Patients with Moderate Non-Culprit Coronary Lesions of Recent Acute Coronary Syndrome.

Fractional flow reserve (FFR) measurement was compared to dobutamine stress echocardiography (DSE) instable angina (SA) with stable coronary lesion (s) (SCL (s) ) in a few trials; however, similar comparisons in patients with acute coronary syndrome (ACS) with non-culprit lesion (s) (NCL (s) ) are lacking. Our objectives were to prospectively evaluate the diagnostic performance of FFR with two different cutoff values (< 0.80 and < 0.75) relative to DSE in moderate (30%-70% diameter stenosis) NCLs (ACS group) and to compare these observations with those measured in SCLs (SA group). One hundred seventy-five consecutive patients with SA (n = 86) and ACS (n = 89) with 225 coronary lesions (109 SCLs and 116 NCLs) were enrolled. In contrast to the ACS cohort in SA patients, normal DSE was associated with higher FFR values compared to those with abnormal DSE (P = 0.051 versus P = 0.006). In addition, in the SA group, a significant correlation was observed between DSE (regional wall motion score index at peak stress) and FFR (r = -0.290; P = 0.002), whereas a similar association was absent (r = -0.029; P = 0.760) among ACS patients. In the SA group, decreasing the FFR cutoff value (< 0.80 versus < 0.75) improved the concordance of FFR with DSE (70.6% versus 81.7%) without altering its discriminatory power (area under the curve; 0.68 versus 0.63; P = 0.369), whereas in the ACS group, concordance remained similar (69.0% versus 71.6%) and discriminatory power decreased (0.62 versus 0.51; P = 0.049), respectively. In conclusion, lesion-specific FFR assessment may have different relevance in patients with moderate NCLs than in patients with SCLs.

Clinical Utility of Stress Echocardiography in Remote Indigenous and Non-Indigenous Populations: A 10-Year Study in Central Australia.

BACKGROUND: Remote Central Australia has a large Indigenous population and a significant burden of cardiovascular disease. Stress echocardiography has been previously validated as a useful investigation for long-term prognostication. However, there are no prior studies assessing its utility in remote or Indigenous populations. METHOD: Consecutive individuals undergoing stress echocardiography in Central Australia between 2007 and 2017 were included. Stress echocardiography was performed and reported via standard protocols. Individuals were followed up for all-cause mortality. RESULTS: One-thousand and eight patients (1,008) (54% Indigenous Australian) were included. After a mean follow-up of 3.5±2.4 years, 54 (5%) patients were deceased. Overall, 797 (79%) patients had no abnormalities during rest or stress echocardiography, with no difference according to ethnicity (p>0.05). In patients with a normal test, annual mortality averaged 1.3% over 5 years of follow-up, with annual mortality significantly higher in Indigenous compared to non-Indigenous individuals (1.8% vs 0.6% respectively). In those with an abnormal test, annual mortality was 4.4% vs 1.3% in Indigenous and non-Indigenous individuals respectively. Increasing age, Indigenous ethnicity and cardiometabolic comorbidities were associated with mortality in univariate analyses (p<0.05 for all). In multivariate models, only chronic kidney disease remained predictive of mortality, with other associations (including Indigenous ethnicity) becoming attenuated. CONCLUSION: This is the first study to report on the use of stress echocardiography in a remote or Indigenous population. A normal stress echocardiogram in remote Indigenous individuals was able to identify a lower risk group of patients in this setting. Although Indigenous individuals with a normal test still had a higher annual rate of mortality compared to non-Indigenous individuals, this association appeared to be mediated by cardiometabolic comorbidities.

Prognostic impact of stress echocardiography with discordant stress electrocardiography in patients with suspected coronary artery disease.

