Improvements in 25 Years of Implantable Cardioverter Defibrillator Therapy

In 1980, Dr. Michel Mirowski and his team inserted the first implantable cardioverter defibrillator (ICD) in a patient. Initially, ICD therapy was not widely accepted, and many physicians actually considered this therapy unethical. Large secondary and primary prevention trials, demonstrating a beneficial effect of ICD therapy in selected patients not only on arrhythmic death but also on all-cause mortality, stimulated a rapid growth in the number of implants and increased patient’s and physician’s acceptance. Improvements in size and weight, arrhythmia discrimination capabilities, battery technology, shock waveform and output, monitoring capabilities and defibrillator electrode technology eventually resulted in the current large number of yearly implants. Today, almost 40 years after the conception of the ICD and 25 years after the first human implant, ICD therapy is the treatment of choice for patients at risk for life-threatening arrhythmias either as secondary or primary prevention. Furthermore, with the more recent addition of resynchronisation therapy to standard ICD therapy, it became possible to treat selected patients with advanced symptoms of heart failure and to lower the risk of sudden death

Environmental enrichment reduces signs of boredom in caged mink

Animals housed in impoverished cages are often labelled 'bored'. They have also been called 'apathetic' or 'depressed', particularly when profoundly inactive. However, these terms are rarely operationally defined and validated. As a negative state caused by under-stimulation, boredom should increase interest in stimuli of all kinds. Apathy (lack of interest), by contrast, should manifest as decreased interest in all stimuli, while anhedonia (loss of pleasure, a depressive symptom) should specifically decrease interest in normally rewarding stimuli. We tested the hypotheses that mink, a model carnivore, experience more boredom, depression-like apathy, or anhedonia in non-enriched (NE) cages than in complex, enriched (E) cages. We exposed 29 subjects (13 E, 16 NE) to ten stimuli categorized a priori as aversive (e.g. air puffs), rewarding (e.g. evoking chasing) or ambiguous/neutral (e.g. candles). Interest in stimuli was assessed via latencies to contact, contact durations, and durations oriented to stimuli. NE mink contacted all stimuli faster (P = 0.003) than E mink, and spent longer oriented to/in contact with them, albeit only significantly so for ambiguous ones (treatment*type P<0.013). With stimulus category removed from statistical models, interest in all stimuli was consistently higher among NE mink (P<0.0001 for all measures). NE mink also consumed more food rewards (P = 0.037). Finally, we investigated whether lying down while awake and stereotypic behaviour (both increased by NE housing) predicted these responses. Lying awake positively co-varied with certain measures of increased exploration. In contrast, stereotypic 'scrabbling' or locomotion (e.g. pacing) did not. Overall, NE mink showed no evidence of apathy or depression, but instead a heightened investigation of diverse stimuli consistent with boredom. This state was potentially indicated by spending much time lying still but awake (although this result requires replication). Boredom can thus be operationalized and assessed empirically in non-human animals. It can also be reduced by environmental enrichment

Atrioventricular and interventricular delay optimization in cardiac resynchronization therapy: physiological principles and overview of available methods

In this review, the physiological rationale for atrioventricular and interventricular delay optimization of cardiac resynchronization therapy is discussed including the influence of exercise and long-term cardiac resynchronization therapy. The broad spectrum of both invasive and non-invasive optimization methods is reviewed with critical appraisal of the literature. Although the spectrum of both invasive and non-invasive optimization methods is broad, no single method can be recommend for standard practice as large-scale studies using hard endpoints are lacking. Current efforts mainly investigate optimization during resting conditions; however, there is a need to develop automated algorithms to implement dynamic optimization in order to adapt to physiological alterations during exercise and after anatomical remodeling

The Lead Extractor's Toolbox: A Review Of Current Endovascular Pacemaker And ICD Lead Extraction Techniques

Recently introduced pacemaker leads float freely within the veins and myocardium. Later on, fibrous encapsulation of the lead develops 1. These adhesions not only occur at the lead tip but are commonly found anywhere along the whole length of the lead at sites where the lead is in contact with the vein or the myocardium 1,2,3,4. These adhesions hamper lead removal as tight scar tissue can withhold the leads during traction. This not only occurs at the level of the flings and tines of passive fixation leads but at any level of the lead body, especially at sites of unequal diameter for example electrodes and defibrillator coils. Further the lead tip is often larger than the lead body due to the fixation mechanism and adhering scar tissue and can become impacted on withdrawal in the narrow canal provided by the fibrous envelope. Force applied to leads is limited by the tensile strength of the insulation and conductor coils of the leads. They may severe with forceful traction, and denuded indwelling lead fragments have a higher incidence of thrombo-fibrotic complications and may maintain infection 5,6,7,8. Force is also limited by the impact of traction on the veins and myocardium. Unopposed traction can lead to invagination of the myocardium, myocardial rupture, arrhythmia, hypotension or avulsion of a tricuspid valve leaflet 9,10,11,12,13. Therefore, additional tools have been developed to assist in freeing the lead body from the adhesions as well as the lead tip from the myocardium, to prevent laceration of the myocardium and to provide enough room for the lead to be withdrawn whilst preventing disintegration of the lead. We describe the technical aspects of current endovascular techniques, the results, the complications and shortly discuss the indications