Efficacy of Computed Tomography-Based Evaluation of Myocardial Extracellular Volume Combined With Red Flags for Early Screening of Concealed Cardiac Amyloidosis in Patients With Atrial Fibrillation.

BACKGROUND: The prevalence of transthyretin amyloid cardiomyopathy (ATTR-CM) in atrial fibrillation (AF) patients remains unclear. We explored the efficacy of computed tomography-based myocardial extracellular volume (CT-ECV) combined with red flags for the early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.Methods and Results: Patients referred for AF ablation at Oita University Hospital were prescreened using the red-flag signs defined by echocardiographic or electrocardiographic findings, medical history, symptoms, and blood biochemical findings. Myocardial CT-ECV was quantified in red flag-positive patients using routine pre-AF ablation planning cardiac CT with the addition of delayed-phase cardiac CT scans. Patients with high (>35%) ECV were evaluated using technetium pyrophosphate (99 mTc-PYP) scintigraphy. A cardiac biopsy was performed during the planned AF ablation procedure if 99 mTc-PYP scintigraphy was positive. Between June 2022 and June 2023, 342 patients were referred for AF ablation. Sixty-seven (19.6%) patients had at least one of the red-flag signs. Myocardial CT-ECV was evaluated in 57 patients because of contraindications to contrast media, revealing that 16 patients had high CT-ECV. Of these, 6 patients showed a positive 99 mTc-PYP study, and 6 patients were subsequently diagnosed with wild-type ATTR-CM via cardiac biopsy and genetic testing. CONCLUSIONS: CT-ECV combined with red flags could contribute to the systematic early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.

Impact of the COVID-19 Pandemic on the Long-Term Prognosis of Acute Myocardial Infarction in Japan.

Background During the early phase of the coronavirus disease 2019 (COVID-19) pandemic, a global reduction in hospitalizations for acute myocardial infarction (AMI) was observed. Generally, patients experienced increased severity of AMI with delays in time from symptom onset to treatment during the pandemic. However, the impact of the COVID-19 pandemic on in-hospital mortality among patients with AMI remains unclear. This study aimed to compare the long-term prognosis of patients with AMI during the COVID-19 pandemic to that observed in the pre-pandemic period and to evaluate the influence of the COVID-19 pandemic on the prognosis of patients with AMI. Methods We reviewed the data of patients admitted to our hospital for AMI treatment between April 1, 2018, and March 31, 2021. The time from admission to major adverse cardiac events (MACE), as well as the time from admission to all-cause death, were examined between the pandemic period (April 1, 2020, to March 31, 2021) and the pre-pandemic period (April 1, 2018, to March 31, 2020). Results Eighty patients were included in the study, and those admitted during the pandemic exhibited a higher likelihood of advanced age, lower levels of LDL-cholesterol, and a reduced prevalence of hypertension. The 2.5-year MACE-free survival and overall survival rates between the patients during the pre-pandemic and pandemic periods were not significantly different. Conclusion The long-term prognosis of patients with AMI during the COVID-19 pandemic remains unclear. In this study, we reported that the 2.5-year MACE-free survival and overall survival rates of the patients with AMI admitted during the COVID-19 pandemic were not significantly different from those during the pre-pandemic period. The impact of the COVID-19 pandemic on the prognosis of patients with AMI appears to vary according to the study population.

Remission of Cardiac Sarcoidosis after the Administration of Methotrexate as First-line Drug Therapy.

A 54-year-old woman developed new-onset heart failure and was diagnosed with cardiac sarcoidosis. An implantable cardioverter-defibrillator with biventricular pacing was implanted before immunosuppressive therapy to prevent sudden death. The patient refused oral steroids because she disliked their specific side effects and potential adverse events with long-term use; therefore, methotrexate was chosen as an alternative first-line drug. Nine months after starting oral therapy, 18F-fluorodeoxyglucose-positron emission tomography revealed remission of sarcoidosis, disappearance of heart failure symptoms, marked improvement in cardiac contractility, and a reduced frequency of ventricular arrhythmias.

Handgrip exercise does not alter CO2 -mediated cerebrovascular flow-mediated dilation.

