Baseline Heart Rate Research Articles

Abstract 4136776: Prognostic Value of Resting Heart Rate and Heart Rate Variability in the 12-lead Electrocardiogram: Mortality Data From the CODE Nationwide Database

Introduction: Resting Heart Rate (HR) and Heart Rate Variability (HRV) reflect autonomic control, and are implicated as prognostic factors. We aimed to evaluate the prognostic value of HR and HRV in a cohort from a nationwide telemedicine network. Methods: We assessed unique ECGs recorded from patients ≥16 years-old, from the tele-ECG database of the Telehealth Network of Minas Gerais, Brazil, between 2010 and 2017. Variables of interest were HR and standard deviation of normal RR intervals (SDNN). Self-informed data were collected: sex, age, risk factors (hypertension, dyslipidemia, diabetes, smoking) and comorbidities (myocardial infarction, Chronic Obstructive Pulmonary Disease, and Chagas disease). Outcomes of interest were all-cause and cardiovascular mortality, assessed by ICD codes reported in death certificates, through linkage with the Mortality Information System. Cox regression was applied to evaluate the association between HR and HRV and the outcomes, in 4 models: 1. Unadjusted; 2. Adjusted for sex and age; 3. Model 2 + risk factors + clinical comorbidities; 4. Model 3 + HRV or HR, respectively. Results: At total 992.611 individuals were included, median age of 55 years, 60% women. In 6 years, there were 33.292 deaths (3,37%), 21% due to cardiovascular causes. Patients who died had higher prevalence of all risk factors and comorbidities, as well as higher HR: 76 (IQR 66-87) vs. 74 (IQR 65-83) bpm, p<0.001 and lower HRV: 84 (IQR 51-127) vs. 114 (IQR 74-153), p<0.001. After adjustments (model 4), all HR quartiles were independently associated a progressively increased risk of all-cause mortality, being 88% higher for the 4 th quartile (HR=1.88 (95%CI 1.77–1.89). Similarly, the 1 st and 2 nd HRV quartiles remained associated with increased all-cause mortality (1 st quartile HR=1.42 (95%CI 1.37–1.47) in the final model. For cardiovascular mortality, HR was also an independent predictor, with a progressively higher risk, with a 77% increase (HR=1.77 95%CI 1.65–1.91) in the 4 th quartile. HRV was also an independent predictor of cardiovascular death, with a 33% risk increase (HR=1.33, 95%CI 1.23–1.44) for the 1 st quartile. Male gender, age, and all risk factors and comorbidities were also independent predictors of all-cause and cardiovascular mortality. Conclusions: In a large cohort of Brazilian adults, baseline HR and HRV were independent predictors of all-cause and cardiovascular mortality, after adjustment for clinical variables and autonomic indexes.

Abstract 4138420: Impact of the American Heart Association Get-With-The-Guidelines Heart Failure A.S.I.A. Program in Taiwanese hospitals

Introduction: The American Heart Association (AHA) Get With the Guidelines – Heart Failure program has been implemented for years in the United States with extensive literature supporting its benefits. In 2022, the AHA Heart Failure Adherence to Science Implementation in Asia (HF A.S.I.A.) powered by Get With The Guidelines program was first introduced in five Asian countries. Research Question: This study aims to explore the impact of this program's implementation in Taiwanese hospitals. Methods: Data were sourced from the Taiwan Society of Cardiology-HF-Registry 2020, a prospective registry that tracks HF cases from 27 hospitals in Taiwan between 2020 and 2024. Among these, four hospitals began participating in the HF A.S.I.A. program in January 2022. This study compared patients from hospitals that participated and did not participate in the HF A.S.I.A. program. Results: A total of 1,933 HF patients with a left ventricular ejection fraction ≤ 40% were included, comprising 460 participants from the HF A.S.I.A. program and 1,473 non-participants. The HF A.S.I.A. group was younger, had significantly lower systolic blood pressure, larger left ventricular diameter, and experienced more frequent prior hospitalizations for HF. However, there were no significant differences between the two groups in terms of baseline heart rate, estimated glomerular filtration rate, blood potassium levels, and most comorbidities. During the study period, due to changes in payment policies, the use of angiotensin receptor neprilysin inhibitor (ARNI) decreased in the non-participant group, while the use of sodium glucose co-transporter 2 inhibitor (SGLT2i) increased. Conversely, the use of ARNI in the HF A.S.I.A. group continued to rise in line with guideline recommendations and the usage of SGLT2i was higher than in the non-participant group. After adjustment, one-year lost to follow-up rate was significantly lower (3.0% vs. 5.6%, p =0.032) and all-cause mortality rate trended non-significantly lower (7.6% vs. 11.4%, p =0.096) among the HF A.S.I.A. group. Conclusion: Despite enrolling sicker patients, participation in HF A.S.I.A. program was associated with higher quality of HF care.

