Sleep Disordered Breathing and Arrhythmia Burden in Pacemaker Recipients

Background: Sleep disordered breathing (SDB), a common condition among patients with permanent pacemaker (PM), is associated with greater incidence of cardiac arrhythmias. Scarce availability of sleep laboratories and the high costs of nocturnal‐attended polysomnography limit the routine screening of patients with PM for SDB. We investigated whether a novel PM that utilizes variations in transthoracic impedance to record the fluctuations in breathing pattern and minute ventilation could be used to screen patients for SDB. Methods: Twenty patients who underwent dual‐chamber PM implantation were studied. The Talent 3 DR PM (SORIN Group Italy S.r.l., Milan, Italy) calculates apnea‐hypopnea index (AHI) by computing minute ventilation signal derived from transthoracic impedance measurements. Within a month after PM implantation, an in‐home respiratory monitoring was performed to evaluate the accuracy of PM‐derived AHI. Patients were followed for mean ± standard deviation, 487 ± 166 days. The PM was checked at each follow‐up visit to retrieve the information about recurrent arrhythmias. Results: Eleven patients were diagnosed with SDB by an in‐home respiratory monitoring. An AHI derived from an in‐home respiratory monitoring was similar to pacemaker‐derived AHI (27 ± 14 vs 16 ± 13 events/hour, P = 0.15). The cumulative incidence of cardiac arrhythmias, including atrial fibrillation, extrasystolic beats, sustained and nonsustained ventricular tachycardia, and supraventricular tachycardia was similar in patients with and without SDB. Conclusion: SDB is highly prevalent in patients with permanent pacemaker. Screening for SDB with Talent 3 DR PM may facilitate diagnosis and treatment of SDB. (PACE 2010; 33:1462–1466)     

Uncommon complication of endoscopic ureterolithotripsy: The stone granuloma

Endoscopic management of urolithiasis is one of the commonest urological procedures today. It is usually safe and effective but one of the possible complications is ureteral obstruction. Stone fragmentation after ballistic lithotripsy and ureteral wall perforation could explain the mechanism responsible for this occurrence. We report a case of stone granuloma, occurring after a ballistic ureterolithotripsy.     

Permanent Mechanical Catheter Ablation of an Accessory Pathway in a Child

Permanent mechanical ablation of an accessory atrioventricular pathway was observed in an infant during intracavitary electrophysiological mapping. The persistent lack of preexcitation was confirmed during a 15-month follow-up period.     

Low Energy Intracardiac Cardioversion of Persistent Atrial Fibrillation

The aims of the study were to verify the efficacy and safety of low energy internal Cardioversion (LEIC) in patients with persistent at rial fibrillation (AF) and to identify the factors affecting the at rial defihrillation threshold (ADT). Forty-nine patients with persistent (lasting ≥ 10 days) AF underwent LEIC. In each patient, two 6 Fr custom-made catheters with large active surface areas were positioned in the coronary sinus (cathode) and the lateral right wall (anode), respectively, for shock delivery, and a tetrapolar lead was placed in the fight ventricular apex for R wave synchronization. Truncated, biphasic (3 ms+3 ms). exponential shocks were used, beginning at 50 V and increasing in steps of 50 V until sinus rhythm had been restored. Mild sedation (diazepam 5 mg IV) was administered to 12 patients. Sinus rhythm was restored in all the subjects with mean voltage and energy levels of 352.0 ± 80.3 V and 8.2 ± 3.4 J, respectively. The ADT in patients pretreated with amiodarone (6.4 ± 1.8 J) was lower than that of patients who had not received any antiarrhythmic drugs (9.2 ± 3.7) (P = 0.04). No ventricular arrhythmias were induced by any of the atrial shocks, and no other complications were observed. During a mean follow-up of 162.9 ± 58.7 days, AF recurred in 21 (43%) patients; 71% of these occurred in the first week after Cardioversion. LEIC is effective in restoring sinus rhythm in patients with persistent AF. The technique seems to be safe and does not require general anesthesia or, in most cases, sedation. Patients pretreated with amiodarone have lower ADTs.     