Handgrip exercise (HG), a small muscle exercise, improves cognitive function and is expected to provide a useful exercise mode to maintain cerebral health. However, the effect of HG on cerebral blood flow regulation is not fully understood. The present study aimed to examine the effect of acute HG on cerebral endothelial function as one of the essential cerebral blood flow regulatory functions. Thirteen healthy young participants performed interval HG, consisting of 4 sets of 2 min HG at 25% of maximum voluntary contraction with 3 min recovery between each set. Cognitive performance was evaluated before and at 5 and 60 min after interval HG using the Go/No-Go task (reaction time and accuracy). The diameter and blood velocity of the internal carotid artery (ICA) were measured using a duplex Doppler ultrasound system. To assess cerebral endothelial function, hypercapnia (30 s of hypercapnia stimulation, end-tidal partial pressure of CO2 : +9 mmHg)-induced cerebrovascular flow-mediated dilatation (cFMD) was induced, calculated as relative peak dilatation from baseline diameter. The shear rate (SR) was calculated using the diameter and blood velocity of the ICA. As a result, cognitive performance improved only at 5 min after interval HG (reaction time, P = 0.008; accuracy, P = 0.186), whereas ICA SR during interval HG and cFMD after interval HG were unchanged (P = 0.313 and P = 0.440, respectively). These results suggest that enhancement in cerebral endothelial function is not an essential mechanism responsible for acute HG-induced cognitive improvement. NEW FINDINGS: What is the central question of this study? Does handgrip exercise, a small muscle exercise, improve cerebral endothelial function? What is the main finding and its importance? Acute interval isometric handgrip exercise (2 min of exercise at 25% maximum voluntary contraction, followed by 3 min of recovery, repeated for a total of 4 sets) did not improve cerebral endothelial function. Since the cerebrovascular shear rate did not change during exercise, it is possible that acute handgrip exercise is not sufficient stimulation to improve cerebral endothelial function.

Usefulness of Prehospital 12-Lead Electrocardiography System in ST-Segment Elevation Myocardial Infarction Patients in Oita　- Comparison Between Urban and Rural Areas, Weekday Daytime and Weekday Nighttime/Holidays.

BACKGROUND: We have reported that a prehospital 12-lead electrocardiography system (P-ECG) contributed to transport of suspected acute coronary syndrome (ACS) patients to appropriate institutes and in this study, we compared its usefulness between urban and rural areas, and between weekday daytime and weekday nighttime/holiday.Methods and Results: Consecutive STEMI patients who underwent successful primary percutaneous coronary intervention after using P-ECG were assigned to the P-ECG group (n=123; 29 female, 70±13 years), and comparable STEMI patients without using P-ECG were assigned to the conventional group (n=117; 33 females, mean age 70±13 years). There was no significant difference in door-to-reperfusion times between the rural and urban cases (70±32 vs. 69±29 min, P=0.73). Door-to-reperfusion times in the urban P-ECG group were shorter than those in the urban conventional group for weekday nighttime/holiday (65±21 vs. 83±32 min, P=0.0005). However, there was no significance different between groups for weekday daytime. First medical contact to reperfusion time (90±22 vs. 105±37 min, P=0.0091) in the urban P-ECG group were significantly shorter than in the urban conventional groups for weekday nighttime/holiday, but were not significantly different between the groups for weekday daytime. CONCLUSIONS: P-ECG is useful even in urban areas, especially for patients who develop STEMI during weekday nighttime or while on a holiday.

Role of polyunsaturated fatty acids in Japanese patients with coronary spastic angina.

BACKGROUND: n-3 polyunsaturated fatty acids (PUFAs) reduce the risk of ischemic heart disease. However, there are few reports of a relationship between n-3 PUFAs and coronary spastic angina (CSA). This study aimed to assess the age-dependent role of serum levels of fatty acid in patients with CSA. METHODS AND RESULTS: We enrolled 406 patients who underwent ergonovine tolerance test (ETT) during coronary angiography for evaluation of CSA. All ETT-positive subjects were diagnosed as having CSA. We categorized the patients by age and results of ETT as follows: (1) young (age ≤ 65 years) CSA-positive (n = 32), (2) young CSA-negative (n = 134), (3) elderly (age > 66 years) CSA-positive (n = 36), and (4) elderly CSA-negative (n = 204) groups. We evaluated the serum levels of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid, and dihomo-gamma-linolenic acid. In the young groups, the serum levels of EPA (64.3 ±â€¯37.7 µg/mL vs. 49.4 ±â€¯28.8 µg/mL, p = 0.015) and DHA (135.7 ±â€¯47.6 µg/mL vs. 117.4 ±â€¯37.6 µg/mL, p = 0.020) were significantly higher in the CSA-positive group than in the CSA-negative group, respectively. However, this was not the case with elderly groups. In the multivariate analysis in young groups, the serum levels of EPA (p = 0.028) and DHA (p = 0.049) were independently associated with the presence of CSA, respectively. CONCLUSION: Our results suggested that the higher serum levels of EPA and/or DHA might be involved in the pathophysiology of CSA in the young population but not in the elderly population.