INTRODUCTION: During stress echocardiography, the echocardiologist routinely collects both echocardiographic images and stress electrocardiogram (ECG) concurrently. The managing physician faces a dilemma when the stress ECG and stress echocardiography results are discordant; for example, when a patient has negative stress echocardiography but positive stress ECG. We therefore sought to evaluate the prognostic value of stress echocardiography in relation to concordant or discordant stress ECG findings in our local Singapore setting, which has a well-defined Southeast Asian population. METHODS: This was a retrospective observational study of all patients who underwent stress echocardiography in 2012 at Changi General Hospital, Singapore. All study patients were followed up for 18 months via electronic medical records. RESULTS: There was no difference in the major adverse cardiovascular events (MACE) outcome of patients with normal stress echocardiography and normal stress ECG (reference group) as compared with patients with normal stress echocardiography but positive (discordant) stress ECG (odds ratio 2.02, 95% confidence interval 0.82‒4.98; p = 0.125). CONCLUSION: This study will help to reassure cardiologists that discordant results (negative stress echocardiography but positive stress ECG) do not portend a higher risk of MACE when compared to concordant results (i.e. both stress echocardiography and stress ECG are negative).

Sex-based impact of carotid plaque in patients with chest pain undergoing stress echocardiography.

OBJECTIVE: Women with suspected angina without history of coronary artery disease (CAD) less frequently have flow-limiting stenosis (FL-CAD) and more often have microvascular disease, affecting predictive accuracy of stress echocardiography (SE) for detection of FL-CAD. We postulated that carotid plaque burden (CPB) assessment would improve detection of FL-CAD and risk stratification. METHODS: Consecutive consenting patients assessed by SE on clinical grounds for new-onset chest pain also underwent simultaneous carotid ultrasound. Patients were followed for major adverse events (MAE): all-cause mortality, non-fatal myocardial infarction and unplanned revascularisation. Carotid plaque presence and burden (CPB) were assessed. RESULTS: After a mean of 2617±469 days (range 17-3740), of 591 recruited patients, 573 (97%) outcome data (314 females) were obtainable. Despite lower pretest probability of CAD in females versus males (14.9±0.8 vs 20.5±1.3, respectively, p<0.0001), prevalence of myocardial ischaemia was similar (p=0.08). Females also had lower prevalence of both carotid plaque (p<0.0001) and FL-CAD (p<0.05). CPB improved the positive predictive value of SE for detection of FL-CAD (from 34.5% to 60%) in females but not in males. Absence of CPB in females with myocardial ischaemia ruled out FL-CAD in 93% versus 57% in males. CPB was the only independent predictor of MAE (p=0.012) in females, whereas in males both SE (p<0.0001) and CPB (p=0.003) remained significant. CONCLUSION: In females with new-onset stable angina without a history of cardiovascular disease, CPB improved the predictive accuracy of myocardial ischaemia for flow-limiting CAD. However, CPB provided incremental risk stratification in both sexes.

Medicaid expansion and resource utilization in the emergency department.

BACKGROUND: The Affordable Care Act (ACA) has impacted the insurance mix of emergency department (ED) visits, yet the degree to which this has influenced provider behavior is not clear. METHODS: This was a difference-in-differences (DID) analysis of ED-visit data from five states in 2013 and 2014. Sample states included 3 expanding Medicaid under the ACA, 1 rejecting ACA funding and delaying an eligibility expansion, and 1 with no eligibility change. We included self-pay and Medicaid patients aged 27 to 64 years. A subsample analysis was done for chest pain visits. DID logistic models were estimated for likelihood of admission for given Medicaid-paid ED visits in expansion states as compared to non-expansion states. Among chest pain visits we assessed likelihood given visits resulted in admission or advanced cardiac imaging, where clinician discretion may be more significant. RESULTS: A total of 8,157,748 ED visits with primary payer Medicaid and self-pay were included, of which 331,422 were for chest pain. The proportion of visits paid for by Medicaid rose in expansion states by between 15.8% and 38.9%. Medicaid eligibility expansion was associated with increased odds of admission (OR 1.070 [95% CI 1.051-1.089]). Among chest pain visits, expansion was associated with increased odds of admission (OR 1.294 [95% CI 1.144-1.464]), but not advanced cardiac imaging (OR 1.099 [95% CI 0.983-1.229]). CONCLUSION: Medicaid expansion was associated with small increases in ED visit admissions across the board and among the subgroup of patients presenting with chest pain.

