Sinus node recovery time

Propafenone causes sinus node slowing that could lead to sinoatrial block. It may lengthen the sinus node recovery time with minimal effects on sinus cycle length. 

Chronotropic effect negative. Ethanol (50%) extract of the fresh leaf, administered by gastric intubation to rats at a dose of 40 mL/kg, produced weak activity. Results were significant at p < 0.05 level ". Glycerin/ ethanol extract of the fresh leaf, administered intragastrically to dogs at a dose of 20 mg/kg, produced an increase in length of sinusal cycle (16%), sinoatrial conduction time (27%), and sinus node recovery time (31%) . 

During an episode of lithium toxicity (serum concentration 3.86 mmol/1), a 42-year-old woman developed sinus bradycardia that required a temporary pacemaker (124). There was marked prolongation of sinus node recovery time. Lithium was withdrawn and the patient underwent hemodialysis once daily for 3 days sinus node recovery time normalized. The presence of nontoxic concentrations of carbamazepine may have contributed to the condition. 

In three patients in whom cibenzoline had caused sinus node dysfunction, normal sinus node recovery time was restored by cilostazol (12). 

Encainide has been reported to cause sinus node arrest in association with prolonged sinus node recovery time (19). It also raises the pacing threshold in patients with chronic implanted pacemakers (20), although this has not been reported to increase the failure rate of pacemakers. 

Procainamide prolongs the QT interval (7) and can cause dysrhythmias. It can also impair cardiac conduction and can cause bradycardia and heart block (1). In the sick sinus syndrome it can alter sinus node recovery time (8), although the clinical significance of this is not clear. 

Fig. 9A Abnormal sinus node recovery time (SNRT). The atria are paced (arrows) at 150 bpm for 30 s. Notice that the patient has AV node block during pacing. With cessation of pacing, a junctional beat occurs, but it takes 2.2 s for spontaneous sinus node activity to return.

Fentanyl enhances vagal tone and can cause bradycardia. In 27 children undergoing catheter ablation under propofol anesthesia, which has minimal effect on the sinus node, electrophysiological stimulation was performed before and after a bolus dose of fentanyl 2 micrograms/kg and a subsequent infusion of 0.075 micrograms/kg/minute [64 ]. There was an increase in calculated sinus node recovery time but no change in sinoatrial conduction time after fentanyl, suggesting that fentanyl -I- propofol impairs sinus node recovery and therefore... 

Fujii K, Iranami H, Nakamura Y, Hatano Y. Fentanyl added to propofol anesthesia elongates sinus node recovery time in pediatric patients with paroxysmal supraventricular tachycardia. Anesth Analg 2009 108(2) 456-60. 

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