thromboxane-b2 and Tachycardia--Supraventricular

PSVT attack of >20min and frequency >160 is well-recognized model of myocardial dysfunction. We measured 6-keto-PGF1alpha and TXB(2) before and after adenosine administration to assess its cardioprotective potential. A total of 64 patients were randomly assigned as having acute episode of PSVT to adenosine or verapamil group. A bolus of 6mg of adenosine up to the maximum dose of 12 or 5mg of verapamil up to the maximum dose of 10mg were given, until the sinus rhythm was restored. The levels of PGI(2), TXA(2) and TAS were measured in three different time intervals. In adenosine group all parameters were normalized after 20min of conversion to sinus rhythm. The ratio of PGI(2)/TXA(2) increased after 5min of conversion to SR (P<0.01). Also, the ratio of TXA(2)/TAS was decreased for ADO (P<0.01). This is the first study to demonstrate that adenosine exerts cardioprotective effect.

Topics: 6-Ketoprostaglandin F1 alpha; Adenosine; Adult; Cardiotonic Agents; Female; Humans; Male; Middle Aged; Myocardial Ischemia; Prostaglandins; Tachycardia, Paroxysmal; Tachycardia, Supraventricular; Thromboxane A2; Thromboxane B2; Verapamil

Forty-two consecutive patients were checked for profiles of platelet aggregability before, during, and 10 and 30 minutes after catheter ablation. They were randomized into Group A (n = 20) who accepted intravenous aspirin (in 0.015 g/kg body weight) and Group P (n = 22) who accepted only placebo treatment. Blood samples were drawn from ascending aorta (Ao) and main pulmonary artery (MPA) simultaneously at each time period. In Group P, the EC50 of substrate induced platelet aggregability decreases significantly during (for ADP, from 1.72 to 0.78 mumol/L for samples from Ao, P < 0.0001; and from 1.68 to 0.69 mumol/L for MPA, P < 0.0001; for collagen, from 2.26 to 1.34 micrograms/mL for Ao, P < 0.005, and from 2.40 to 1.64 micrograms/mL, P < 0.0001) and 10 minutes after successful ablation (for ADP, to 0.70 mumol/L for Ao, P < 0.000, and to 0.61 mumol/L for MPA, P < 0.0001; for collagen, to 1.54 micrograms/mL for Ao, P < 0.01, and to 1.63 micrograms/mL, P < 0.0001), and then returned to baseline levels 30 minutes later (all P = NS) compared with comparative baseline levels. The levels of thromboxane B2 (TXB2) had the similar evolution. The evolution of platelet aggregability profiles was not associated with total energy dose, duration of energy application, duration of procedure, impedance, and ablation site. However, there were moderate positive correlations between the TXB2 levels and tip temperatures (r = 0.56, P < 0.05 for Ao and r = 0.65, P < 0.01 for MPA). These results suggest that increased platelet aggregability can occur during and 10 minutes after radiofrequency current ablation and antiplatelet therapy can maintain "flat" response of platelet aggregability to radiofrequency energy, which may provide possible benefits in preventing the occurrence of the complication.

Topics: Adenosine Diphosphate; Adult; Aorta; Aspirin; Catheter Ablation; Collagen; Electric Impedance; Female; Follow-Up Studies; Humans; Male; Monitoring, Intraoperative; Placebos; Platelet Aggregation; Platelet Aggregation Inhibitors; Postoperative Care; Pulmonary Artery; Tachycardia, Supraventricular; Temperature; Thromboxane B2; Time Factors

Blood endogenous prostaglandins, E, F2 alpha, prostacyclin and thromboxane levels were measured in the ascending aorta and the coronary sinus of 32 patients (29 males and 3 females) with paroxysmal supraventricular arrhythmias (atrial fibrillation and supraventricular tachycardia) during the sinus rhythm and an arrhythmic paroxysm. Group 1 was made up by 22 patients with idiopathic cardiac rhythm disorders, and group 2 comprised 10 coronary patients with arrhythmias. A relationship was demonstrated between cardiac endogenous prostanoids balance and the clinical pattern of cardiac rhythm abnormality (duration and frequency of paroxysms) as well as changes in cardiac prostanoid rations associated with tachyarrhythmic paroxysms.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Chronic Disease; Coronary Disease; Dinoprost; Female; Humans; Male; Middle Aged; Prostaglandins; Prostaglandins E; Prostaglandins F; Tachycardia, Paroxysmal; Tachycardia, Supraventricular; Thromboxane B2