The value of serial echocardiography in risk assessment of patients with paroxysmal atrial fibrillation

Progression from paroxysmal to persistent atrial fibrillation (AF) is associated with increased morbidity and mortality. We examined the association of left atrial (LA) remodeling by serial echocardiography, and AF progression over an extended follow-up period. Two-hundred ninety patients (mean age 61  ±  11 years, 73% male) who underwent transthoracic echocardiography performed at first presentation for non-valvular paroxysmal AF (PAF) and repeat echocardiogram 1-year later, were followed for progression to persistent AF. LA and left ventricular (LV) dimensions, volumes, LA reservoir, conduit and booster pump strains, LV global longitudinal systolic strain (GLS) assessed by 2D speckle tracking, and PA-TDI (time delay between electrical and mechanical LA activation- reflecting the extent of LA fibrosis) were compared on serial echocardiography. Sixty-nine (24%) patients developed persistent AF over a mean follow-up period of 6.3 years. At baseline, patients with subsequent persistent AF had larger LA dimensions (46 mm vs. 42 mm, p < 0.001), indexed LA volumes (41 ml/m2 vs. 34 ml/m2, p < 0.001), lower LA reservoir and conduit strain (17.6% vs. 27.6%, p < 0.001; 10.5% vs. 16.3%, p < 0.001; respectively) and longer PA-TDI (155 ms vs. 132 ms, p < 0.001) compared to the PAF group. Patients with subsequent persistent AF showed over time significant enlargement in LA volumes (from 37.7 ml/m2 to 42.4 ml/m2, p < 0.001), lengthening of PA-TDI (from 142.2 ms to 162.2 ms, p = 0.002), and decline in LA reservoir function (from 21.9% to 18.1%, p = 0.024) after adjusting for age, gender, diabetes and LV GLS. There were no changes in LA diameter, LA conduit or booster pump function. Conversely, the PAF group showed no decline in LA function. Patients who developed persistent AF had larger LA size and impaired LA function and atrial conduction times at baseline, compared to patients who remained PAF. Over the 1-year time course of serial echocardiographic evaluation, there was progression of LA remodeling in patients who subsequently developed persistent AF, but not in patients who remained in PAF.

Early Effects of Ticagrelor Versus Clopidogrel on Peripheral Endothelial Function After Non-ST-Elevation Acute Coronary Syndrome and Assessment of Its Relationship With Coronary Microvascular Function

Peripheral endothelial dysfunction is an independent predictor of adverse long-term prognosis after acute coronary syndrome. Data are lacking on the effects of oral P2Y12-inhibitors on peripheral endothelial function in non-ST-elevation acute coronary syndrome (NSTEACS). Furthermore, the relation between peripheral endothelial function and invasive indexes of coronary microvascular function in NSTEACS is unclear. Between March 2018 and July 2020, hospitalized patients with NSTEACS were randomized (1:1) to ticagrelor or clopidogrel. Peripheral endothelial function was assessed with brachial artery flow-mediated vasodilation (FMD). Invasive indexes of coronary microvascular function were obtained using an intracoronary pressure-temperature sensor-tipped wire. In 70 patients included, mean age was 58.6 years, 78.6% (n = 55) were male and 20% (n = 14) had diabetes mellitus. Compared with clopidogrel, ticagrelor significantly improved FMD (14.2 ± 5.4% vs 8.9 ± 5.3%, p <0.001) after a median treatment time of 41.2 hours. The FMD was significantly correlated with the index of microcirculatory resistance (IMR) measured in the infarct-related artery (r = -0.38, p = 0.001), with a stronger correlation found in those who did not have percutaneous coronary intervention (r = -0.52, p = 0.03). Using receiver operating characteristic curve analysis, an FMD of 8.2% identified an IMR of >34 as the threshold, with 77.6% sensitivity and 52.4% specificity. In patients who did not have a percutaneous coronary intervention, an FMD of 11.49% identified an IMR of >34 with 84.6% sensitivity and 80% specificity. In conclusion, ticagrelor significantly improved peripheral endothelial function compared with clopidogrel in patients with NSTEACS. There was a significant correlation between brachial artery FMD and IMR of the infarct-related artery.

Utility of prehospital electrocardiogram interpretation in ST-segment elevation myocardial infarction utilizing computer interpretation and transmission for interventional cardiologist consultation

Objectives

We examined the appropriateness of prehospital cardiac catheter laboratory activation (CCL‐A) in ST‐segment elevation myocardial infarction (STEMI) utilizing the University of Glasgow algorithm (UGA) and remote interventional cardiologist consultation.

Background

The incremental benefit of prehospital electrocardiogram (PH‐ECG) transmission on the diagnostic accuracy and appropriateness of CCL‐A has been examined in a small number of studies with conflicting results.

Methods

We identified consecutive PH‐ECG transmissions between June 2, 2010 and October 6, 2016. Blinded adjudication of ECGs, appropriateness of CCL‐A, and index diagnoses were performed using the fourth universal definition of MI. The primary outcome was the appropriate CCL‐A rate. Secondary outcomes included rates of false‐positive CCL‐A, inappropriate CCL‐A, and inappropriate CCL nonactivation.

Results

Among 1088 PH‐ECG transmissions, there were 565 (52%) CCL‐As and 523 (48%) CCL nonactivations. The appropriate CCL‐A rate was 97% (550 of 565 CCL‐As), of which 4.9% (n = 27) were false‐positive. The inappropriate CCL‐A rate was 2.7% (15 of 565 CCL‐As) and the inappropriate CCL nonactivation rate was 3.6% (19 of 523 CCL nonactivations). Reasons for appropriate CCL nonactivation (n = 504) included nondiagnostic ST‐segment elevation (n = 128, 25%), bundle branch block (n = 132, 26%), repolarization abnormality (n = 61, 12%), artefact (n = 72, 14%), no ischemic symptoms (n = 32, 6.3%), severe comorbidities (n = 26, 5.2%), transient ST‐segment elevation (n = 20, 4.0%), and others.

Conclusions

PH‐ECG interpretation utilizing UGA with interventional cardiologist consultation accurately identified STEMI with low rates of inappropriate and false‐positive CCL‐As, whereas using UGA alone would have almost doubled CCL‐As. The benefits of cardiologist consultation were identifying “masquerading” STEMI and avoiding unnecessary CCL‐As.

Late Outcomes of Patients With Prehospital ST-Segment Elevation and Appropriate Cardiac Catheterization Laboratory Nonactivation