Prospective multicenter Polish Stress Echocardiography Registry (PolStress-Echopro) - the role in clinical practice.

BACKGROUND: Stress echocardiography (SE) is becoming an increasingly frequently performed diagnostic examination in Poland. After the published retrospective PolSTRESS Registry, this prospective study is the first one available so far. OBJECTIVES: The aim of the study was to analyze SE tests, taking into account the clinical characteristics of the patients, indications, applied protocols, and diagnostic and therapeutic decisions. MATERIAL AND METHODS: Reference cardiological centers in Poland were asked for a 1-month prospective analysis of the data obtained. The study included 189 SE examinations. To evaluate coronary artery disease (CAD) (178 tests), all 17 centers performed dobutamine SE (DSE) (100%), 3 centers (17%) performed pacing, while cycle ergometer and treadmill SE were performed by 1 (5%) and 2 (11%) centers, respectively. In patients with valvular heart disease (VHD) (11 tests), 3 centers (16%) performed SE to evaluate low-flow/low-gradient aortic stenosis (AS), 4 (22%) in asymptomatic AS and 1 (5%) to evaluate mitral regurgitation. RESULTS: For CAD assessment, a positive result was found in 37 (20%) patients, negative in 109 (61%) and nondiagnostic in 32 (19%). In the CAD group, coronarography was performed in 41 (23%) people. The analysis of the significance of the SE results for decision-making on interventional measures revealed that 30 patients (from the total study population of 189) were referred for the intervention. CONCLUSIONS: The most commonly used SE is the DSE. Negative test results allowed in almost half of the patients to resign from invasive coronarography. Stress echocardiography should be more frequently used in patients with VHD in the qualification for invasive treatment.

Apparent Declining Prognostic Value of a Negative Stress Echocardiography Based on Regional Wall Motion Abnormalities in Patients With Normal Resting Left Ventricular Function Due to the Changing Referral Profile of the Population Under Study.

Background Cardiology guidelines identify the low-risk response during stress echocardiography as the absence of regional wall motion abnormalities. Methods From 1983 to 2016, we enrolled 5817 patients (age 63±12 years; 2830 males) with suspected coronary artery disease, normal regional, and global left ventricular function at rest and during stress (exercise in 692, dipyridamole in 4291, and dobutamine in 834). Based on timing of enrollment, 4 groups were identified in chronological order of recruitment: years 1983 to 1989, group 1 (n=211); years 1990 to 1999, group 2 (n=1491); years 2000 to 2009, group 3 (n=3285); and years 2010 to 2016, group 4 (n=830). Results There were 240 (4%) events (119 deaths and 121 infarctions) in the follow-up. At 1-year follow-up, the event rate was 0.5% (95% CI, 0.05-0.95), 1.5% (95% CI, -1.18 to 1.82), 1.9% (95% CI, 1.63-2.17), and 1.7% (95% CI, 1.01-2.39; χ2, 9.0; P=0.03) in groups 1 to 4, respectively. At multivariable Cox analysis, independent predictors of future events were age (hazard ratio (HR), 1.05; 95% CI, 1.04-1.07; P<0.0001), male sex (HR, 1.57; 95% CI, 1.20-2.04; P=0.001), diabetes mellitus (HR, 1.78; 95% CI, 1.34-2.37; P<0.0001), smoking habit (HR, 1.40; 95% CI, 1.05-1.85; P=0.02), and ongoing anti-ischemic therapy (HR, 1.50; 95% CI, 1.15-1.97; P=0.003) Conclusions Over the past 3 decades, we observed a progressive decline in the prognostic value of a negative test based on regional wall motion abnormalities, likely reflecting both an increase in risk in patients, as well as a potential decrease in test performance due to concomitant anti-ischemic therapy.