Abstract 4136181: Automated Personalized Modulation of the Sympathetic “fight-or-flight” Reflex In Vivo Using Implantable Microdevices for Enhancing Neurocardiac Function and Reducing Mortality Risk.

Background: The sympathetic nervous system (SNS) is a critical regulator of cardiovascular function. Whereas acute SNS activation elicits positive inotropy and confers survival advantage, persistent SNS hyperactivity is maladaptive and can lead to arrhythmias, cardiac arrest and heart failure. Hypothesis: Automated optogenetic modulation of the sympathetic stress response in vivo enhances neurocardiac function while avoiding sympathetic hyperactivity-mediated pathological effects. Methods: In normal guinea pigs, we virally transduced excitatory and/or inhibitory channelrhodopsins to the stellate ganglia (SG), the primary sympathetic input to the heart. We studied in situ effects of graded activation of SG opsins (e.g., phasic vs tonic) on cardiac function (e.g., ECG, heart rate) with and without perfusing agents (e.g., β-blockers, antioxidants). In vivo studies used novel implanted µLED devices for wireless body signal streaming (e.g., ECG) and neurophotonic SG opsin modulation closed-loop to dynamic analyses of physiological demand versus ECG-based cardiac risk prediction. Results: Compared to baseline heart rate (218±16 bpm), pulsed activation of inhibitory opsins reduced heart rate by ~25% (156±12; delta=67±14 bpm; p<0.0003; N=5). Pulsed activation of excitatory opsins increased heart rate by ~30% (285±28; delta=65±19 bpm; p<0.0002; N=5). Interestingly, prolonged (>20 min) tonic excitation of the SG caused desensitization, possibly as an intrinsic safety mechanism. Whereas graded SG excitation or inhibition at different LED intensities elicited prompt changes in heart rate, repeated activation of excitatory opsins led to quick desensitization. Our ongoing studies are aimed at understanding how and when SG modulation can enhance cardiac function, trigger intrinsic cardioprotective mechanisms, or cause pathological effects. Conclusion: Automated neurophotonic optogenetic excitation or inhibition of the SG is a robust personalized strategy for modulating cardiovascular function. The ability to rapidly and accurately modulate the sympathetic stress reflex in a graded manner can lead to more timely, effective, and appropriate physiological responses while avoiding undesired pathophysiological responses.

Abstract 4136812: Optimal Pacing for Cerebral Perfusion: Elucidating Relationship Between Resting Pacemaker Heart Rate and Pulse Pressure

Background: Cognitive decline and dementia are significant global health concerns, with hypertension being a major risk factor. Increasingly, the elderly population is receiving pacemakers, and the pacing rates are set as low as 50bpm. Moreover, the relationship between blood pressure (BP) components, particularly diastolic BP (DBP) and pulse pressure (PP), and the risk of cognitive decline or dementia remains complex. The highest risk is observed in patients with low DBP and concurrently increased PP, likely indicating vascular stiffness. To our knowledge, no studies have assessed the programming of pacemakers to increase heart rates to target DBP and PP improving cerebral perfusion. Objectives: In patients with permanent pacemakers, resting heart rate (HR) can be artificially increased, and its consequence on hemodynamics, including PP, can be easily measured. This study aims to investigate the impact of increasing resting HR on PP in patients with poor vascular compliance. Secondary outcomes include evaluating changes in DBP, SBP, and cardiac output, as well as assessing patient tolerance to higher-paced heart rates through recording subjective symptoms. Methods: The study will employ a prospective cross-sectional interventional design. Digital plethysmography will be utilized to measure hemodynamic parameters, including systolic blood pressure (SBP), DBP, PP, and cardiac output, at baseline resting-paced heart rates. Subsequently, the pacemaker resting heart rate will be incrementally increased to a final rate of 100 beats per minute (bpm), with measurements taken 2-5 minutes after each change. Results: Ten out of twenty patients were recruited, with a mean age of 75.3 years old. The median change in PP from baseline HR of 70 to 100 was -8.7% (IQR -18.8 - +2.8, p= 0.114), SBP 4.2% (IQR 0 – 11.9, p=0.059), and DBP 20.1% (IQR 12.9 -23, p=0.005). There were no adverse outcomes and no patient-reported symptoms during higher pacing rates. Conclusion: This study provides the basis for proof of concept. Since an increased HR decreases PP, this will be subsequently tested against improvement in cerebral perfusion by cerebral Doppler studies, and its impact on cognitive function will be tested. This has the potential to change the standard of practice for patients with pacemakers and allow for collaboration across multiple specialties such as neurology, geriatric medicine and cardiology.