Background Patients with suspected ST-segment-elevation myocardial infarction (STEMI) and cardiac catheterization laboratory nonactivation (CCL-NA) or cancellation have reportedly similar crude and higher adjusted risks of death compared with those with CCL activation, though reasons for these poor outcomes are not clear. We determined late clinical outcomes among patients with prehospital ECG STEMI criteria who had CCL-NA compared with those who had CCL activation. Methods and Results We identified consecutive prehospital ECG transmissions between June 2, 2010 to October 6, 2016. Diagnoses according to the Fourth Universal Definition of myocardial infarction (MI), particularly rates of myocardial injury, were adjudicated. The primary outcome was all-cause death. Secondary outcomes included cardiovascular death/MI/stroke and noncardiovascular death. To explore competing risks, cause-specific hazard ratios (HRs) were obtained. Among 1033 included ECG transmissions, there were 569 (55%) CCL activations and 464 (45%) CCL-NAs (1.8% were inappropriate CCL-NAs). In the CCL activation group, adjudicated index diagnoses included MI (n=534, 94%, of which 99.6% were STEMI and 0.4% non-STEMI), acute myocardial injury (n=15, 2.6%), and chronic myocardial injury (n=6, 1.1%). In the CCL-NA group, diagnoses included MI (n=173, 37%, of which 61% were non-STEMI and 39% STEMI), chronic myocardial injury (n=107, 23%), and acute myocardial injury (n=47, 10%). At 2 years, the risk of all-cause death was higher in patients who had CCL-NA compared with CCL activation (23% versus 7.9%, adjusted risk ratio, 1.58, 95% CI, 1.24-2.00), primarily because of an excess in noncardiovascular deaths (adjusted HR, 3.56, 95% CI, 2.07-6.13). There was no significant difference in the adjusted risk for cardiovascular death/MI/stroke between the 2 groups (HR, 1.23, 95% CI, 0.87-1.73). Conclusions CCL-NA was not primarily attributable to missed STEMI, but attributable to "masquerading" with high rates of non-STEMI and myocardial injury. These patients had worse late outcomes than patients who had CCL activation, mainly because of higher rates of noncardiovascular deaths.

Impact of Ticagrelor Versus Clopidogrel on Coronary Microvascular Function After Non-ST-Segment-Elevation Acute Coronary Syndrome

BACKGROUND

Coronary microvascular dysfunction after acute coronary syndrome is an important predictor of long-term prognosis. Data is lacking on the effects of oral P2Y₁₂-inhibitors on coronary microvascular function in non-ST-segment-elevation acute coronary syndrome. The aim of this study was to compare the acute effects of ticagrelor versus clopidogrel pretreatment on coronary microvascular function in non-ST-segment-elevation acute coronary syndrome patients.

METHODS

Hospitalized non-ST-segment-elevation acute coronary syndrome patients were randomized (1:1) to ticagrelor or clopidogrel. The index of microcirculatory resistance, coronary flow reserve, and resistive reserve ratio were obtained using an intracoronary pressure-temperature sensor-tipped wire.

RESULTS

In total, 128 patients were randomized between March 2018 and July 2020. Mean age 59.2±11.8 years, 84% were male, mean Global Registry of Acute Coronary Events score was 93.7±24.5. Intracoronary physiological measurements were obtained in 118 patients (60 ticagrelor, 58 clopidogrel). In the infarct-related artery, the ticagrelor group had lower baseline index of microcirculatory resistance (22.0 [13.0-34.9] versus 27.7 [19.3-29.8]; P=0.02) and higher baseline resistive reserve ratio (3.0 [2.3-4.4] versus 2.4 [1.7-3.4]; P=0.01) compared with the clopidogrel group. A total of 88 patients underwent percutaneous coronary intervention (PCI; 45 ticagrelor, 43 clopidogrel). The ticagrelor group had lower post-PCI index of microcirculatory resistance (22.0 [15.0-29.0] versus 27.0 [18.5-47.5]; P=0.02) and higher post-PCI resistive reserve ratio (3.0 [1.8-3.8] versus 1.8 [1.5-3.4]; P=0.006) compared with the clopidogrel group. The coronary flow reserve was not significantly different between the 2 groups at baseline or post-PCI. No between-group differences were seen in any of the indices in the non-infarct-related artery.

CONCLUSIONS

In non-ST-segment-elevation acute coronary syndrome patients, ticagrelor significantly improved coronary microvascular function before and after PCI compared with clopidogrel.

REGISTRATION

URL: https://www.anzctr.org.au; Unique identifier: ACTRN12618001610224.

An Unexpected Cause of Heart Failure in a Young Woman With Treated Lymphoma

Arteriovenous fistula is a rare complication of lumbar surgery that may cause high-output cardiac failure. We describe the case of a patient with treated lymphoma and recent spinal surgery who presented with heart failure. Logical deduction from clinical and imaging findings helped us arrive at this unusual diagnosis. (Level of Difficulty: Intermediate.)

Impact of Targeted Therapies for Coronary Microvascular Dysfunction as Assessed by the Index of Microcirculatory Resistance

Coronary microvascular dysfunction (CMD) has emerged as an important therapeutic target in the contemporary management of ischemic heart disease. However, due to a lack of a reliable traditional "gold standard" test for CMD, optimal treatment remains undefined. The index of microcirculatory resistance (IMR) is an intra-coronary wire-based technique that provides a more reliable and quantitative assessment of CMD and has been increasingly used as a preferred endpoint for evaluating CMD treatment strategies in recent studies. IMR can help diagnose CMD in angina patients with non-obstructive epicardial coronary disease, predict peri-procedural myocardial infarction in stable patients undergoing coronary stenting, and predict long-term prognosis after acute myocardial infarction. Studies of IMR in the setting of non-ST-elevation acute coronary syndromes are still lacking. This review critically appraises the current published literature evaluating targeted therapies for CMD using IMR as the assessment tool and provides insights into evidence gaps in this important field. The index of microcirculatory resistance has rapidly evolved from a research tool to being the new "gold standard" test for evaluating coronary microvascular dysfunction.

Consensus guidelines for interventional cardiology services delivery during covid-19 pandemic in Australia and new Zealand

The global coronavirus disease (COVID-19) pandemic poses an unprecedented stress on healthcare systems internationally. These Health system-wide demands call for efficient utilisation of resources at this time in a fair, consistent, ethical and efficient manner would improve our ability to treat patients. Excellent co-operation between hospital units (especially intensive care unit [ICU], emergency department [ED] and cardiology) is critical in ensuring optimal patient outcomes. The purpose of this document is to provide practical guidelines for the effective use of interventional cardiology services in Australia and New Zealand. The document will be updated regularly as new evidence and knowledge is gained with time. Goals Considerations.

Impact of Diabetes and Increasing Body Mass Index Category on Left Ventricular Systolic and Diastolic Function

BACKGROUND

Diabetes and obesity are both worldwide growing epidemics, and both are independently associated with increased risk for heart failure and death. The aim of this study was to examine the additive detrimental effect of both diabetes and increasing body mass index (BMI) category on left ventricular (LV) myocardial systolic and diastolic function.

METHODS

The present retrospective multicenter study included 653 patients (337 with type 2 diabetes and 316 without diabetes) of increasing BMI category. All patients had normal LV ejection fractions. LV myocardial systolic (peak systolic global longitudinal strain and peak systolic global longitudinal strain rate) and diastolic (average mitral annular e' velocity and early diastolic global longitudinal strain rate) function was quantified using echocardiography.

RESULTS

Increasing BMI category was associated with progressively more impaired LV myocardial function in patients with diabetes (P < .001). Patients with diabetes had significantly more impaired LV myocardial function for all BMI categories compared with those without diabetes (P < .001). On multivariate analysis, both diabetes and obesity were independently associated with an additive detrimental effect on LV myocardial systolic and diastolic function. However, obesity was associated with greater LV myocardial dysfunction than diabetes.

CONCLUSION

Both diabetes and increasing BMI category had an additive detrimental effect on LV myocardial systolic and diastolic function. Furthermore, increasing BMI category was associated with greater LV myocardial dysfunction than diabetes. As they frequently coexist together, future studies on patients with diabetes should also focus on obesity.

