Clinical significance of slow paroxysmal atrial tachycardia.

This study examines the clinical setting, characteristics, and follow-up of 173 patients who had slow paroxysmal atrial tachycardia (SPAT) (greater than 4 beats, rate less than 150 bpm) during 24-hour Holter monitoring. These episodes were classified by probable mechanism according to recognized ECG criteria and included AV nodal reentry (AVNR), sinoatrial nodal reentry (SANR), and automatic (A). There were 76 males (44%) with a mean age of 72 years and 97 females (56%) with a mean age of 73 years. The indications for Holter recording revealed that the SANR and A subgroups had a higher frequency of cerebral symptoms compared to AVNR (p less than 0.01). Chest pain was more common in the SANR group as compared to the other two groups (p less than 0.01). There was no difference in the frequency of palpitation in the three subgroups. The mean rate of SPAT for the entire group was 115.2 +/- 14 and these episodes had a mean duration of 5.58 +/- 3.07 seconds. The SANR subgroup had a significantly slower rate (107.1 +/- 9.2) as compared to the AVNR subgroup (p less than 0.01). One hundred fourteen patients were available for follow-up. The average period of follow-up was similar for all three groups. At follow-up the frequency of sick sinus syndrome as determined clinically and permanent pacemaker insertion was significantly greater in the SANR subgroup (p less than 0.01) as compared to the other subgroups which did not differ from each other.