***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background —Recovery of function is possible in patients with ischemic cardiomyopathy when left ventricular dysfunction is caused by stunning or hibernation . It is plausible that recovery of function after revascularization may take a longer time in hibernating myocardium compared with stunned myocardium . Accordingly , the time courses of functional recovery in hibernating and stunned myocardium were compared . Methods and Results — Patients ( n=26 ) with ischemic cardiomyopathy undergoing surgical revascularization  were studied ; regional perfusion ( resting 201Tl single-photon emission CT ) , glucose utilization ( 18F-2-deoxyglucose single-photon emission CT ) , and contractile function ( 2D echocardiography ) were assessed before revascularization . Dysfunctional segments with normal perfusion/glucose utilization were considered to be stunned , and dysfunctional segments with reduced perfusion/preserved glucose utilization were considered to be hibernating . Contractile function was reevaluated 3 months ( early ) and 14 months ( late ) after revascularization . Of the 266 dysfunctional segments , 57 ( 22 % ) were stunned , 62 ( 23 % ) were hibernating , and 147 ( 55 % ) were scar tissue . In stunned myocardium , contractile function improved significantly at 3 months , without further improvement at 14 months ; 61 % of the stunned segments improved at 3 months , and 9 % improved at 14 months . In hibernating myocardium , contractile function improved at 3 months , with a further improvement at 14 months ; 31 % of the hibernating segments improved at 3 months , and 61 % showed ( additional ) recovery at 14 months . Conclusions —Stunned myocardium is likely to demonstrate early recovery of function , whereas hibernating myocardium may take a longer time to ( fully ) recover in function after revascularization BACKGROUND In 10 % to 15 % of patients with ST-segment elevation myocardial infa rct ion ( STEMI ) , concurrent coronary chronic total occlusion ( CTO ) in a non-infa rct -related artery is present and is associated with increased morbidity and mortality . OBJECTIVES The EXPLORE ( Evaluating Xience and Left Ventricular Function in Percutaneous Coronary Intervention on Occlusions After ST-Elevation Myocardial Infa rct ion ) trial evaluated whether patients with STEMI and concurrent CTO in a non-infa rct -related artery benefit from additional percutaneous coronary intervention ( PCI ) of CTO shortly after primary PCI . METHODS From November 2007 through April 2015 , we enrolled 304 patients with acute STEMI who underwent primary PCI and had concurrent CTO in 14 centers in Europe and Canada . A total of 150 patients were r and omly assigned to early PCI of the CTO ( CTO PCI ) , and 154 patients were assigned to conservative treatment without PCI of the CTO ( no CTO PCI ) . Primary outcomes were left ventricular ejection fraction ( LVEF ) and left ventricular end diastolic volume ( LVEDV ) on cardiac magnetic resonance imaging after 4 months . RESULTS The investigator-reported procedural success rate in the CTO PCI arm of the trial was 77 % , and the adjudicated success rate was 73 % . At 4 months , mean LVEF did not differ between the 2 groups ( 44.1 ± 12.2 % vs. 44.8 ± 11.9 % , respectively ; p = 0.60 ) . Mean LVEDV at 4 months was 215.6 ± 62.5 ml in the CTO PCI arm versus 212.8 ± 60.3 ml in the no-CTO PCI arm ( p = 0.70 ) . Subgroup analysis revealed that patients with CTO located in the left anterior descending coronary artery who were r and omized to the CTO PCI strategy had significantly higher LVEF compared with patients r and omized to the no-CTO PCI strategy ( 47.2 ± 12.3 % vs. 40.4 ± 11.9 % ; p = 0.02 ) . There were no differences in terms of 4-month major adverse coronary events ( 5.4 % vs. 2.6 % ; p = 0.25 ) . CONCLUSIONS Additional CTO PCI within 1 week after primary PCI for STEMI was feasible and safe . In patients with STEMI and concurrent CTO , we did not find an overall benefit for CTO PCI in terms of LVEF or LVEDV . The finding that early CTO PCI in