Non-inferiority trials in cardiology: what clinicians need to know

Clinical trials traditionally aim to show a new treatment is superior to placebo or standard treatment, that is, superiority trials. There is an increasing number of trials demonstrating a new treatment is non-inferior to standard treatment. The hypotheses, design and interpretation of non-inferiority trials are different to superiority trials. Non-inferiority trials are designed with the notion that the new treatment offers advantages over standard treatment in certain important aspects. The non-inferior margin is a predetermined margin of difference between the new and standard treatment that is considered acceptable or tolerable for the new treatment to be considered ‘similar’ or ‘not worse’. Both relative difference and absolute difference methods can be used to define the non-inferior margin. Sequential testing for non-inferiority and superiority is often performed. Non-inferiority trials may be necessary in situations where it is no longer ethical to test any new treatment against placebo. There are inherent assumptions in non-inferiority trials which may not be correct and which are not being tested. Successive non-inferiority trials may introduce less and less effective treatments even though these treatments may have been shown to be non-inferior. Furthermore, poor quality trials favour non-inferior results. Intention-to-treat analysis, the preferred way to analyse randomised trials, may favour non-inferiority. Both intention-to-treat and per-protocol analyses should be recommended in non-inferiority trials. Clinicians should be aware of the pitfalls of non-inferiority trials and not accept non-inferiority on face value. The focus should not be on the p values but on the effect size and confidence limits.

Defining Subclinical Myocardial Dysfunction and Implications for Patients With Diabetes Mellitus and Preserved Ejection Fraction

Left ventricular (LV) global longitudinal strain (GLS) can detect subclinical myocardial systolic dysfunction in individuals with diabetes. The present study investigates the clinical usefulness and incremental net benefit of identifying subclinical myocardial systolic dysfunction in individuals with diabetes. A cohort of 397 type 2 diabetic individuals was followed up for the occurrence of all-cause mortality. Clinical and echocardiographic data of diabetic patients were assessed retrospectively. LV GLS was evaluated on transthoracic echocardiography using speckle tracking imaging. Subclinical LV systolic dysfunction was defined as LV GLS > -17.0% from 104 healthy volunteers recruited from the community. A total of 178 (44.8%) diabetic individuals had evidence of subclinical LV systolic dysfunction and 46 (11.6%) died during follow-up. The presence of subclinical LV systolic dysfunction was independently associated with all-cause mortality on follow-up (hazard ratio [HR] 2.83, 95% confidence interval [CI] 1.40 to 5.71, p = 0.004). Diabetic individuals without subclinical LV systolic dysfunction had similar survival as the general population (standardized mortality ratio 0.94, 95% CI 0.52 to 1.58). Decision curve analysis showed identification of subclinical LV systolic dysfunction and quantification of LV GLS provided an incremental net clinical benefit at risk stratifying patients for risk of death at 5 years. In conclusion, subclinical LV systolic dysfunction is independently associated with all-cause mortality in diabetic patients. Decision curve analyses suggest use of LV GLS and identification of subclinical LV systolic dysfunction is clinically useful, and provided incremental net clinical benefit for diabetic individuals.

Assessing Coronary Microvascular Dysfunction in Ischaemic Heart Disease: Little Things Can Make a Big Difference

The role of coronary microvascular dysfunction (CMD) in the pathogenesis of ischaemic heart disease and in determining long-term prognosis is increasingly recognised. In selected patients, a comprehensive coronary assessment including an assessment of microvascular function may help refine risk stratification and improve patient outcomes. Various non-invasive and invasive techniques have been developed to assess the coronary microcirculation. Many of these tests utilise the indicator-dilution principle to determine coronary or myocardial blood flow. However, these techniques are often limited by their variability and lack of specificity for the coronary microvasculature. Consequently, there is still paucity of data on targeted therapies for CMD and their implications on long-term clinical outcomes, particularly in the setting of non-ST elevation acute coronary syndromes. Recent technical advancements, such as the index of microcirculatory resistance, have largely overcome these limitations and are able to provide novel insights into the assessment and treatment of CMD. This review summarises the currently available techniques for the assessment of CMD and provides an overview of its clinical implications.

Alterations in Layer-Specific Left Ventricular Global Longitudinal and Circumferential Strain in Patients With Aortic Stenosis: A Comparison of Aortic Valve Replacement versus Conservative Management Over a 12-Month Period

BACKGROUND

Impairment in left ventricular (LV) systolic strain in aortic stenosis (AS) is well documented. However, alterations in layer-specific LV global longitudinal strain (GLS) and global circumferential strain (GCS) and their recovery following surgical aortic valve replacement (AVR) have not been established. The aim of this study was to examine layer-specific changes in GLS and GCS in patients with AS undergoing AVR and compare these patients with those managed conservatively over 12 months.

METHODS

Eighty-six patients (mean age, 68.8 ± 12 years; 60 men) with AS (19 mild, 15 moderate, and 52 severe) were prospectively recruited. Patients with coronary disease or other significant valvular disease were excluded. Forty patients (46.5%) with severe AS underwent AVR. All patients underwent baseline echocardiography. Patients managed conservatively underwent follow-up echocardiography at 12 months. Patients undergoing AVR underwent follow-up echocardiography at 1 week and 3, 6, and 12 months after AVR.

RESULTS

There was worsening in subendocardial but not subepicardial or transmural GLS even in mild AS (-20.9 ± 1.0% vs -20.6 ± 0.8%, P = .012). In moderate AS, worsening in subendocardial (-19.6 ± 0.9% vs -18.2 ± 1.5%, P = .003), subepicardial (-14.9 ± 1.0% vs -13.8 ± 1.2%, P = .004), and transmural (-17.1 ± 0.9% vs -15.8 ± 1.3%, P = .03) GLS and a trend toward significant worsening in subendocardial GCS (-29.8 ± 5.16% vs -27.5 ± 5%, P = .054) were seen. Conservatively managed patients with severe AS had significant worsening in subendocardial (-16.1 ± 1.6% vs -13.9 ± 2.6%, P = .021), subepicardial (-11.6 ± 1.1% vs -10.1 ± 2.1%, P = .027), and transmural (-13.6 ± 1.3% vs -11.8 ± 2.3%, P = .02) GLS and subendocardial (-24.9 ± 3.6% vs -20.8 ± 4.5%, P = .002) and transmural (-16.9 ± 1.7% vs -14.3 ± 3.5%, P = .04) GCS on follow-up. Patients after AVR demonstrated significant improvement in GLS (from 3 months) and GCS (from 6 months) in both myocardial layers.

CONCLUSIONS

Patients with AS managed conservatively had worsening of GLS over 12 months despite preserved LV ejection fraction, detected earliest in the subendocardial layer. GCS became progressively impaired in moderate and severe AS. Improvement in LV strain after AVR was seen earlier with GLS (from 3 months) than with GCS (from 6 months) in both myocardial layers.

