Cardiac resynchronization therapy in the real world: comparison with the COMPANION study.

BACKGROUND: Several clinical trials have confirmed that cardiac resynchronization therapy (CRT) improves outcomes in well defined patient populations. It is uncertain, however, whether outcomes are similar in real-world clinical settings. This study compared outcomes after CRT with defibrillator (CRT-D) in a large real-world private-practice cardiology setting with those in the COMPANION multicenter trial. METHODS AND RESULTS: A total of 429 consecutive patients who received CRT-D for standard indications (group 1) were retrospectively compared with the 595 patients (group 3) in the COMPANION CRT-D cohort regarding survival and survival free of cardiovascular (CV) hospitalization. A subgroup of the group 1 patients who met the COMPANION entrance criteria (group 2) was also compared with the COMPANION cohort (group 3) both with and without propensity-matching statistical analysis. Survival and survival free of CV hospitalization was better in group 1 than in group 3. Survival in group 2 with and without propensity matching was similar to group 3. However, survival free of CV hospitalization was better in the real-world patients (group 2) even after adjustment for differences in baseline characteristics. CONCLUSIONS: Survival and CV hospitalization outcomes in a real-world clinical setting are as good as, or better than, those demonstrated in the COMPANION research trial.

Pacemaker optimization in nonresponders to cardiac resynchronization therapy: left ventricular pacing as an available option.

BACKGROUND: Echocardiographic (ECHO)-guided pacemaker optimization (PMO) in cardiac resynchronization therapy (CRT) nonresponders acutely improves left ventricular (LV) function. However, the chronic results of LV pacing in this group are less understood. METHODS: We retrospectively studied 28 CRT nonresponders optimized based on ECHO to LV pacing and compared them to 28 age- and gender-matched patients optimized to biventricular (BiV) pacing. ECHOs with tissue Doppler imaging assessed LV hemodynamics before, immediately after, and 29 ± 16 months after PMO. Also, 56 age- and gender-matched CRT responders were included for comparison of clinical outcomes. RESULTS: PMO resulted in acute improvements in longitudinal LV systolic function and several measures of dyssynchrony, with greater improvements in the LV paced group. Chronic improvements in ejection fraction (EF) (3.2 ± 7.7%), and left ventricle end-systolic volume (LVESV) (-11 ± 36 mL) and one dyssynchrony measure were seen in the combined group. Chronically, both LV and BiV paced patients improved some measures of systolic function and dyssynchrony although response varied between the groups. Survival at 3.5 years was similar (P = 0.973) between the PMO (58%) and nonoptimized groups (58%) but survival free of cardiovascular hospitalization was significantly (P = 0.037) better in the nonoptimized group. CONCLUSIONS: CRT nonresponders undergoing PMO to either LV or BiV pacing have acute improvements in longitudinal systolic function and some measures of dyssynchrony. Some benefits are sustained chronically, with improvements in EF, LVESV, and dyssynchrony. A strategy of ECHO-guided PMO results in survival for CRT nonresponders similar to that of CRT patients not referred for PMO.

Rejecting salient distractors: Generalization from experience.

Distraction impairs performance of many important, everyday tasks. Attentional control limits distraction by preferentially selecting important items for limited-capacity cognitive operations. Research in attentional control has typically investigated the degree to which selection of items is stimulus-driven versus goal-driven. Recent work finds that when observers initially learn a task, the selection is based on stimulus-driven factors, but through experience, goal-driven factors have an increasing influence. The modulation of selection by goals has been studied within the paradigm of learned distractor rejection, in which experience over a sequence of trials enables individuals eventually to ignore a perceptually salient distractor. The experiments presented examine whether observers can generalize learned distractor rejection to novel distractors. Observers searched for a target and ignored a salient color-singleton distractor that appeared in half of the trials. In Experiment 1, observers who learned distractor rejection in a variable environment rejected a novel distractor more effectively than observers who learned distractor rejection in a less variable, homogeneous environment, demonstrating that variable, heterogeneous stimulus environments encourage generalizable learned distractor rejection. Experiments 2 and 3 investigated the time course of learned distractor rejection across the experiment and found that after experiencing four color-singleton distractors in different blocks, observers could effectively reject subsequent novel color-singleton distractors. These results suggest that the optimization of attentional control to the task environment can be interpreted as a form of learning, demonstrating experience's critical role in attentional control.

