[The acute treatment of supraventricular tachycardia with endovenous amiodarone]. / Trattamento acuto delle tachicardie sopraventricolari con amiodarone endovena.

In the present study we evaluated 35 patients of both sexes, aged 21-84, with newly occurring supraventricular tachyarrhythmias, 19 atrial fibrillation (AF), 6 atrial flutter (FL) and 10 paroxysmal supraventricular tachycardias (PSVT). They were treated with a single amiodarone infusion up to two hours after the restoration of a stable sinus rhythm or to a maximus dose of 2,400 mg (in 24 hours). Plasma amiodarone concentration and QTc were measured at the restoration of sinus rhythm and twelve hours after the amiodarone withdrawal. Amiodarone infusion restored a stable sinus rhythm in all 10 patients of the PSVT group (100%), in 5 of the FL group (83%) and in 16 of the AF group (84%). The average dose needed to stop PSVT was lesser than for AF and FL (M + SE: 473.3 +/- 36.88 vs 1842.1 + 259.6 vs 1548.8 +/- 345.5 mg; p less than 0.001). The average plasma amiodarone concentration at the restoration of sinus rhythm was 2450.4 +/- 175.9 SE ng/ml in all the tachyarrhythmias as a whole without any statistically significant difference among PSVT, FL and AF. Moreover no correlation exists between plasma amiodarone concentrations and the amount of amiodarone infused. QTc showed a statistically significant transient lengthening at the restoration of sinus rhythm, but not twelve hours after amiodarone withdrawal. In conclusion, a single dose of amiodarone is effective and safe in all newly occurring supraventricular tachyarrhythmias, without any important side effect and with a high therapeutic index in pharmacologic cardioversion as alternative treatment to cardioversion.

The oxygen affinity of normal human whole blood measured by double tonometry. I. P50 and n factor.

The Authors refer that the oxygen affinity, determined by double tonometry, in normal adult whole blood, is mainly expressed by a P50 of 26.13 +/- 4.31% and by an n factor of 2.63 +/- 6.63%. These results are in good agreement with those reported in the literature, but here are some doubts that pO2 and SO2 alone, i.e. the data drawn from all the tonometric procedures, can give a full idea of the affinity. In fact, this one is a complicate process, modulated by a number of allosteric effectors. Most of them, like pH, temperature and pCO2 can be always kept at a fixed standard level, whereas DPG, the main one, cannot.