Relation of Echocardiographic Markers of Left Atrial Fibrosis to Atrial Fibrillation Burden

In patients with atrial fibrillation (AF), left atrial (LA) fibrosis is a major determinant of the progression to, and burden of AF. LA reservoir strain and total atrial conduction time (PA-TDI) reflect LA fibrotic content. We aimed to investigate the relation between LA reservoir strain and PA-TDI in AF patients and control subjects. Six-hundred two patients (mean age 56 years, 53% men) with first episode of AF and 342 controls (mean age 64 years, 71% men) without structural heart disease underwent echocardiography. LA volumes, PA-TDI, LA reservoir strain, and left ventricular global longitudinal strain (GLS) were compared. Compared with controls, patients with paroxysmal AF and patients with persistent AF had longer PA-TDI (128 ± 25 millisecond, 140 ± 31 millisecond, and 154 ± 33 millisecond, respectively; p <0.001) and a progressive decline in LA reservoir strain (36.9 ± 11.6%, 29.8 ± 13.4%, 24.2 ± 12.3%, respectively; p <0.001). LA reservoir strain was negatively correlated with PA-TDI (r = -0.43, p <0.001). On multivariate analyses, LA reservoir strain, diabetes mellitus, and burden of AF were independent correlates of PA-TDI (R² = 0.23, p <0.001); whereas only PA-TDI was an independent correlate of LA reservoir strain (R² = 0.43, p <0.001); controlling for age, hypertension, coronary artery disease, body mass index, severity of mitral regurgitation, left ventricular global longitudinal strain, and LA volume. In conclusion, PA-TDI and LA reservoir strain are negatively correlated in all subjects, irrespective of the presence or burden of AF. Patients with persistent AF have longer PA-TDI and impaired LA reservoir strain compared with paroxysmal AF and controls, suggesting increasing burden of fibrosis and LA structural remodeling in the progression of AF.

Cardiac dysfunction in type II diabetes: a bittersweet, weighty problem, or both?

AIMS

Weight loss in obese patients leads to improved left ventricular (LV) function. It is unclear whether improving glycaemic control has additional benefits to weight loss alone in patients with type 2 diabetes, or if benefits of weight loss are mediated through improving glycaemic control. This case-control study examined the incremental impact of these approaches on LV function.

METHODS

Three groups of age, gender, and baseline HbA1c-matched patients with type 2 diabetes and suboptimal glycaemic control were followed-up for 12 months. Group 1 patients did not improve HbA1c ≥ 1 % (10.9 mmol/mol) or lose weight. Group 2 improved HbA1c ≥ 1 % but did not lose weight. Group 3 improved HbA1c ≥ 1 % (10.9 mmol/mol) and lost weight. All patients underwent transthoracic echocardiogram at baseline and at follow-up.

RESULTS

At baseline, three groups were comparable in all clinical and metabolic parameters except Group 3 had highest body mass index. The three groups had similar echocardiographic parameters except Group 3 had the worst LV systolic function [global longitudinal strain (GLS)]. At follow-up, LV ejection fraction and diastolic function improved with a reduction in filling pressures in Group 2 and more so in Group 3. LV filling pressures in Group 1 increased. There was a significant improvement in GLS in Group 2 and more so in Group 3. Despite GLS being the worst in Group 3 at baseline, this was comparable between Groups 2 and 3 at follow-up.

CONCLUSIONS

In overweight patients with type 2 diabetes, weight loss and improved glycaemic control had additive beneficial effects on improving LV systolic and diastolic function.

Coronary microvascular function in patients with type 2 diabetes mellitus

AIMS

The aims of this study were to compare the index of microcirculatory resistance (IMR) and its determinants in diabetes mellitus (DM) and non-DM patients with vascular risk factors, and to evaluate the potential differential involvement of coronary microvascular beds.

METHODS AND RESULTS

Fifty-six patients (32 with DM), without significant epicardial coronary disease, had IMR measured in the anterior and posterior circulations. There was no significant difference in the anterior compared to posterior circulation IMR in the whole group (27 vs. 26, p=0.92) or in the DM subgroup (35 vs. 28, p=0.31). DM patients had higher anterior circulation IMR compared to non-DM patients (27 vs. 15, p=0.009). Posterior circulation IMR was higher than anterior circulation IMR in non-DM patients (25 vs. 16, p=0.01). Multivariate determinants of higher anterior circulation IMR in DM were dyslipidaemia, hypertension, worsening glycaemic control, and higher body mass index; metformin had a protective effect.

CONCLUSIONS

There is differential involvement of the coronary microvascular beds. In the presence of risk factors, microvascular function of the posterior circulation was affected before the anterior; DM patients had worse microvascular function in the anterior but not posterior circulation compared to patients without DM. Vascular risk factors, including DM, adversely affect coronary microvascular function, and their treatment was associated with improvement.

Weight Loss with Sleeve Gastrectomy in Obese Type 2 Diabetes Mellitus: Impact on Cardiac Function

Background

Diabetic cardiomyopathy is an increasingly prevalent health issue, with no specific management options. We examined the impact of weight loss with sleeve gastrectomy on diabetic cardiomyopathy.

Methods

Eight obese patients with type 2 diabetes undergoing sleeve gastrectomy had left ventricular (LV) systolic and diastolic function assessed by global longitudinal strain (GLS) and septal early diastolic velocity (e’) using echocardiography, before and 9 months after surgery.

Results

Following surgery, mean weight loss was 28.0 ± 16 kg; body mass index (BMI) decreased from 44 ± 9 to 35 ± 6 kg/m² (p < 0.001). Glycaemic control improved with glycated haemoglobin (HbA1c) improving from 9.2 % at baseline to 6.7 % at follow-up (p = 0.002), with a corresponding improvement in LV GLS from −13.2 ± 3.7 to −19.7 ± 2.2 % (p < 0.001), and LV ejection fraction from 60 ± 5 to 70 ± 4 % (p < 0.001). Improvement in GLS was associated with the amount of weight lost (ρ = 0.81, p = 0.015). LV septal e’ velocities increased, and LV filling pressures decreased after surgery.

Conclusions

Weight loss with sleeve gastrectomy in obese patients with type 2 diabetes is effective in improving glycaemic control in subjects with type 2 diabetes and results in significant improvement in both systolic and diastolic myocardial function.

Impact of Improved Glycemic Control on Cardiac Function in Type 2 Diabetes Mellitus

BACKGROUND

Patients with type 2 diabetes mellitus are at risk of heart failure. Specific therapeutic interventions for diabetic heart disease are still elusive. We aimed to examine the impact of improved glycemic control on left ventricular (LV) function in these patients.

METHODS AND RESULTS

A total of 105 subjects with type 2 diabetes mellitus (aged 54±10 years) and poor glycemic control received optimization of treatment for blood glucose, blood pressure, and cholesterol to recommended targets for 12 months. LV systolic and diastolic function, measured by LV global longitudinal strain (GLS) and septal e' velocities, were compared before and after optimization. At baseline, patients had impaired LV systolic (GLS -14.9±3.2%) and diastolic function (e' 6.2±1.7 cm/s). After 12 months, glycated hemoglobin (HbA1c) decreased from 10.3±2.4% to 8.3±2.0%, which was associated with significant relative improvement in GLS of 21% and septal e' of 24%. There was a progressively greater improvement in GLS as patients achieved a lower final HbA1c. Patients achieving an HbA1c of <7.0% had the largest improvement. The 15 patients whose HbA1c worsened experienced a decline in GLS. Patients who improved their HbA1c by ≥1.0% had a significantly higher relative improvement in e' than those who did not (32% versus 8%; P=0.003). Baseline GLS, decrease in body mass index, and treatment with metformin were additional independent predictors of GLS improvement.

CONCLUSIONS

Improvements in glycemic control over a 12-month period led to improvements in LV systolic and diastolic function. This may have long-term prognostic implications.

Effects of dipeptidyl peptidase-4 inhibitors on cardiac and endothelial function in type 2 diabetes mellitus: A pilot study

AIMS

Recent studies have raised concerns regarding increased heart failure in patients on dipeptidyl peptidase-4 inhibitors. We examined whether dipeptidyl peptidase-4 inhibitors, compared to non-incretin-based therapies, have differential effects on left ventricular and endothelial function in patients with type 2 diabetes mellitus.

