1,721,058 research outputs found
Inappropriate implantable cardioverter-defibrillator therapy during exercise: What is the mechanism?
No full textFar-field oversensing of atrial signals: an unusual cause for very short V-V intervals and inappropriate implantable cardioverter defibrillator therapy
No full textUnusual cause for an increase of the sensing integrity counter in a patient with inappropriate implantable cardioverter-defibrittator therapy
No full textWe describe the case of a patient who presented with multiple implantable cardioverter-defibrillator (ICD) shock discharges 12 months after device implantation. Upon device interrogation, intermittent oversensing of electrical noise and potential ICD lead failure were suggested by a significant increase in the sensing integrity counter (SIC), a cumulative count of very short ventricular sensed intervals. Analysis of stored episodes, however, revealed that inappropriate ICD therapy had been caused by intermittent T-wave oversensing (TWO), and that the increase of the SIC resulted from the coincidence of TWO and premature ventricular complexes (PVCs). T-wave oversensing resolved and the SIC did not increase any more during follow-up after adjustment of ventricular sensitivity. The coincidence of TWO and PVCs should therefore be considered as an uncommon cause for short ventricular sensed intervals in ICD patients presenting with a suspect increase in the SIC
Takotsubo cardiomyopathy with an unusual pattern of regional left ventricular wall motion abnormalities
No full textSirs: Takotsubo cardiomyopathy, first described in the early 1990s in Japan [ 3], is characterized by a transient dysfunction of the left ventricle with initially, often severely reduced ejection fraction [ 4, 5]. In many patients, it is associated with electrocardiographic changes, elevated myocardial biomarkers and symptoms like chest pain and dyspnoea [ 7]. Thereby, it often mimics an acute coronary syndrome ( ACS) despite angiographic absence of obstructive coronary artery disease. In a recent review of 14 studies with a total of 286 patients [ 4], Takotsubo cardiomyopathy had a prevalence of up to 2.2% in patients with ST- segment elevation ACS. It occurred mostly in women ( 89%) older than 50 years and was often preceded by emotional ( 27%) or physical stress ( 38%). Sympathetic hyperactivity has therefore been proposed as an underlying mechanism [ 8], but the precise pathophysiology is still unkown. Takotsubo cardiomyopathy has also been described as transient apical ballooning syndrome due to the typical pattern of regional wall motion disturbances of the left ventricle. Most patients demonstrate akinesis or dyskinesis of the apex and the adjacent midventricular walls with preserved or hyperkinetic contractile function of the basal left ventricular segments, resembling at end- systole the Tako- tsubo, a Japanese octopus trap with a round bottom and a narrow neck. However, it has also been associated with other patterns of regional left ventricular contractile dysfunction [ 1, 2]. Here we describe a patient with a typical history but an atypical manifestation of Takotsubo cardiomyopathy
Supraventricular tachycardia with 'A-A-V' response upon ventricular entrainment and transient 2:1 AV conduction block
No full text1-Year performance of a defibrillation lead with a small electrode surface for high impedance pacing: A randomized, controlled study
No full textA small electrode surface reduces pacing current drain and can extend generator longevity. The study evaluated the performance of a tined, quadripolar defibrillation lead (model 6944) that has a small-surfaced, steroid-eluting electrode tip for high impedance pacing. In a prospective, controlled study, 34 patients with conventional ICD indications were randomized one to one to receive the high impedance model 6944 or a tined defibrillation lead with a conventional sized, steroid-eluting electrode tip model 6942. Lead Performance was evaluated at implant, prior to hospital discharge, and 1, 3, 6, and 12 months thereafter. Baseline characteristics did not differ significantly between patients implanted with lead model 6942 (n = 16) or model 6944 (n = 17). One patient randomized to receive the model 6942 was excluded from the study and was implanted with an active-fixation lead after stable lead positioning was neither possible with the 6942 nor with the 6944 electrode. No other lead related adverse events were observed. At implant, there were no significant differences between pacing thresholds, sensing performance, defibrillation impedances, and defibrillation thresholds in both groups, but pacing impedance of the model 6944 (988.6 +/- 217.7 Omega) was approximately twice as high as in the model 6942 (431.7 +/- 83.7 Omega; P < 0.0001). This difference remained highly significant throughout the observation period of 12 months, while R wave amplitudes and pacing thresholds remained equal in both lead models. The use of a tined defibrillation lead with a small, steroid-eluting electrode tip appears safe and results in a high pacing impedance without compromising system performance
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