Prevalencia y determinantes clínicos de ecocardiografía de esfuerzo no concluyente en pacientes con dolor torácico / Inconclusive exercise stress echocardiography in patients with chest pain: prevalence and clinical determinants

No disponible

Prognostic Utility of Stress Testing and Cardiac Biomarkers in Menopausal Women at Low to Intermediate Risk for Coronary ARTery Disease (SMART Study): 5-Year Outcome.

BACKGROUND: In women with low to intermediate risk of coronary artery disease (CAD), prognostic detection strategies have been controversial. We present the follow-up data of the SMART trial in peri/postmenopausal women at low to intermediate risk of CAD. OBJECTIVES: To determine the value of contrast stress echocardiography (CSE), stress electrocardiogram (sECG), and serum biomarkers for prediction of cardiovascular events (CE) in peri/postmenopausal women at low to intermediate risk of CAD. MATERIALS AND METHODS: From January 2004 to August 2007, 400 peri/postmenopausal women were prospectively enrolled. All women had detailed risk factor assessment, and underwent simultaneous CSE (Definity®, Lantheus Medical Imaging) and sECG. Laboratories included brain natriuretic peptide (BNP), atrial natriuretic peptide, endothelin, and high sensitivity C-reactive protein. Wall motion score index was based on a 16-segment model. Abnormal CSE was defined as new or worsening wall motion abnormality at stress, while abnormal sECG was ≥1 mm horizontal/downsloping ST segment depression/elevation (80 mseconds duration). Self-reported outcome data were collected from a mailed Women's Heart Clinic Questionnaire. CE outcomes included all-cause mortality, nonfatal myocardial infarction (MI), heart failure, chest pain hospitalization or development of typical angina (CP), and revascularization (REVASC). Adjusted Cox proportional hazard ratios (HR; 95% confidence intervals) were reported. RESULTS: A total of 366 women (54.4 ± 5.5 years, Framingham risk 6.5% ± 4.4%) completed simultaneous CSE and sECG. Forty-two (11.5%) had abnormal CSE, while sECG was abnormal in 22 (6%) women. Follow-up (4.4 ± 1.2 years) was available in 315/366 (86%) women (78% exercise-CSE, 22% dobutamine-CSE). In those who completed follow-up, CSE was abnormal in 33 women (10.5%) and sECG was abnormal in 21 (6.7%). In 33 women with abnormal CSE, sECG was abnormal in 7 (21.2%) and normal in 26 (79%), p = 0.0004. CE occurred in 27 (8.6%) women: 8 all-cause mortality, 2 nonfatal MI, 13 CP, and 4 REVASC. CE occurred in 21% versus 7% of women with abnormal versus normal CSE, p = 0.014 and 38% versus 6% of women with abnormal versus normal sECG, p < 0.0001. Rest BNP was higher in women with CE versus those without (p = 0.018). Abnormal sECG and abnormal CSE were associated with CE, while only abnormal sECG was an independent predictor of CE (adjusted HR 10.3 [1.9-61.4], p = 0.007). Of the laboratory results, only BNP was associated with CE (adjusted HR 2.9 [1.1-7.3], p = 0.028). CONCLUSIONS: sECG and rest BNP were independent predictors of subsequent CE within 5 years in peri/postmenopausal women at low to intermediate risk of CAD.

Influencia del riesgo cardiovascular en la predicción y el momento de aparición de eventos cardiacos tras ecocardiograma de esfuerzo sin isquemia / Influence of cardiovascular risk in the prediction and timing of cardiac events after exercise echocardiogram testing without ischemia

