Acute complications of electrophysiology and pacing procedures: identification and management.

Non-pharmacologic interventional techniques for treatment and management of almost all cardiac arrhythmias have greatly expanded over the past decade. These newer interventional electrophysiologic techniques continue to demonstrate increasing success at achieving their targeted goals, and enhancing the patient's quality of life. However, like all interventional procedures, complications may result. In this article we provide the reader with an overview of the more common and significant adverse events that may follow electrophysiologic and pacing procedures, and how best to recognize and manage these complications. After providing the reader with an overview of the complications inherent to all electrophysiologic procedures, we will detail the adverse events intrinsic to specific therapeutic electrophysiologic interventions (DC cardioversion, pharmacologic-based cardioversion, antitachycardia pacing, and ablation of specific arrhythmias). In the last part of the review, we will delineate complications associated with pacing procedures (pacemaker and defibrillator implantation, biventricular pacing and pacing lead extraction).

New insights into the mechanism of neurally mediated syncope.

OBJECTIVE: To determine the role of the cerebral cortex in neurally mediated syncope, the electroencephalograms (EEG) of patients recorded during head up tilt table test were analysed. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: 18 patients with syncope or near syncope underwent head up tilt table test with simultaneous ECG and EEG monitoring. METHODS: Standard 70 degrees tilt table test was done with simultaneous ECG and EEG monitoring. EEG waveforms were analysed by both visual inspection and spectral analysis. RESULTS: 6 of 18 patients (33%) had a positive tilt table test. Before syncope slow waves increased in patients with a positive test. In addition, five of six tilt positive patients (83%) had slow wave activity that lateralised to the left side of the brain (mean (SD) 822 (724) v 172 (215) micro V(2), p < 0.05), while none of the tilt negative patients exhibited lateralisation (24 (15) v 26 (19) micro V(2), NS). Spectral analysis showed that the lateralisation occurred in the delta frequency. The lateralisation preceded the event by 5-56 seconds (18 (21) seconds). CONCLUSIONS: EEG activity lateralises to the left hemisphere of the brain before syncope. The lateralisation precedes syncope and is associated with the onset of bradycardia, hypotension, and clinical symptoms. These findings suggest that the central nervous system may have a role in neurally mediated syncope.

The eosinophilic response and haematological recovery after treatment for Plasmodium falciparum malaria.

To examine a possible relationship between the immune response and haematological recovery after acute falciparum malaria, we followed peripheral blood eosinophil counts and haemoglobin concentrations for 4 weeks after starting effective treatment in 70 adult Thai patients. Eosinophils are induced by Th-2 cytokines as well as other stimuli. Eosinophil counts were elevated in only 8 (11%) of the subjects at presentation, but were increased in 65 (93%) by day 7. Eosinophil counts then decreased markedly by day 14, followed by a second increase until day 28. A significant positive correlation was found between peak eosinophil counts on day 7 and the haemoglobin concentration on day 28, both in 16 subjects without stool parasites (r = 0.65, P = 0.006) and in 54 patients with stool parasites (r = 0.32; P = 0.0019). These results suggest that a robust eosinophilic response shortly after completing antimalarial therapy predicts a good recovery from malaria-associated anaemia.