Can Alterations in Cerebrovascular CO2 Reactivity Be Identified Using Transfer Function Analysis without the Requirement for Carbon Dioxide Inhalation?

The present study aimed to examine the validity of a novel method to assess cerebrovascular carbon dioxide (CO2) reactivity (CVR) that does not require a CO2 inhalation challenge, e.g., for use in patients with respiratory disease or the elderly, etc. In twenty-one healthy participants, CVR responses to orthostatic stress (50° head-up tilt, HUT) were assessed using two methods: (1) the traditional CO2 inhalation method, and (2) transfer function analysis (TFA) between middle cerebral artery blood velocity (MCA V) and predicted arterial partial pressure of CO2 (PaCO2) during spontaneous respiration. During HUT, MCA V steady-state (i.e., magnitude) and MCA V onset (i.e., time constant) responses to CO2 inhalation were decreased (p < 0.001) and increased (p = 0.001), respectively, indicative of attenuated CVR. In contrast, TFA gain in the very low-frequency range (VLF, 0.005-0.024 Hz) was unchanged, while the TFA phase in the VLF approached zero during HUT (-0.38 ± 0.59 vs. 0.31 ± 0.78 radians, supine vs. HUT; p = 0.003), indicative of a shorter time (i.e., improved) response of CVR. These findings indicate that CVR metrics determined by TFA without a CO2 inhalation do not track HUT-evoked reductions in CVR identified using CO2 inhalation, suggesting that enhanced cerebral blood flow response to a change in CO2 using CO2 inhalation is necessary to assess CVR adequately.

Cognitive Function among Young Women's Football Players in the Summer Heat.

Recently, there has been a growing focus on studies related to women's football. However, the cognitive function of female football players has not been extensively characterized. Thus, we explored how the cognitive function of female football players was altered during a series of matches in summer and examined day-to-day variations in cognitive function with regard to dehydration status. Resting cognitive function was assessed from 17 young women football players during the Japan Club Youth Women's football tournament, which spanned eight consecutive days. Cognitive function initially improved, with this improvement sustained throughout the tournament. It is worth noting that ten participants experienced symptoms of dehydration at least once during the tournament; however, these symptoms were not found to be linked to impaired cognitive function, suggesting that resting cognitive function remains unaffected during summer matches, even in the presence of dehydration symptoms.

Role of computed tomography-based evaluation of skeletal muscle area in predicting cardiovascular outcomes in patients with chronic heart failure after cardiac resynchronization therapy.

AIM: This study aimed to determine possible associations between sarcopenia and poor cardiovascular outcomes in patients with chronic heart failure after cardiac resynchronization therapy. METHODS: This retrospective study evaluated 120 patients who underwent cardiac resynchronization therapy between March 2004 and June 2018. In total, 58 patients who underwent computed tomography within 30 days of cardiac resynchronization therapy implantation were eligible for inclusion, and their data were analyzed (25 women; 33 men; mean age 71.6 ± 8.7 years). Skeletal muscle area was measured at the third lumbar vertebra, and skeletal muscle index was calculated. Major adverse cardiovascular events included cardiovascular death, hospitalization due to heart failure, cerebral infarction, acute myocardial infarction and cardiac arrest. RESULTS: During the follow-up period (mean 868 ± 617 days), major adverse cardiovascular events occurred in 22 of 58 patients (38%). The patients were allocated to two groups according to sex-based tertiles of skeletal muscle index. The lowest tertile was defined as the low skeletal muscle index group. Kaplan-Meier survival analysis showed that the low skeletal muscle index group had a higher incidence of major adverse cardiovascular events (log-rank 4.38; P = 0.036). Cox proportional hazards regression analysis also showed that low skeletal muscle index values were significantly associated with major adverse cardiovascular events (hazard ratio 3.08; 95% confidence interval 1.26-7.66, P = 0.014). CONCLUSIONS: Decreases in skeletal mass index on computed tomography might predict the occurrence of major adverse cardiovascular events in patients with chronic heart failure who underwent cardiac resynchronization therapy. Geriatr Gerontol Int 2022; 22: 1013-1018.