Introducción y objetivos: La influencia del riesgo cardiovascular en el pronóstico de pacientes con ecocardiograma de esfuerzo (EE) sin isquemia inducible no se ha evaluado. El objetivo es determinar predictores de eventos, con especial atención al riesgo cardiovascular. Métodos: Se incluyó a 1.640 pacientes con EE sin isquemia: 1.206 sin cardiopatía isquémica (CI), cuyo riesgo de muerte cardiovascular se estimó según el SCORE (Systematic COronary Risk Evaluation) europeo, y 434 con CI. El objetivo primario fue la supervivencia libre de eventos (SLEv) (muerte cardiaca, síndrome coronario agudo no fatal y revascularización en el seguimiento). Resultados: Tras una mediana de seguimiento de 35 [23-54] meses, no hubo diferencias significativas entre la SLEv de los pacientes con SCORE ? 10 o diabetes y pacientes con CI (el 89,8 frente al 87,1%). Al año la SLEv era alta en todos los grupos (el 99,4% si SCORE < 5; el 100% si SCORE 5-9; el 98% si SCORE ? 10 o diabetes y el 97% si CI), con un descenso a los 3 años si SCORE ? 10 o diabetes (94,5%), similar al de los pacientes con CI (91,1%, diferencias no significativas). Las tasas de eventos anualizadas fueron del 2,8 y el 2,55% respectivamente, significativamente superiores a las de los grupos con SCORE < 5 (0,6%) y 5-9 (0,12%). Los eventos más frecuentes fueron el síndrome coronario agudo sin elevación del segmento ST no fatal y la revascularización. Fueron predictores de eventos cardiacos: la CI conocida, un SCORE ? 10 o diabetes, el aclaramiento de creatinina, la fracción eyección del ventrículo izquierdo y el dolor durante la EE. Conclusiones: Un EE sin isquemia implica buen pronóstico inicial, posteriormente modulado por el riesgo cardiovascular (AU)

Introduction and objectives: There have been no analyses of the influence of cardiovascular risk as a predictor of events in patients with exercise echocardiography (EE) without ischemia. Our objective was to determine the predictors of cardiac events, paying special attention to cardiovascular risk. Methods: This study included 1640 patients with EE without ischemia. Of these,there were 1206 with no previously known coronary artery disease (CAD), whose risk of a fatal cardiovascular disease event was estimated according to the European SCORE (Systematic COronary Risk Evaluation) risk assessment system, and 434 with known CAD. The primary endpoint was cardiac event-free survival (EFS) (cardiac death, nonfatal acute coronary syndrome, and coronary revascularization). Results: After a median follow-up of 35 [23-54] months, no differences were found in cardiac EFS between patients with a SCORE 10 or diabetes and patients with previous CAD (89.8% vs 87.1%). In the first year, cardiac EFS was high in all groups (99.4% if SCORE < 5; 100% if 5-9; 98% if 10 or diabetes and 97% in patients with CAD). In the third year, cardiac EFS was similar in the group with SCORE 10 or diabetes (94.5%) and patients with CAD (91.1%, P = NS). In these patients, the annualized event rate was 2.8% and 2.55%, respectively, and was significantly higher than in groups with SCORE < 5 (0.6%) and SCORE 5-9 (0.12%). The most frequent events were non—ST-segment elevation acute coronary syndrome and late revascularization. Predictors of cardiac events were previous CAD, SCORE 10 or diabetes mellitus, creatinine clearance, left ventricular ejection fraction, and chest pain during EE. Conclusions: Initial outcome after an EE without ischemia is favorable but is subsequently modulated by cardiovascular risk (AU)

Polish Stress Echocardiography Registry (Pol-STRESS registry) - a multicentre study. Stress echocardiography in Poland: numbers, settings, results, and complications.

