Correlation of Non-Invasive Transthoracic Doppler Echocardiography with Invasive Doppler Wire-Derived Coronary Flow Reserve and Their Impact on Infarct Size in Patients with ST-Segment Elevation Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention

Background: Coronary microvascular dysfunction is associated with adverse prognosis after ST-segment elevation myocardial infarction (STEMI). We aimed to compare the invasive, Doppler wire-based coronary flow reserve (CFR) with the non-invasive transthoracic Doppler echocardiography (TTDE)-derived CFR, and their ability to predict infarct size. Methods: We included 36 patients with invasive Doppler wire assessment on days 3-7 after STEMI treated with primary percutaneous coronary intervention (PCI), of which TTDE-derived CFR was measured in 47 vessels (29 patients) within 6 h of the invasive Doppler. Infarct size was assessed by cardiac magnetic resonance at a median of 8 months. Results: The correlation between invasive and non-invasive CFR was modest in the overall cohort (rho 0.400, p = 0.005). It improved when only measurements in the LAD artery were considered (rho 0.554, p = 0.002), with no significant correlation in the RCA artery (rho -0.190, p = 0.435). Both invasive (AUC 0.888) and non-invasive (AUC 0.868) CFR, measured in the recanalized culprit artery, showed a good ability to predict infarct sizes ≥18% of the left ventricular mass, with the optimal cut off values of 1.85 and 1.80, respectively. Conclusions: In patients with STEMI, TTDE- and Doppler wire-derived CFR exhibit significant correlation, when measured in the LAD artery, and both have a similarly strong association with the final infarct size.

Noninvasive evaluation of dynamic microvascular dysfunction in ischemia and no obstructive coronary artery disease patients with suspected vasospasm

INTRODUCTION

In patients with ischemia and no obstructive coronary artery disease (INOCA), a dynamic coronary microvascular dysfunction (CMD) is frequent but difficult to capture by noninvasive means.The aim of our study was to assess dynamic CMD in INOCA patients with stress echocardiography after vasoconstrictive and vasodilator stimuli.

METHODS

In this prospective single-center study, we have enrolled 40 INOCA patients (age 56.3 ± 13 years, 32 women). All participants underwent stress echocardiography with hyperventilation (HYP), followed by supine bicycle exercise (HYP+EXE) and adenosine (ADO). Stress echocardiography included an assessment of regional wall motion abnormality (RWMA) and coronary flow velocity (CFV) in the distal left anterior descending (LAD) coronary artery.

RESULTS

HYP induced a 30% increase in rate pressure product (rest = 10 244 ± 2353 vs. HYP = 13 214 ± 3266 mmHg x bpm, P  < 0.001) accompanied by a paradoxical reduction in CFV (HYP< rest) in 21 patients (52%). HYP alone was less effective than HYP+EXE in inducing anginal pain (6/40, 15% vs. 10/40, 25%, P  = 0.046), ST segment changes (6/40, 15% vs. 24/40, 60%, P  < 0.001), and RWMA (6/40, 15% vs. 13/40, 32.5%, P  = 0.008). ADO-induced vasodilation was preserved (≥2.0) in all patients.

CONCLUSION

In patients with INOCA, a coronary vasoconstriction after HYP is common, in absence of structural CMD detectable with ADO. HYP+EXE test represents a more powerful ischemia inducer than HYP alone. Stress echocardiography with LAD-CFV may allow the noninvasive assessment of dynamic and structural coronary microcirculation during stress.

Prognostic Value of Mitral Regurgitation in Patients with Primary Hypertrophic Cardiomyopathy

Background and Objectives: Mitral valve pathology and mitral regurgitation (MR) are very common in patients with hypertrophic cardiomyopathy (HCM), and the evaluation of mitral valve anatomy and degree of MR is important in patients with HCM. The aim of our study was to examine the potential influence of moderate or moderately severe MR on the prognosis, clinical presentation, and structural characteristics of HCM patients. Materials and Methods: A prospective study examined 176 patients diagnosed with primary asymmetric HCM. According to the severity of the MR, the patients were divided into two groups: Group 1 (n = 116) with no/trace or mild MR and Group 2 (n = 60) with moderate or moderately severe MR. All patients had clinical and echocardiographic examinations, as well as a 24 h Holter ECG. Results: Group 2 had significantly more often the presence of the obstructive type of HCM (p < 0.001), syncope (p = 0.030), NYHA II class (p < 0.001), and atrial fibrillation (p = 0.023). Also, Group 2 had an enlarged left atrial dimension (p < 0.001), left atrial volume index (p < 0.001), and indirectly measured systolic pressure in the right ventricle (p < 0.001). Patients with a higher grade of MR had a significantly higher E/e' (p < 0.001) and, as a result, higher values of Nt pro BNP values (p < 0.001) compared to Group 1. Kaplan-Meier analysis demonstrated that the event-free survival rate during a median follow-up of 88 (IQR 40-112) months was significantly higher in Group 1 compared to Group 2 (84% vs. 45% at 8 years; log-rank 20.4, p < 0.001). After adjustment for relevant confounders, the presence of moderate or moderately severe MR remained as an independent predictor of adverse outcomes (HR 2.788; 95% CI 1.221-6.364, p = 0.015). Conclusions: The presence of moderate or moderately severe MR was associated with unfavorable long-term outcomes in HCM patients.

Predictors of diastolic deceleration time of coronary flow velocity of infarct related and reference coronary artery assessed by transthoracic Doppler echocardiography in the chronic phase of successfully reperfused anterior myocardial infarction: relation to infarct size

Introduction

High-frequency transthoracic Doppler echocardiography (TDE) enables the assessment of flow velocity and velocity pattern in different coronary arteries, including the assessment of diastolic deceleration time (DDT) of coronary flow velocity. Short DDT of infarct related artery (IRA) (<600 msec) in the acute phase of anterior myocardial infarction (MI) is the predictor of adverse left ventricular (LV) remodeling and prognosis. The significance of DDT of coronary flow velocity assessment in the chronic phase of anterior MI is not well established. Our study aimed to establish the predictors of DDT of the coronary flow velocity of infarct related (left anterior descendent-DDT of LAD) and reference coronary artery, evaluated by TDE, and to assess their relation to infarct size in the chronic phase of successfully reperfused first anterior MI.

Methods

Our study included 40 consecutive patients (34 men, mean age 52 ± 12 years) one month after the first anterior STEMI and single vessel disease successfully treated with primary PCI. All patients underwent SPECT MPI for the assessment of LV volumes, ejection fraction, and percentage of the myocardium with fixed perfusion abnormalities and echocardiographic examination including the evaluation of DDT of IRA and reference coronary artery TDE.

Results

DDT of LAD correlated significantly to the WMSI (r = -0.467, p = 0.002), LV end-systolic volume (r = -0.412, p = 0.008), LV ejection fraction (r = 0.427, p = 0.006), while the strongest correlation was observed between DDT of LAD and the extent of fixed perfusion abnormality (r = -0.627, p < 0.0001), Multivariate analysis revealed percentage of fixed perfusion abnormalities along with DDT of reference coronary artery as the independent predictors of DDT of IRA. DDT of IRA shorter than 886 msec predicts large fixed perfusion abnormalities (>20%) with a sensitivity of 89% and specificity of 62% (AUC 0.842).

Conclusion

DDT of LAD assessed by TDE in the chronic phase of successfully reperfused first anterior MI is a usefull variable for the assessment of microcirculatory function that exclusively reflects the extent of microvascular damage and relates to infarct size.

Heart Rate Recovery as a Predictor of Long-Term Adverse Events after Negative Exercise Testing in Patients with Chest Pain and Pre-Test Probability of Coronary Artery Disease from 15% to 65

BACKGROUND

The prognosis of patients with chest pain after a negative exercise test is good, but some adverse events occur in this low-risk group. The aim of our study was to identify predictors of long-term adverse events after a negative exercise test in patients with chest pain and a lower intermediate (15-65%) pre-test probability of coronary artery disease (CAD) and to assess the prognostic value of exercise electrocardiography and exercise stress echocardiography in this group of patients.

METHODS

We identified from our stress test laboratory database 862 patients with chest pain without previously known CAD and with a pre-test probability of CAD ranging from 15 to 65% (mean 41 ± 14%) who underwent exercise testing. Patients were followed for the occurrence of death, non-fatal myocardial infarction (MI) and clinically guided revascularization.

RESULTS

During the median follow-up of 94 months, 87 patients (10.1%) had an adverse event (AE). A total of 30 patients died (3.5%), 23 patients suffered non-fatal MI (2.7%) and 34 patients (3.9%) had clinically guided revascularization (20 patients percutaneous and 14 patients surgical revascularizations). Male gender, age, the presence of diabetes and a slow heart rate recovery (HRR) in the first minute after exercise were independently related to the occurrence of AEs. Adverse events occurred in 10.3% of patients who were tested by exercise stress echocardiography and in 10.0% of those who underwent stress electrocardiography (p = 0.888).

CONCLUSION

The risk of AEs after negative exercise testing in patients with a pre-test probability of CAD of 15-65% is low. Male patients with a history of diabetes and slow HRR in the first minute after exercise have an increased risk of an adverse outcome.

Additive negative prognostic value of coronary flow reserve in patients with left bundle branch block without inducible ischemia and without known coronary artery disease

Background

Left bundle branch block (LBBB) can be isolated thing, but it is also often associated with underlying coronary artery disease (CAD). Stress echocardiography (SECHO) is widely used as an imaging method for the diagnosis of CAD. However, the diagnostic value of stress echocardiography in patients (pts) with LBBB is limited.