Abstract Su506: A Comparison of Synchronized Versus Unsynchronized Mechanical Chest Compressions in a Swine Model

Background: The proportion of cardiac arrest presenting with pulseless electrical activity (PEA), which includes pseudo-PEA, is increasing and survival remains dismal. We hypothesized that mechanical chest compressions synchronized to native cardiac contractions improve coronary perfusion pressure (CPP) during resuscitation of pseudo-PEA. Methods: We developed a model of pseudo-PEA by infusing high dose esmolol intravenously into anaesthetized, intubated, and central arterial and venous catheterized swine to a goal of 45 mm Hg mean arterial blood pressure (MAP). We then provided alternating synchronized and unsynchronized chest compressions for 52 seconds preceded by 8 second breaks consecutively four times. We repeated the protocol two to three times with one minute breaks after each four minute block. Synchronized compressions were provided 1:1 with native contractions during systole and unsynchronized compressions were provided at 100 beats per minute (BPM). We measured average CPP, MAP, and heartrate (HR) for 5 beats immediately preceding the onset of chest compressions and for 30 seconds 10 seconds after the onset of compressions. We computed the difference in continuous CPP during compressions compared to the immediately preceding baseline for each interval. We developed a mixed linear model with outcome variable average CPP during compressions minus baseline, fixed variable compression type, and random variable animal. Results: We included four animals. Mean baseline HR was 78.9 BPM, MAP 55.2, and CPP 44.0. Chest compressions increased CPP from baseline an average 4.0 mm Hg when unsynchronized and 6.4 mm Hg synchronized. The adjusted difference was 2.5 mm Hg (95% CI 0.3 – 4.6). Conclusions: Synchronized chest compressions significantly increased CPP 2.5 mm Hg (62%) more than unsynchronized chest compressions despite a lower compression rate in a medication-induced swine model of pseudo-PEA. Further refinement and application to patients suffering pseudo-PEA cardiac arrest appear warranted.

Risk factors of hypotension during cesarean section with spinal anesthesia in parturients with COVID-19: a retrospective study in comparison with pregnant women without COVID-19.

The incidence of hypotension in parturients with coronavirus disease (COVID-19) undergoing regional anesthesia remains controversial. This study aimed to investigate the incidence of hypotension during spinal anesthesia in parturients infected with COVID-19, as well as to identify associated risk factors. This retrospective study compared COVID-19-positive parturients who underwent cesarean section under spinal anesthesia (COVID-19 group) with a control group between January 2017 and June 2022. We reviewed the medical records and collected the following information: basic patient characteristics, spinal anesthesia, and newborn-related data. Compared with the control group, the COVID-19 group did not show any significant differences in terms of hypotension occurrence and vasopressor usage. A positive correlation was noted in the COVID-19 group between heart rate and duration of hospital stay (P < 0.001, Spearman's rho = 0.422). In subgroup analysis of the COVID-19 group, group with a baseline heart rate ≥ 100 (group H) had lower Apgar scores at 1 min, longer hospital stays, and more severe COVID-19 symptoms than the with a baseline heart rate < 100 (group L). Moreover, in group H, there was a positive correlation between the heart rate and the lowest systolic blood pressure after spinal anesthesia (P = 0.012, Spearman's rho = 0.528). Parturients with COVID-19 do not appear to have a higher risk of hypotension during cesarean section under spinal anesthesia than those without COVID-19. Given the close association between preoperative heart rate and extent of hypotension in parturients with COVID-19 undergoing spinal anesthesia, vigilant monitoring of vital signs by anesthesiologists is crucial during the perioperative period.