the left anterior descending coronary artery subgroup was beneficial warrants further investigation . ( Evaluating Xience and Left Ventricular Function in Percutaneous Coronary Intervention on Occlusions After ST-Segment Elevation Myocardial Infa rct ion ; NTR1108 ) OBJECTIVES This study explored whether cardiac magnetic resonance ( CMR ) could help select patients who could benefit from revascularization by identifying inducible myocardial ischemia and viability in the perfusion territory of the artery with chronic total occlusion ( CTO ) . BACKGROUND The benefit of revascularization using percutaneous coronary intervention ( PCI ) in CTO is controversial . CMR offers incomparable left ventricular ( LV ) systolic function assessment in addition to potent ischemic burden quantification and reliable myocardial viability analysis . Whether CMR guided CTO revascularization would be helpful to such patients has not yet been explored fully . METHODS A prospect i ve study of 50 consecutive CTO patients was conducted . Of 50 patients undergoing baseline stress CMR  , 32 ( 64 % ) were selected for recanalization based on the presence of significant inducible perfusion deficit and myocardial viability within the CTO arterial territory . Patients were rescanned 3 months after successful CTO recanalization . RESULTS At baseline , myocardial perfusion reserve ( MPR ) in the CTO territory was significantly reduced compared with the remote region ( 1.8 ± 0.72 vs. 2.2 ± 0.7 ; p = 0.01 ) . MPR in the CTO region improved significantly after PCI ( to 2.3 ± 0.9 ; p = 0.02 vs. baseline ) with complete or near-complete resolution of CTO related perfusion defect in 90 % of patients . Remote territory MPR was unchanged after PCI ( 2.5 ± 1.2 ; p = NS vs. baseline ) . The LV ejection fraction increased from 63 ± 13 % to 67 ± 12 % ( p < 0.0001 ) and end-systolic volume decreased from 65 ± 38 to 56 ± 38 ml ( p < 0.001 ) 3 months after CTO PCI . Importantly , despite minimal post-procedural infa rct ion due to distal embolization and side branch occlusion in 8 of 32 patients ( 25 % ) , the total Seattle Angina Question naire score improved from a median of 54 ( range 45 to 74 ) at baseline to 89 ( range 77 to 98 ) after CTO recanalization ( p < 0.0001 ) . CONCLUSIONS In this small group of patients showing CMR evidence of significant myocardial inducible perfusion defect and viability , CTO recanalization reduces ischemic burden , favors reverse remodeling , and ameliorates quality of life AIMS The aim of the present study was to investigate the effects of successful PCI CTO on absolute myocardial blood flow ( MBF ) and functional recovery . METHODS AND RESULTS Patients with a documented CTO were prospect ively examined for ischaemia and viability with [15O]H2O positron emission tomography ( PET ) and late gadolinium enhancement cardiac magnetic resonance imaging ( LGE-CMR ) . Sixty-nine consecutive patients , in whom PCI was successful , underwent follow-up PET and CMR after approximately 12 weeks to evaluate potential improvement of MBF as well as systolic function . After PCI  , stress MBF in the CTO area increased from 1.22±0.36 to 2.40±0.90 mL·min-1·g-1 ( p<0.001 ) , whilst stress MBF in the remote area also increased significantly between baseline and follow-up PET ( 2.58±0.68 to 2.77±0.77 mL·min-1·g-1 , p=0.01 ) . The ratio of stress MBF between CTO and remote area was 0.49±0.13 at baseline and increased to 0.87±0.24 at follow-up ( p<0.001 ) . The MBF defect size of the CTO area decreased from 5.12±1.69 to 1.91±1.75 myocardial segments after PCI ( p<0.001 ) . Left ventricular ejection fraction ( LVEF ) increased significantly ( 46.4±11.0 vs. 47.5±11.4 % , p=0.01 ) at follow-up . CONCLUSIONS The vast majority of CTO patients with documented ischaemia and viability showed significant improvement in stress MBF and a reduction of ischaemic burden after successful percutaneous revascularisation with only minimal effect on LVEF The present study aim ed to assess the mechanisms of effects of percutaneous coronary intervention ( PCI )  for chronic total occlusion ( CTO ) from two different aspects : left ventricular ( LV ) systolic function assessed by two-dimensional speckle tracking echocardiography ( 2D-STE ) and electrical stability evaluated by late potential on signal-averaged electrocardiogram ( SAECG ) . We conducted a prospect i ve observational study with consecutive CTO-PCI patients .  