Prehospital 12-Lead Electrocardiography System in Oita Assisted Transport of "True" Acute Coronary Syndrome Patients to Optimal Institutes.

BACKGROUND: Mobile cloud electrocardiography (C-ECG) can reduce the door-to-balloon time of acute coronary syndrome (ACS) patients, so we hypothesized it would also assist in transporting ACS-suspected patients to the optimal institutes.Methods and Results: Initially, 10 fire departments in Oita had 10 ambulances equipped with C-ECG. Ambulance crews recorded a 12-lead ECG from the patient at the first point of contact and transmitted them to 18 hospitals (13 institutions (PCII) with 24-h availability for percutaneous coronary intervention (PCI) and 5 regional core hospitals (RCH) without 24-h PCI) for analysis by a cardiologist. During 41 months, 476 ECGs suspected to be ACS were transmitted and analyzed. Of these, 24 ECGs transmitted to PCII were judged as not requiring PCI, and the patients were directly transported to a RCH (PCII-RCH); 35 ECGs sent to a RCH were judged as requiring PCI, and the patients were directly transported to a PCII (RCH-PCII). The prevalence of cardiovascular disease was significantly higher in the RCH-PCII group than in the PCII-RCH group (P<0.01). There was no significant difference in the door-to-balloon time between the RCH-PCII and the group in which the C-ECG was sent to a PCII and the patients were transported directly to PCII (PCII-PCII) (49±14 vs. 59±20 min, P=0.14). CONCLUSIONS: Prehospital 12-lead ECG can assist in transporting ACS-suspect patients to the optimal treatment facility.

Influence of cardiac output response to the onset of exercise on cerebral blood flow.

PURPOSE: Change in cardiac output (Q) contributes to cerebral blood flow (CBF) regulation at rest and even during steady-state exercise. At the onset of cycling exercise, Q increases acutely and largely via muscle pump. The purpose of the present study was to examine whether onset exercise-induced a large increase in Q contributes to CBF regulation at the onset of exercise. METHODS: In 20 young healthy participants (10 males and 10 females), Q, mean arterial pressure (MAP), and mean blood velocities of middle and posterior cerebral arteries (MCA Vm and PCA Vm) were continuously measured during light cycling exercise for 3 min. RESULTS: At the onset of exercise, Q increased acutely to the peak (P < 0.001), while the CBF peak responses were not significantly higher than the values during the steady-state exercise (MCA Vm and PCA Vm; P = 0.183 and P = 0.101, respectively). The change in Q was correlated with that of MCA Vm or PCA Vm from resting baseline to the steady-state exercise (r = 0.404, P < 0.001 and r = 0.393, P < 0.001, respectively). However, the change in Q was not correlated with that of MCA Vm or PCA Vm at the onset of exercise (P = 0.853 and P = 0.893, respectively). Any sex differences in the onset response of peripheral and cerebral hemodynamics to exercise were not observed. CONCLUSION: These findings suggest that the acute change in Q does not contribute to CBF regulation at the onset of exercise for protecting cerebral vasculature against a large and acute elevation in Q at the onset of exercise.

Potential efficacy of multipoint pacing in the reduction of mitral regurgitation volume: a case report.

A 70-year-old woman who had cardiac sarcoidosis and severe tethering mitral regurgitation (MR) and had been implanted with a biventricular pacemaker experienced recurrent hospitalisation due to decompensated heart failure (HF). Application of MultiPoint™ pacing reduced the MR volume and maintained the symptoms under control; however, the predicted longevity of the device significantly decreased because of the very high threshold of the added pacing site. Transcatheter mitral valve repair (TMVR) using MitraClip® was performed to further diminish the severe MR, thereby enabling the switch from highly consumptive multipoint pacing (MPP) to energy-saving single-point pacing. MPP could further reduce MR compared to the conventional single-point pacing, and this could be a bridging therapy to TMVR in some patients implanted with a biventricular pacemaker. This is the first case to report that switching from conventional single-point pacing to MPP decreased the MR, to some extent, resulting in the improvement of HF symptoms.

