Intra‐ and Interatrial Conduction Delay:

Abstract

Atrial conduction disorders are frequent in elderly subjects and/or those with structural heart diseases, mainly mitral valve disease, hyperthrophic cardiomyopathies, and hypertension. The resultant electrophysiological and electromechanical abnormalities are associated with a higher risk of paroxysmal or persistent atrial tachyarrhythmias, either atrial fibrillation, typical or atypical flutter or other forms of atrial tachycardias. Such an association is not fortuitous because intra- and interatrial conduction abnormalities delays disrupt (spatial and temporal dispersion) electrical activation, thus promoting the initiation and perpetuation of reentrant circuits. Preventive therapeutic interventions induce variable, sometimes paradoxical effects as with the proarrhythmic effect of class I antiarrhythmic drugs. Similarly, atrial pacing may promote proarrhythmias or an antiarrhythmic effect according to the pacing site(s) and mode. Multisite atrial pacing was conceived to correct, as much as possible, abnormal activation induced by spontaneous intra- or interatrial conduction disorders or by single site atrial pacing, which are situations responsible for commonly refractory arrhythmias. Atrial electrical resynchronization can also be used to correct mechanical abnormalities like left heart AV dyssynchrony resulting from intraatrial conduction delays.

Assessment of Atrial Electromechanical Coupling and Influential Factors in Nonrheumatic Paroxysmal Atrial Fibrillation

“…15 Therefore, these results support the hypothesis that the P-A2 and the dispersion of P-A2 are partly determined by left atrial enlargement. According to Omi et al, the prolongation of P-A could be explained not only by left atrial enlargement but also by the time delay from atrial electric activation to myocardial contraction.…”

Tissue Doppler echocardiography can be a useful technique to evaluate atrial conduction time

“…The changes resulting in intra-and interatrial conduction delay can prepare convenient atrial substrate for AF. Anisotropy and dispersion of refractory periods resulting from the decrease in electrical connections and depositon of connective tissue between the myocytes cause atrial conduction abnormalities [8,20]. Cohen and Scherf [21] was first described the concept of interatrial block.…”

“…Among the noninvasive and invasive methods to evaluate the interatrial conduction, the basic and the most frequently used one is the electrocardiographic P wave duration and morphology [8]. Also, there are some echocardiographic methods to measure interatrial conduction times by the evaluation www.cardiologyjournal.org of cardiac electromechanical events.…”

Clinical benefit of atrio-ventricular delay optimization in patients with a dual-chamber pacemaker: a pilot study. The CBRAVO trial (NCT01998256)

“…Beside the lengthening due to the P sense offset, one could hypothesize that larger atrial pacing percentages are found in sicker atria, showing delayed conduction. Similarly, evidence exists about a linear relationship between the degree of IACD and extent of left atrial mechanical dysfunction 2 . In this context we showed a higher prevalence of an important IACD in patients with sick sinus and bradycardia-tachycardia syndrome, in the elderly and in postoperative patients.…”