METHODS

A total of 25 type 2 diabetes mellitus patients commenced on a dipeptidyl peptidase-4 inhibitor were compared with 50 matched controls. Left ventricular systolic and diastolic function and flow-mediated dilatation were compared before and 12 months after treatment.

RESULTS

At baseline, both dipeptidyl peptidase-4 inhibitor and control groups had elevated HbA1c and comparable subclinical left ventricular dysfunction (left ventricular global longitudinal strain: -15.4% vs -15.9%, p = 0.538; e' velocities: 6 vs 6 cm/s, p = 0.151, where e' is the peak mitral annular early diastolic tissue velocity). After 12 months, both groups had similar improvement in HbA1c. However, patients on dipeptidyl peptidase-4 inhibitors had greater improvement in systolic (ΔGLS: 3.6% vs 1.3%, p < 0.001), despite no significant differences in weight, blood pressure or lipid parameters in both groups. Diastolic (Δe': 38% vs 17%, p = 0.001) and endothelial function improved in the dipeptidyl peptidase-4 inhibitor group but not the control group (ΔFMD: 5% vs -1%, p = 0.029).

CONCLUSION

We demonstrated significant improvements in LV systolic, diastolic and endothelial function in patients treated with a dipeptidyl peptidase-4 inhibitor over 12 months. These beneficial effects may provide some reassurance regarding the cardiovascular safety of dipeptidyl peptidase-4 inhibitors.

Left ventricular diastolic reserve in patients with type 2 diabetes mellitus

AIMS

Diastolic reserve is the ability of left ventricular filling pressures to remain normal with exercise. Impaired diastolic reserve may be an early sign of diabetic cardiomyopathy. We aimed to determine whether diastolic reserve differs in type 2 diabetes (DM) compared with non-DM, and to identify clinical, anthropological, metabolic and resting echocardiographic correlates of impaired diastolic reserve in patients with DM.

METHODS AND RESULTS

237 patients (aged 53±11 years, 133 DM, ejection fraction 68±9%) underwent rest and exercise echocardiography. Mitral E and septal e' were measured at rest, immediately post, and 10 min into recovery. Analysis of covariance (ANCOVA) and binary regression with continuous outcomes were used to model e' and E/e' changes with exercise to identify impaired diastolic reserve defined as post-exercise E/e' ≥15. After adjusting for baseline differences, patients with DM immediately post-exercise had a lower septal e', a lower Δe' (1.2 vs 2.3 cm/s, p=0.006) and a higher Δ septal E/e' (1.7 vs 0.08, p<0.001) than patients without DM. In patients with normal resting E/e' of ≤8 (n=130), DM had a significantly higher post-exercise septal E/e' and a higher Δseptal E/e' (2.63 vs 0.50, p<0.001). E/e' in patients with DM remained significantly elevated up to 10 min post-exercise. Hypertension, longer duration of insulin therapy, poorer glycaemic control, worse renal function, larger left atrial volume and lower septal e' were independent correlates of impaired diastolic reserve in patients with DM.

CONCLUSIONS

Patients with DM have impaired diastolic reserve manifest as a blunted e' response with exercise, persisting into recovery. Clinical, anthropometric, metabolic and echocardiographic correlates of impaired diastolic reserve in patients with DM were identified. An impaired LV diastolic reserve may be the underlying pathophysiological mechanism in patients with DM with unexplained exertional dyspnoea and may allow earlier detection of DM cardiomyopathy.

Endothelial function and left ventricular diastolic functional reserve in type 2 diabetes mellitus

Background

Endothelial dysfunction is an early feature of vascular disease. Left ventricular (LV) diastolic reserve is the ability of the left ventricle to augment diastolic function with exercise and may be impaired in patients with diabetes mellitus (DM). It is unclear if endothelial dysfunction is related to impaired LV diastolic reserve and diminished exercise capacity.

Methods

96 patients with type 2 DM and 10 controls had brachial artery reactivity testing, followed by exercise echocardiography. The brachial artery diameter was measured at rest and during reactive hyperaemia. LV diastolic reserve was measured as Δe′ with exercise and diastolic reserve index (Δe′/rest e′). Exercise capacity was calculated by metabolic equivalents (METs).

Results

Compared with controls, patients with DM had lower rest e′ (7 vs 9 cm/s, p=0.002), lower Δe′(1 vs 4 cm/s, p=0.023), lower Δe′/rest e′ (0.20 vs 0.47, p=0.003) and reduced flow mediated dilation (FMD, 5 vs 15%, p<0.001). FMD was correlated with Δe′ (r=0.65, p<0.001), diastolic reserve index (r=0.61, p<0.001) and post-exercise septal E/e′ (r=−0.50, p<0.001), but not with rest e′ (r=0.13, p=0.177). FMD was an independent predictor of Δe′ (β=0.002, p<0.001, R²=0.47) and diastolic reserve index (β=0.030, p<0.001, R²=0.41). Younger age (p<0.001), male gender (p=0.014), lower body mass index (p<0.001), lower rest E/e′ (p=0.042) and higher FMD (p=0.025) were independent predictors of higher METs (R²=0.52, p<0.001).

Conclusions

Patients with DM had impaired endothelial function and LV diastolic dysfunction. LV diastolic reserve and exercise capacity are linked to endothelial function. Targeting vascular risk factors to improve endothelial function may improve LV diastolic reserve and exercise capacity.

Evaluation of coronary microvascular function by left ventricular contractile reserve with low-dose dobutamine echocardiography

AIMS

Coronary microvascular function has important diagnostic and prognostic implications but routine assessment is difficult. The index of microcirculatory resistance (IMR) is a reliable but invasive measure. We evaluated whether left ventricular contractile reserve (CR), measured with strain imaging on dobutamine echocardiography (DSE), is a reliable non-invasive measure of coronary microvascular function.

METHODS AND RESULTS

Forty-five patients underwent low-dose DSE and invasive coronary angiography with IMR measurement in the left anterior descending artery. Global mean peak systolic longitudinal strain was measured in three apical views at rest, and with low-dose DSE. CR was the difference between the resting and low-dose values. Mean IMR was 19.8 (range 6-104): mean peak global systolic strain at rest was -17.90% and at low-dose was -21.46%, giving a mean CR of +3.6% (20% relative increase). IMR and CR were significantly correlated, IMR(-1)=(0.0014×CR+0.05), r=0.64, p<0.001. CR of ≥10% relative increase identified IMR <25 (100% sensitivity and specificity) and <16 (93% sensitivity, 50% specificity [AUC=0.84]). CR ≥20% identified IMR of <16 (78% sensitivity, 82% specificity) with CR ≥ 41% having 100% specificity.

CONCLUSIONS

LV CR with low-dose DSE may be used to estimate IMR non-invasively. An impaired CR indicates coronary microvascular dysfunction.

