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# Aspect on Poincare diagram supports the hypothesis of
atrioventricular re-entry during atrial fibrillation

### Corlan Alexandru Dan,
Bălănescu Serban,
Cinteză Mircea,
Vasilescu Ileana,
Dorobantu Maria,
Vinereanu Dragos,
Dimulescu Doina,
Gherasim
Leonida,

### Eur Heart J 16 (suppl):275-275, 1995

## ABSTRACT

BACKGROUND: 1. In patients having both a slow and a fast
AV node pathway, with different refractory periods, an impulse
from atria leads to a reciprocal beat if it comes
in the refractory period of the slow pathway. This condition
should be far more common during atrial fibrillation (AF) than
after a SV premature beat.
2. Poincare diagrams of ventricular rhythm are graphics in which every
pair of R-R intervals is represented by a plot, with x corresponding
to an interval and y to the next.
AF with unimodal RR distribution appears as a single group of points
(type A). AF with both short (S) and long (L) cycles has either type B (L-L,
L-S and S-L pairs), type C (L-L, L-S, S-L, S-S) or type D (S-S, S-L,
L-S). Each kind of pair appears as a group of points.
PURPOSE: We assessed the statistical properties of groups of
points in order to detect their potentially
different pathogenic mechanisms.

METHODS: We performed 174 rest one hour single lead ECG recordings
in 97 patients with AF of various etiology.
We developed a computer program which calculated
the correlation coefficient (r), the ovality
of every group of points and other parameters.
Ovality (ov) was defined as the ratio between the
dispersion on the group on the first (45 °) axis
and on the second (135 °) axis. Higher ovality as well
as higher correlation coefficient reflect
closer dependence between one RR cycle and the next.
RESULTS: In types B, C and D the correlation coefficient of S-S pairs
is significantly higher (p<0.000001) than that of L-L pairs,
and is also significantly higher (p;0.0001) than that of the
single group in the A type. Same is true about ovality (p<0.000001
and respectivelly p<0.001).

Type | N | param | L-L | L-S | S-L | S-S |

A | 105 | r | 0.11 ±0.09 | - | - | - |

| | ov | 1.11 ±0.12 | - | - | - |

B | 34 | r | 0.04 ±0.07 |
0.12 ±0.09 | 0.06 ±0.17 | - |

| | ov | 1.02 ±0.10 | 1.11 ±0.09 |
1.00 ±0.0 | - |

C | 26 | r | 0.04 ±0.09 | 0.13 ±0.09 |
0.02 ±0.05 | 0.21 ±0.11 |

| | ov | 1.00 ±0.07 | 1.11 ±0.1 |
0.96 ±0.06 | 1.20 ±0.14 |

D | 9 | r | - | 0.07 ±0.09 | 0.08 ±0.17 |
0.19 ±0.12 |

| | ov | - | 1.02 ±0.13 | 1.03 ±0.25 |
1.20 ±0.17 |

CONCLUSION: The higher correlation between S-S cycle sequences is
compatible with the hypothesis that the short cycles are given by
reentry in the AV node, with one part of the reentry circuit through the
atrial myocardium, because most of the circuit parameter would change
little from one cycle to the next. The long cycles may be given by a less
predictable mechanism, such as concealed conduction.