Associations between heart rate, deformational echocardiographic parameters and clinical outcomes in patients with atrial fibrillation

Abstract Background The relationship between baseline heart rates and cardiac function in patients with atrial fibrillation (AF) remains unknown, as does its impact on long-term outcomes. Methods Patients with newly diagnosed AF and available echocardiography images were included. Conventional echocardiography measurement and myocardial deformation analyses using two-dimensional speckle-tracking echocardiography were performed during AF. Clinical endpoints included first-time hospitalization for ischemic stroke, heart failure (HF), all-cause mortality, and composite endpoint. Results Patients were categorized into groups according to baseline heart rates: 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 beats per minutes (bpm). As heart rates increased, there was a stepwise decrease of peak atrial longitudinal systolic strain (PALS: 14.6 ± 5.3%, 14.7 ± 5.5%, 14.1 ± 4.6%, 13.4 ± 4.7%,12.6 ± 4.9%, 12.1 ± 4.5%, 11.2 ± 5.2% and 10.8±4.1% in 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively; P &amp;lt; 0.001)) and LV strain (-13.8 ± 3.9%, -14.5 ± 4.0%, -13.4 ± 3.4%, -13.4 ± 3.6%, -12.5 ± 3.6%, -11.9 ± 3.8%, -10.3 ± 3.8%, and -10.2 ± 3.8%, in 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively; P &amp;lt; 0.001)(Figure). The lowest risk of composite endpoint was observed for patients whose heart rate between 60 to 69 bpm (Figure). Compared to the 60-69 heart rate group, faster heart rates were associated with increased risk of ischemic stroke (adjusted hazard ratios [aHR] 4.448 in the ≥120 bpm group), HF (aHR 1.909 in the ≥120 bpm group), mortality (aHRs 2.487, 2.810, 4.569, 4.760 in the 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively), and composite endpoint (aHRs 2.034, 2.349, 3.492 in the 100-109, 110-119, and ≥120 bpm groups, respectively) (all P &amp;lt; 0.05). Conclusion In patients with AF, heart rate is closely linked to cardiac function and plays a pivotal role in long-term prognosis. Faster heart rates were associated with worse LA/LV functions and increased risk of clinical events. Favorable outcomes were found at heart rates below 100 bpm, with even better LA/LV function noted at heart rates below 80 bpm.

Beta-blocker use and outcomes in patients with heart failure and mildly reduced and preserved ejection fraction

Abstract Background Concerns have been raised about the appropriateness of use and safety of beta-blockers (BBs) in patients with heart failure and mildly reduced (HFmrEF) and preserved ejection fraction (HFpEF). However, randomized trial evidence is still lacking. Purpose To perform an observational analysis of the association between BB use and clinical outcomes in a large dataset of patients with HFmrEF and HFpEF. Methods We pooled individual patient data from four large HFmrEF/HFpEF trials (I-Preserve, TOPCAT, PARAGON-HF, and DELIVER). The associations between baseline BB use and outcomes were analyzed. The primary outcome was the composite of cardiovascular death or HF hospitalization. Results Among the 16,951 patients included, the mean left ventricular ejection fraction (LVEF) was 56.8%, and 13,400 (79.1%) had HFpEF (LVEF ≥50%). Overall, 12,812 patients (75.6%) received a BB. The median bisoprolol-equivalent dose of BB was 5.0 (Q1-Q3: 2.5-5.0) mg with BB continuation rates of 95.1% at 1 year and 93.1% at 2 years (in patients who survived more than 1 and 2 years, respectively). Overall, the hazard ratio (HR) for the primary outcome did not differ between BB users and non-users (HR: 0.98 [95% CI: 0.91-1.05]) but among patients with HFmrEF, BB users had a lower HR (0.84 [95% CI 0.71-0.98]), whereas in HFpEF the HR was similar BB users and non-users (0.99 [95% CI 0.92-1.08]). However, after comprehensive adjustment for known prognostic variables, including NT-proBNP, BB use was associated with a better outcome in the overall cohort (HR 0.81 [0.74-0.88]), and this association was maintained across the range of LVEF (Figure 1). In subgroup analyses, the risk of the primary outcome was similar in BB users and non-users with or without a history of myocardial infarction, with or without a history of hypertension, or with or without a baseline heart rate &amp;lt;70 bpm. By contrast, a better outcome with BB use was seen in patients with atrial fibrillation compared to those without atrial fibrillation (Figure 2). Conclusions Although this is an observational analysis of non-randomized treatment, there was no suggestion that BB use was associated with worse HF outcomes even after extensive adjustment for other prognostic variables. Figure Legends Figure 1. Association between beta-blocker use and outcomes across the range of LVEF. Risk in beta-blocker users versus non-users is shown as an adjusted continuous hazard ratio Figure 2. Association between beta-blocker use and non-use in the overall population and clinically relevant patient subgroups, shown as an adjusted hazard ratio (HR). The outcome analyzed was the composite of CV death or HF hospitalization (primary outcome)Figure 1Figure 2