BACKGROUND: Stress echocardiography (SE) is widely used in Europe. No collective data have been available on the use of SE in Poland until now. AIM: To evaluate the number of SE investigations performed in Poland, their settings, complications, and results. METHODS: In this retrospective survey, referral cardiology centres in Poland were asked to fill in a questionnaire regarding SE examinations performed from May 1, 2014 to May 1, 2015. RESULTS: The study included data from 17 university hospitals and large community hospitals, which performed 4611 SE exa-minations, including 4408 tests in patients investigated for coronary artery disease (CAD) and 203 tests to evaluate valvular heart disease (VHD). To evaluate CAD, all centres performed dobutamine SE (100%), 10 centres performed pacing SE (58.8%), while cycle ergometer SE and treadmill SE were performed by six (35.3%) and five (29.4%) centres, respectively. Dipyridamole SE was performed in one centre. All evaluated centres (100%) performed SE to evaluate low-flow/low-gradient aortic stenosis, eight (47%) performed SE to evaluate asymptomatic aortic stenosis, and also eight (47%) performed SE to evaluate mitral regurgitation. The mean number of examinations per year was 271 per centre. Most centres performed more than 100 examinations per year (11 centres, 64.7%). We did not identify any cardiac death during SE examination in any of the centres. Myocardial infarction occurred in three (0.07%) patients. Non-sustained ventricular tachycardia occurred in 52 (1.1%) SE examinations. The rates of minor complications were low. SE to evaluate CAD was more commonly performed in the hospital settings using cycle ergometer (72.6%), treadmill (87.6%), and low-dose dobutamine (68.0%), while a dipyridamole test was more frequently employed in ambulatory patients (77.6%). No significant differences between the rates of examina-tions performed in the ambulatory and hospital settings were found for high-dose dobutamine and pacing SE. Examinations to evaluate VHD were significantly more frequently performed in the hospital settings. SE examinations accounted for more than one third of all stress tests performed in the surveyed centres over the study period. CONCLUSIONS: Stress echocardiography is a safe diagnostic method, and major complications are very rare. Despite European recommendations, SE examinations to evaluate CAD are performed less frequently than electrocardiographic exercise tests, although they already comprise a significant proportion of all stress tests. It seems reasonable to promote SE further for the evaluation of both CAD and VHD.

Stress echocardiography: An overview for use in pediatric and congenital cardiology.

Currently, the role of stress echocardiography primarily resides in diagnosing acquired coronary artery disease (CAD) in adults. Besides an increasing concern for traditional CAD in young patients due to obesity and other chronic pediatric diseases, there is also a growing population of adolescents and young adults with "at risk" coronary arteries due to: reimplanted coronaries in congenital heart disease, anomalous origin of the native coronary arteries, coronary abnormalities in Kawasaki's disease, and posttransplant coronary vasculopathy. Stress echocardiography is well suited for routine screening and monitoring in these patients. Also, due to the ability of stress echocardiography to provide real-time cardiac imaging, it is useful in areas beyond coronary ischemia. Utilizing Doppler derived velocities and pressure gradients, one is able to further evaluate and risk-stratify patients with valvular heart disease. In addition, stress echocardiography is useful in evaluating other areas including ventricular and coronary reserve. The benefits of stress echocardiography are it is: readily available, portable, and relatively cheap. It can be performed without sedation or radiation exposure which becomes very important in younger patients that require periodic monitoring. Stress echocardiography can also evaluate functional abnormalities instead of relative perfusion defects. Overall, stress echocardiography is currently an underutilized imaging modality that has a wide, and expanding, range of application in the practice of pediatric and congenital cardiology.

Prognostic Value of Left Ventricular Deformation Parameters in Patients with Severe Aortic Stenosis: A Pilot Study of the Usefulness of Strain Echocardiography.

BACKGROUND: In patients with aortic stenosis, subtle alterations in myocardial mechanics can be detected by speckle-tracking echocardiography before reduction of left ventricular ejection fraction (LVEF). METHODS: In this prospective study, 162 patients with aortic stenosis with an average aortic valve area of 0.7 ± 0.2 cm2 and a mean LVEF of 60 ± 11% were included. Global longitudinal strain (GLS) and mechanical dispersion (SD of time from Q/R on the electrocardiogram to peak strain in 16 left ventricular segments) were assessed using echocardiography, and all-cause mortality (n = 37) was recorded during 37 ± 13 months of follow-up. RESULTS: Overall, nonsurvivors had more pronounced mechanical dispersion and worse GLS compared with survivors (74 ± 24 vs 61 ± 18 msec [P < .01] and -14.5 ± 4.4% vs -16.7 ± 3.6% [P < .01], respectively). In the 42 conservatively treated patients without surgical aortic valve replacement, a similar pattern was observed in nonsurvivors versus survivors (mechanical dispersion, 80 ± 24 vs 57 ± 14 msec [P < .01]; GLS, -14.0 ± 4.9% vs -17.1 ± 3.8% [P = .04], respectively). Mechanical dispersion was significantly associated with mortality (hazard ratio per 10-msec increase, 1.23; 95% CI, 1.07-1.42; P < .01) in a Cox model adjusted for LVEF and with aortic valve replacement treatment as a time-dependent covariate. Continuous net reclassification improvement showed that mechanical dispersion was incremental to LVEF, GLS, and valvulo-arterial impedance when adjusting for aortic valve replacement treatment in the total population. CONCLUSION: Increased mechanical dispersion may be a risk marker providing novel prognostic information in patients with aortic stenosis.

