Limits...
Mechanisms of vortices termination in the cardiac muscle

View Article: PubMed Central - PubMed

ABSTRACT

We propose a solution to a long-standing problem: how to terminate multiple vortices in the heart, when the locations of their cores and their critical time windows are unknown. We scan the phases of all pinned vortices in parallel with electric field pulses (E-pulses). We specify a condition on pacing parameters that guarantees termination of one vortex. For more than one vortex with significantly different frequencies, the success of scanning depends on chance, and all vortices are terminated with a success rate of less than one. We found that a similar mechanism terminates also a free (not pinned) vortex. A series of about 500 experiments with termination of ventricular fibrillation by E-pulses in pig isolated hearts is evidence that pinned vortices, hidden from direct observation, are significant in fibrillation. These results form a physical basis needed for the creation of new effective low energy defibrillation methods based on the termination of vortices underlying fibrillation.

No MeSH data available.


Related in: MedlinePlus

Fibrillation termination in the isolated pig hearts. The success rate of defibrillation in 486 experiments by five biphasic E-pulses. (a) Success rate versus normalized frequency  where fd is the dominant frequency of fibrillation. Error bars: the standard deviation. The blue curve is obtained by mixture (50 : 50) of two theoretical curves shown in figure 5. (b,c) Success rate for defibrillation energies not exceeding , for frequencies  shown near each curve. Normalized energy , where e1 is the threshold E50 energy of defibrillation by 1 shock. (b) shows graphs for , (c) shows graphs for . Graphs (b,c) and the experimental curve in (a) are calculated from data in [38]. Image (a) indicates that in about a half of fibrillation experiments, the frequencies of the vortices were not significantly different. The optimal pacing frequency  is below the arrhythmia frequency  as it should be for terminating pinned vortices. These experiments provide evidence that pinned vortices, hidden from direct observation, are significant in fibrillation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5383855&req=5

RSOS170024F6: Fibrillation termination in the isolated pig hearts. The success rate of defibrillation in 486 experiments by five biphasic E-pulses. (a) Success rate versus normalized frequency where fd is the dominant frequency of fibrillation. Error bars: the standard deviation. The blue curve is obtained by mixture (50 : 50) of two theoretical curves shown in figure 5. (b,c) Success rate for defibrillation energies not exceeding , for frequencies shown near each curve. Normalized energy , where e1 is the threshold E50 energy of defibrillation by 1 shock. (b) shows graphs for , (c) shows graphs for . Graphs (b,c) and the experimental curve in (a) are calculated from data in [38]. Image (a) indicates that in about a half of fibrillation experiments, the frequencies of the vortices were not significantly different. The optimal pacing frequency is below the arrhythmia frequency as it should be for terminating pinned vortices. These experiments provide evidence that pinned vortices, hidden from direct observation, are significant in fibrillation.

Mentions: Results of about 500 experiments with vortices termination in the isolated pig hearts are presented in figure 6. Fibrillation was induced and terminated as in [15,16]. In terms of the normalized pacing frequency , the numbers n of the experiments were: n=18 for ; n=28 for ; n=39 for ; n=65 for ; n=91 for ; n=127 for ; n=62 for ; n=50 for and n=7 for .Figure 6.


Mechanisms of vortices termination in the cardiac muscle
Fibrillation termination in the isolated pig hearts. The success rate of defibrillation in 486 experiments by five biphasic E-pulses. (a) Success rate versus normalized frequency  where fd is the dominant frequency of fibrillation. Error bars: the standard deviation. The blue curve is obtained by mixture (50 : 50) of two theoretical curves shown in figure 5. (b,c) Success rate for defibrillation energies not exceeding , for frequencies  shown near each curve. Normalized energy , where e1 is the threshold E50 energy of defibrillation by 1 shock. (b) shows graphs for , (c) shows graphs for . Graphs (b,c) and the experimental curve in (a) are calculated from data in [38]. Image (a) indicates that in about a half of fibrillation experiments, the frequencies of the vortices were not significantly different. The optimal pacing frequency  is below the arrhythmia frequency  as it should be for terminating pinned vortices. These experiments provide evidence that pinned vortices, hidden from direct observation, are significant in fibrillation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383855&req=5

RSOS170024F6: Fibrillation termination in the isolated pig hearts. The success rate of defibrillation in 486 experiments by five biphasic E-pulses. (a) Success rate versus normalized frequency where fd is the dominant frequency of fibrillation. Error bars: the standard deviation. The blue curve is obtained by mixture (50 : 50) of two theoretical curves shown in figure 5. (b,c) Success rate for defibrillation energies not exceeding , for frequencies shown near each curve. Normalized energy , where e1 is the threshold E50 energy of defibrillation by 1 shock. (b) shows graphs for , (c) shows graphs for . Graphs (b,c) and the experimental curve in (a) are calculated from data in [38]. Image (a) indicates that in about a half of fibrillation experiments, the frequencies of the vortices were not significantly different. The optimal pacing frequency is below the arrhythmia frequency as it should be for terminating pinned vortices. These experiments provide evidence that pinned vortices, hidden from direct observation, are significant in fibrillation.
Mentions: Results of about 500 experiments with vortices termination in the isolated pig hearts are presented in figure 6. Fibrillation was induced and terminated as in [15,16]. In terms of the normalized pacing frequency , the numbers n of the experiments were: n=18 for ; n=28 for ; n=39 for ; n=65 for ; n=91 for ; n=127 for ; n=62 for ; n=50 for and n=7 for .Figure 6.

View Article: PubMed Central - PubMed

ABSTRACT

We propose a solution to a long-standing problem: how to terminate multiple vortices in the heart, when the locations of their cores and their critical time windows are unknown. We scan the phases of all pinned vortices in parallel with electric field pulses (E-pulses). We specify a condition on pacing parameters that guarantees termination of one vortex. For more than one vortex with significantly different frequencies, the success of scanning depends on chance, and all vortices are terminated with a success rate of less than one. We found that a similar mechanism terminates also a free (not pinned) vortex. A series of about 500 experiments with termination of ventricular fibrillation by E-pulses in pig isolated hearts is evidence that pinned vortices, hidden from direct observation, are significant in fibrillation. These results form a physical basis needed for the creation of new effective low energy defibrillation methods based on the termination of vortices underlying fibrillation.

No MeSH data available.


Related in: MedlinePlus