Baseline heart rate as a key prognostic indicator in AMI patients with cardiogenic shock undergoing successful primary PCI

Abstract Background Cardiogenic shock presents as a critical condition in patients experiencing acute myocardial infarction (AMI). Even that primary percutaneous coronary intervention (PCI) has become widespread, the mortality rate of AMI complicated with cardiogenic shock remains high. However, comprehensive prognostic stratification remains elusive. Objective Our study sought to elucidate the relationship between baseline parameters and prognostic outcomes in AMI patients with cardiogenic shock. Methods From the GETBACK-AMI multicenter retrospective registry encompassing 935 AMI patients who underwent primary PCI and attained TIMI 3 flow upon final angiography. There were 73 patients diagnosed with cardiogenic shock were ultimately analyzed. The primary endpoint of our study was all-cause mortality. Results Over a median follow-up duration of 425 days, 17 patients (23%) succumbed, of which 14 were in-hospital fatalities. Employing the Cox regression model, we identified that heart rate (HR) at the time of admission bore a potent and independent correlation with the primary endpoint (hazard ratio: 1.04 [95% CI: 1.01-1.06], p=0.002), even post-adjustment for various covariates. ROC analysis pinpointed an admission HR of 82 bpm as the threshold for the primary endpoint. Kaplan-Meier curves further highlighted a pronounced elevation in the primary endpoint occurrence rate for patients with HR &amp;gt; 82 bpm compared to those with HR &amp;lt; 82 bpm (53% vs. 13%, p=0.0002). Conclusions Within our multicenter study cohort, a heightened admission HR was demonstrably linked to increased mortality in AMI patients with cardiogenic shock who reached a final TIMI 3 flow. This readily accessible and impactful prognostic marker may guide clinicians in identifying high-risk patients, subsequently allowing for enhanced support and interventions to optimize patient outcomes.

The importance of heart rate on left ventricular global longitudinal strain in echocardiography: novel insights facilitated by automated deep learning methods

Abstract Background Heart rate (HR) is assumed to influence echocardiographic measurements. Consequently, HR needs to be considered for accurate assessment of cardiac function. Despite left ventricular global longitudinal strain (LV GLS) being recognised as a valuable measure of cardiac function, its normal reference ranges remain confined to patients within a limited range of resting HR. So far, time-consuming manual analyses and high measurement variability have precluded comprehensive assessment of the interplay between HR and LV GLS. Using fully automated GLS measurements provided by novel deep learning (DL) methods, it is now possible to evaluate changes in LV GLS across a wide range of HR. Purpose To improve echocardiographic assessments across a wide range of HR intervals, we aimed to study the influence of controlled HR variations on LV GLS using programmable pacemakers and fully automated DL measurements. Methods Participants with sinus node dysfunction and implanted programmable pacemakers were enrolled. Echocardiographic acquisitions were obtained at baseline HR and during stepwise increments by 10 beats/min, targeting a range from 50 to 140 beats/min. Recordings of cine-loops including 10 cardiac cycles were obtained for the four-chamber, two-chamber, and apical long axis view. LV GLS was measured for all cycles using a fully automated DL method developed by our group, and presented as mean of the three standard apical views for all patients at each HR level. A linear mixed model was used for construction of an overall trendline based on the estimated fixed effects across all 50 patients, stating patient number as the random effect. The correlation between HR and LV GLS was evaluated by a likelihood ratio test. Results Fifty patients were included, 52% females, mean age 68 years (27 to 88 years). All patients had preserved atrioventricular conduction. Resting HR ranged from 50 to 87 beats/min (mean 64 beats/min). At baseline echocardiographic acquisition, most participants were within normal ranges for LV volumes, systolic and diastolic function. A total of about 13,000 cardiac cycles were automatically analysed by the DL method. The overall trend demonstrated a linear relation between increasing HR and decreasing absolute LV GLS (Figure 1). Across HR increments from 50 to 140 beats/min, there was a 32% (22%–42%) reduction in absolute LV GLS, declining from -17.1% to -11.7%. The strong correlation between changes in HR and LV GLS was further supported by a highly significant likelihood ratio test (p-value &amp;lt;0.001). Conclusions There was a reduction of absolute LV GLS with increasing HR. These findings emphasize the importance of integrating HR considerations into clinical echocardiography practice. Moreover, the results highlight that DL methods can unlock substantially richer insights from individual patient data, offering a new pathway towards more personalized and precise cardiac diagnostics.Figure 1