Rationale and design of a randomized trial on the impact of aldosterone antagonism on cardiac structure and function in diabetic cardiomyopathy

Development of a cardiomyopathy in diabetes mellitus is independent of traditional risk factors, with no clinical trials targeting specific therapeutic interventions. Myocardial fibrosis is one of the key mechanisms and aldosterone is a key mediator of myocardial fibrosis. We propose that aldosterone antagonism will improve cardiac function. We aim to evaluate the efficacy of selective aldosterone receptor antagonism with eplerenone added to optimal medical treatment in improving cardiac structure and function in diabetic cardiomyopathy. We will randomize 130 patients with type 2 diabetes mellitus, stable metabolic control and impaired left ventricular (LV) systolic or diastolic function, to either eplerenone (target dose 50mg) or matching placebo, in addition to optimal medical therapy for 12 months. The primary endpoints are changes in LV systolic and diastolic function, measured by echocardiographic 2-dimensional speckle tracking strain and strain rate and tissue Doppler imaging. The secondary endpoints include changes in echocardiographic markers and plasma biomarkers of collagen turnover; left atrial dimensions and function, incidence of atrial fibrillation and changes in exercise capacity and dyspnea score. The present study will assess whether specific aldosterone antagonism with eplerenone in addition to standard therapy will prevent progression or reverse cardiac dysfunction in diabetic cardiomyopathy using sensitive, robust and quantifiable echocardiographic measures that allow early detection of change. The study may offer a new direction in the management of this condition.

Supporting Treatment decision making to Optimise the Prevention of STROKE in Atrial Fibrillation: the STOP STROKE in AF study. Protocol for a cluster randomised controlled trial

BACKGROUND

Suboptimal uptake of anticoagulation for stroke prevention in atrial fibrillation has persisted for over 20 years, despite high-level evidence demonstrating its effectiveness in reducing the risk of fatal and disabling stroke.

METHODS

The STOP STROKE in AF study is a national, cluster randomised controlled trial designed to improve the uptake of anticoagulation in primary care. General practitioners from around Australia enrolling in this 'distance education' program are mailed written educational materials, followed by an academic detailing session delivered via telephone by a medical peer, during which participants discuss patient de-identified cases. General practitioners are then randomised to receive written specialist feedback about the patient de-identified cases either before or after completing a three-month posttest audit. Specialist feedback is designed to provide participants with support and confidence to prescribe anticoagulation. The primary outcome is the proportion of patients with atrial fibrillation receiving oral anticoagulation at the time of the posttest audit.

DISCUSSION

The STOP STROKE in AF study aims to evaluate a feasible intervention via distance education to prevent avoidable stroke due to atrial fibrillation. It provides a systematic test of augmenting academic detailing with expert feedback about patient management.

Age- and gender-specific differences in the prognostic value of CT coronary angiography

OBJECTIVE

To evaluate the potential age- and gender-specific differences in the incidence and prognostic value of coronary artery disease (CAD) in patients undergoing CT coronary angiography (CTA).

DESIGN AND PATIENTS

In this multicentre prospective registry study, 2432 patients (mean age 57 ± 12, 56% male) underwent CTA for suspected CAD. Patients were stratified into four groups according to age <60 or ≥60 years and, male or female gender.

MAIN OUTCOME MEASURES

A composite end point of cardiac death and non-fatal myocardial infarction.

RESULTS

CTA results were normal in 991 (41%) patients, showed non-significant CAD in 761 (31%) patients and significant CAD in the remaining 680 (28%) patients. During follow-up (median 819 days, 25-75th centile 482-1142) a cardiovascular event occurred in 59 (2.4%) patients. The annualised event rate was 1.1% in the total population (men=1.3% and women=0.9%). In patients aged <60 years, the annualised event rate of male and female patients was 0.6% and 0.5%, respectively. Among patients aged ≥60 years the annualised event rate was 1.9% in male and 1.1% in female patients. Observations on CTA predicted events in male patients, both age <60 and ≥60 years and in female patients age ≥60 years (log-rank test in all groups, p<0.01). However, CTA provided limited prognostic value in female patients aged <60 years (log-rank test, p=0.45).

CONCLUSIONS

After age and gender stratification, CTA findings were shown to be of limited predictive value in female patients aged <60 years as compared with male patients at any age and female patients aged ≥60 years.

Influence of left ventricular geometry and function on aortic annular dimensions as assessed with multi-detector row computed tomography: implications for transcatheter aortic valve implantation

AIMS

Evaluate changes in aortic annular dimensions in relation to severe aortic stenosis (AS) and left ventricular (LV) dysfunction.

METHODS AND RESULTS

Mean aortic annular diameters and geometries were compared between 90 severe AS patients and 111 controls by multi-detector row computed tomography (MDCT). All severe AS patients were also dichotomized into two groups based on the presence of preserved (≥ 50%) or impaired (<50%) LV ejection fraction (EF). The influence of LV geometry and function on changes in aortic annular dimensions was examined. Patients with severe AS had similar aortic annular dimensions and geometries compared with controls even after correcting for baseline differences in age and body surface area (BSA). However, severe AS patients with LV dysfunction (LVEF <50%) had significantly larger mean aortic annular diameter (26.4 ± 1.9 vs. 24.5 ± 2.1 mm, P < 0.001) compared with patients with preserved LVEF. The presence of LV dysfunction, male gender, and larger BSA were independent determinants of a larger aortic annulus on MDCT.

CONCLUSION

In severe AS patients, the presence of LV dysfunction, not the presence of severe AS, was an independent determinant of a larger aortic annular diameter.

Study protocol: the DESPATCH study: delivering stroke prevention for patients with atrial fibrillation - a cluster randomised controlled trial in primary healthcare

Background

Compelling evidence shows that appropriate use of anticoagulation in patients with nonvalvular atrial fibrillation reduces the risk of ischaemic stroke by 67% and all-cause mortality by 26%. Despite this evidence, anticoagulation is substantially underused, resulting in avoidable fatal and disabling strokes.

Methods

DESPATCH is a cluster randomised controlled trial with concealed allocation and blinded outcome assessment designed to evaluate a multifaceted and tailored implementation strategy for improving the uptake of anticoagulation in primary care. We have recruited general practices in South Western Sydney, Australia, and randomly allocated practices to receive the DESPATCH intervention or evidence-based guidelines (control). The intervention comprises specialist decisional support via written feedback about patient-specific cases, three academic detailing sessions (delivered via telephone), practice resources, and evidence-based information. Data for outcome assessment will be obtained from a blinded, independent medical record audit. Our primary endpoint is the proportion of nonvalvular atrial fibrillation patients, over 65 years of age, receiving oral anticoagulation at any time during the 12-month posttest period.

Discussion

Successful translation of evidence into clinical practice can reduce avoidable stroke, death, and disability due to nonvalvular atrial fibrillation. If successful, DESPATCH will inform public policy, providing quality evidence for an effective implementation strategy to improve management of nonvalvular atrial fibrillation, to close an important evidence-practice gap.

Trial registration

Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12608000074392

Evaluation of troponin T criteria for periprocedural myocardial infarction in patients with acute coronary syndromes

In patients with acute coronary syndromes undergoing percutaneous coronary intervention (PCI), the diagnosis of periprocedural myocardial infarction is often problematic when the pre-PCI levels of cardiac troponin T (TnT) are elevated. Thus, we examined different TnT criteria for periprocedural myocardial infarction when the pre-PCI TnT levels were elevated and also the associations between the post-PCI cardiac marker levels and outcomes. We established the relation between the post-PCI creatine kinase-MB (CKMB) and TnT levels in 582 patients (315 with acute coronary syndromes and 272 with stable coronary heart disease). A post-PCI increase in the CKMB levels to 14.7 μg/L (3 × the upper reference limit [URL] in men) corresponded to a TnT of 0.23 μg/L. In the 85 patients with acute coronary syndromes and normal CKMB, but elevated post peak TnT levels before PCI (performed at a median of 5 days, interquartile range 3 to 7), the post-PCI cardiac marker increases were as follows: 21 (24.7%) with a ≥ 20% increase in TnT, 10 (11.8%) with an CKMB level >3 × URL, and 12 (14%) with an absolute TnT increase of >0.09 μg/L (p <0.005 for both). In the patients with stable coronary heart disease and post-PCI cardiac markers > 3× URL compared to those without markers elevations, the rate of freedom from death or nonfatal myocardial infarction was 88% for those with TnT elevations versus 99% (p <0.001, log-rank) and 84% for those with CKMB elevations versus 98% (p <0.001, log-rank). Of the patients with acute coronary syndromes, the post-PCI marker levels did not influence the outcomes. In conclusion, in patients with acute coronary syndromes and elevated TnT levels undergoing PCI several days later, ≥20% increases in TnT were more common than absolute increments in the TnT or CKMB levels of >3× URL. Also, periprocedural cardiac marker elevations in patients with acute coronary syndromes did not have prognostic significance.