Dobutamine Stress Echocardiography: Impact of Abnormal Blood Potassium Levels on Cardiac Arrhythmias.

BACKGROUND: Guidelines suggest that an abnormal blood potassium level is a relative contraindication to performing dobutamine stress echocardiography (DSE). However, this has not been previously studied. METHODS: We reviewed a consecutive series of patients who had potassium testing within 48 hours of undergoing DSE for the evaluation of myocardial ischemia over a 10-year period (N = 13,198). Normal potassium range in our laboratory is 3.6-5.2 mmol/L. Hemolyzed samples were not included. The association of potassium levels with the development of supraventricular and ventricular arrhythmias was assessed. RESULTS: The incidence of clinically significant arrhythmias was very low (supraventricular tachycardia/atrial fibrillation, 4.9%; nonsustained ventricular tachycardia, 2.9%; sustained ventricular tachycardia or ventricular fibrillation, 0.1%), confirming the overall safety of DSE. Most arrhythmias (88%) occurred in patients with normal potassium levels, and arrhythmia rates remained low in patients with potassium abnormalities. Patients with hyperkalemia had a lower risk of developing mild (odds ratio [OR], 0.39; 95% CI, 0.22-0.71) and severe (OR, 0.13; 95% CI, 0.01-0.68) supraventricular arrhythmias as well as mild ventricular arrhythmias (OR, 0.58; 95% CI, 0.40-0.83). Even though events were rare, patients with severe hypokalemia (potassium levels ≤ 3.1 mmol/L) had an increased risk of supraventricular arrhythmia and ventricular ectopy. CONCLUSIONS: DSE is safe even in the setting of abnormalities in blood potassium concentrations, and hence cancellation of DSE in patients with potassium abnormalities does not appear warranted. Elevated potassium levels are associated with lower rates of clinically significant supraventricular and ventricular arrhythmias. While remaining at relatively low risk, patients with very low potassium levels (≤3.1 mmol/L) at the time of DSE have a modestly increased risk of arrhythmia. Consideration could be given to correcting severe hypokalemia prior to DSE.

Mitral systolic velocity at peak exercise predicts impaired exercise capacity in patients with heart failure with preserved ejection fraction.

BACKGROUND: Nearly half of patients with heart failure have normal left ventricular ejection fraction (LVEF), but their prognosis is no better than those with reduced LVEF. Although peak oxygen consumption (VO2 ) is an independent predictor of mortality in heart failure, it is unclear how cardiac function during exercise contributes to peak VO2 . Therefore, we explored the useful parameters measured by exercise stress echocardiography to predict peak VO2 in patients with heart failure with preserved LVEF (HFpEF). METHODS AND RESULTS: We assessed 80 patients being investigated for effort intolerance or dyspnea and finally analyzed 50 patients who satisfied the HFpEF criteria. Mean peak VO2 was 16.4±2.8 mL/kg/min. Twenty-three patients (46.0%) achieved a peak VO2 <16.0 mL/kg/min (Weber class C or D). There was a significant relationship between mitral systolic velocity (S') and cardiac output (CO) at rest (R=.55, P<.0001) and peak exercise (R=.64, P<.0001). The absolute increase in S' from rest to peak exercise also correlated with the absolute increase in CO (R=.32, P=.02). Multivariate logistic regression analysis showed that S' at peak exercise independently predicted peak VO2 . Receiver-operator characteristic curve analysis identified that an S' at peak exercise of ≤8.13 cm/s predicted a peak VO2 <16.0 mL/kg/min (sensitivity 95.7%, specificity 44.4%, area under curve 0.70, 95% confidence interval 0.55-0.84, P=.004). CONCLUSIONS: Mitral systolic velocity at peak exercise accurately reflects peak VO2 and may facilitate stratification of risk in patients with HFpEF.

