Kaoru Nakazato

Gender-related differences on signal-averaged electrocardiograms in healthy subjects

Abstract In conclusion, filtered QRS duration in time-domain analysis of SAEs was influenced by gender and body characteristics in healthy subjects; however, the parameters in spectral turbulence analysis were not.

Dislodgment of an Atrial Screw‐In Pacing Lead 10 Years After Implantation

Dislodgment of an atrial screw‐in pacing lead is quite rare. This report describes a rare case of an atrial screw‐in lead dislodgment 10 years after implantation. Although it is an uncommon complication, very late dislodgment can occur postoperatively, and careful follow‐up is necessary. (PACE 2004; 27:264–265)

What is the optimal increase in resting heart rate with low dose isoproterenol infusion for tilt-induced vasovagal response?

Summary: Isoproterenol is widely used as a provocative medium for vasovagal responses during tilt testing. Dose of isoproterenol infusion is generally titrated empirically by increase in resting heart rate before tilt up. To determine the optimal increase in resting heart rate with isoproterenol for tilt‐induced vasovagal responses, we studied 97 consecutive patients with unexplained syncope. After the end of a negative baseline tilt (80° for 30 min), the isoproterenol tilt was performed using one of two protocols: two‐stage isoproterenol‐tilt protocol, with doses of 0.01 and 0.02 μg/kg per min for 10 min each, or one‐stage isoproterenol‐tilt protocol, with a dose of 1 or 2 μg/min for 10 min. The resting heart rate increase was defined as a percentage increase in the resting heart rate after isoproterenol infusion, compared to the baseline heart rate before the tilt test. In 117 tilt procedures, 28 (93%) of the 30 positive responses occurred with a resting heart rate increase of ≥21%. With the resting heart rate increase of 60 and 100%, 18 (60%) and 27 (90%) positive responses were observed, respectively. In conclusion, the minimum resting heart rate increase of ≥21% was required to provoke a vasovagal response during subsequent isoproterenol‐tilt (80° for 10 min). Preferably, heart rate should be increased to 60‐100% by isoproterenol titration before tilting.

Runaway Pacemaker Caused by a Stuck Accelerometer

We report a case of runaway pacemaker with a ventricular pacing rate of 190 beats/min. The runaway occurred when the accelerometer became stuck due to the magnet application during VVIR pacing. Runaways in modern pacemakers are particularly rare, but they do still occur. The best solution for this phenomenon is generator replacement.

Efficacy and safety of controlled-release isosorbide-5-mononitrate for patients with stable effort angina pectoris: A randomized, double-blind, placebo-controlled study

A major limitation of the use of nitrates is the development of “nitrate tolerance”. The widely accepted treatment of preventing tolerance is to provide a period of “low nitrate interval”. Then, a new controlled‐release isosorbide‐5‐mononitrate (I‐CR) has been developed.