Purpose

To evaluate negative prognostic value of coronary flow reserve (CFR) in pts with LBBB without inducible ischemia and without known CAD.

Methods

This retrospective study included 224 pts (98, 43.8% male gender, average age 66±11 years) with LBBB and without known CAD. All the pts had negative SECHO test according the Bruce protocol. Risk factors for CAD (diabetes, smoking, hypertension, high cholesterol and positive family history of CAD), Duke treadmill score, functional capacity (Metabolic Equivalents - METs) were recorded in all pts. Out of 224 pts, in 64 (29.5%) coronary flow reserve on the left anterior descending artery was assessed using pulsed Doppler echocardiography with adenosine in a dose of 140μcg/kg/body weight during 3 minutes. As the normal value we took value of CFR ≥2. Median follow up of the pts was 72 months (IQR 56.25–132 months) for the occurrence of MACE (cardiovascular death (CVD), non-fatal myocardial infarction (nfMI), coronary artery bypass graft (CABG) and percutaneous coronary revascularization (PCI).

Results

Out of 224 pts, 6 (2.7%) had positive SECHO test, 2 pts (0.9%) had died due to non-cardiac causes and 11 pts (4.9%) were lost to follow up so they were excluded from further analysis. The remaining 204 pts were divided in 2 groups: 1. pts with only negative SECHO (n=144, 68.8%); 2. pts with negative SECHO and normal CFR (n=64, 31.2%). During the follow-up period 22 out of 205 pts (10.7%) had an adverse event (6 CVD, 6 nfMI, 5 CABG, 8 PCI). Between the two groups there was no significant difference in risk factors and parameters of the SECHO test. Pts with CFR had significantly lower rate of MACE compared to the pts with only SECHO test (2, 3.1% vs 20, 14.2%, p=0.018, respectively). Using the Cox regression analysis, univariate predictors of MACE were insulin dependent diabetes (HR 10.851 [95% CI 2.095–56.220], p=0.004), Duke score (HR 0.603 [95% CI 0.414–0.878], p=0.008), and MET (HR 0.393 [95% CI 0.209–0.737], p=0.004). In the multivariate analysis only the insulin dependent diabetes remained an independent predictor of MACE (HR 6.906 [95% CI 1.100–43.363], p=0.039). Using the Kaplan-Meier survival curve we see that the pts with SECHO test and CFR had shorter event-free time compared to the pts with SECHO test (136.3±3.6 months vs 149.8±2.9 months, Log Rank 4.022, p=0.045) (Figure 1).

Conclusion

Normal value of CFR has good negative prognostic value in pts with LBBB without inducible ischemia and without known CAD, while pts with insulin dependent diabetes have more pronounced risk for the occurrence of adverse events.

Funding Acknowledgement

Type of funding sources: None.

Haemodynamic indicators of arteriolar dysregulation during combined hyperventilation and exercise test in patients with ANOCA (SESPASM)

Introduction

In patients with angina and non-obstructed coronary arteries (ANOCA), functional dysregulation such as epicardial coronary spasm and microvascular dysfunction (microvascular spasm and /or impaired microvascular dilatation) frequently coexist.

The aim was to analyse haemodynamic indicators of arteriolar dysregulation during combined hyperventilation and exercise stress echo test in patients with ANOCA.

Methods

In a prospective study we enrolled 38 patients (56±13 years, 31 females) with ANOCA, proven by normal coronary angiogram. Stress echocardiography protocol with Doppler measurements of coronary flow consisted of hyperventilation test for spasm provocation (HYP, respiratory rate of 30 per min for 5') followed by supine bicycle exercise test (HYP+EXE) for assessment of endothelium dependent function. Adenosine test was done (ADO 140 mcg/kg in 1 min) for estimation of endothelium independent vasodilatation. Coronary flow velocity (CFV) was assessed in distal LAD by Transthoracic Doppler echocardiography at the end of the each stage of the test. Abnormal response to HYP was a CFV ratio (stress/rest) &lt;1.0 (vasoconstrictor response). CFV ratio at peak HYP+ EXE was an indicator of endothelial dependent vasodilatation (&lt;2 blunted response). An abnormal response to ADO was a CFV reserve &lt;2.0 (blunted vasodilatory response).

Results

The double product increased during HYP in comparison to rest (13263 vs 10321, p&lt;0.001), and further increased with EXE (23817 vs HYP, p&lt;0.001). Chest pain was present in 6 pts during HYP, and in additional three pts during HYP+EXE (15.8% vs 23.7%, p=0.25). ST segment depression was present in 6 pts during HYP and 23 during HYP+EXE (15.79% vs 60.52%, p&lt;0.001). Wall motion abnormality was provoked with HYP in three pts (7.89%) and in ten (26.3%) with HYP+EXE (p=0.016). CFV ratio was abnormal for vasoconstriction during HYP in 16 (42.1%) and blunted in 23 (60.52%) pts during HYP+EXE (Fig 1). Vasodilation during ADO was preserved in all patients, but one. There was significant difference between CFV reserve during HYP+EXE vs ADO (1.98±0.49 vs 2.53±0.43 respectively, p&lt;0.001) (Fig. 2).

Conclusion

Our results indicate that HYP induce microvascular dysfunction with vasospastic component which is reflected in reduced CFV ratio. This prevents the normal hyperemic response during EXE in more than a half of patients. Endothelial independent vasodilatation during ADO hyperemia was perserved in all patients, excluding structural microvasculature remodeling. HYP+EXE provocation with noninvasive measurement of coronary flow is a promising test for assessing mechanism of arteriolar dysregulation in ANOCA patients.

Funding Acknowledgement

Type of funding sources: None.

Diagnostic accuracy of instantaneous wave-free ratio at rest and during dobutamine provocation to assess myocardial bridging relevance

Background

Diastolic fractional flow reserve (d-FFR) during dobutamine provocation (DOB) was found to be a more reliable physiological index for the functional assessment of myocardial bridging (MB). However, d-FFR calculation is complicated and time-consuming, and therefore several authors have suggested the use of instantaneous wave-free ratio (iFR) to overcome these issues.

Purpose

The aim of our study was to assess diagnostic performance of d-FFR and iFR at rest and during DOB with exercise-induced myocardial ischemia as reference.

Methods

Twenty-four symptomatic patients (17 males, mean age 58±8 years) with MB and systolic compression ≥50% diameter stenosis on the left anterior descending (LAD) artery were included. Exercise stress-echocardiography test (SE), and both d-FFR and iFR in the distal segment of LAD at rest and peak DOB (30–50μg/kg/min), were performed in all patients. Optimal cut-off values and diagnostic performance of resting and hyperemic d-FFR and iFR were assessed using SE.

Results

Exercise-SE was positive for myocardial ischemia in 7/24 patients (29%). The area-under-the-receiver-operating-characteristic curve (ROC-AUC) for exercise-induced myocardial ischemia was 0.64 (95% CI: 0.400–0.885) for resting d-FFR, 0.62 (95% CI: 0.378–0.866) for resting iFR, 1.000 (95% CI: 0.999–1.000) for d-FFR at peak DOB, and 0.96 (95% CI: 0.895–1.000) for iFR at peak DOB. No significant difference in ROC-AUC was observed between d-FFR and iFR at peak DOB (p=0.243). The best cut-off value for both d-FFR and iFR at peak DOB was &lt;0.76 with similar sensitivity and negative predictive values (100 vs. 100% for both), but lower specificity and positive predictive value for iFR in identifying MB associated with exercise-induced ischemia (94% vs. 82%; 88% vs. 70%, respectively). Compared with exercise-induced myocardial ischemia, the diagnostic accuracy of d-FFR and iFR at peak DOB was 96% (kappa=0.903, p&lt;0.001) and 88% (kappa=0.731, p&lt;0.001), respectively.

Conclusions

iFR during DOB provocation showed similar diagnostic accuracy as d-FFR to identify the functionally significant MB when compared with exercise-induced myocardial ischemia.

Funding Acknowledgement

Type of funding sources: None.

Comparison of SCORE and SCORE 2 risk prediction tools in contemporary very high risk european population

Background

New SCORE 2 algorithm overperformed SCORE algorithm in population with decreasing prevalence of cardiovascular (CV) morbidity and mortality. However, there is limited data in risk stratification with SCORE 2 model in contemporary populations from very high risk countries.

Aim

The aim of this study was to compare risk prediction using SCORE 2 and SCORE model and to compare the proportions of patients requiring statin treatment in primary prevention.

Methods

Our study included 1317 patients (511, 38.8% male gender, average age 54±8) without known CV disease aged 40 to 70 years. Data on CV risk factors were prospectively collected in 20 primary care centers throughout the Serbia from January 2020. to December 2020. Based on the CV risk profile, patients were stratified into 4 categories: low, moderate, high and very high risk according to SCORE model and into 3 categories: low to moderate, high and very high risk according to SCORE 2 model. The number of patients requiring statin treatment was assessed according to the risk category and value of LDL cholesterol in SCORE model and the value of non-HDL cholesterol in SCORE 2 model.

