Atrial contribution to cardiac output in complete heart block

Samet, Philip; Bernstein, William H.; Nathan, David A.; Lopez, Anthony

doi:10.1016/0002-9149(65)90002-0

Cited by 148 publications

(17 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…II) The missing atria were added to the heart model as they contribute a considerable fraction of the total cardiac output under conditions of an increased heart rate. Atrial contraction increases the preload and thereby contributes to the cardiac output by up to 10% [6]. III) An electrical heart stimulator was added.…”

Section: Resultsmentioning

confidence: 99%

A graphical simulation software for instruction in cardiovascular mechanics physiology

2011

View full text Add to dashboard Cite

BackgroundComputer supported, interactive e-learning systems are widely used in the teaching of physiology. However, the currently available complimentary software tools in the field of the physiology of cardiovascular mechanics have not yet been adapted to the latest systems software. Therefore, a simple-to-use replacement for undergraduate and graduate students' education was needed, including an up-to-date graphical software that is validated and field-tested.MethodsSoftware compatible to Windows, based on modified versions of existing mathematical algorithms, has been newly developed. Testing was performed during a full term of physiological lecturing to medical and biology students.ResultsThe newly developed CLabUZH software models a reduced human cardiovascular loop containing all basic compartments: an isolated heart including an artificial electrical stimulator, main vessels and the peripheral resistive components. Students can alter several physiological parameters interactively. The resulting output variables are printed in x-y diagrams and in addition shown in an animated, graphical model. CLabUZH offers insight into the relations of volume, pressure and time dependency in the circulation and their correlation to the electrocardiogram (ECG). Established mechanisms such as the Frank-Starling Law or the Windkessel Effect are considered in this model. The CLabUZH software is self-contained with no extra installation required and runs on most of today's personal computer systems.ConclusionsCLabUZH is a user-friendly interactive computer programme that has proved to be useful in teaching the basic physiological principles of heart mechanics.

show abstract

Section: Resultsmentioning

confidence: 99%

A graphical simulation software for instruction in cardiovascular mechanics physiology

2011

View full text Add to dashboard Cite

show abstract

“…Previous studies on heart block and sequential atrio ventricular pacemakers have demonstrated that properly timed atrial contractions are important to maintain ade quate left ventricular end-diastolic volume, systolic pres sure, and stroke volume in both animals and humans [11][12][13][14][15][16][17][18]. Atrioventricular synchrony is important not only to maintain left ventricular diastolic filling but also for nor mal closure of the atrioventricular valve [19].…”

Section: Discussionmentioning

confidence: 99%

Effect of Atrial and Ventricular Activation Interval on Hemodynamics during Atrioventricular and Ventriculoatrial Pacing: Determination from Pressure-Volume Loops in Dogs

Matsui

Iwasaka²,

Karakawa³

et al. 1995

Cardiology

View full text Add to dashboard Cite

To determine the effect of relative timing of atrial and ventricular activation on hemodynamic indices, we evaluated pressure-volume loops during pacing at 160 beats/min with various atrioventricular intervals in dogs. End-systolic pressure, end-diastolic volume, and stroke volume were reduced during pacing at atrioventricular intervals of 0 ms, compared with 80 ms. These changes were more significant during pacing at atrioventricular intervals of-50 and -100 ms than at 0 ms. During tachycardia, the abnormal timing of atrial contraction leads to unfavorable hemodynamic change and the degree of the changes are determined by the ventriculoatrial activation interval.

show abstract

“…In the majority of patients with normal sinus node function treated with ventricularly programmed pacemakers, the cardiac output loss resulting from atrioventricular dissociation does not manifest itself clinically. However, the clinical course in patients with a limited ability to augment ventricular stroke volume in response to physical activity, or those with ventricular pacemaker induced tachyarrhythmias (Kastor and Leinbach, 1973;Waxman and Wald, 1977), may be much improved by synchronising ventricular stimulation to atrial systole, thereby taking advantage of the atrial contribution to cardiac output and physiological heart rate change (Nathan et al, 1963;Samet et al, 1965;Karlof, 1975). The atrial (P wave) synchronous pacemaker (VAT) consists of an atrial sensing amplifier and a ventricular stimulating oscillator arranged and connected to the heart as shown in Fig.…”

Section: Clinical Applicationmentioning

confidence: 99%

Electrophysiological and haemodynamic basis for application of new pacemaker technology in sick sinus syndrome and atrioventricular block.

Sutton¹,

Citron²

1979

Heart

View full text Add to dashboard Cite

SUMMARY A fundamental description of pacemaker systems which are commercially available or in clinical validation is given as a background for their application in a series of 62 consecutive patients presenting over a period of 1 year for permanent cardiac pacing. The patients (23 (37%) sick sinus syndrome, 38 (61%) atrioventricular block, and 1 ventricular tachycardia) were studied electrophysiologically and haemodynamically to allow the appropriate application of a pacemaker system. In sick sinus syndrome, 8 patients had permanent atrial pacing, 14 ventricular pacing, and 1 atrioventricular sequential pacing; in atrioventricular block, 8 patients had atrial synchronous ventricular inhibited pacing and the remaining 30 had ventricular pacing. A high incidence of atrial fibrillation, 9 patients, and abnormal sinus node function, 15 patients, precluded wider use of atrial synchrony. The results show benefit in acute haemodynamic studies of using systems including atrial sensing and/or pacing, and with greater availability of atrioventricular sequential and still more advanced pacemakers with dual sensing as well as dual pacing the majority of patients may be offered this benefit. Permanent, implanted cardiac pacemakers have been used clinically since 1959 (Elmqvist and Senning, 1960). As is common with new treatments, the initial indications for use were very narrow, in this instance intended primarily for ventricular stimulation in cases of complete atrioventricular block with Adams-Stokes seizures. These early pacing systems maintained a constant regular cardiac rhythm by stimulating the ventricles asynchronously at a fixed rate, usually 70 pulses per minute. As a fuller understanding of cardiac pacing was realised, indications for use expanded to include management of symptomatic bradyarrhythmias, tachyarrhythmias, and restoration of optimal haemodynamics. As a result, the operational types of artificial pacemakers evolved so that there now exists an armamentarium of atrial and ventricular pacemaker systems, each appropriate to certain pathological situations within a broad range of cardiac diseases.

show abstract

Atrial contribution to cardiac output in complete heart block

Cited by 148 publications

References 21 publications

A graphical simulation software for instruction in cardiovascular mechanics physiology

A graphical simulation software for instruction in cardiovascular mechanics physiology

Effect of Atrial and Ventricular Activation Interval on Hemodynamics during Atrioventricular and Ventriculoatrial Pacing: Determination from Pressure-Volume Loops in Dogs

Electrophysiological and haemodynamic basis for application of new pacemaker technology in sick sinus syndrome and atrioventricular block.

Contact Info

Product

Resources

About