Sinus node function: comparative study between directly measured and indirectly estimated sinoatrial conduction time in man

ABSTRACT

Assessment of sinus node dysfunction is important in many disease states as syncope, sick sinus syndrome and arrhythmia. Sinoatrial conduction time [SACT] is one of the important measurements of sinus node function. There are three methods for measurement of SACT Direct method and two indirect methods by premature atrial stimulation [Strauss] and by continuous atrial pacing [Narula]. The aim of this study was to compare between these three methods. 24 patients with various forms of acquired heart diseases were studied during cardiac catheterization that was performed for evaluation of their heart disease. Quadripolar electrode catheters and programmable stimulator were used. Results indicated that SACT by direct method ranged from 20 to 70 msec. [mean 41 +/- 12 msec.], SACT by Strauss method ranged from 10 to 170 msec. [range 70 +/- 44 msec.]. By Narula method range was 20 to 165 msec. [mean 59 +/- 40 msec.]. There was no significant correlation between the three methods. It was concluded that two indirect methods of estimating sinoatrial conduction time by Strauss and Narula methods are not sensitive; sinus nodal electrogram is more precise for accurate estimation of sinoatrial conduction time in man; spontaneous cycle length bears no relation to values of SACT measured by any of these methods: