The Changes Of Concentration And Release Mechanism Of Atrial Natriuretic Peptide In Patients With Atrioventricular Versus Atrioventricular Nodal Supraventricular Reentrant Tachycardias

Objective To investigate the concentration changes and release mechanism of atria! natriuretic peptide (ANP) in patients with atrioventricular nodal versus atrioventricular supraventricular reentrant tachycardias. Plasma levels of ANP in femoral artery(FA) , femoral vein(FV), right atria(RA) ,and coronary sinus(CS) were measured. The changes of the peak right atrial pressure( peak RAP), and FA pressure were measured before and during onset of tachycardia. Tachycardia rates were also recorded.Methods Forty patients were divided into atrioventricular nodal reentrant tachycardias (AVNRT) group (n=17) and atrioventricular reentrant tachycardias (AVRT) group(n=23).After puncture of subclavicular vein, FA, and FV, we placed the F7 CS catheter (with a cavum in it) into CS , F6 pigtail catheter into the center of right atria, and F6 pacing catheter in RV .Pacing rate at SlSl=300ms was used to induce tachycardias . The levels of ANP in CS, FA, FV, and RA with peak RAP and FA pressure were measured before and 5 min after onset of tachycardia . The tachycardia heart rate was also recorded.Results During tachycardias, ANP in CS, FA, FV, and RA plasma levels significantly increased both in AVNRT and AVRT groups (P< 0.001). The values of ANP levels in CS, FA,FV and RA plasma in the AVNRT group after 5 min onset of tachycardia had more significant increases than those of the AVRT group( P<0.05 ).The range of ANP levels of each group was CS>A>A>V. Before and 5 min after onset of tachycardia the peak RAP of each group had a marked increase(P< 0.001). After onset of tachycardia the higher values of peak RAP in AVNRT groups had more significant increases than those of the AVRT group ( P=0.008) , but there was no significant difference in peak RAP between AVNRT and AVRT groups ( P>0.05) . Following tachycardia, significant correlations were found between the changes in plasma levels of ANP (CS. FA, FV, and RA ) and peak RAP or amount of increase values ( P<0.01) . There was a marked fall in FA pressure in both groups at the onset of tachycardias (P<0.001) . There were significant correlations among the plasma levels of ANP , the change in peak RAP, and the fall of BP (P<0.001). Otherwise, there was no correlation between the rate of tachycardias and the fall of BP (P>0.05) .No significant changes in plasma levels of ANP or peak RAP were found in one patient of AVNRT group. In this subject, induced tachycardia was atypical (long HA) and did not significantly alter plasma levels of ANP, peak RAP and FA systolic pressure, before or after the elicitation of similar tachycardia.Conclusion The range of the plasma levels of ANP in each group is CS>RA>FA>FV. During onset of tachycardias of AVNRT and AVRT , the plasma levels of ANP in CS, FA,FV and RA significantly increased. This study demonstrates that the release of ANP during tachycardia (both AVRT and AVNRT) is primarily dependent on increased atrial pressure and not atrial rate. The ANP levels (CS, FA,FV and RA plasma) in patients with AVNRT have also more significant increases than those of patients with AVRT . The different plasma levels of ANP between AVRT and AVNRT are mainlycaused by the change in value of peak RAP instead of the heart rate. There are significant negative correlations between the plasma levels of ANP and the fall of BP . Otherwise, there is no correlation between the rate of tachycardia and the fall of BP. There is no difference in heart rate between AVRT and AVNRT. Atypical (long HA) AVNRT may not significantly alter plasma levels of ANP, peak RAP, and FA systolic pressure, before or after the elicitation of similar tachycardia.