Results

Overall, 589 patients (44.7%) were smokers, mean value of total cholesterol was 6.2±1.1 mmol/L, LDL 3.9±1.1, HDL 1.4±0.5, non HDL 4.8±1.2 mmol/L. Systolic blood pressure was 138.6±19.6, diastolic blood pressure was 85.3±10.4 mmHg and was BMI 26.9±5.2. Based on the SCORE model 166 patients (12.6%) were classified into low risk category, 658 (49.9%) into moderate, 276 (20.9%) into high risk and 217 (16.6%) into very high risk category. Based on the SCORE 2 model 30 (2.8%) patients were classified into low to moderate, 273 (18%) and 1014 (79.2%) into very high risk category. There was significantly less patients in low to moderate group in SCORE 2 model compared to SCORE model (30, 2.8% vs 824, 62.6%, p&lt;0.001 respectively) and significantly more patients with very high risk (1014, 79.2% vs 217, 16.6%, p&lt;0.001), but without significance difference in the high risk group (Figure 1). The use of SCORE 2 model resulted in significantly higher proportion of patients requiring statin treatment 93% vs. 43% using SCORE model (p&lt;0.001).

Conclusion

The use SCORE 2 risk prediction tool, in comparison to SCORE model, results in significant higher proportion of patients being classified as very high risk category with the increase number of patients requiring statin treatment in primary prevention.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Krka Farma

Role of different echocardiographic modalities in the assessment of microvascular function in women with ischemia and no obstructive coronary arteries

This review summarizes current knowledge about echocardiographic modalities used to assess microvascular function and left ventricular (LV) systolic function in women with ischemia and no obstructive coronary arteries (INOCA). Although the entire pathophysiological background of this clinical entity still remains elusive, it is primarily linked to microvascular dysfunction which can be assessed by coronary flow velocity reserve. Subtle impairments of LV systolic function in women with INOCA are difficult to assess by interpretation of wall motion abnormalities. LV longitudinal function impairment is considered to be an early marker of subclinical systolic dysfunction and can be assessed by global longitudinal strain quantification.

Assessment of left ventricular contractile reserve during hyperventilation and exercise in patients with ANOCA

Funding Acknowledgements

Type of funding sources: None.

Introduction. Mechanism of ischemia in patients with angina and no obstructive coronary artery disease (ANOCA), is often unrecognized since invasive tests are seldom done and proper noninvasive test is not established yet.

The aim of our study was to assess changes in ventricular function during hyperventilation test  (HYP) designed to provoke vasoconstriction, immediately followed by supine bicycle exercise to increase ischemic stimuli in patients with ANOCA (HYP + EXE).

Methods. : In a prospective study, we enrolled 29 ANOCA patients  (age 59.6 ±11 years, 27 females) with previously normal angiograms. All patients underwent SE testing with hyperventilation (HYP, respiratory rate of 30 per min for 5"), immediately followed by supine bicycle exercise (HYP + EXE). Ventricular function was assessed based on left ventricular contractile reserve (LVCR), calculated by ratio of the ventricular force at the peak of the each stress level and rest. Force was assessed as the quotient between systolic arterial pressure and end-systolic volume determined by two-dimensional echocardiography. Values range from normal (&gt; 2.0) to mild (1.5–2.0), moderate (1.01–1.49), and severe (≤1.0) dysfunction. For LVCR HYP values are shifted towards lower values (abnormal &lt; 1.1).

Results. Chest pain or dyspnea were present in 4/29 pts during HYP, and in 7/29 patients during HYP + EXE (13.8% vs 24.1 %, p = 0.001). Three patients showed wall motion abnormalities with hyperventilation and additional two patients with HYP + EXE. LVCR HYP response was normal in 19/29 (65.5%) pts and abnormal in 10/29 (34.5%) pts. LVCR HYP + EXE response was normal in 9/29 (31%) pts, 4/29 (13.8%) pts had mild, 11/29 (37.9%) pts had moderate and 5/29 (17.3%) pts had severe dysfunction.

Conclusion. In patients with ANOCA subtle changes in LV function occurred with HYP and EXE stress more often than wall motion abnormality. Measurement of contractile reserve might be a useful tool in assessment of ischemia and ventricular dysfunction in patients with ANOCA. Abstract Figure 1.  Abstract Figure 2.

Specific impact of cardiovascular risk factors on coronary microcirculation in patients with subclinical hypothyroidism

Background

Although thyroid hormones have significant effect on cardiovascular system, the impact of subtle thyroid dysfunction such as subclinical hypothyroidism (SCH) remains to be determined. We investigated coronary flow reserve (CFR) in patients with subclinical hypothyroidism.

Methods

Thirty two subjects with SCH and eighteen control subjects with normal serum thyroid hormones and thyroid-stimulating hormone (TSH) levels were included in the study. TSH, free thyroxine, free triiodothyronine, glucose, insulin, HbA1c, cholesterol, triglyceride and plasma levels of C-reactive protein were measured. Coronary diastolic peak flow velocities in left anterior descending coronary artery were measured at baseline and after adenosine infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocity.

Results

CFR values were not significantly different between the two groups (SCH 2.76±0.35 vs controls 2.76±0.42). There was a significant correlation of CFR with waist to hip ratio, hypertension, smoking habits, markers of glucose status (glucose level, HbA1c, insulin level, HOMA IR), cholesterol, LDL-cholesterol and triglyceride levels in SCH group, whereas only cholesterol level showed significant correlation with CFR in controls. There was no correlation between CFR and thyroid hormones.

Conclusions

We concluded that there is a different impact of cardiovascular risk factors on CFR in SCH patients compared to healthy control and that these two groups behave differently in the same circumstances under the same risk factors. The basis for this difference could be that the altered thyroid axis "set point" changes the sensitivity of the microvasculature in patients with SCH to known risk factors.

The Value of Stress Echocardiography Imaging and Functional Parameters in Patients with aVR Lead ST-Segment Elevation during an Exercise Stress Test to Detect Significant Left Main Stenosis

OBJECTIVE

To evaluate the role of functional and imaging parameters during exercise stress echocardiography (SE) in the presence of ST-segment elevation (ST-E) in aVR leads to predict significant left main/left main equivalent/or ostial left anterior descending (LAD) stenosis (LM+).

METHODS

The study population included 548 patients with ECG and echo markers of myocardial ischemia, in whom diagnostic coronary angiography was performed. We analyzed the patients' clinical characteristics, ECG changes, wall motion score index (WMSI) by stress echocardiography (SE), as well as functional capacity during exercise (METs) and Duke treadmill score.

RESULTS

aVR ST-segment elevation was found in 60/548 (11%) patients, whereas aVR ST-E was found in 23/57 patients with left main LM stenosis (Sn 40%, Sp 92%, PPV 38%, NPV 93%). When aVR ST-E was combined with other functional/imaging parameters, patients with aVR ST-E and LM+ had significantly worse functional capacity in METs (5.0±2.2 vs. 6.7±2.3, P=0.005), lower Duke score (-6.8±6.8 vs. -3.6±4.1, P=0.049), and higher deterioration of WMSI (0.51±0.24 vs. 0.39±0.24, P=0.046). Significant multivariable predictors of the left main (LM) stenosis were aVR ST-E and positive SE in LAD territory in the whole group of patients, and Delta WMSI, Duke score and METs achieved in patients presented with aVR ST-E during exercise.

CONCLUSION

The aVR ST-segment alone has intermediate sensitivity in detecting significant LM stenosis in patients referred to SE testing for chest pain. When combined with other functional and imaging parameters, including poor exercise functional capacity in METs, lower Duke score or greater WMA in the territory of LAD, its diagnostic power to detect LM significantly increases.

Prognostic Value of Transthoracic Doppler Echocardiography Coronary Flow Velocity Reserve in Patients With Asymmetric Hypertrophic Cardiomyopathy

Background

Microvascular dysfunction might be a major determinant of clinical deterioration and outcome in patients with hypertrophic cardiomyopathy (HCM). However, long‐term prognostic value of transthoracic Doppler echocardiography (TDE) coronary flow velocity reserve (CFVR) on clinical outcome is uncertain in HCM patients. Therefore, the aim of our study was to assess long‐term prognostic value of CFVR on clinical outcome in HCM population.

Methods and Results

We prospectively included 150 HCM patients (82 women; mean age 48±15 years). Patients’ clinical characteristics, echocardiographic and CFVR findings (both for left anterior descending [LAD] and posterior descending artery [PD]), were assessed in all patients. The primary outcome was a composite of: HCM related death, heart failure requiring hospitalization, sustained ventricular tachycardia and ischemic stroke. Patients were stratified into 2 subgroups depending on CFVR LAD value: Group 1 (CFVR LAD>2, [n=87]) and Group 2 (CFVR LAD≤2, [n=63]). During a median follow‐up of 88 months, 41/150 (27.3%) patients had adverse cardiac events. In Group 1, there were 8/87 (9.2%), whereas in Group 2 there were 33/63 (52.4%, P<0.001 vs. Group 1) adverse cardiac events. By Kaplan‐Meier analysis, patients with preserved CFVR LAD had significantly higher cumulative event‐free survival rate compared to patients with impaired CFVR LAD (96.4% and 90.9% versus 66.9% and 40.0%, at 5 and 8 years, respectively: log‐rank 37.2, P<0.001). Multivariable analysis identified only CFVR LAD≤2 as an independent predictor for adverse cardiac outcome (HR 6.54; 95% CI 2.83–16.30, P<0.001), while CFVR PD was not significantly associated with outcome.

Conclusions

In patients with HCM, impaired CFVR LAD (≤2) is a strong, independent predictor of adverse cardiac outcome. When the aim of testing is HCM risk stratification and CFVR LAD data are available, the evaluation of CFVR PD is redundant.

