On the role of ventricular conduction time in rate stabilization for atrial fibrillation

A simulation framework for dual chamber heart rhythm and cardiac pacing

A previously developed open source computer model allows realistic simulation of ventricular intervals in atrial fibrillation, while taking into account of ventricular pacing. In this paper, we further improve this model and present a new simulation framework based on an integrated dual-chamber heart and pacer (IDHP) model. The IDHP model incorporates more realistic atrial and ventricular rhythm generators and an industry-standard dual-chamber pacemaker timing control logic. Moreover, it simulates various interactions between intrinsic heart activity and extrinsic cardiac pacing. The IDHP model provides a new simulation platform where it is possible to bench test advanced pacemaker algorithms in the presence of different types of cardiac rhythms.

Ventricular rate smoothing for atrial fibrillation: a quantitative comparison study

AIMS

To quantitatively compare the ventricular rate-smoothing (VRS) effects of different ventricular pacing (VP) protocols for atrial fibrillation (AF).

METHODS AND RESULTS

Using a recently developed open-source model that can simulate the ventricular response in AF and VP, the performance of fixed-rate pacing and four previously published VRS algorithms were assessed by the mean RR (mRR), the root mean square of successive RR differences (RMSSD), the percentage of ventricular senses (VS%), and the percentage of short RR intervals (sRR%). All pacing protocols cause rate-dependent reduction of RMSSD, VS%, and sRR% with or without shortening of mRR compared to spontaneous AF. Fixed-rate pacing was more sensitive to the intrinsic rate than the VRS algorithms. The performance was generally comparable between different VRS algorithms, although higher mRR and VS% can be achieved at the expense of larger RMSSD and sRR%.

CONCLUSION

The effect of VP on ventricular rhythm in AF depends on both intrinsic rate and the aggressiveness of the pacing protocol. Adequate rate control is necessary for effective operation of the VRS algorithm. Choosing VRS algorithm should balance between the beneficial effects of rate regularization and the negative effects of increasing heart rate and percentage of VP.

Open source model for generating RR intervals in atrial fibrillation and beyond

Background

Realistic modeling of cardiac inter-beat (RR) intervals is highly desirable for basic research in cardiac electrophysiology, clinical management of heart diseases, and developing signal processing tools for ECG analysis.

Methods

We present an open source computer model that is capable to generate realistic time series of RR intervals in both physiologic and pathologic conditions. Detailed model structure and the software implementation are described.

Results

Examples are provided on how to use this model to generate RR intervals in atrial fibrillation with ventricular pacing, normal sinus rhythm with heart rate variability, and typical atrial flutter with atrioventricular block. The extensibility of the model is also discussed.

Conclusion

The present computer model provides a unified platform wherein various types of ventricular rhythm can be simulated. The availability of this open source model promises to support and stimulate future studies.