Progression of partial to advanced interatrial block
ABSTRACT Interatrial block (IAB), prolonged conduction between the atria, is denoted by P waves of 110 milliseconds or more and may manifest as partial or advanced. Theoretically, partial IAB may progress to its advanced counterpart if conduction delay increases to complete block. However, there have been no reports of such progression, and electrophysiologic studies have not shown this phenomenon. We briefly review the interatrial conducting pathways of IAB and present the first documentation of possible progression of partial to advanced IAB.
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ABSTRACT: Obstructive sleep apnea (OSA) is a common disorder that affects 5% of the adult North American population. It is associated with atrial arrhythmias and stroke. The mechanisms of this association remain unclear. The aim to the study was to identify the factors associated with interatrial block (IAB) among patients with OSA. Patients referred for polysomnography were studied. Sleep apnea severity (apnea-hypopnea index [AHI]) was measured in each subject. 12-lead ECGs were scanned and amplified (× 10); P-wave duration and dispersion were measured using a semi-automatic caliper. IAB was defined as a P-wave duration ≥ 120 ms. Data from 180 consecutive patients was examined. Moderate-severe OSA (mean AHI = 56.2 ± 27.9) was present in 144 (OSA group). The remaining 36 had mild or no OSA (mean AHI = 5.6 ± 3.6) and were used as controls. Age distribution between the groups did not differ and there were more males in the OSA group (69.4% vs 47.2%, p = 0.01). Obesity (78.5% vs 39.4%, p 〈 0.001) and hypertension (51.4% vs 27.8%, p 〈 0.01) were more prevalent in the OSA group. IAB was more prevalent in patients with moderate-severe OSA (34.7% OSA vs 0% controls, p 〈 0.001). In linear regression, age and AHI 〉 30 were independent predictors of maximum P-wave duration (p = 0.001 and p 〈 0.001, respectively). P-wave dispersion was significantly higher in the severe OSA group (14.6 ± 7.5 for OSA, 8.9 ± 3.1 controls, p 〈 0.001). Older age and moderate-severe OSA are predictors of IAB. P-wave dispersion is increased in patients with moderate-severe OSA. This may partly explain the high prevalence of atrial arrhythmias in patients with OSA.Cardiology journal 01/2011; 18(2):171-5. · 1.22 Impact Factor
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ABSTRACT: Interatrial block (IAB) denotes a conduction delay between the two atria (P-wave duration ≥110 ms). Depending on the severity of the block, IAB can be partial or advanced. Even though several studies have reported a high prevalence of IAB, it still remains a diagnosis many neglect without any follow-up. The crisis in IAB is undramatic until predictable complications appear. Nevertheless, the danger in IAB is real because of the major associations with multiple medical conditions, including atrial fibrillation, myocardial ischemia, left atrial enlargement, and systemic emboli. There are different treatment options for IAB to eliminate its consequences, including pacing and medical management with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. Pacing has been shown to give promising results and could potentially prevent conditions related to cardiovascular disease such as hypertension or diabetes mellitus. Given the high prevalence of IAB, together with its potentially serious consequences, and yet being largely ignored, we stress attention to this potentially dangerous pandemic and raise consideration for further investigations.Iranian Journal of Medical Sciences 03/2014; 39(2):84-93.
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ABSTRACT: Interatrial conduction disorders are frequent in patients with structural heart diseases, including hypertension, coronary disease, and hypertrophic cardiomyopathy, and they are strongly associated with atrial tachyarrhythmias, especially atrial fibrillation and flutter. Conduction delays lead to dispersion of refractory periods and participate in initiating and maintaining reentry circuits, facilitating atrial arrhythmias. In this case, the changing pattern over time is a manifestation of progressive atrial remodeling and conduction delay. The terminal negative component of the P wave in the inferior leads suggests block of the electrical impulse in the Bachman bundle zone, with retrograde activation of the left atria via muscular connections at the coronary sinus. This has been reproduced in experimental models and confirmed by endocardial mapping. Physicians should be aware of the association between advanced interatrial block and development of atrial arrhythmias as its recognition could prompt early and aggressive antiarrhythmic treatment.Annals of Noninvasive Electrocardiology 09/2014; DOI:10.1111/anec.12208 · 1.08 Impact Factor