Cut-off value of coronary flow velocity reserve obtained by transthoracic Doppler echocardiography during intravenous infusion of dobutamine for diagnosis of functional significant myocardial bridging

Background

Recent studies showed that coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) during inotropic stimulation with dobutamine (DOB), in comparison to vasodilation with adenosine, provides more reliable functional evaluation of myocardial bridging (MB). However, the adequate cut-off value of CFVR during DOB for diagnosing functional significant MB has not been fully established.

Purpose

The purpose of the study was to evaluate the adequate cut-off value of TTDE- CFVR during DOB for diagnosis of functional significant MB.

Methods

This prospective study included 79 patients (54 males, mean age 55±10 years) with angiographic evidence of isolated MB on the left anterior descending artery (LAD) and systolic compression ≥50% diameter stenosis. Exercise stress-echocardiography test (ExSE) and TTDE-CFVR in the distal segment of LAD during DOB infusion (DOB: 10–40μg/kg/min) were performed in all patients. Percent diameter stenosis (DS) of MB at end-systole and end-diastole were analyzed using quantitative coronary angiography.

Results

Exercise-SE was positive for myocardial ischemia in 22/79 (28%). CFVR during peak DOB was significantly lower in SE-positive group in comparison to SE-negative group (1.94±0.16 vs. 2.78±0.53, p&lt;0.001). ROC analysis identifies the optimal CFVR during peak DOB cut-off value &lt;2.1 (AUC 0.985, 95% CI: 0.965–1.000, p&lt;0.001), with a sensitivity of 96% and specificity of 95%, positive predictive value of 88%, and negative predictive value of 98%, for identifying functionally significant MB associated with stress-induced myocardial ischemia. The categorical agreement between TTDE-CFVR at peak DOB and ExSE was high (kappa value = 0.877, p&lt;0.001). Multivariate logistic regression analysis showed that percent DS at end-diastole was the only independent predictor of ischemic CFVR value &lt;2.1 (OR: 1.136, 95% CI: 1.045–1.235, p=0.003).

Conclusion

A cut-off value &lt;2.1 of CFVR during DOB infusion obtained by TTDE may adequate discriminate functional significant MB that induce myocardial ischemia which is caused by an incomplete diastolic MB-decompression.

Funding Acknowledgement

Type of funding sources: None.

Noninvasive functional testing in ANOCA: hyperventilation-exercise study for spasm (SESPASM)

Introduction

In patients with angina and no obstructive coronary artery disease (ANOCA), different mechanisms of ischaemia, epicardial spasm, microvascular spasm, and impaired microvascular dilatation frequently coexist.

The aim was to assess CFVR changes during coronary vasoconstrictor and vasodilator stimuli in patients with ANOCA.

Methods

In a prospective single center study, we enrolled 29 ANOCA patients (age 59.6±11 years, 27 females) with previously normal angiograms. All underwent SE testing with hyperventilation (HYP, respiratory rate of 30 per min for 5') followed by supine bicycle exercise (HYP+EXE); and adenosine CFV evaluation (ADO 140 mcg/kg in 1 min) on the other day. Coronary flow velocity (CFV) was assessed in distal LAD by Transthoracic Doppler echocardiography. The ratio of peak/rest changes of CFV during HYP in LAD was taken as an index of vasoconstriction, and CFV reserve was evaluated after EXE. An abnormal response to HYP was a CFV ratio &lt;1.0 (vasoconstrictor response). An abnormal response to ADO was a CFV reserve &lt;2.0 (blunted vasodilatory response). CFVR at peak HYP+ EXE was an indicator of endothelial dependent vasodilatation.

Results

The double product increased during HYP, in comparison to rest (13213 vs 10517, p&lt;0.01), and further increased with EXE (23387 vs HYP, p&lt;0.001). Chest pain or dyspnea were present in 4/29 pts during HYP, and in 7/29 patients during HYP+EXE (13.8% vs 24.1%, p=0.001). ST segment depression (≥1mm) was present in 7/29 patients during HYP, and 14/29 during HYP+EXE (24.13% vs 48.3%, p&lt;0.01). Five patients (17%) showed regional wall motion abnormalities with HYP+EXE. CFVR response was abnormal in 19/29 (65%) patients during HYP+EXE, and abnormal for vasoconstriction during HYP in 13 (44%). Vasodilation during ADO was preserved in all patients.There was significant difference between CFVR response during HYP+EXE and ADO (1.9±0.35 vs 2.47±0.42 respectively, p&lt;0.01), and between CFVR HYP and ADO (1.28±0.29 vs 2.47±0.42, p&lt;0.001).

Conclusion

In patients with ANOCA, HYP+EXE is a more powerful ischemic stress than HYP alone. In over one-half of patients HYP+EXE unmasks abnormalities in CFVR response and/or regional wall motion, likely unmasking the underlying endothelium dependent microcirculatory dysfunction with enhanced vasoconstriction in 44% of the patients and mixed vasoconstriction and reduced relaxation in 65%.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): University Clinical Centre of Serbia, Faculty of Medicine

Focal Myocarditis after Mild COVID-19 Infection in Athletes

COVID-19 infection in athletes usually has a milder course, but in the case of complications, myocarditis and even sudden cardiac death may occur. We examined an athlete who felt symptoms upon returning to training after asymptomatic COVID-19 infection. Physical, laboratory, and echocardiography findings were normal. The cardiopulmonary exercise test was interrupted at submaximal effort due to severe dyspnea in the presence of reduced functional capacity in comparison to previous tests. Cardiac magnetic resonance (CMR) detected the focal myocarditis. After three months of recovery, CMR still revealed the presence of focal myocarditis and the persistence of decreased functional capacity. This case raises the question of screening athletes even after asymptomatic forms of COVID-19 infection.

Hemodynamic Heterogeneity of Reduced Cardiac Reserve Unmasked by Volumetric Exercise Echocardiography

Background: Two-dimensional volumetric exercise stress echocardiography (ESE) provides an integrated view of left ventricular (LV) preload reserve through end-diastolic volume (EDV) and LV contractile reserve (LVCR) through end-systolic volume (ESV) changes. Purpose: To assess the dependence of cardiac reserve upon LVCR, EDV, and heart rate (HR) during ESE. Methods: We prospectively performed semi-supine bicycle or treadmill ESE in 1344 patients (age 59.8 ± 11.4 years; ejection fraction = 63 ± 8%) referred for known or suspected coronary artery disease. All patients had negative ESE by wall motion criteria. EDV and ESV were measured by biplane Simpson rule with 2-dimensional echocardiography. Cardiac index reserve was identified by peak-rest value. LVCR was the stress-rest ratio of force (systolic blood pressure by cuff sphygmomanometer/ESV, abnormal values ≤2.0). Preload reserve was defined by an increase in EDV. Cardiac index was calculated as stroke volume index * HR (by EKG). HR reserve (stress/rest ratio) <1.85 identified chronotropic incompetence. Results: Of the 1344 patients, 448 were in the lowest tertile of cardiac index reserve with stress. Of them, 303 (67.6%) achieved HR reserve <1.85; 252 (56.3%) had an abnormal LVCR and 341 (76.1%) a reduction of preload reserve, with 446 patients (99.6%) showing ≥1 abnormality. At binary logistic regression analysis, reduced preload reserve (odds ratio [OR]: 5.610; 95% confidence intervals [CI]: 4.025 to 7.821), chronotropic incompetence (OR: 3.923, 95% CI: 2.915 to 5.279), and abnormal LVCR (OR: 1.579; 95% CI: 1.105 to 2.259) were independently associated with lowest tertile of cardiac index reserve at peak stress. Conclusions: Heart rate assessment and volumetric echocardiography during ESE identify the heterogeneity of hemodynamic phenotypes of impaired chronotropic, preload or LVCR underlying a reduced cardiac reserve.

Prognostic value of mitral regurgitation in patients with asymmetric hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Introduction

Since mitral regurgitation (MR) is a very common finding in patients with hypertrophic cardiomyopathy (HCM), the evaluation of the mitral valve anatomy and the degree of MR is of utmost importance in this population. However, data regarding the prognostic value of different degrees of MR in HCM remains scarce.

Purpose

The aim of this study was to determine whether the presence of a higher degree of MR affects: 1) long term prognosis; 2) clinical and echocardiographic presentation of HCM patients.

Material and Methods

We included prospectively 102 patients, diagnosed with primary asymmetric HCM. The degree of MR was determined echocardiographicaly according to current recommendations of the American Association of Echocardiography. According to the MR severity, patients were divided into 2 groups: Group 1 (n = 52) with no/trace or mild MR and Group 2 with moderate or moderate to severe MR. All patients had clinical and echocardiographic examination, 24-hour Holter ECG and NT pro BNP analysis performed. The primary outcome was a composite of: 1) HCM related death or sudden death; 2) hospitalization due to acute heart failure; 3) sustained ventricular tachycardia; 4) ischemic stroke.