Reduction of bleeding complications on puncture site after percutaneous coronary intervention using a 6.5-French sheathless guiding catheter.

BACKGROUND: Reducing complications at the puncture site after percutaneous coronary intervention (PCI) is important. The diameter of a 6.5-French (Fr) sheathless guiding catheter (GC) is smaller by approximately 2-Fr compared to a 6-Fr conventional sheath. In the present study, we investigated the post-PCI puncture site complications of a transradial approach in each gender while using a 6.5-Fr sheathless GC. METHODS AND RESULTS: Our study consisted of 332 patients who underwent transradial coronary intervention (TRI) between August 2017 and July 2019. We classified the patients into either the 6.5-Fr sheathless GC (Asahi, Intecc, Aichi, Japan) Group (Sheathless group: n = 182 males, 58 females) or the 6-Fr sheathed GC Group (Sheathed group: n = 150 males, 36 females). We determined the complications at the puncture site: oozing, subcutaneous hemorrhage, formation of hematoma, pseudoaneurysms, and peripheral neuropathy. The body mass index of the patients was greater in the sheathless GC group compared to the sheathed GC group (24.5 ± 3.5 kg/m2 vs. 23.6 ± 3.7 kg/m2, p = 0.02). In males, there was no significant difference in the complication rate at the puncture site between the sheathless GC and sheathed GC groups (19.3% vs. 18.6%, p = 0.88). However, the complication rate at the puncture site in females was higher in the sheathed GC group than in the sheathless GC group (36% vs. 15.5%, p = 0.02). A multiple logistic regression analysis revealed that the use of a 6.5-Fr sheathless GC independently reduced the complications in female patients (p = 0.006). CONCLUSION: The use of the 6.5-Fr sheathless GC system in a transradial approach reduced the complications at the puncture site in female patients. The 6.5-Fr sheathless GC system may be a safe option for them compared to the conventional sheath system.

Site-specific different dynamic cerebral autoregulation and cerebrovascular response to carbon dioxide in posterior cerebral circulation during isometric exercise in healthy young men.

Different cerebral blood flow (CBF) responses to exercise between the posterior cerebral artery (PCA) and vertebral artery (VA) have been previously observed, though the physiological mechanisms remain unknown. There is regional heterogeneity in sympathetic innervation between the PCA and VA, which may affect CBF regulation, especially during sympathoexcitation. Thus, in the present study, we hypothesized that different CBF regulatory mechanisms between PCA and VA contribute to heterogeneous CBF responses to isometric exercise. To test this hypothesis, in thirteen healthy young men, dynamic cerebral autoregulation (CA) and cerebrovascular CO2 reactivity (CVR), were identified in each artery during a 2-min isometric handgrip (IHG) exercise at 30% of maximum voluntary contraction. Similar to previous data, PCA cerebrovascular conductance (CVC) index was decreased from rest (P < 0.004), but not VA CVC during IHG exercise (P > 0.084). Dynamic CA in both PCA and VA were unaltered during the IHG exercise (P = 0.129). On the other hand, PCA CVR was increased during the IHG exercise (P < 0.001) while VA CVR was unchanged (P = 0.294). In addition, individual exercise-induced changes in end-tidal partial pressure of CO2 was related to the individual change in PCA blood velocity (P < 0.046), but was not observed for VA blood flow (P > 0.420). Therefore, these exercise-induced differences in CVR between PCA and VA may contribute to exercise-induced heterogeneous CBF response in the posterior cerebral circulation. These findings indicate that the site-specific posterior CBF should be considered in further research for assessing posterior cerebral circulation.

Validity of transcranial Doppler ultrasonography-determined dynamic cerebral autoregulation estimated using transfer function analysis.

