Background The traditional nitroglycerin (NTG) head-up tilt test (HUTT) is time-consuming and the test duration is a barrier to widespread utilization in clinical practice. It was hypothesized that a short-duration protocol is not inferior to the traditional protocol regarding the positivity rate and has a similar distribution of hemodynamic response. Methods and results Patients undergoing HUTT were randomized 1:1 to a 10 min passive phase plus a 10 min 0.3 mg NTG if the passive phase was negative (Fast) or to a 20 min passive phase plus a 15 min 0.3 mg NTG if the passive phase was negative (Traditional). A sample size of 277 patients for each group achieved 80% power to detect an expected difference of 0% with a non-inferiority margin of -10% using a one-sided t-test and assuming a significant level alpha of 0.025. A total of 554 consecutive patients (mean age 46.6 ± 19.3 years, 47.6% males) undergoing HUTT for suspected vasovagal syncope were randomly assigned to the Fast (n = 277) or Traditional (n = 277) protocol. A positive response was defined as the induction of syncope in presence of hypotension/bradycardia, and was observed in 167 (60.3%) patients with Fast and in 162 (58.5%) patients with the Traditional protocol. There was a trend of lesser vasodepressor response (14.8% Fast vs. 20.6% Traditional) which was significant during the passive phase (P = 0.01). Conclusion The diagnostic value of the Fast HUTT protocol is similar to that of the Traditional protocol and therefore the Fast protocol can be used instead of the Traditional protocol.

Epicardial fat volume (EFV), also known as epicardial adipose tissue (EAT), sometimes acts as a protector against heart problems; however, in excess volume was found to be associated with cardiovascular structural and functional abnormalities. This study aims to establish a threshold between normal and abnormal values for EFV/EAT in asymptomatic subjects, as well as to assess whether excess EFV/EAT is associated with significant structural and functional abnormalities, including coronary artery calcium score (CACS). A total of 220 asymptomatic patients, were screened utilizing Early Cardiovascular Disease Risk Score (ECVDRS), and CT for CACS and EFV/EAT quantification. Out of the 220 subjects, 69 had a 0 CACS and were included in this analysis. These 69 were then further categorized into 3 groups: Group 1 (Normal subjects; n=20) with ECVDRS < 3, and ACC/AHA risk score < 5%; Group 2 (n= 16) with elevated EFV/EAT and no abdominal visceral obesity; Group 3 (n=33) with elevated EFV/EAT and abdominal visceral obesity. The average EFV/EAT was identified to be 69 cm3 +/- 20 in females and 68 cm3 +/- 15 in males among Group 1, which indicate the normal values for EFV/EAT. It was also found that elevated EFV/EAT without (Group 2) or with (Group 3) abdominal visceral adiposity was associated with significant vascular abnormalities, as compared to the normal group among these populations of asymptomatic patients with 0 CACS. Elevated EFV/EAT is a novel cardiovascular risk marker regardless of gender, which might be the culprit for major cardiovascular risk factors.

Background Excess epicardial fat volume (EFV) has been recently implicated in cardiovascular structural and functional abnormalities. It has been associated with abnormal microvascular stiffness (as reflected by radial artery waveform; C2), which may result in microvascular dysfunction and contribute to the atypical chest pain syndrome without obstructive coronary artery disease (CAD). Women have been statistically shown to present with atypical chest pain more often than men and specifically without obstructive CAD. The aim of this study is to assess whether excess EFV in female subjects is associated with significant microvascular dysfunction (i.e., C2), in subjects without obstructive CAD. Results We screened 596 asymptomatic subjects, ages 20–79, using the Early Cardiovascular Health Risk Scoring System (ECVHRS), which has been reported. Out of the 596 total subjects, 230 subjects had a CACS. Out of these 230 subjects, 77 subjects (45 females; 32 males) had a 0 CACS. The 45 females from this cohort were the subjects of this study, and they were further categorized into 3 groups: group 1 (normal EFV, non-obese female subjects; n=16), females with ECVHRS < 3 and ACC/AHA risk score < 5%; group 2 (n = 9), females with elevated EFV and no abdominal visceral obesity; and group 3 (n=20), females with elevated EFV and abdominal visceral obesity. The average EFV was determined to be 72±20 cm3 among group 1, which indicates the values for normal EFV. The results in group 2 indicate that excess EFV is contributing to the development of microvascular dysfunction, resulting in abnormal micro-arterial (C2) elasticity (p< 0.00001), increase in resting blood pressure (p =0.0001), an abnormal rise in blood pressure (BP) at rest and post-mild protocol exercise (PME) (p = < 0.00001), and abnormal increase in carotid intima-media thickness (CIMT) (p = 0.000164). Conclusion Excess EFV appears to be not only a novel cardiovascular risk marker, but also the culprit for other cardiovascular risk markers. Based on these findings, elevated EFV may contribute to the development of the atypical chest pain syndrome in females without obstructive CAD. Additionally, EFV is emerging as a potential clinically relevant significant cardiovascular risk biomarker and may become a target to reduce cardiovascular morbidity and mortality.

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