Results

Patients with higher MR degree had more frequent chest pain (p = 0.039), syncope (p = 0.041) and NYHA II functional class (p &lt; 0.001). Group 2 patients had mostly obstructive form of HCM (p &lt; 0.001) with more frequent presence of previous atrial fibrillation (AF) (p = 0.032), as well as the new onset of AF (p = 0.014) compared to patients in Group 1. Patients with higher MR degree had significantly more SAM (p &lt; 0.001) resulting in a more frequent eccentric MR jet (p &lt; 0.001), along with calcified mitral annulus (p = 0.007), enlarged left atrial volume index (p &lt; 0.001), and elevated right ventricular pressure (p = 0.001). As a result of higher MR grade, Group 2 had higher E/e" values (p &lt; 0.001), elevated LV filling pressure (lateral E/e’ &gt;10), as well as higher levels of NT pro BNP (p = 0.001). By Kaplan-Meier analysis we demonstrated that the event free survival rate during follow up of median 75 (IQR 48-103) months was significantly higher in Group 1 compared to the Group 2 (79% vs. 46%, p &lt; 0.001), Figure 1. After adjustment for relevant confounders, moderate/moderate to severe MR remained as an independent predictor of adverse outcome (hazard ratio 2.58, 95% CI: 1.08-6.13, p &lt; 0.001).

Conclusion

Presence of moderate, or moderate to severe MR was associated with poor long-term outcome of HCM patients. These results indicate the importance of an adequate MR assessment and detailed evaluation of the mitral valve anatomy in the prediction of complications and adequate treatment of patients with HCM.

Abstract Figure.

Long term perspective with LBBB: role of stress echocardiography

Background

Previous studies have shown that left bundle branch block (LBBB), as a relatively common electrocardiographic (ECG) abnormality, represents the condition with often non benign and sometimes adverse outcome.

Purpose

The Aim of our study was to determine the predictive value of a stress echocardiography test in patients with LBBB.

Methods

Our study population included 189 patients (88 male, 46.6%, mean age 63.08±9.65) with diagnosed left bundle branch block who performed stress echocardiography (SECHO) according to Bruce protocol. Median follow-up of the patients was 56 months (IQR 48–71 months) for the occurrence of cardiovascular death and non-fatal myocardial infarction, repeat revascularization (coronary artery bypass grafting-CABG or percutaneous coronary intervention-PCI).

Results

Out of 189 patients, 32 (16.9%) patients had positive, while 157 (83.1%) patients had negative SECHO test. During the follow up period 28 patients had major adverse cardiac event: 1 nonfatal myocardial infarction, 6 heart failure hospitalizations, 5 CABGs, 8 PCIs, while 8 patients had cardiac death. Using the Cox regression analysis, univariate predictors of adverse cardiac events were diabetes mellitus (HR 4.530 [95% CI 1.355–15.141], p=0.014), PCI (HR 4.288 [95% [95% CI 2.010–9.144], p&lt;0.001) and positive SECHO test (HR 2.289 [95% CI 1.006–5207], p=0.048). In the multivariate analysis only previous PCI remained independent predictor of adverse events (HR 3.650 [95% CI 1.665–8.003], p=0.001). p=0.048). Using the Kaplan-Meier survival curve the patients with negative SECHO had better outcome compared to patients with positive SECHO (140/160; 87,5% vs 21/29; 72.4%, p=0.035) and much longer event-free time (77.4±1.6 months vs 67.1±5.4 months, Log Rank 4.136, p=0.042)

Conclusion

Patients with LBBB and negative SEHO test have good prognosis. Patients with history of CAD and diabetes mellitus and LBBB are at increased risk for future events and need periodical reassessment.

Funding Acknowledgement

Type of funding source: None

Time-dependent improvement in coronary flow reserve in collateral donor artery following successful recanalization of the Coronary Chronic Total Occlusion

Background

Coronary chronic total occlusion (CTO) is characterized by the presence of collateral blood vessels which can provide additional blood supply to CTO-artery dependent myocardium. Successful CTO recanalization is followed by significant decrease in collateral donor artery blood flow and collateral derecruitment.

Purpose

Study aim was to assess time-dependent changes in coronary flow reserve (CFR) in collateral donor artery after CTO recanalization and identify factors that influence these changes.

Methods

Our study enrolled 31 patients with CTO scheduled for percutaneous coronary intervention (PCI). Non-invasive CFR was measured before PCI in collateral donor artery, and 24h and 6 months post-PCI in CTO and collateral donor artery. Gated SPECT MIBI was performed before PCI, while quality of life was assessed by Seattle angina questionnaire (SAQ) pre-PCI, and 6 months after PCI.

Results

Collateral donor artery showed significant increase in CFR 24h after CTO recanalization compared to pre-PCI values (2.30±0.49 vs. 2.71±0.45, p=0.005), which remained unchanged after 6 months (2.68±0.24). Maximum baseline blood flow velocity of the collateral donor artery showed significant decrease measured 24h post-PCI compared to pre-PCI values (0.28±0.06 vs. 0.24±0.04m/s), and remained similar after 6-months. There was no significant difference in maximum hyperemic blood flow velocity pre-PCI, 24h and 6 months post-PCI. CFR change of the collateral donor artery 24h post-PCI compared to pre-PCI values showed inverse correlation with left ventricle ejection fraction (LVEF) measured on SPECT. CFR changes showed no correlation with the changes in quality of life assessed by SAQ post-PCI compared to pre-PCI.

Conclusions

Significant increase in CFR of the collateral donor artery was observed within 24h after successful recanalization of CTO artery, which maintained constant after the 6 months follow-up. This increase was largely driven by the significant reduction in the maximum baseline blood flow velocity within 24h after CTO recanalization compared to pre-PCI values. Our results suggest that possible benefit of CTO recanalization could be the improvement in physiology of the collateral donor artery.

Funding Acknowledgement

Type of funding source: None

Hyperventilation echocardiography in INOCA: the HEROIC study

Background

Patients with ischemia and no obstructive coronary artery disease (INOCA) are a heterogeneous group and an unmet diagnostic challenge. Noninvasive Doppler is a feasible tool to assess coronary flow velocity (CFV) in left anterior descending coronary artery (LAD) during stress echocardiography (SE).

Aim

To assess CFV response during coronary vasoconstrictor and vasodilator stimuli in INOCA patients.

Methods

In a prospective single center study, we enrolled 16 INOCA patients (age 60±12 years, 15 females) with previously normal angiograms. All underwent SE testing with hyperventilation (HYP, respiratory rate of 30 per min for 5') followed by supine bicycle exercise (HYP+EXE); and adenosine CFV evaluation (ADO, 0.84 mg/kg in 1 min) on the other day. The ratio of peak/rest changes of CFV during HYP in LAD was taken as an index of vasoconstriction, and CFV reserve was evaluated after EXE. An abnormal response to HYP was a CFV ratio &lt;1.0 (vasoconstrictor response). An abnormal response to ADO was a CFV reserve &lt;2.0 (blunted vasodilatory response). CFVR at peak HYP+ EXE was an indicator of endothelial dependent vasodilatation.

Results

The double product increased during HYP, in comparison to rest (13 337 vs 9858, p&lt;0.001), and further increase with EXE (21 118 vs HYP, p&lt;0.001). Chest pain or dyspnea were present in 2/16 pts during HYP, and in 5/16 patients during HYP+EXE (12.5% vs 31.25%, p=0.083). ST segment depression (≥1mm) was present in 1/16 patients during HYP, and 3/16 during HYP+EXE. Two patients showed regional wall motion abnormalities with HYP+EXE. CFVR response was blunted in 9/16 patients during HYP+EXE, and abnormal for vasoconstriction during HYP in 6. Vasodilation during ADO was preserved in all patients. There was significant difference between CFVR response during HYP+EXE and ADO (1.9±0.5 vs 2.4±0.4 respectively, p=0.039), and between CFVR HYP and ADO (1.2±0.3 vs 2.4±0.4, p&lt;0.001).

Conclusion

In INOCA patients, HYP+EXE is a more powerful ischemic stress than HYP alone and unmasks abnormalities in regional wall motion and/or CFV response in over one- half of patients, likely unmasking the underlying abnormal coronary vasomotor response of large epicardial and/ or small coronary vessels. INOCA patients show profound heterogeneity of coronary vasomotor responses which can be detected with a combined vasodilator - vasoconstrictor SE approach with CFV assessment. The clarification of underlying coronary microcirculatory heterogeneity is the prerequisite for a personalized treatment, and can be easily extracted from CFV-SE. Normal INOCA hearts are all alike, every abnormal heart is abnormal in its own way.

Funding Acknowledgement

Type of funding source: None

The prognostic value of coronary flow reserve of left anterior descending artery in non-diagnostic or inconclusive stress echocardiography tests

Background

Relevant number of all stress echocardiography results are non-diagnostic or inconclusive. Such importance cannot be ignored as previous studies have shown that these patients have higher risk for adverse events. Non-invasive transthoracic Doppler derived coronary flow reserve (CFR) of left anterior descending (LAD) artery, as additional test, is an effective tool to predict adverse cardiac events in various clinical settings.

Purpose

The aim of this study was to investigate the value of CFR of LAD in predicting outcome.

Methods

122 patients, (35,8% with previous MI) with nondiagnostic stress echocardiography results (target heart rate not reached, chest pain without ECG and echo changes) and with inconclusive stress echocardiography results (target heart rate reached, chest pain with ECG changes and without echo changes) were referred for transthoracic

Doppler echocardiographic CFR assessment of LAD. CFR was calculated as the ratio between maximal hyperemic and baseline coronary flow velocity. CFR ≤2 was considered abnormal. All patients were followed for major adverse cardiac events (MACE): nonfatal myocardial infarction, hospitalization, revascularization (CABG or PCI) and death.