Transcranial Doppler ultrasonography (TCD) is used widely to evaluate dynamic cerebral autoregulation (dCA). However, the validity of TCD-determined dCA remains unknown because TCD is only capable of measuring blood velocity and thus only provides an index as opposed to true blood flow. To test the validity of TCD-determined dCA, in nine healthy subjects, dCA was evaluated by transfer function analysis (TFA) using cerebral blood flow (CBF) or TCD-measured cerebral blood velocity during a perturbation that induces reductions in TCD-determined dCA, lower body negative pressure (LBNP) at two different stages: LBNP - 15 mmHg and - 50 mmHg. Internal carotid artery blood flow (ICA Q) was assessed as an index of CBF using duplex Doppler ultrasound. The TFA low frequency (LF) normalized gain (ngain) calculated using ICA Q increased during LBNP at - 50 mmHg (LBNP50) from rest (P = 0.005) and LBNP at - 15 mmHg (LBNP15) (P = 0.015), indicating an impaired dCA. These responses were the same as those obtained using TCD-measured cerebral blood velocity (from rest and LBNP15; P = 0.001 and P = 0.015). In addition, the ICA Q-determined TFA LF ngain from rest to LBNP50 was significantly correlated with TCD-determined TFA LF ngain (r = 0.460, P = 0.016) despite a low intraclass correlation coefficient. Moreover, in the Bland-Altman analysis, the difference in the TFA LF ngains determined by blood flow and velocity was within the margin of error, indicating that the two measurement methods can be interpreted as equivalent. These findings suggest that TCD-determined dCA can be representative of actual dCA evaluated with CBF.

Effect of breath-hold on the responses of arterial blood pressure and cerebral blood velocity to isometric exercise.

PURPOSE: The present study examined the effect of breath-hold without a Valsalva maneuver during isometric exercise on arterial blood pressure (ABP) and cerebral blood flow (CBF). METHODS: Twenty healthy adults (15 men and five women) randomly performed only breath-hold without a Valsalva maneuver (BH), and an isometric handgrip exercise for 30 s at 40% of individual maximal voluntary contraction with continuous breathing (IHG) and with breath-hold without the Valsalva maneuver (IHG-BH). Mean ABP (MAP) and blood velocity in the middle (MCA Vmean) and posterior cerebral arteries (PCA Vmean) were continuously measured throughout each protocol. RESULTS: MAP was elevated during the IHG-BH compared with IHG (P < 0.001) and BH (P = 0.001). Similarly, both MCA Vmean and PCA Vmean were higher during IHG-BH compared with IHG and BH (all P < 0.001). Moreover, the relative change in MAP from the baseline was correlated with that in both cerebral blood velocities during the BH (MCA Vmean: r = 0.739, P < 0.001 and PCA Vmean: r = 0.570, P = 0.009) and IHG-BH (MCA Vmean: r = 0.755, P < 0.001 and PCA Vmean: r = 0.617, P = 0.003) condition, but not the IHG condition (P = 0.154 and P = 0.306). CONCLUSION: These results indicate that during isometric exercise, a breath-hold enhances an exercise-induced increase in MAP and, consequently, MCA Vmean and PCA Vmean.

Proposal criteria of paradoxical low-flow low-gradient aortic stenosis for predicting prognosis in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: Paradoxical low-flow, low-gradient (PLF-LG) aortic stenosis (AS) is associated with poor prognosis in patients undergoing transcatheter aortic valve implantation (TAVI). This study aimed to verify the conventional criteria of PLF-LG AS (left ventricular ejection fraction [LVEF] > 50%, mean aortic valve pressure gradient [AVPG] < 40 mm Hg and stroke volume index [SVI] < 35 ml/m2 by measuring Doppler method) compatible for predicting prognosis in patients undergoing TAVI. MATERIALS AND METHODS: A total of 128 consecutive patients who underwent TAVI for AS with LVEF > 50% were enrolled. The primary endpoint was the hospital readmission due to heart failure (HRHF) and the secondary endpoint was all-cause mortality after hospital discharge. The patients were classified by both the conventional criteria of PLF-LG AS and the proposal criteria of PLF-LG AS if mean aortic valve pressure gradient (AVPG) < 40 mmHg and SVI by measuring Simpson's method < cut off value based on the ROC curve for predicting HRHF. RESULTS: According to the conventional criteria, only 6 patients were diagnosed with PLF-LG AS. However, according to the proposal criteria, 16 patients were diagnosed with PLF-LG AS. Fourteen patients developed HRHF during the follow-up period after TAVI. Based on the ROC curves, SVI by measuring Simpson's method (cut off value = 25 ml/m2) had higher sensitivity and specificity for predicting HRHF (AUC = 0.74, p = 0.0013) than SVI by measuring Doppler method (AUC = 0.63, p = 0.045). The multivariate analysis revealed that PLF-LG AS defined by the proposal criteria (HR: 5.25; 95% CI: 1.60-17.16; p = 0.0073) but not by the conventional criteria was independently associated with HRHF. PLF-LG AS defined by the conventional criteria and the proposal criteria were not associated with all-cause mortality in the univariate analysis. CONCLUSIONS: Our results demonstrated that new criteria of PLF-LG AS defined as SVI < 25 ml/m2 measured by Simpson's method could predict HRHF in patients with severe AS who underwent TAVI.

