Dual-Chamber Pacing for Hypertrophic Cardiomyopathy: A Randomized, Double-Blind, Crossover Trial

AbstractObjectives. In a double-blind, randomized, crossover trial we sought to evaluate the effect of dual-chamber pacing in patients with severe symptoms of hypertrophic obstructive cardiomyopathy.Background. Recently, several cohort trials showed that implantation of a dual-chamber pacemaker in patients with severely symptomatic hypertrophic obstructive cardiomyopathy can relieve symptoms and decrease the severity of the left ventricular outflow tract gradient. However, the outcome of dual-chamber pacing has not been compared with that of standard therapy in a randomized, double-blind trial.Methods. Twenty-one patients with severely symptomatic hypertrophic obstructive cardiomyopathy were entered into this trial after baseline studies consisting of Minnesota quality-of-life assessment, two-dimensional and Doppler echocardiography and cardiopulmonary exercise tests. Nineteen patients completed the protocol and underwent double-blind randomization to either DDD pacing for 3 months followed by backup AAI pacing for 3 months, or the same study arms in reverse order.Results. Left ventricular outflow tract gradient decreased significantly to 55 ± 38 mm Hg after DDD pacing compared with the baseline gradient of 76 ± 61 mm Hg (p < 0.05) and the gradient of 83 ± 59 mm Hg after AAI pacing (p < 0.05). Quality-of-life score and exercise duration were significantly improved from the baseline state after the DDD arm but were not significantly different between the DDD arm and the backup AAI arm. Peak oxygen consumption did not significantly differ among the three periods. Overall, 63% of patients had symptomatic improvement during the DDD arm, but 42% also had symptomatic improvement during the AAI backup arm. In addition, 31% had no change and 5% had deterioration of symptoms during the DDD pacing arm.Conclusions. Dual-chamber pacing may relieve symptoms and decrease gradient in patients with hypertrophic obstructive cardiomyopathy. In some patients, however, symptoms do not change or even become worse with dual-chamber pacing. Subjective symptomatic improvement can also occur from implantation of the pacemaker without its hemodynamic benefit, suggesting the role of a placebo effect. Long-term follow-up of a large number of patients in randomized trials is necessary before dual-chamber pacing can be recommended for all patients with severely symptomatic hypertrophic obstructive cardiomyopathy.(J Am Coll Cardiol 1997;29:435–41

Timing and Tempo of Early and Successive Adaptive Radiations in Macaronesia

The flora of Macaronesia, which encompasses five Atlantic archipelagos (Azores, Canaries, Madeira, Cape Verde, and Salvage), is exceptionally rich and diverse

Shift of the western boundary of the distribution area of Micromeria cristata (Hampe) Griseb. and Steptorhamphus tuberosus (Jacq.) Grossh.

During field investigations of Mt Rumija, two new taxa for the flora of Montenegro were recorded: Micromeria cristata (Hampe) Griseb. and Steptorhamphus tuberosus (Jacq.) Grossh. From the phytogeographic point of view these data indicate a change in the distribution area of both taxa, which have shifted to the west. Ashort overview of the taxonomic treatment of both genera is given

Scared Straight and Other Juvenile Awareness Programs for Preventing Juvenile Delinquency: A Systematic Review

Programs like ‘Scared Straight’ involve organized visits to prison facilities by juvenile delinquents or children at risk for becoming delinquent. The programs are designed to deter participants from future offending by providing first-hand observations of prison life and interaction with adult inmates. Results of this review indicate that not only does it fail to deter crime but it actually leads to more offending behavior. Government officials permitting this program need to adopt rigorous evaluation to ensure that they are not causing more harm to the very citizens they pledge to protect

Toward conservational anthropology: addressing anthropocentric bias in anthropology

Anthropological literature addressing conservation and development often blames 'conservationists' as being neo-imperialist in their attempts to institute limits to commercial activities by imposing their post-materialist eco-ideology. The author argues that this view of conservationists is ironic in light of the fact that the very notion of 'development' is arguably an imposition of the (Western) elites. The anthropocentric bias in anthropology also permeates constructivist ethnographies of human-animal 'interactions,' which tend to emphasize the socio-cultural complexity and interconnectivity rather than the unequal and often extractive nature of this 'interaction.' Anthropocentrism is argued to be counteractive to reconciling conservationists' efforts at environmental protection with the traditional ontologies of the interdependency of human-nature relationship

Probing the structure of diacetylenic phospholipid tubules with fluorescent lipophiles.

Novel lipid structures called tubules can be prepared from diacetylenic phospholipids. We have prepared fluorescent tubules from mixtures of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphatidylcholine and 1 mol% fluorescent lipophiles to study the characteristics of the tubule lipid matrix. We have found that once formed, tubules do not incorporate lipophiles from the aqueous phase into their lipid matrix. The spectral characteristics of the fluorophore laurodan in tubules, and the lack of diffusion of N-nitrobenzoxydiazol phosphatidylethanolamine in tubules, have allowed us to characterize the microenvironment of these structures as being extremely rigid and tightly packed. Despite their rigid characteristic, tubules are formed from intact liposomes as demonstrated by the formation of doubly labeled tubules from two populations of liposomes, each of which contained a different nonexchangeable fluorescent lipophile

Memory for Implied Versus Directly Stated Advertising Claims

An experiment tested young adults\u27 memory for advertising slogans that either stated a strong claim directly or only implied the same claim by stating it in a much weaker form. Several advertising slogans were inserted into a story. There were two versions of each slogan, asserted and implied. The asserted version made a claim very directly and strongly (e.g.Alka‐Seltzer stops common aches). The implied version only suggested the stronger claim (e.g.Alka‐Seltzer helps lessen common aches). Subjects read the story, which contained one of the two versions of each ad. After subjects finished reading the story, they were asked to recall all the brands and products. Then they performed a multiple choice task testing memory for the content of the advertising claims. While results showed no difference on the recall task, subjects on the multiple choice task frequently falsely recognized implied claims as asserted but seldom the reverse. Although they correctly recognized more asserted than implied claims, they were more confident in their correct memory for the implied claims. Results were applied to the problem of deceptive advertising. Copyright © 1989 Wiley Subscription Services, Inc., A Wiley Compan