Results

Measured values of CFR LAD were in the range 1,52- 4,00 (mean: 2,4±0.44). CFR LAD was abnormal in 22 (18%), and preserved in 100 patients (82%). During median follow-up of 23 months (interquartile range 9–35), 14 patients underwent revascularization (2 had CABG, 12 had PCI). There were no myocardial infarctions, hospitalizations or cardiovascular deaths in the follow-up period. Patients with lower CFR values (CFR≤2) had a higher event rate and shorter event free survival time compared to those with CFR&gt;2, event rate (9/22, 40,9% vs 5/98 5,1%; p&lt;0.0001) and event free time (22±3 vs 33±1 months; p&lt;0.0001) by Kaplan Maier analyses, (Log Rank 24.42; p&lt;0.001).

Conclusions

Preserved CFR of LAD (&gt;2.0) predicts excellent survival in patients with non-diagnostic and inconclusive stress echocardiography.

Funding Acknowledgement

Type of funding source: None

Prompt and consistent improvement of coronary flow velocity reserve following successful recanalization of the coronary chronic total occlusion in patients with viable myocardium

Background

Coronary chronic total occlusion (CTO) is characterized by the presence of collateral blood vessels which can provide additional blood supply to CTO-artery dependent myocardium. Successful CTO recanalization is followed by significant decrease in collateral donor artery blood flow and collateral derecruitment, but data on coronary hemodynamic changes in relation to myocardial function are limited. We assessed changes in coronary flow velocity reserve (CFVR) by echocardiography in collateral donor and recanalized artery following successful opening of coronary CTO.

Methods

Our study enrolled 31 patients (60 ± 9 years; 22 male) with CTO and viable myocardium by SPECT scheduled for percutaneous coronary intervention (PCI). Non-invasive CFVR was measured in collateral donor artery before PCI, 24 h and 6 months post-PCI, and 24 h and 6 months in recanalized artery following successful PCI of CTO.

Results

Collateral donor artery showed significant increase in CFVR 24 h after CTO recanalization compared to pre-PCI values (2.30 ± 0.49 vs. 2.71 ± 0.45, p = 0.005), which remained unchanged after 6-months (2.68 ± 0.24). Baseline blood flow velocity of the collateral donor artery significantly decreased 24 h post-PCI compared to pre-PCI (0.28 ± 0.06 vs. 0.24 ± 0.04 m/s), and remained similar after 6 months, with no significant difference in maximum hyperemic blood flow velocity pre-PCI, 24 h and 6 months post-PCI. CFVR of the recanalized coronary artery 24 h post-PCI was 2.55 ± 0.35, and remained similar 6 months later (2.62 ± 0.26, p = NS).

Conclusions

In patients with viable myocardium, prompt and significant CFVR increase in both recanalized and collateral donor artery, was observed within 24 h after successful recanalization of CTO artery, which maintained constant during the 6 months.

Trial registration

ClinicalTrials.gov (Number NCT04060615).

Impairment of coronary flow velocity reserve and global longitudinal strain in women with cardiac syndrome X and slow coronary flow

BACKGROUND

Microvascular dysfunction (MVD) is associated with adverse prognosis and may account for abnormal stress tests and angina symptoms in women with cardiac syndrome X (CSX). The aim of our study was to assess MVD by coronary flow velocity reserve (CFVR) and left ventricular (LV) contractile function by LV global longitudinal strain (LVGLS) in CSX patients with respect to presence of slow coronary flow (SCF). It was of additional importance to evaluate clinical status of CSX patients using Seattle Angina Questionnaire.

METHODS AND RESULTS

Study population included 70 women with CSX (mean age 61 ± 7 years) and 34 age-matched controls. CSX group was stratified into two subgroups depending on SCF presence: CSX-Thrombolysis In Myocardial Infarction (TIMI) 3- normal flow subgroup (n = 38) and CSX-TIMI 2- SCF subgroup (n = 32) as defined by coronary angiography. LVGLS measurements and CFVR of left anterior descending (LAD) and posterior descending (PD) artery were performed. CFVR-LAD and PD were markedly impaired in CSX group compared to controls (2.34 ± 0.25 vs 3.05 ± 0.21, p < 0.001; 2.32 ± 0.24 vs 3.01 ± 0.13, p < 0.001), and furthermore decreased in CSX-TIMI 2 patients. Resting, peak, and ΔLVGLS were all significantly impaired in CSX group compared to controls (for all p < 0.001), and furthermore reduced in CSX-TIMI 2 subgroup. Strongest correlation was found between peak LVGLS and CFVR LAD (r = -0.784, p < 0.001) and PD (r = -0.772, p < 0.001). CSX-TIMI 2 subgroup had more frequent angina symptoms and more impaired quality of life.

CONCLUSIONS

MVD in CSX patients is demonstrated by reduction in CFVR and LVGLS values. SCF implies more profound impairment of microvascular and LV systolic function along with worse clinical presentation.

The Coronary ARteriogenesis with combined Heparin and EXercise therapy in chronic refractory Angina (CARHEXA) trial: A double-blind, randomized, placebo-controlled stress echocardiographic study

BACKGROUND

Coronary collateral circulation exerts protective effects on myocardial ischaemia due to coronary artery disease and can be promoted by exercise with heparin co-administration. Whether this arteriogenetic effect is accompanied by functional improvement of left ventricle during stress and lessening of angina symptoms remains unknown.

AIMS

To evaluate the anti-ischaemic efficacy of heparin plus exercise in coronary artery disease.

METHODS

In a prospective, single-centre, randomized, double-blind study we recruited 32 'no-option' patients (27 males; mean age 61 ± 8 years) with stable angina, exercise-induced ischaemia and coronary artery disease not suitable for revascularization. All underwent a two-week cycle of exercise (two exercise sessions per day, five days per week) and were randomized (n = 16 per group) to intravenous placebo (0.9% saline) versus unfractionated heparin (5.000 IU intravenously), 10 min prior to exercise. We assessed Canadian Cardiovascular Society angina class, stress electrocardiogram and echo parameters (wall motion score index) and computed tomography angiography for collaterals.

RESULTS

After two-week cycle, Canadian Cardiovascular Society class statistically decreased in both groups (heparin plus exercise group: 2.6 ± 0.7 to 1.9 ± 0.7, p < 0.001, exercise group: 2.4 ± 0.7 to 2.1 ± 0.9, p = 0.046). Only the heparin plus exercise group improved time-to-ST segment depression (before 270, 228-327 s vs. after 339, 280-360 s, p = 0.012) and wall motion score index (before 1.38 ± 0.25 vs. after 1.28 ± 0.18, p = 0.005). By multi-slice computed tomography angiography, collaterals improved in 12/15 (80%) in the heparin plus exercise group versus 2/16 (12.5%) in the exercise group (p < 0.001).

CONCLUSION

A two-week, 10-test cycle of heparin plus exercise is better than exercise in improving angina class, myocardial ischaemia and collaterals by computed tomography angiography.

P328 Relation between CHA2DS2-VASc and impaired heart rate recovery in patients without inducible myocardial ischemia

Background

Heart rate recovery (HRR) has been shown to predict cardiovascular and all-cause morbidity and mortality in different populations. Recent studies have indicated the CHA2DS2-VASc score can be used as predictor of mortality in patients with coronary artery disease, without atrial fibrillation. However, the relation between these two parameters has not yet been documented.

The Aim: The aim of this study was to determine the relation between CHA2DS2-VASc score and impaired heart rate recovery in patients without inducible myocardial ischemia.

Methods

Our study comprised of 2699 consecutive patients (1319 male, 42.8%, average age 60 ± 11 years) who underwent treadmill exercise testing (stress echocardiography or stress echocardiography) according to Bruce protocol for the assessment of myocardial ischemia. We excluded patients with the systolic heart failure (left ventricle ejection fraction &lt;45%) and those with inducible ischemia. CHA2DS2-VASc score was calculated according to the guidelines. Duke treadmill score, functional capacity (Metabolic Equivalents - METs), chronotropic competence (CC), body mass index (BMI) were calculated in all patients. HRR was calculated as the difference between heart rate at the peak stress and heart rate in the first minute of rest. Slow HRR was defined as ≤18 beats/min.

Results

Out of 2699 patients, 378 (12.3%) had a positive test and they were excluded from further analysis. Of the remaining 2321 patients, 251 (10.8%) had an impaired HRR, whereas 2070 (89.2%) had normal HRR. Previously known coronary artery disease (previous myocardial infarction, percutaneous coronary intervention or coronary artery bypass graft surgery) had 78 (3.4%) patients. Patients with impaired HRR had significantly higher CHA2DS2-VASc score (3.1 ± 1.3 vs 2.3 ± 1.2, p &lt; 0.001), higher resting heart rate (76.9 ± 16.1 vs 73.3 ± 12.3bpm, p &lt; 0.001), higher systolic blood pressure at rest (122.1 ± 13.9 vs 117.2 ± 13.4mmHg, p &lt; 0.001), higher diastolic blood pressure at rest (73.7 ± 7.5 vs 72.3 ± 7.2mmHg, p &lt; 0.001), higher rate of hyperlipproteinemia (176/251, 70.1% vs 1294/2070, 62.5%, p &lt; 0.001), higher BMI (27.3 ± 3.6 vs 26.4± 3.6kg/m2, p &lt; 0.001), shorter duration of the test (5.2 ± 1.8 vs 6.4 ± 1.9 minutes, p &lt; 0.001). lower Duke score (4.6 ± 2.4 vs 6.1 ± 2.4 minutes, p &lt; 0.001). lower MET (6.3 ± 1.8 vs 7.5 ± 1.9, p &lt; 0.001) and higher rate of chronotropic incompetence (173/251, 68.9% vs 1036/2070, 50%, p &lt; 0.001) compares to the patients with normal HRR. Multivariate predictors of impaired HRR were higher CHA2DS2-VASc score (p &lt; 0.001), not achieved THR (p &lt; 0.001), higher heart rate at rest (p = 0.001), higher systolic blood pressure at rest (p = 0.001) and shorter duration of test (p = 0.046).

