The relationship between HbA(1c) and GA% differs in diabetic patients with end-stage renal disease who perform either PD or HD compared to those without nephropathy. HbA(1c) significantly underestimates glycemic control in peritoneal and hemodialysis patients relative to GA%.

A 43-year-old man with dilated cardiomyopathy and atrial fibrillation underwent radiofrequency ablation of the His bundle with implantation of a ventricular pacemaker. After the procedure, a telemetry recording revealed a spike without a captured QRS complex followed by a 3 1 ⁄2 -second pacemaker pause (Fig 1). In this situation what is the most likely pacemaker malfunction: (1) output failure; (2) failure to capture (exit block); (3) oversensing of atrial fibrillation waves or myopotentials; (4) electromagnetic interference; or (5) none of the above?The pacemaker pause is the result of a 9-beat run of rapid, slightly irregular ventricular tachycardia that is nearly isoelectric in the monitored lead. The pacemaker is functioning normally. A clue to the diagnosis of ventricular tachycardia lies with the simultaneous occurrence of pacemaker non-capture and transient pacemaker inhibition. None of the listed causes of pacemaker malfunction could account for both. Output failure in a permanent pacemaker is a serious but rare abnormality, unless it is due to pacer suppression. Inhibition due to atrial fibrillation waves, myopotentials, or electromagnetic interference, however, would not explain why the third spike was actually delivered but did not result in capture. A run of ventricular tachycardia, on the other hand, in which the first beat was inscribed just before the third pacemaker spike, would adequately explain why one pacemaker impulse failed to stimulate the ventricle and subsequent pacemaker activity was transiently suppressed. 1,2 It is important to note not only the absence of baseline undulations in electrocardiogram segments preceding and following the pause but also the appropriate resumption of ventricular pacing about 800 ms after the onset of the last QRS complex of the ventricular tachycardia. REFERENCES1. Garson A. Stepwise approach to the unknown pacemaker ECG.