Left atrial parameters predict incident atrial fibrillation and flutter in patients with heart failure with reduced ejection fraction

Abstract Background Left atrial (LA) function parameters have shown prognostic value in relation to incidence of atrial fibrillation in the general population, but this remains to be investigated in patients with heart failure with reduced ejection fraction (HFrEF). Purpose This study aimed to investigate the relationship between LA function parameters and the risk of incident atrial fibrillation/atrial flutter (AF/AFL) in patients with HFrEF. Methods Subjects free of AF/AFL were retrospectively included from a HF clinic and followed using the Danish National Patient Registry. Cox proportional hazards regression was used to assess the prognostic value of LA function parameters. These included LA ejection fraction (LAEF), peak atrial longitudinal strain (PALS), peak atrial contractile strain (PACS) and LA conduit strain (LACS). In addition, multivariable Cox regression was performed to adjust for demographic and echocardiographic parameters, including LA volume index (LAVi). The LA function parameters that remained significant in adjusted analysis were examined using cubic splines, and cutoff values corresponding to a hazard ratio (HR) equal to 1 were derived from these. Results The total study population consisted of 435 subjects with a left ventricular ejection fraction (LVEF) ≤45% (mean age 65.6±11.7 years, male sex 70.1%) free from AF/AFL at baseline. During a median follow-up of 11.4 years [IQR: 10.8, 14.2], 111 (25.5%) developed AF/AFL. Subjects who met the outcome were generally older (69.0±8.8 years vs. 64.4±12.4, p&amp;lt;0.001), had lower baseline heart rate, and a higher prevalence of moderate or severe valve disease (12.6% vs. 3.1%, p&amp;lt;0.001). They also had higher LV mass index and LV internal diastolic diameter index, but similar LVEF. These subjects had larger LAVi (30 ml/m2 [IQR: 24, 38] vs. 26 ml/m2 [IQR: 20, 32], p&amp;lt;0.001), while LAEF (33±14.8% vs. 39±14.9%, p&amp;lt;0.001), PALS (20.3% [IQR: 16.2, 26.5] vs. 23.2% [IQR: 18.6, 29.6], p=0.001), and PACS (9.7% [IQR: 6.9, 13.5] vs. 12.0% [IQR: 7.8, 16.4], p=0.004) were all significantly lower. LACS was similar between groups. In univariable Cox regression, all LA parameters were significant predictors of the AF/AFL (LAEF: HR 0.98 per 1% increase, 95% CI 0.96-0.99, p=0.0002, PALS: HR 0.96 per 1% increase, 95% CI 0.94–0.98, p=0.0008, PACS: HR 0.95 per 1%, 95% CI 0.93–0.98, p=0.0024, LACS: HR 0.96, 95% per 1% increase CI 0.92–0.998, p=0.039. In adjusted analysis, however, only LAEF (HR 0.98, 95% CI 0.976-0.995, p=0.0087) and PACS (HR 0.96, 95% CI 0.993–0.999, p=0.044) remained significant. Splines were constructed for LAEF and PACS (Figure 1), and a cutoff for increased risk of AF/AFL at 38% for LAEF and 12% for PACS, respectively, were derived (Figure 2). Conclusion LAEF and PACS are associated with risk of incident AF/AFL in patients with HFrEF, independent of clinical and echocardiographic risk factors. Our results suggest an increased risk of AF/AFL at LAEF below 38% and PACS below 12%.Figure 1 SplinesFigure 2 Cumulative incident curves

Awake lumbar spine surgery performed under spinal versus conventional anesthesia.