Predictors of death and occurrence of appropriate implantable defibrillator therapies in patients with ischemic cardiomyopathy

Most patients with chronic ischemia and an implantable cardiac defibrillator (ICD) for primary prevention do not experience therapies for ventricular arrhythmias on follow-up. The present study aimed to identify independent clinical, electrocardiographic, and echocardiographic predictors of death and occurrence of ICD therapy in patients with chronic ischemic cardiomyopathy and ICD for primary prevention. A total of 424 patients with chronic ischemic cardiomyopathy, ejection fraction ≤ 35%, and New York Heart Association (NYHA) class ≥ II were recruited. All patients underwent echocardiography before ICD insertion. Primary outcome was all-cause mortality; secondary outcome was occurrence of appropriate ICD therapy on follow-up. Primary and secondary outcomes occurred in 84 and 95 patients, respectively. Patients who died were more likely to have diabetes (hazard ratio [HR] 1.67, 95% confidence interval [CI] 1.00 to 2.79, p = 0.049), higher NYHA class (HR 1.96, 95% CI 1.15 to 3.33, p = 0.013), lower peri-infarct strain on echocardiogram (HR 1.25, 95% CI 1.07 to 1.46, p = 0.005), and lower glomerular filtration rate (HR 1.01, 95% CI 1.00 to 1.03, p = 0.022). Only peri-infarct strain (HR 1.22, 95% CI 1.09 to 1.36, p < 0.001) predicted the occurrence of ICD therapy on follow-up. In conclusion, in chronic ischemic patients with an ICD for primary prevention, the presence of diabetes, renal dysfunction, higher NYHA class, and impaired peri-infarct zone function were predictors of all-cause mortality. In contrast, only impaired peri-infarct zone function determined the occurrence of appropriate ICD therapy on follow-up.

Myocardial steatosis and biventricular strain and strain rate imaging in patients with type 2 diabetes mellitus

BACKGROUND

Magnetic resonance spectroscopy can quantify myocardial triglyceride content in type 2 diabetic patients. Its relation to alterations in left (LV) and right (RV) ventricular myocardial functions is unknown.

METHODS AND RESULTS

A total of 42 men with type 2 diabetes mellitus were recruited. Exclusion criteria included hemoglobin A(1c) >8.5, known cardiovascular disease, diabetes-related complications, or blood pressure >150/85 mm Hg. Myocardial ischemia was excluded by a negative dobutamine stress test. LV and RV volumes and ejection fraction were quantified by magnetic resonance imaging. LV global longitudinal and RV free wall longitudinal strain, systolic strain rate, and diastolic strain rate were quantified by echocardiographic speckle tracking analyses. Myocardial triglyceride content was quantified by magnetic resonance spectroscopy and dichotomized on the basis of the median value of 0.76. The median age was 59 years (25th and 75th percentiles, 54 and 62 years). Median diabetes diagnosis duration was 4 years, and median glycohemoglobin level was 6.2 (25th and 75th percentiles, 5.9 and 6.8). There were no differences in LV and RV end-diastolic and end-systolic volume indexes and ejection fraction between patients with high (≥0.76) and those with low (<0.76) myocardial triglyceride content. However, patients with high myocardial triglyceride content had greater impairment of LV and RV myocardial strain and strain rate. The myocardial triglyceride content was an independent correlate of LV and RV longitudinal strain, systolic strain rate, and diastolic strain rate.

CONCLUSIONS

High myocardial triglyceride content is associated with more pronounced impairment of LV and RV functions in men with uncomplicated type 2 diabetes mellitus.

Longitudinal mechanics of the periinfarct zone and ventricular tachycardia inducibility in patients with chronic ischemic cardiomyopathy

BACKGROUND

Quantification of segmental left ventricular (LV) strain by speckle-tracking echocardiography can identify transmural infarcts in patients with chronic ischemic cardiomyopathy. The aim of the study was to explore the relationship between the LV longitudinal peak systolic strain (LPSS) of the infarct, periinfarct, and remote zones and monomorphic ventricular tachycardia (VT) inducibility on electrophysiologic (EP) study.

METHODS

A total of 134 patients with chronic ischemic cardiomyopathy scheduled for EP study were included. The protocol consisted of clinical, electrocardiographic, and echocardiographic evaluation, including LV longitudinal strain analysis using speckle-tracking echocardiography, immediately before EP study. An infarct segment was defined as a longitudinal strain value of greater than -5%, and a periinfarct segment was defined as immediately adjacent to an infarct segment.

RESULTS

The infarct zone had the most impaired longitudinal strain (-0.5% ± 3.0%), whereas the periinfarct and remote zones had more preserved longitudinal strain (-10.8% ± 1.9% and -14.5% ± 3.0%, respectively; analysis of variance, P < .001). Seventy-two (54%) patients had inducible monomorphic VT on EP study. There was no significant difference in LV ejection fraction (31% ± 9% vs 32% ± 11%, P = .29) between inducible and noninducible patients. Longitudinal peak systolic strain of the periinfarct zone was more impaired in inducible patients (-9.8% ± 1.5% vs -11.0% ± 2.1%, P = .001), but no differences in LPSS of the infarct (-0.5% ± 3.2% vs -0.4% ± 2.7%, P = .75) and remote (-14.6% ± 2.8% vs -14.5% ± 3.4%, P = .92) zones were observed. Only LPSS of the periinfarct zone (OR 1.43, 95% CI 1.15-1.78, P = .001) was independently related to monomorphic VT inducibility on multiple logistic regression.

CONCLUSIONS

Longitudinal strain analysis may be a useful imaging tool to risk stratify ischemic patients for malignant ventricular arrhythmia.

Induction of glucocorticoid receptor-beta expression in epithelial cells of asthmatic airways by T-helper type 17 cytokines

BACKGROUND

Corticosteroid insensitivity in asthmatics is associated with an increased expression of glucocorticoid receptor-beta (GR-beta) in many cell types. T-helper type 17 (Th17) cytokine (IL-17A and F) expressions increase in mild and in difficult-to-treat asthma. We hypothesize that IL-17A and F cytokines alone or in combination, induce the expression of GR-beta in bronchial epithelial cells.

OBJECTIVES

To confirm the expression of the GR-beta and IL-17 cytokines in the airways of normal subjects and mild asthmatics and to examine the effect of cytokines IL-17A and F on the expression of GR-beta in bronchial epithelial cells obtained from normal subjects and asthmatic patients.

