ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01438.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

On the basis of earlier studies of the behavior of the central venous blood temperature at rest and during exercise, we have developed an algorithm for the rate control of cardiac pacemakers. The central venous blood temperature serves as the control variable for the pacing rate. Control is effected via two different characteristic lines that relate pacing rate and temperature. A rest characteristic line relates absolute temperature values to heart rate and exercise lines relate relative changes in temperature to heart rate changes. The rest characteristic corresponds to conditions of slow temperature fluctations (e.g., fever and temperature changes due to circardian rhythm) and has a slope of 15 to 20 bpm per centigrade degree of temperature change. Starting at this rest characteristic, there are exercise characteristic lines that have a much greater slope and serve to regulate the pacing rate under exercise conditions. The two characteristics are distinguished via the temperature change per unit of time. In addition, a return characteristic connects the rest and exercise characteristics. This algorithm allows for optimized rate adaption of physiological cardiac pacemakers by central venous blood temperature. Clinical studies with the implanted device (Intermedics Nova MR) prove the correct function and beneficial effect of this algorithm in patients' everyday life.

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01439.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The effects of sympathetic imbalance with left dominance on the electrocardiogram was studied in 12 open‐chest anesthetized dogs. Heart rate was held constant (80 or 150 bpm) by right vagal stimulation and atrial pacing, To minimize vagai‐sympathetic interactions, the intensity of vagal stimulation was well below the threshold for asystole. Electrocardiographic recordings were obtained from three ECC leads (II, X, and Z). Transection of the right stellate increased the T‐wave amplitude in lead II (0.12 ± 0.05 mV, P<0.05) but had no effect on the QT interval in any lead. Left stellate transect ion after right transection decreased the T‐wave amplitude in lead II (0.13 ± 0.06 mV, P<0.05) but did not alter the QT interval in any lead. Electrical stimulation of the decentralized left stellate for periods of 3 or 15 sec prolonged the QT interval by as much as 21 msec, but the average changes were considerably less (± 6.0 msec) and were not significant. Left stellate stimulation for 30 or 60 seconds shortened the QT by as much as 30 msec (P<0.05). All periods of left stellate stimulation significantly increased the T‐wave amplitude in lead II. The electrocardiographic changes induced by sympathetic imbalance were similar at both heart rates. The results do not support the presence of a significant degree of “silent” repolarization after the end of the T wave in the normal canine e

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01440.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01441.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Propafenone is a new antiarrhythmic compound that has an unusual spectrum of pharmacological actions. Its dominant action in cardiac muscle is to block the fast sodium channel with slow onset and offset kinetics. Thus it has a marked depressant effect on conduction with a modest effect in prolonging the effective refractory period in fibers that are fast‐channel dependent. In addition, it has beta‐blocking and calcium‐channel blocking actions that are likely to affect its overall spectrum of activity. Propafenone should be effective in suppressing both ventricular as well as supraventricular arrhyt

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01442.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Propafenone is a potent type Ic antiarrhythmic agent that has activity against a wide variety of supraventricular and ventricular arrhythmias. Clinical administration must be individualized, based on an appreciation of propafenone pharmacokinctics and dose‐response relationships, which are quite complex. Although a “therapeutic” plasma concentration is achieved in most patients with 300 mg orally every eight hours and plasma concentrations reach steady state after three days, marked interpatient differences in plasma concentrations occur. In addition, the effective plasma concentration required for arrhythmia suppression varies markedly in individual patients. Oral propafenone is subjected to a marked “first‐pass” hepatic elimination via a saturable oxidative pathway. This can result in a tenfold increase in plasma concentrations as the dose is increased from 150 to 450 mg. Accumulation of metabolites, notably 5‐OH propafenone, probably contributes to the net antiarrhythmic effect of oral propafenone during chronic oral administration. Propafenone may exacerbate ventricular arrhythmias in 20–15% of patients. This does not appear to be dose‐dependent, nor is it associated with a definite prolongati

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01443.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The effects of propafenone on left ventricular function and hemodynamics are presented in this study. In one group of 13 patients who underwent electrophysiological testing and subsequent chronic oral therapy with propafenone, eight had left ventricular ejection fractions determined by nuclear study before and during therapy with the drug. Initial measurements ranged from 22% to 39% (mean 30%), while those on chronic therapy showed no statistical difference and ranged from 22% to 48% (mean 30%). In a separate dose titration study of 14 patients, left ventricular ejection fraction showed a modest but significant decrease (52%± 9% to 48%± 11%; p<0.05). This change was more marked in patients with an initial low ejection fraction. Propafenone appears to be safe in these patients but should be administered with caution in patients with particularly low ejection fraction

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01444.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The effectiveness of propafenone versus quinidine for the therapy of ventricular premature beats was evaluated in a placebo‐controlled double‐blind parallel study. A total of 105 patients was entered; 53 patients were randomly assigned to receive propafenone (600 mg/day and 900 mg/day during low‐and high‐dose weeks, respectively) and 52 patients were randomly assigned to receive quinidine (800 mg/day and 1,600 mg/day, respectively). Both drugs significantly reduced ventricular ectopy at both dose levels; there was no statistically significant difference between the two drugs in effectiveness, although a higher percentage of patients responded to propafenone. Side effects resulting in discontinuation of therapy were more common with quinidine. This study confirms the effectiveness of propafenone in the therapy of ventricular prematur

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01445.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Propafenone is a new antiarrhythmic agent that inhibits the fast sodium channel and decreases phase 0 of the cardiac action potential. Since it has relatively little effect on the action potential duration, it has been classified as a type IC agent. Propafenone prolongs electrocardiographic intervals including PR and QRS. In addition, atrial and ventricular refractory periods generally are lengthened. Initial reports suggest a favorable effect on suppressing conduction over accessory pathways. Propafenone has been shown to have effectiveness in suppressing life‐threatening ventricular arrhythmias as well. Electrophysiological testing is useful, but data such as mode of induction and rate of induced tachycardia should be considered in addition to inducibility statu

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01446.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Propafenone is a newv IC antiarrhythmic agent that is effective for suppression of spontaneously occurring ventricular arrhythmia as evauated with monitoring and exercise testing. The incidence of nonserious, but disturbing side effects is low and the drug infrequently is discontinued because of adverse reactions. Serious side effects are primarily cardiac and include arrhythmia aggravation, CHF exacerbation, and conduction abnormalities. These complications occur primarily in those with severe underlying heart disease in whom this drug, like other antiarrhythmic agents, must be used cautiously. If the drug is effective and well tolerated, arrhythmia recurrence can be prevented.

ISSN:0892-1059    

DOI:10.1111/j.1540-8167.1987.tb01447.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY