Desynchronization in a cardiac resynchronization device induced by a pacemaker-mediated tachycardia algorithm.

This report describes the occurrence of desynchronization in a patient with a cardiac resynchronization device programmed with an active pacemaker-mediated tachycardia algorithm based on AV delay modification. Desynchronization was precipitated by sinus tachycardia and the abrupt return of the prevailing AV delay that followed the periodic prolongation of the AV delay mandated by activity of the algorithm. Prevention of desynchronization in this setting requires programming a right ventricular upper rate interval longer than the sum of the programmed ventriculoatrial interval and the AV delay.

Comparison of diagnostic value using a small, single channel, P-wave centric sternal ECG monitoring patch with a standard 3-lead Holter system over 24 hours.

BACKGROUND: To compare simultaneous recordings from an external patch system specifically designed to ensure better P-wave recordings and standard Holter monitor to determine diagnostic efficacy. Holter monitors are a mainstay of clinical practice, but are cumbersome to access and wear and P-wave signal quality is frequently inadequate. METHODS: This study compared the diagnostic efficacy of the P-wave centric electrocardiogram (ECG) patch (Carnation Ambulatory Monitor) to standard 3-channel (leads V1, II, and V5) Holter monitor (Northeast Monitoring, Maynard, MA). Patients were referred to a hospital Holter clinic for standard clinical indications. Each patient wore both devices simultaneously and served as their own control. Holter and Patch reports were read in a blinded fashion by experienced electrophysiologists unaware of the findings in the other corresponding ECG recording. All patients, technicians, and physicians completed a questionnaire on comfort and ease of use, and potential complications. RESULTS: In all 50 patients, the P-wave centric patch recording system identified rhythms in 23 patients (46%) that altered management, compared to 6 Holter patients (12%), P<.001. The patch ECG intervals PR, QRS and QT correlated well with the Holter ECG intervals having correlation coefficients of 0.93, 0.86, and 0.94, respectively. Finally, 48 patients (96%) preferred wearing the patch monitor. CONCLUSIONS: A single-channel ambulatory patch ECG monitor, designed specifically to ensure that the P-wave component of the ECG be visible, resulted in a significantly improved rhythm diagnosis and avoided inaccurate diagnoses made by the standard 3-channel Holter monitor.

Adherence to the current guidelines for bradycardic pacing in the octogenarian and nonagenarian populations.

AIM: A significant proportion of single-chamber ventricular pacemakers are implanted in octogenarian and nonagenarian patients. We aimed to assess whether the current pacing guideline is adhered for these populations. METHODS: We retrospectively identified patients ≥80 years of age, who received their first pacemaker from July 2010 to June 2013. RESULTS: A total of 356 patients were identified. Mean age was 86.1 years and 82.6 years for single and dual-chamber pacemakers respectively (p<0.05). Total procedure-related complications occurred in 9.5% and were comparable between both groups (p=0.08). At the time of implantation, 185 patients who received single-chamber pacemaker were in sinus rhythm (52%). They were older (86.2±4.3 vs 82.6±2.9, p<0.05), more likely to have ischaemic and valvular heart disease (68 vs 27, p= 0.02 and 22 vs 13, p=0.01, respectively), and cognitive impairment (34 vs 0, p= 0.001). They were also more likely to be discharged to a residential care facility (17 vs 1, p<0.01). CONCLUSION: The utility of dual-chamber pacemaker in this age group remains below expectation and did not comply with current cardiac pacing guidelines. The presence of older age, multiple co-morbidities, cognitive impairment and residential care on discharge likely influenced the type of device implanted.

Digital implantable loop recorders in the investigation of syncope in children: benefits and limitations.

BACKGROUND: Conventional diagnostic methods for detecting arrhythmogenic causes of syncope in children are poor. Digital implantable loop recorders are of proven value in adults. OBJECTIVES: The purpose of this study was to evaluate digital implantable loop recorders in the investigation of syncope in children. METHODS: We reviewed the clinical and technical records of 18 consecutive patients (6 female and 12 male; age