Location-specific effects of attention during visual short-term memory maintenance.

Recent neuroimaging studies suggest that early sensory areas such as area V1 are recruited to actively maintain a selected feature of the item held in visual short-term memory (VSTM). These findings raise the possibility that visual attention operates in similar manners across perceptual and memory representations to a certain extent, despite memory-level and perception-level selections are functionally dissociable. If VSTM operates by retaining "reasonable copies" of scenes constructed during sensory processing (Serences et al., 2009, p. 207, the sensory recruitment hypothesis), then it is possible that selective attention can be guided by both exogenous (peripheral) and endogenous (central) cues during VSTM maintenance. Yet, the results from the previous studies that examined this issue are inconsistent. In the present study, we investigated whether attention can be directed to a specific item's location represented in VSTM with the exogenous cue in a well-controlled setting. The results from the four experiments suggest that, as observed with the endogenous cue, the exogenous cue can efficiently guide selective attention during VSTM maintenance. The finding is not only consistent with the sensory recruitment hypothesis but also validates the legitimacy of the exogenous cue use in past and future studies.

Visual statistical learning can drive object-based attentional selection.

Recent work on statistical learning has demonstrated that environmental regularities can influence aspects of perception, such as familiarity judgments. Here, we ask if statistical co-occurrences accumulated from visual statistical learning could form objects that serve as the units of attention (i.e., object-based attention). Experiment 1 demonstrated that, after observers first viewed pairs of shapes that co-occurred in particular spatial relationships, they were able to recognize the co-occurring pairs, and were faster to discriminate two targets when they appeared within a learned pair ("object") than when the targets appeared between learned pairs, demonstrating an equivalent of an object-based attention effect. Experiment 2 replicated the results of Experiment 1 using a different set of shape pairs, and revealed a negative association between the attention effect and familiarity judgments of the co-occurred pairs. Experiment 3 reports three control experiments that validated the task procedure and ruled out alternative accounts.

Prolonged disengagement from distractors near the hands.

Because items near our hands are often more important than items far from our hands, the brain processes visual items near our hands differently than items far from our hands. Multiple experiments have attributed this processing difference to spatial attention, but the exact mechanism behind how spatial attention near our hands changes is still under investigation. The current experiments sought to differentiate between two of the proposed mechanisms: a prioritization of the space near the hands and a prolonged disengagement of spatial attention near the hands. To differentiate between these two accounts, we used the additional singleton paradigm in which observers searched for a shape singleton among homogenously shaped distractors. On half the trials, one of the distractors was a different color. Both the prioritization and disengagement accounts predict differently colored distractors near the hands will slow target responses more than differently colored distractors far from the hands, but the prioritization account also predicts faster responses to targets near the hands than far from the hands. The disengagement account does not make this prediction, because attention does not need to be disengaged when the target appears near the hand. We found support for the disengagement account: Salient distractors near the hands slowed responses more than those far from the hands, yet observers did not respond faster to targets near the hands.

Experience-dependent attentional tuning of distractor rejection.

Irrelevant salient distractors often capture attention, but given a sufficiently specific search template, these salient items no longer capture attention. In the present experiments, we investigated whether specific target templates are sufficient to resist capture, or whether experience with the salient distractors is also necessary. To test this hypothesis, observers completed four blocks of trials, each with a different-colored irrelevant singleton present on half of the trials. Color singletons captured attention early within a block, but after sufficient experience with the irrelevant singletons, those singletons no longer captured attention in the second halves of the blocks. This result suggests that to resist capture, a specific target template must be accompanied by experience-dependent attentional tuning to distractor properties.