Several studies have previously reported an increased platelet aggregability in patiens with VVI pacemakers; moreover, some authors have showed that antiplatelet drugs may be effective in reducing platelet aggregation, thus suggesting an increased formation of platelet activation markers in these patients. In this respect, platelet aggregability was investigated in twenty five VVI patients and fifteen control subjects. In addition, p-thromboglobulin (p-TG) and platelet factor 4 (PF4) plasma levels were measured to determine the degree of platelet activation before and after ticlopidine treatment.
Plasma p-TG and PF4 levels were significantly increased in VVI patients as compared with control subjects ( 147.84 ± 44.15 vs 75.64 ± 31.77, P < 0.001 and 62.90 ± 71.93 vs 21.88 ± 11.10, p < 0,001; respectively). Additionally, plasma p- TG and PF4 levels after ticlopidine treatment were significantly decreased as compared with that before ticlopidine treatment (43.69 ± 16.56 vs 147.84 ± 44.45, P < 0.001 and 15.07 ±7.17 vs 62.90 ± 71.93, P < 0.001; respectively).
Our data confirm an increased of platelet aggregability in patients with VVI pacemakers and show the efficacy of ticlopidine in reducing platelet aggregability.
Key words: VVI pacemaker, platelet aggregability, p-thromboglobulin, platelet factor 4.
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