2D-STE and SAECG were performed before PCI , and after 1-day and 3-months of procedure . 2D-STE computed global longitudinal strain ( GLS ) and regional longitudinal strain ( RLS ) in CTO area , collateral blood-supplying donor artery area , and non-CTO/non-donor area . A total of 37 patients ( 66 ± 11 years , 78 % male ) were analyzed . RLS in CTO and donor areas and GLS were significantly improved 1-day after the procedure , but these improvements diminished during 3 months . The improvement of RLS in donor area remained significant after 3-months the index procedure ( pre-PCI −13.4 ± 4.8 % vs. post-3 M −15.1 ± 4.5 % , P = 0.034 ) . RLS in non-CTO/non-donor area and LV ejection fraction were not influenced . Mitral annulus velocity was improved at 3-month follow-up ( 5.0 ± 1.4 vs. 5.6 ± 1.7 cm/s , P = 0.049 ) . Before the procedure , 12 patients ( 35 % ) had a late potential . All components of the late potential ( filtered QRS duration , root-mean-square voltage in the terminal 40 ms , and duration of the low amplitude signal < 40 μV ) were not  improved . CTO-PCI  improved RLS in the donor area at 3-month follow-up without changes of LV ejection fraction . Although higher prevalence of late potential in the current population compared to healthy population was observed , late potential as a surrogate of arrhythmogenic substrate was not influenced by CTO-PCI Background In congestive heart failure patients , a single measurement of left ventricular ejection fraction ( LVEF ) provides important prognostic information . The importance , if any , of improvement or worsening in serial LVEF has not been defined . The Department of Veterans Affairs Cooperative Vasodilator-Heart Failure Trials ( V-HeFT ) data base was analyzed to determine the prognostic importance of LVEF changes . Methods and Results The data bases for V-HeFT I ( n = 642 ) and V-HeFT II ( n=804 ) were analyzed . All patients had heart failure with documented exercise intolerance and abnormal LVEF or cardiac dilatation by chest x-ray or echocardiography . Radionuclide LVEF was obtained at baseline , within 6 months , and at least yearly after r and omization to treatment . Cumulative survival subsequent to LVEF follow-up measurements was calculated for strata defined by LVEF change from baseline . In V-HeFT I , patients treated with hydralazine/isosorbide dinitrate ( H-I ) experienced a significant ( P < O.OOl ) increase in LVEF and a survival advantage over those treated with placebo and prazosin . In V-HeFT II , both treatment groups showed significant improvements in LVEF , with the increase with H-I greater than that with enalapril , and enalapril provided a significant survival advantage overH-L. Change ( > 5 ) in LVEF from baseline at 6 months ( V-HeFT I ) and 1 year ( V-HeFT II ) were the strongest predictors of mortality among the serial measurements and were significant after adjustment for therapy and baseline LVEF . Baseline clinical variables were not helpfulin predicting the patients who would experience an improvement in LVEF . Conclusions In patients with heart failure , serial measurements of LVEF provide additional important prognostic information . Vasodilator therapy with H-I is associated with an improvement in LVEF and prognosis .  Vasodilator therapy with enalapril improves LVEF less than H-I but provides an additional survival benefit In recent years , several clinical trials conducted on selected middle-aged patients have documented the positive effects of new pharm 
    Output:
    
Successful CTO PCI is associated with a statistically significant improvement in LV ejection fraction and decrease in LV end-systolic volume , that may reflect a beneficial effect of CTO recanalization on LV remodeling .