Integrated respiratory chemoreflex-mediated regulation of cerebral blood flow in hypoxia: Implications for oxygen delivery and acute mountain sickness.

NEW FINDINGS: What is the central question of this study? To what extent do hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral oxygen delivery, with corresponding implications for susceptibility to acute mountain sickness? What is the main finding and its importance? We provide evidence for site-specific regulation of cerebral blood flow in hypoxia that preserves oxygen delivery in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. External carotid artery vasodilatation might prove to be an alternative haemodynamic risk factor that predisposes to acute mountain sickness. ABSTRACT: The aim of the present study was to determine the extent to which hypoxia-induced changes in the peripheral and central respiratory chemoreflex modulate anterior and posterior cerebral blood flow (CBF) and oxygen delivery (CDO2 ), with corresponding implications for the pathophysiology of the neurological syndrome, acute mountain sickness (AMS). Eight healthy men were randomly assigned single blind to 7 h of passive exposure to both normoxia (21% O2 ) and hypoxia (12% O2 ). The peripheral and central respiratory chemoreflex, internal carotid artery, external carotid artery (ECA) and vertebral artery blood flow (duplex ultrasound) and AMS scores (questionnaires) were measured throughout. A reduction in internal carotid artery CDO2 was observed during hypoxia despite a compensatory elevation in perfusion. In contrast, vertebral artery and ECA CDO2 were preserved, and the former was attributable to a more marked increase in perfusion. Hypoxia was associated with progressive activation of the peripheral respiratory chemoreflex (P < 0.001), whereas the central respiratory chemoreflex remained unchanged (P > 0.05). Symptom severity in participants who developed clinical AMS was positively related to ECA blood flow (Lake Louise score, r = 0.546-0.709, P = 0.004-0.043; Environmental Symptoms Questionnaires-Cerebral symptoms score, r = 0.587-0.771, P = 0.001-0.027, n = 4). Collectively, these findings highlight the site-specific regulation of CBF in hypoxia that maintains CDO2 selectively in the posterior but not the anterior cerebral circulation, with minimal contribution from the central respiratory chemoreflex. Furthermore, ECA vasodilatation might represent a hitherto unexplored haemodynamic risk factor implicated in the pathophysiology of AMS.

Effect of intermittent isometric handgrip exercise protocol with short exercise duration on cognitive performance.

The handgrip exercise, a small muscle exercise, is useful for exercise therapy, particularly in the elderly and bedridden patients. The isometric handgrip (IHG) exercise has been utilized in training programs to reduce resting blood pressure; however, the acute effects of the IHG exercise on cognitive performance are not fully understood. The present study aimed to investigate the effect of an intermittent IHG exercise protocol with short exercise duration, which minimizes the arterial blood pressure response to exercise, on cognitive performance. Twenty-two young healthy subjects performed the intermittent IHG exercise protocol, which consisted of 30-s IHG and 45-s recovery × 16 trials; the exercise intensity of the IHG exercise was 30% of the maximal voluntary contraction. Cognitive performance was evaluated before and after the exercise with the Go/No-Go and memory recognition tasks. Specifically, the reaction time (RT) and performance accuracy were measured. The intermittent IHG exercise protocol did not change the RT or performance accuracy of either the Go/No-Go task (P = 0.222 and P = 0.260, respectively) or the memory recognition task (P = 0.427 and P = 0.245, respectively). These findings suggest that the intermittent IHG exercise protocol with short exercise duration may not provide enough stimulation to improve cognitive performance despite being useful as a safe exercise therapy in the elderly and in patients with cardiovascular disease.