Conclusion

CHA2DS2-VASc score is an independent predictor of impaired HRR in patients without inducible ischemia.

P1508The Coronary Arteriogenesis with combined Heparin and Exercise therapy in chronic refractory Angina (CARHEXA) trial: a double-blind randomized placebo-controlled stress echocardiographic study

Background

Coronary collateral circulation exerts protective effects on myocardial ischemia due to coronary artery disease (CAD) and can be promoted by exercise (E) with heparin (H) co-administration. Whether this arteriogenetic effects is accompanied by functional improvement of left ventricle (LV) during stress remains unknown.

Purpose

To establish the stress-induced functional effects on LV regional and global function of 2-week cycle of H+E in patients with “no-option” CAD.

Methods

In a prospective, single-center, double-blind, randomized, parallel-group study we recruited 32 “no-option” patients (27 males; mean age of 61±8 years), with stable angina and CTO, refractory to OMT, not suitable for revascularization and with E-induced ischemia. All underwent 2-week cycle of E (2 E test per day, 5 days a week) and were pre-treated with i.v. 0.9% saline or unfractionated H (100 IU/kg up to maximum of 5.000IU, 10 min prior to E). Canadian Class Score (CCS) and 12-lead E-ECG for time-to-1 mm ST-segment depression were assessed at entry and after treatment. LV function was evaluated during treadmill exercise with conventional and advanced imaging indices: Wall Motion Score Index (WMSI); Ejection Fraction (EF); Force (systolic blood pressure/end-systolic volume); Global Longitudinal Strain (GLS).

Results

Post-treatment exercise-time and CCS improved in both groups. In H+E patients exercise-time improved from 369.8±107.8 sec to 475.3±114.6 sec (p=0.001) while in E patients improved from 384±152.7 sec to 464.8±134.1 sec (p=0.019). CCS score changed in H+E from 2.6±0.7 to 1.9±0.7 (p=0.000), and in E group from 2.4±0.7 to 2.1±0.9 (p=0.046). At peak exercise, H+E was different from E group for EF and GLS (see Table).

Effects of H+E on SE parameters H+E p P+E p *H+E vs P+E STRESS Time 0 vs Time 1 Time 0 vs Time 1 Time 0 Time 1 WMSI 1.377 vs 1.279 0.005 1.404 vs 1.376 0.290 0.626 0.255 EF (%) 60.9 vs 64.8 0.016 61.2 vs 57.8 0.284 0.943 0.016 Force (mmHg/mL) 6.36 vs 6.5 0.158 5.82 vs 4.68 0.209 0.760 0.098 GLS (%) −16.96 vs −18.50 0.001 −15.79 vs −15.60 0.380 0.325 0.027 SE = stress echocardiography; H+E = heparin+exercise; P+E = placebo+exercise; Time 0 = before randomization; Time 1 = after 2-week therapy cycle. *p values.

Conclusion

A 2-week, H+E cycle is associated with improvement in regional and global LV function during exercise, concordantly shown by conventional (WMSI, EF) and advanced (GLS) echocardiographic indices of LV function. This integrates and supplements the classical objective index based on ST-segment depression, unable to localize and quantify the functional consequences of therapy on myocardial ischemia.

P2710Anti-ischemic effect of 2-week cycle of heparin plus exercise-to-ischemia twice daily in patients with “no-option” angina: the CARHEXA trial

Background

Coronary collateral circulation (CCC) exerts protective effects on myocardial ischemia due to coronary artery disease (CAD), but the anti-ischemic, pro-CCC effects of exercise (E) with or without heparin (H) co-administration remain unclear.

Purpose

To establish the anti-ischemic functional efficacy of 2-week cycle of E-to-ischemia twice daily, with or without unfractionated i.v. H immediately before E, in patients with “no-option” CAD

Methods

In a prospective, single-center, parallel group study design we recruited 32 “no-option” patients (27 males; mean age of 61±8 years) with at least one chronically occluded coronary artery and stable angina, refractory to optimal medical management, not suitable for revascularization therapy and with E-induced ischemia. All underwent a 2-week cycle of E (2 E test per day, 5 days a week, for 2 weeks) and were randomized, with a double-blind design, to i.v. placebo (0.9% saline) versus unfractionated H (100 IU/kg up to a maximum of 5.000 IU iv, 10 min prior to E). Seattle stable angina questionnaire (SAQ), 12-lead E-ECG for time-to-ischemia (treadmill exercise testing), and MDCT angiography for CCC imaging (Rentrop score, from 0= absent to 3= full opacification of occluded vessel) were assessed at entry and re-assessed after treatment for symptomatic, ECG, and anatomic end-points respectively.

Results

In H+E group (n=16), time to 1 mm ST segment depression (ST-D) increased, and CCC improved, p<0.05. On the contrary, no difference was observed in E group (n=16) in the pre-specified end-points (p>0.05) (see table). Clinically important change of more 10 points in SAQ was observed regarding physical limitation, angina stability and disease perception in H+E patients, and in only angina frequency in E group.

The ECG and angiographic results Heparin + Exercise Placebo + Exercise Rentrop baseline 0.73±0.88 1.06±1.06 Rentrop 2-week 1.6±0.99* 1.19±1.05 Time to ST-D base (s) 269±64 273±176 Time to ST-D 2-week (s) 328±65* 306±151 *p<0.05.

Conclusion

A 2-week, 10 E test cycles are well tolerated and effective particularly with H in ameliorating symptoms, E-induced ischemia and CCC in “no-option” CAD patients with refractory angina.

P1511Promising prognostic value of negative stress echocardiography in patients with incomplete revascularization after successful primary PCI

Background

The specific role of non-invasive functional testing in a risk stratification of patients with incomplete revascularization after primary percutaneous coronary intervention (pPCI) still needs to be evaluated. The aim of our study was to assess negative prognostic value of stress echocardiography (SECHO) after successful pPCI and incomplete revascularization of non-culprit lesions.

Methods

Our study consisted of 202 patients (mean age 59±10 years, male 142) successfully treated with pPCI, who performed SECHO according to Bruce protocol in order to assess residual ischemia in coronary artery with non-culprit lesion. Duke treadmill score, functional capacity (Metabolic Equivalents - METs), achieved target heart rate (THR), heart rate recovery (HRR), wall motion score index (WMSI) and ejection fraction were interrogated in all patients. Slow HRR was defined as ≤18 beats/min. Median follow-up of the patients was 70 months (IQR 55–83 months) for the occurrence of cardiovascular death and non-fatal myocardial infarction. We also assessed the independent predictors for the occurrence of the adverse events.

Results

Out of 202 patients, 42 (20.8%) had positive SECHO test, 4 patients (1.98%) had died due to non-cardiac causes and 7 patients (3.5%) were lost to follow-up. From the remaining 149 patients with negative SECHO, 13 (8.7%) had an adverse event (7 cardiovascular deaths and 6 non-fatal MI). Negative predictive value of SECHO test was 91.3%. Univariate predictors of adverse events were slow HRR (HR 4.343 [95% CI 1.473–14.011], p=0.008), and not achieved THR (HR 0.322 [95% CI 0.105–0.985], p=0.047). By multivariate analysis, only slow HRR remained independent predictor of adverse events (HR 3.324 [95% CI 1.013–10.906], p=0.048).

Conclusion

SECHO test has excellent negative prognostic value in patients with incomplete revascularization of non-culprit lesions after successful pPCI. Still, particular care should be taken to the patients with slow HRR and negative SECHO due to increased risk for the occurrence of adverse events.

Acknowledgement/Funding

Ministry of Education and Science of the Republic of Serbia (Grant No III41022)

Nature of Cardiac Rehabilitation Around the Globe

BACKGROUND

Cardiac rehabilitation (CR) is a clinically-effective but complex model of care. The purpose of this study was to characterize the nature of CR programs around the world, in relation to guideline recommendations, and compare this by World Health Organization (WHO) region.

METHODS

In this cross-sectional study, a piloted survey was administered online to CR programs globally. Cardiac associations and local champions facilitated program identification. Quality (benchmark of ≥ 75% of programs in a given country meeting each of 20 indicators) was ranked. Results were compared by WHO region using generalized linear mixed models.

FINDINGS

111/203 (54.7%) countries in the world offer CR; data were collected in 93 (83.8%; N = 1082 surveys, 32.1% program response rate). The most commonly-accepted indications were: myocardial infarction (n = 832, 97.4%), percutaneous coronary intervention (n = 820, 96.1%; 0.10), and coronary artery bypass surgery (n = 817, 95.8%). Most programs were led by physicians (n = 680; 69.1%). The most common CR providers (mean = 5.9 ± 2.8/program) were: nurses (n = 816, 88.1%; low in Africa, p < 0.001), dietitians (n = 739, 80.2%), and physiotherapists (n = 733, 79.3%). The most commonly-offered core components (mean = 8.7 ± 1.9 program) were: initial assessment (n = 939, 98.8%; most commonly for hypertension, tobacco, and physical inactivity), risk factor management (n = 928, 98.2%), patient education (n = 895, 96.9%), and exercise (n = 898, 94.3%; lower in Western Pacific, p < 0.01). All regions met ≥ 16/20 quality indicators, but quality was < 75% for tobacco cessation and return-to-work counseling (lower in Americas, p = < 0.05).