Performance of Firth-and logF-type penalized methods in risk prediction for small or sparse binary data.

BACKGROUND: When developing risk models for binary data with small or sparse data sets, the standard maximum likelihood estimation (MLE) based logistic regression faces several problems including biased or infinite estimate of the regression coefficient and frequent convergence failure of the likelihood due to separation. The problem of separation occurs commonly even if sample size is large but there is sufficient number of strong predictors. In the presence of separation, even if one develops the model, it produces overfitted model with poor predictive performance. Firth-and logF-type penalized regression methods are popular alternative to MLE, particularly for solving separation-problem. Despite the attractive advantages, their use in risk prediction is very limited. This paper evaluated these methods in risk prediction in comparison with MLE and other commonly used penalized methods such as ridge. METHODS: The predictive performance of the methods was evaluated through assessing calibration, discrimination and overall predictive performance using an extensive simulation study. Further an illustration of the methods were provided using a real data example with low prevalence of outcome. RESULTS: The MLE showed poor performance in risk prediction in small or sparse data sets. All penalized methods offered some improvements in calibration, discrimination and overall predictive performance. Although the Firth-and logF-type methods showed almost equal amount of improvement, Firth-type penalization produces some bias in the average predicted probability, and the amount of bias is even larger than that produced by MLE. Of the logF(1,1) and logF(2,2) penalization, logF(2,2) provides slight bias in the estimate of regression coefficient of binary predictor and logF(1,1) performed better in all aspects. Similarly, ridge performed well in discrimination and overall predictive performance but it often produces underfitted model and has high rate of convergence failure (even the rate is higher than that for MLE), probably due to the separation problem. CONCLUSIONS: The logF-type penalized method, particularly logF(1,1) could be used in practice when developing risk model for small or sparse data sets.

Prognostic Value of Myocardial Perfusion Analysis in Patients with Coronary Artery Disease: A Meta-Analysis.

BACKGROUND: Myocardial perfusion (MP) imaging during stress myocardial contrast echocardiography (MCE) improves the detection of coronary artery disease (CAD). However, its prognostic value to predict cardiac events in patients with known or suspected CAD is still undefined. METHODS: A search was conducted for single- or multicenter prospective studies that evaluated the prognostic value of stress MCE in patients with known or suspected CAD. A database search was performed through June 2015. Effect sizes of relative risk ratios (RRs) with their corresponding 95% CIs were used to evaluate the association between the occurrence of total cardiac events (cardiac death, nonfatal myocardial infarction, coronary revascularization) and hard cardiac events (cardiac death and nonfatal myocardial infarction) in subjects with normal and abnormal MP measured by MCE. The Cochran Q statistic and the I2 statistic were used to assess heterogeneity. RESULTS: A comprehensive literature search of the MEDLINE, Google Scholar, Cochrane, and Embase databases identified 11 studies enrolling a total of 4,045 patients. The overall analysis of RRs revealed that patients with abnormal MP were at higher risk for total cardiac events compared with patients with normal MP (RR, 5.58; 95% CI, 3.64-8.57; P < .001), with low heterogeneity among trials (I2 = 48.15%, Q = 7.71, P = .103). Similarly, patients with abnormal MP were at higher risk for hard cardiac events compared with patients with normal MP (RR, 4.99; 95% CI, 1.75-14.32; P = .003), with significant heterogeneity among trials (I2 = 81.48%, Q = 21.59, P < .001). CONCLUSIONS: The results of this meta-analysis suggest that MP assessment using stress MCE is an effective prognostic tool for predicting the occurrence of cardiac events in patients with known or suspected CAD.