Complete Atrioventricular Block during Ablation of Atrial Flutter

We report the case of a 51‐year‐old patient who developed a complete atrioventricular (AV) block during the isthmic radiofrequency catheter ablation of a typical atrial flutter. The cause was an acute occlusion of the segment three of the right coronary artery. His recanalization was associated with the immediate restoration of a normal AV conduction. The complication is exceptional (one of 740 consecutive atrial flutter ablations). (PACE 2010; 516–519)     

Sevoflurane for central catheter placement in neonatal intensive care: a randomized trial

Objective: To compare the efficacy and safety of sevoflurane deep sedation with glucose and nonnutritive sucking (GNNS) in reducing the duration of the procedure and in preventing pain‐related effects during peripherally inserted central catheter (PICC) placement. Background: PICC placement in neonatal intensive care is a delicate and stressful procedure that requires pain prevention. GNNS has been recommended in this situation but remain often inefficient. Methods: We designed a randomized controlled study in a sixteen‐bed pediatric and neonatal unit in a tertiary hospital. Fifty‐nine neonates at >28 weeks of gestation with continuous positive airway pressure or invasive mechanical ventilation and requiring PICC placement were included. Patients were randomized to receive inhaled sevoflurane (IS) or glucose and non‐nutritive sucking (GNNS). Procedural duration and conditions, hemodynamic and respiratory parameters, occurrence of movements and complications were compared ( http://clinicaltrials.gov trial register no. NCT00420693). Results: The two groups had similar demographics. There were no between‐group differences in procedural duration (P = 0.84) despite greater immobility in IS group (P = 0.017). IS was also associated with fewer episodes of hypertension (P = 0.003), tachycardia (P < 0.001), and bradycardia (P = 0.02). Occurrences of hypotension were not different between the groups (P = 0.06). The GNNS group showed more desaturation during the 4 h after the procedure (P = 0.03). Complications during intensive care stay did not differ between groups. Conclusion: Inhaled sevoflurane does not make easier catheters placement but prevent pain‐related symptoms. Because sevoflurane is responsible for hypotension, it requires careful monitoring and treatment adaptation.     

Effect of prior exercise in Pi/PC ratio and intracellular pH during a standardized exercise. A study on human muscle using [31P]NMR

Seven subjects underwent a standard localized exercise of calf muscles in order to investigate whether the metabolic exercise-induced steady-state, as revealed by the evaluation of inorganic phosphate/phosphocreatine ratio, depends on the conditioning of the muscle just prior to the exercise. The experimental protocols consisted of two separate experiments using first [³¹P]nuclear magnetic resonance spectroscopy and second (on 3 subjects) infrared oxyphotometry to respectively follow variation of energy metabolism and tissular deoxygenation. The exercise consisted of 240 successive plantar flexions (0.5 Hz frequency) against a high load equivalent to SO% of the maximal voluntary contraction. This exercise was accomplished before cold exercise and after warm exercise, a warming-up period bringing to approximately 50% of Vo_2max. The results showed that: (1) steady-state level of phosphate/phosphocreatine and intracellular acidosis was significantly lowered by warming-up; (2) cold and warm exercise steady-state of calculated adenosine diphosphate values were not significantly different; (3) cold exercise rapidly induced a high tissular deoxygenation that is not observed during warm exercise; and (4) time-constant of phosphocreatine resynthesis is lowered after warm exercise but the initial slope of time-evolution is not modified. Parallel experiments also showed that phosphate/phosphocreatine steady-state was not modified in comparison with warm exercise when the same power of exercise was reached by stepwise incrementation of the charge. From these results we postulate that a better tissue oxygenation due to a global or localized warming-up allows to reach the same mechanical performance with a lower decrease of PCr content, owing to a faster adjustment of oxidative metabolism during the transitional period. However the aerobic pathway flux during the steady-state is probably the same before and after the warming-up despite different values of phosphate/phosphocreatine. As a consequence it can be assumed that this ratio is not a good indicator of the rate of muscle oxidative metabolism during the steady-state phase of the exercise.