INTERPRETATION

This first-ever survey of CR around the globe suggests CR quality is high. However, there is significant regional variation, which could impact patient outcomes.

Cardiac Rehabilitation Availability and Density around the Globe

BACKGROUND

Despite the epidemic of cardiovascular disease and the benefits of cardiac rehabilitation (CR), availability is known to be insufficient, although this is not quantified. This study ascertained CR availability, volumes and its drivers, and density.

METHODS

A survey was administered to CR programs globally. Cardiac associations and local champions facilitated program identification. Factors associated with volumes were assessed using generalized linear mixed models, and compared by World Health Organization region. Density (i.e. annual ischemic heart disease [IHD] incidence estimate from Global Burden of Disease study divided by national CR capacity) was computed.

FINDINGS

CR was available in 111/203 (54.7%) countries; data were collected in 93 (83.8% country response; N = 1082 surveys, 32.1% program response rate). Availability by region ranged from 80.7% of countries in Europe, to 17.0% in Africa (p < .001). There were 5753 programs globally that could serve 1,655,083 patients/year, despite an estimated 20,279,651 incident IHD cases globally/year. Volume was significantly greater where patients were systematically referred (odds ratio [OR] = 1.36, 95% confidence interval [CI] = 1.35-1.38) and programs offered alternative models (OR = 1.05, 95%CI = 1.04-1.06), and significantly lower with private (OR = .92, 95%CI = .91-.93) or public (OR = .83, 95%CI = .82-84) funding compared to hybrid sources.Median capacity (i.e., number of patients a program could serve annually) was 246/program (Q25-Q75 = 150-390). The absolute density was one CR spot per 11 IHD cases in countries with CR, and 12 globally.

INTERPRETATION

CR is available in only half of countries globally. Where offered, capacity is grossly insufficient, such that most patients will not derive the benefits associated with participation.

Prognostic Value of Preserved Coronary Flow Velocity Reserve by Noninvasive Transthoracic Doppler Echocardiography in Patients With Angiographically Intermediate Left Main Stenosis

BACKGROUND

The potential of angiography to evaluate the hemodynamic severity of a left main coronary artery (LM) stenosis is limited. Noninvasive transthoracic Doppler echocardiographic coronary flow velocity reserve (CFVR) evaluation of intermediate coronary stenosis has demonstrated remarkably high negative prognostic value. The aim of this study was to assess clinical outcomes in patients with angiographically intermediate LM stenosis and preserved CFVR (>2.0) as evaluated by transthoracic Doppler echocardiographic CFVR.

METHODS

The initial study population included 102 patients with intermediate coronary stenosis of the LM referred for transthoracic Doppler echocardiographic CFVR assessment. Peak diastolic CFVR measurements were performed in the distal segment of the left anterior descending coronary artery after intravenous adenosine (140 μg/kg/min), and CFVR was calculated as the ratio between maximal hyperemic and baseline coronary flow velocity. Nineteen patients had impaired CFVR (≤2.0) and were excluded from further analysis, as well as two patients with poor acoustic windows. The final group consisted of 81 patients (mean age, 60 ± 9 years; 76 men) evaluated for adverse cardiac events including death, myocardial infarction, and revascularization.

RESULTS

Mean follow-up duration was 62 ± 26 months. Mean CFVR was 2.4 ± 0.4. Total event-free survival was 75 of 81 (92.6%), as six patients were referred for revascularization (five patients with coronary artery bypass grafting, one patient with percutaneous coronary intervention). There were no documented myocardial infarctions or cardiovascular deaths in the follow-up period.

CONCLUSIONS

In patients with angiographically intermediate and equivocal LM stenosis and preserved CFVR values of >2.0, revascularization can be safely deferred.

Prognostic Value of Transthoracic Doppler Echocardiography Coronary Flow Velocity Reserve in Patients with Nonculprit Stenosis of Intermediate Severity Early after Primary Percutaneous Coronary Intervention

BACKGROUND

Treatment of nonculprit coronary stenosis during primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction may be beneficial, but the mode and timing of the intervention are still controversial. The aim of this study was to examine the significance and prognostic value of preserved coronary flow velocity reserve (CFVR) in patients with nonculprit intermediate stenosis early after primary percutaneous coronary intervention.

METHODS

Two hundred thirty patients with remaining intermediate (50%-70%) stenosis of non-infarct-related arteries, in whom CFVR was performed within 7 days after primary percutaneous coronary intervention, were prospectively enrolled. Twenty patients with reduced CFVR and positive results on stress echocardiography or impaired fractional flow reserve underwent revascularization and were not included in further analysis. The final study population of 210 patients (mean age, 58 ± 10 years; 162 men) was divided into two groups on the basis of CFVR: group 1, CFVR > 2 (n = 174), and group 2, CFVR ≤ 2 (n = 36). Cardiac death, nonfatal myocardial infarction, and revascularization of the evaluated vessel were considered adverse events.

RESULTS

Mean follow-up duration was 47 ± 16 months. Mean CFVR for the whole group was 2.36 ± 0.40. There were six adverse events (3.4%) related to the nonculprit coronary artery in group 1, including one cardiac death, one ST-segment elevation myocardial infarction, and four revascularizations. In group 2, there were 30 adverse events (83.3%, P < .001 vs group 1), including two cardiac deaths, two ST-segment elevation myocardial infarctions, and 26 revascularizations.

CONCLUSIONS

In patients with CFVR > 2 of the intermediate nonculprit coronary lesion, deferral of revascularization is safe and associated with excellent long-term clinical outcomes.

N-terminal pro-brain natriuretic peptide is related with coronary flow velocity reserve and diastolic dysfunction in patients with asymmetric hypertrophic cardiomyopathy

BACKGROUND

The relations of elevated N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and cardiac ischemia in hypertrophic cardiomyopathy (HCM) patients is uncertain. Therefore we designed the study with the following aims: (1) to analyze plasma concentrations of NT-pro-BNP in various subsets of HCM patients; (2) to reveal the correlations of NT-pro-BNP, myocardial ischemia, and diastolic dysfunction; (3) to assess predictors of the elevated plasma levels of NT-pro-BNP.

METHODS AND RESULTS

In 61 patients (mean age 48.9±16.3 years; 26 male) with asymmetric HCM plasma levels of NT-pro-BNP were obtained. Standard transthoracic examination, tissue Doppler echocardiography with measurement of transthoracic coronary flow velocity reserve (CFVR) in left anterior descending artery (LAD) was done. Mean natural logarithm value of NT-pro-BNP was 7.11±0.95pg/ml [median value 1133 (interquartile range 561-2442)pg/ml]. NT-pro-BNP was significantly higher in patients with higher NYHA class, in obstructive HCM, more severe mitral regurgitation, increased left atrial volume index (LAVI), presence of calcified mitral annulus, elevated left ventricular (LV) filling pressure and in decreased CFVR. Levels of NT-pro-BNP significantly correlated with the ratio of E/e' (r=0.534, p<0.001), LV outflow tract gradient (r=0.503, p=0.024), LAVI (r=0.443, p<0.001), while inversely correlated with CFVR LAD (r=-0.569, p<0.001). When multivariate analysis was done only CFVR LAD and E/e' emerged as independent predictors of NT-pro-BNP.

CONCLUSION

Plasma levels of NT-pro-BNP were significantly higher in HCM patients with more advanced disease. Elevated NT-pro-BNP not only reflects the diastolic impairment of the LV, but it might also be the result of cardiac ischemia in patients with HCM.

Prevalence and risk factors for prolonged QT interval and QT dispersion in patients with type 2 diabetes

AIMS

Prolonged QT interval is associated with cardiac arrhythmias and sudden death. The present study determined the prevalence of prolonged QT interval and QT dispersion and defined their clinical and metabolic predictors in patients with type 2 diabetes.

METHODS

Cross-sectional study included 501 patients with type 2 diabetes. A standard 12-lead electrocardiogram was recorded. QT corrected for heart rate (QTc) >440 ms and QT dispersion (QTd) >80 ms were considered abnormally prolonged. QTc ≥ 500 ms was considered a high-risk QTc prolongation. Demographic, clinical and laboratory data were collected. Independent risk factors for prolonged QTc and QTd were assessed using logistic regression analysis.

RESULTS

Prevalence of QTc > 440 ms and QTd > 80 ms were 44.1 and 3.6 %, respectively. Prevalence of high-risk QTc (≥500 ms) was 2 % only. Independent risk factors for QTc prolongation >440 ms were mean blood glucose (β = 2.192, p < 0.001), treatment with sulphonylurea (β = 5.198, p = 0.027), female gender (β = 8.844, p < 0.001), and coronary heart disease (β = 8.636, p = 0.001). Independent risk factors for QTc ≥ 500 ms were coronary heart disease (β = 4.134, p < 0.001) and mean blood glucose level (β = 1.735, p < 0.001). The independent risk factor for prolonged QTd was only coronary heart disease (β = 5.354, p < 0.001).

CONCLUSIONS

Although the prevalence of prolonged QTc > 440 ms is significant, the prevalence of high-risk QTc (≥500 ms) and QTd > 80 ms is very low in patients with type 2 diabetes. Hyperglycaemia and coronary heart disease are strong predictors of high-risk QTc.