ABNORMALITIES OF ELECTROCARDIOGRAPHIC P-WAVE MORPHOLOGY AND THEIR RELATION TO ELECTROPHYSIOLOGICAL PARAMETERS OF THE ATRIUM IN PATIENTS WITH SICK SINUS SYNDROME

We examined the incidence of long P wave duration in lead II and incre ased P terminal force in lead V1(PTFV1), and their relationship to ele ctrophysiological findings of atrial muscle in 34 patients with sick s inus syndrome (SSS). Patients were divided into three groups: Group I, consisting of 20 patients with various cardiac arrhythmias other than SSS and paroxysmal atrial fibrillation (PAF) who served as controls; Group II, consisting of 18 patients with SSS but without PAF; and Grou p III consisted of 16 patients with SSS and PAF. P wave duration was s ignificantly longer in Group III (122 +/- 11 ms, mean +/- SD, P < 0.00 01) and Group II (111 +/- 15 ms, P < 0.002) than in Group I (98 +/- 10 ms). PTFV1 was greater in Group III (0.052 +/- 0.025 ms) than in Grou p I (0.028 +/- 0.011 ms, P < 0.05). P wave duration and PTFV1 had sign ificantly and/or borderline correlations with longest duration of righ t atrial electrograms (r = 0.84, P < 0.0001 and 0.47, P < 0.02, respec tively), maximal number of fragmented deflections of atrial electrogra ms (r = 0.69, P < 0.0001 and r = 0.51, P < 0.02, respectively), repeti tive atrial firing zone (RAFZ) (r = 0.81, P < 0.0001 and 0.48, P < 0.0 5, respectively) and fragmented atrial activity zone (FAAZ)(r = 0.53, P < 0.01 and r = 0.45, P = 0.06, respectively). We concluded that long P wave duration and increased PTFV1 are electrocardiographic indicato rs for coexistence of electrophysiological abnormalities in the atria in SSS without recognizable heart disease.