (1) alkalinization facilitates the cell membrane hyperpolarization and thus can decrease the voltage-dependent effect of Class Ic drugs, (2) alkalinization could displace propafenone from its tissue receptor sites by an increase in the nonionized fraction.
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Pacing Clin Electrophysiol · Jan 1991
Balance and cognitive impairment in two epileptic patients before and after vagal nerve stimulation.
Balance and cognition were assessed in two patients with uncontrolled complex partial seizures. The patients were on anticonvulsant medications and were treated with left vagal stimulation. Balance and cognition were assessed before and after vagal stimulation, and the results were compared with age matched controls and older patients with Parkinson's disease. Severe impairments of function were found in the epileptic patients, and such negative effects of medication make vagal stimulation a potentially practical alternative treatment for uncontrolled epilepsy.
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Our study included the treatment of transcutaneous cardiac pacing (TCP) in 32 patients: (A) 19 patients were treated in the emergency area for complete symptomatic AV block before endocavitary pacing; (B) five patients were in asystole following DC shock or out-of-hospital cardiac arrest; and (C) eight patients were affected by bifascicular block undergoing emergency surgery and were treated in order to prevent complete AV block. Two transcutaneous stimulators were used. PaceAid-CRC model 50/52 with 20-msec pulse width; the electrodes were positioned on the V3 ECG position and on the back. ⋯ in all but two patients, it was possible to obtain stable cardiac capture; in one patient arrived in hospital in asystole after prolonged cardiac arrest and in the other one was affected by complete AV block, TCP was ineffective. In groups A and B, TCP was maintained for a mean time of 15 minutes; in group C, TCP was tested in all patients, but performed in only one patient during surgery. Mean threshold was 81 mA. Stimulation was well tolerated in all but five patients. TCP is a reliable, noninvasive method that offers the possibility to initiate pacing within seconds and can be used by medical staff. In our opinion, it should be considered as the first choice emergency treatment of severe symptomatic bradycardia. In asystole, beneficial effects can be obtained only if TCP is performed early enough after the onset of arrhythmia.
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The focus of this report is to describe a system for recording surface His-Purkinje and ventricular late potentials on a beat-by-beat basis outside of a shielded environment. An AC magnetic field monitoring device was designed for improved site selection, orientation, and quality control of the acquisition. His-Purkinje signals are detected utilizing spatial averaging and specific channel selection algorithms applied to discriminate random noise from signal. ⋯ While filter ringing was eliminated, discontinuity and distortion of the filtered waveform resulted. The FIR filter with linear phase response retained the integrity and morphology of the complex but because of its flat frequency response, the ST segment was not as well attenuated and it was more difficult to isolate late potentials. A high order FIR filter should be used if the desire is to match the frequency response of the four-pole IIR filter, since the frequency response of the FIR filter is primarily determined by the order of the filter.(ABSTRACT TRUNCATED AT 250 WORDS)