Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the effects of an atrial premature beat on atrial refractory periods, we investigated 11 patients (group A) who were the control group, 12 patients suffering from paroxysmal atrial fibrillation (group B), and 10 patients (group C) without arrhythmias but with cardiopathy or cardiomyopathy. At every eighth complex of a constant atrial electrostimulated rhythm a fixed premature extrastimulus was introduced, and effective and functional refractory periods (ERP and FRP) were measured in three different sites of the right atrium, before and after introduction of this extrastimulus. Average ERP and FRP shortened respectively in group A, from 220.28 +/- 25.68 msec and 281.17 +/- 28.15 msec before extrastimulation, to 190.58 +/- 22.74 msec and 245.88 +/- 19.86 msec after; in group B, from 219.44 +/- 27.38 msec and 284 +/- 30.06 msec to 191.66 +/- 28.72 msec and 253.23 +/- 34.01 msec; and in group C from 229.03 +/- 29.65 msec and 289.67 +/- 51.62 msec to 194.19 +/- 24.6 msec and 237.74 +/- 39.59 msec. The average dispersions of ERP and FRP in group A were, respectively: 41.81 +/- 21.36 msec and 36.36 +/- 18.04 msec before extrastimulation, 28.18 +/- 18.14 msec and 35.45 +/- 15.72 msec after. In group B: 26.66 +/- 19.46 msec and 41.66 +/- 16.96 msec versus 45.83 +/- 23.91 msec and 45 +/- 34.77 msec and in group C: 27 +/- 11.59 msec and 45 +/- 29.15 msec versus 29 +/- 18.52 and 27 +/- 18.88.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Atrial refractory periods after atrial premature beats in patients with paroxysmal atrial fibrillation. 247 34

Little is known about the electrophysiological properties of the atrium predisposing to paroxysmal atrial fibrillation (AF), especially in patients without structural heart disease. This study was conducted to analyze intraatrial conduction, atrial refractoriness, and arrhythmia inducibility in patients with lone paroxysmal AF. An electrophysiological study was performed in 24 patients with a documented history of lone paroxysmal AF but in sinus rhythm at the time of the electrophysiological study. Twelve patients without any history of atrial arrhythmias served as controls. The patients with lone paroxysmal AF showed a significant prolonged local conduction time S1A1 (70 +/- 21 ms vs 36 +/- 12 ms, P < 0.0001), a lack of rate adaptation of the functional refractory period (FRP changes/cycle length changes < 10% in 15 of 24 patients with lone paroxysmal AF vs 1/12 controls, P = 0.002) and a higher incidence of inducible AF with only one extrastimulus (13/24 vs 0/12, P = 0.0014). The total P wave duration in the surface ECG (89 +/- 14 ms vs 83 +/- 8 ms, P = 0.15), the intraatrial conduction time (36 +/- 14 ms vs 28 +/- 8 ms, P = 0.07), the presence of a fragmented atrial electrogram (16/24 vs 7/12, P = 0.62), the absolute value of the effective refractory period (204 +/- 28 ms vs 212 +/- 23 ms, P = 0.42), and the vulnerability index (3.0 +/- 1.5 vs 3.6 +/- 1.5, P = 0.26) were not statistically different between the two groups. The presence of a prolonged (> 50 ms) S1A1 and/or the presence of a lack of rate adaptation of the FRP and/or the presence of inducible AF identified patients with spontaneous lone paroxysmal AF with a sensitivity of 96%, a specificity of 67%, a positive predictive value of 85%, and a negative predictive value of 89%. In patients with lone paroxysmal AF, the electrophysiological study using conventional techniques allows not only to detect AF inducibility using a nonaggressive protocol, but also to reveal several electrophysiological abnormalities related to the atrial substrate itself. This atrial vulnerability may explain the high incidence of recurrences in patients with lone paroxysmal AF.
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PMID:Atrial vulnerability in patients with paroxysmal "lone" atrial fibrillation. 979 92