METHODS

The expression of IL-17A and F, GR-alpha and GR-beta was analysed in bronchial biopsies from mild asthmatics and normal subjects by Q-RT-PCR. Immunohistochemistry for IL-17 and GR-beta was performed in bronchial biopsies from normal and asthmatic subjects. The expression of IL-6 in response to IL-17A and F and dexamethasone was determined by Q-RT-PCR using primary airway epithelial cells from normal and asthmatic subjects.

RESULTS

We detected significantly higher levels of IL-17A mRNA expression in the bronchial biopsies from mild asthmatics, compared with normal. GR-alpha expression was significantly lower in the biopsies from asthmatics compared with controls. The expression of IL-17F and GR-beta in biopsies from asthmatics was not significantly different from that of controls. Using primary epithelial cells isolated from normal subjects and asthmatics, we found an increased expression of GR-beta in response to IL-17A and F in the cells from asthmatics (P< or =0.05). This effect was only partially significant in the normal cells. Dexamethasone significantly decreased the IL-17-induced IL-6 expression in cells from normal individuals but not in those from asthmatics (P< or =0.05).

CONCLUSION

Evidence of an increased GR-beta expression in epithelial cells following IL-17 stimulation suggests a possible role for Th17-associated cytokines in the mechanism of steroid hypo-responsiveness in asthmatic subjects.

Prognostic implications of left atrial volume index in patients in sinus rhythm

The maximum left atrial volume index (LAVI) has been shown to be of prognostic values, but previous studies have largely been limited to older patients with specific cardiovascular conditions. We examined the independent prognostic values of LAVI in a large unselected series of predominantly younger patients in sinus rhythm followed up for a long period. We evaluated 483 consecutive patients (mean age 47.3 years) using transthoracic echocardiography. The median LAVI was 24 ml/m(2). A primary combined end point of cardiovascular death, stroke, heart failure, myocardial infarction, and atrial fibrillation was sought. We had complete follow-up data for 97.3% of the 483 patients. During a median follow-up of 6.8 years, 86 patients (18.3%) reached the primary end point. Older age, male gender, diabetes, hypertension, hypercholesterolemia, chronic renal failure, a history of myocardial infarction or stroke, a mitral E deceleration time of </=150 ms, and LAVI of >/=24 ml/m(2) were univariate predictors of the primary end point. Event-free survival was significantly lower for patients with a LAVI of >/=24 ml/m(2). Age, a history of stroke, hypertension, chronic renal failure, and male gender were independent clinical predictors. A LAVI of >/=24 ml/m(2) was the only independent echocardiographic predictor (hazard ratio 1.72, 95% confidence interval 1.34 to 2.13, p = 0.018), with the chi-square of the Cox model increased significantly with the addition of the LAVI (p <0.001). The LAVI independently predicted an increased risk of cardiovascular death, heart failure, atrial fibrillation, stroke, or myocardial infarction during a median follow-up of 6.8 years. In conclusion, the prognostic values were incremental to the clinical risks and were valid in a younger, general patient population.

Incremental prognostic value of novel left ventricular diastolic indexes for prediction of clinical outcome in patients with ST-elevation myocardial infarction

This study examined the prognostic value of novel diastolic indexes in ST-elevation acute myocardial infarction (AMI), derived from strain and strain rate analysis using 2-dimensional speckle tracking imaging. Echocardiograms were obtained within 48 hours of admission in 371 consecutive patients with first ST-elevation AMI (59.7 +/- 11.6 years old). Indexes of diastolic function including mean strain rate during isovolumic relaxation (SR(IVR)), mean early diastolic strain rate (SR(E)) and mean diastolic strain at peak transmitral E wave (E) were obtained from 3 apical views. Mean early diastolic velocity from 4 basal segments by color-coded tissue Doppler imaging was measured. Indexes of diastolic filling including E/SR(IVR), E/SR(E), E/diastolic strain at E, and E/early diastolic velocity were calculated. The primary end point (composite of death, hospitalization for heart failure, repeat MI, and repeat revascularization) occurred in 84 patients (22.6%) during a mean follow-up of 17.3 +/- 12.2 months. Mean SR(IVR) (p <0.001), multivessel disease (p <0.001), Thrombolysis In Myocardial Infarction grade 0 to 1 flow after percutaneous coronary intervention (p = 0.004), and left ventricular ejection fraction (p = 0.008) were independent predictors of the combined end point on Cox regression analysis. Mean SR(IVR) showed incremental prognostic value over baseline clinical and echocardiographic variables (global chi-square increase from 41.0 to 51.6, p <0.001). After dividing patient population based on median SR(IVR), patients with SR(IVR) < or =0.24/second had significantly higher event rates than others (hazard ratio 2.74, 95% confidence interval 1.61 to 4.67, p <0.001). In conclusion, SR(IVR) was incremental to left ventricular ejection fraction, Thrombolysis In Myocardial Infarction grade 0 to 1 flow after percutaneous coronary intervention, and multivessel disease and superior to other diastolic indexes in predicting future cardiovascular events after AMI. SR(IVR) may be useful in identifying high-risk patients soon after AMI.

Comparison of aortic root dimensions and geometries before and after transcatheter aortic valve implantation by 2- and 3-dimensional transesophageal echocardiography and multislice computed tomography

BACKGROUND

3D transesophageal echocardiography (TEE) may provide more accurate aortic annular and left ventricular outflow tract (LVOT) dimensions and geometries compared with 2D TEE. We assessed agreements between 2D and 3D TEE measurements with multislice computed tomography (MSCT) and changes in annular/LVOT areas and geometries after transcatheter aortic valve implantations (TAVI).

METHODS AND RESULTS

Two-dimensional circular (pixr(2)), 3D circular, and 3D planimetered annular and LVOT areas by TEE were compared with "gold standard" MSCT planimetered areas before TAVI. Mean MSCT planimetered annular area was 4.65+/-0.82 cm(2) before TAVI. Annular areas were underestimated by 2D TEE circular (3.89+/-0.74 cm(2), P<0.001), 3D TEE circular (4.06+/-0.79 cm(2), P<0.001), and 3D TEE planimetered annular areas (4.22+/-0.77 cm(2), P<0.001). Mean MSCT planimetered LVOT area was 4.61+/-1.20 cm(2) before TAVI. LVOT areas were underestimated by 2D TEE circular (3.41+/-0.89 cm(2), P<0.001), 3D TEE circular (3.89+/-0.94 cm(2), P<0.001), and 3D TEE planimetered LVOT areas (4.31+/-1.15 cm(2), P<0.001). Three-dimensional TEE planimetered annular and LVOT areas had the best agreement with respective MSCT planimetered areas. After TAVI, MSCT planimetered (4.65+/-0.82 versus 4.20+/-0.46 cm(2), P<0.001) and 3D TEE planimetered (4.22+/-0.77 versus 3.62+/-0.43 cm(2), P<0.001) annular areas decreased, whereas MSCT planimetered (4.61+/-1.20 versus 4.84+/-1.17 cm(2), P=0.002) and 3D TEE planimetered (4.31+/-1.15 versus 4.55+/-1.21 cm(2), P<0.001) LVOT areas increased. Aortic annulus and LVOT became less elliptical after TAVI.

CONCLUSIONS

Before TAVI, 2D and 3D TEE aortic annular/LVOT circular geometric assumption underestimated the respective MSCT planimetered areas. After TAVI, 3D TEE and MSCT planimetered annular areas decreased as it assumes the internal dimensions of the prosthetic valve. However, planimetered LVOT areas increased due to a more circular geometry.