Modulated Parasystole Complicating Permanent Ventricular Pacing: The Different Influence of Spontaneous and Paced Impulses Upon the Parasystolic Rhythm

A case of modulated ventricular parasystole observed in a patient with a VVIM pacemaker is reported. Analysis reveals that the electronic influence (modulation) effected upon the parasystolic focus by the sinus impulses is different from that exerted by the paced impulses. Furthermore, fusion beats reflect an intermediate modulating effect according to the prevalence of the sinus or the paced wavefront.     

Ventricular Parasystole: A Chronobiologic Study

Previous works have reported circadian rhythms for several cardiovascular parameters. A chronobiologic rhythm is characterized by: mesor (a rhythm-determined average), amplitude (half difference between the highest and lowest values), and acrophase (timing of high point in degrees and/or in hours) along with 95% confidence limits. We performed 24-hour ECG Holler monitoring in seven patients (mean age, 50.6 years) with ventricular parasystole (VP) in order to determine whether the chronotropic activity of parasystolic foci has a circadian rhythm similar to that of the sinus node. For each Holter recording parasystolic rates (PRs) and heart rates (HRs) were calculated every hour. Furthermore, a mean hourly PR and a mean hourly HR were calculated from the hourly PRs and HRs of the patients. The statistic chronobiologic analysis was done by single and mean cosinor methods. Correlation between mean hourly PR and HR was evaluated by Pearson's V coefficient. A statistically significant rhythm (P < 0.05) was found for the single and mean rhythms both of HR and PR. In our patients, HR had acrophase at 1.27 P.M., mesor at 73.28 beats/min, and amplitude at 9.53 beats/min, whereas PR had acrophase at 1.42 P.M., mesor al 38.31 beats/min, and amplitude at 3.64 beats/ min. Chronobiological data and the high direct correlation between mean hourly HRs and mean hourly PRs (r = 0.96, P < 0.001) indicate a similar circadian variability of the chronotropic activity of sinus nodes and parasystolic foci. Although several hypotheses can be made, responsiveness of parasystolic foci to circadian variations of the autonomic nervous system tone (sympathetic and/or vagal) and/or circulating substances (particularly catecholamines) seems the more probable one for explaining our findings.     

Late Sensing Due to Extremely Delayed Right Ventricular Activation in Arrhythmogenic Right Ventricular Cardiomyopathy

A patient with arrhythmogenic right ventricular cardiomyopathy/dysplasia, implanted with a dual-chamber implantable cardioverter-defibrillator programmed in DDD mode, showed an unexpected ventricular sensing dysfunction: despite a very long (320 ms) programmed atrioventricular (AV) interval, ventricular stimuli were delivered in the ST segment after each spontaneous conducted QRS complex. This suggested the presence of ventricular undersensing. When, however, the system was programmed in VVI mode, spontaneous QRS complexes were normally sensed, although electrogram (ECM) analysis revealed that ventricular sensing occurred 160 ms after the beginning of QRS complex. A new ventricular lead was then implanted in the outflow tract of the right ventricle, resulting in normal ventricular sensing function. At the time of intervention, the amplitude of the spontaneous ventricular signal recorded from the old ventricular lead was 2.8 mV. In this patient, no true undersensing occurred although ventricular stimuli were delivered 140 ms after the beginning of spontaneous QRS complexes when the system was in DDD mode: the cause of the apparent pacemaker malfunction was the extremely prolonged ventricular depolarization. Due to fibrofatty muscle replacement, the depolarization wavefront reached the ventricular muscle surrounding the pacemaker lead with such a delay that at the end of the programmed sensed AV interval (320 ms) the ventricular EGM had not yet attained the sensing threshold. This apparent undersensing should, thus, be defined as "late sensing."