Lumbar spine surgery for discectomy or laminectomy is mostly performed under general anesthesia (GA). Here, we explored whether, in a series of 84 patients, better peri-operative outcomes and lower complication rates could be achieved for those undergoing diskectomy/laminectomy under spinal anesthesia (SA) versus GA. From 2022 to 2023, 84 patients were randomly assigned to undergo lumbar discectomy/laminectomy for stenosis under SA: 42 patients versus GAGA: 42 patients. For these two populations, we analyzed and compared multiple variables, including duration of anesthesia, estimated blood loss (EBL), and outcomes (i.e., including pre/post-operative Visual Analogue Scale, Oswestry disability index, and short-form 36 questionnaires). Major advantages of SA versus GA included a reduced mean EBL, shorter mean operative time, reduced mean hospital length of stay, and fewer post-operative side effects. Notably, baseline heart rate or mean arterial blood pressure showed no significant differences between SA and GA groups. Based on this small preliminary sample of patients undergoing lumbar disc/stenosis surgery, it appeared that SA reduced the mean EBL, offered shorter mean operative times, mean hospital lengths of stay, and fewer post-operative side effects versus GA.

Pulse oximetry-based perfusion index as a non-invasive indicator of systemic hemodynamics during spinal anesthesia in cesarean delivery

Background &amp; Objectives: Placental perfusion is not autoregulated and is susceptible to effects of spinal anesthesia (SA) induced hypotension. The perfusion index (PI) is a non-invasive marker of peripheral vascular tone, and a higher PI indicates increased risk of hypotension following SA. This study aims to establish preoperative baseline PI in our local population and its correlation with incidence of intraoperative hypotension. Methods: This prospective observational study recruited 35 parturients who underwent elective lower segment cesarean section (LSCS). Preoperatively, baseline heart rate (HR), systolic blood pressure (SBP), mean arterial pressure (MAP) and PI were documented. SA was performed with 8 to 10 mg of injection bupivacaine 0.5% (hyperbaric) at L3–L4 interspace followed by co-loading with 1 L Hartmann solution. Hypotension was defined as SBP less than 80% of baseline or less than 90 mmHg. A bolus of phenylephrine 50 µg was given as rescue medication to treat the hypotension. Intraoperatively, degree of decrease in SBP, MAP and HR, as well as the amount of phenylephrine required was recorded every minute until delivery of the baby and 3 min thereafter. Results: The correlations between parturients’ baseline PI with the degree of decreases in systolic and mean arterial pressure (r = 0.81, P &lt; 0.001 and r = 0.76, P &lt; 0.001, respectively) and phenylephrine requirement (r = 0.761, p &lt; 0.005) were recorded. This study identified that the patients with cut-off PI value of 3.2 were at higher risk for SA induced hypotension with a sensitivity of 85.9% and a specificity of 87.5% (P = 0.001). Conclusion: The patients with baseline cut-off perfusion index value of more than 3.2 were at higher risk for spinal anesthesia induced hypotension in elective cesarean section. Abbreviations: CO - cardiac output; LSCS - lower segment cesarean section MAP - mean arterial pressure; PI - perfusion index; SA - spinal anesthesia Keywords: Hypotension; Pulse Oximeter; Perfusion Index; Spinal Anesthesia; Cesarean section; Citation: Manap NSA, Zaini RHM, Shukeri WFWM, Omar SC, Abu Bakar MZ, Seevaunnamtum P. Pulse oximetry-based perfusion index as a non-invasive indicator of systemic hemodynamics during spinal anesthesia in cesarean delivery. Anaesth. pain intensive care 2024;28(5):927−932; DOI: 10.35975/apic.v28i5.2570 Received: July 23, 2024; Reviewed: September 02, 2024; Accepted: September 10, 2024

Circadian heart rate fluctuations predict cardiovascular and all-cause mortality in type 2 and type 1 diabetes: a 21-year retrospective longitudinal study.

Circadian heart rate (HR) fluctuations are associated with cardiovascular health. We examined their relationship with microvascular disease and long-term survival in patients with diabetes. In this secondary analysis from the CHAMP1ON cohort of 497 adults with metabolic disease, 349 participants who had type 1 or type 2 diabetes, baseline 24h ambulatory blood pressure and HR monitoring (ABPM), and survival data over a 21-year observational follow-up were included. Clinical features, microvascular complications, and mortality rates were examined in participants with low circadian HR fluctuations (24h-HR SD below the median of 30.4) and blunted nocturnal HR dip (<10%). Low 24h-HR SD and blunted nocturnal HR dip were associated with an adverse cardiometabolic risk profile and 12-23% higher prevalence of cardiac autonomic neuropathy and nephropathy. After 6,251 person-years follow-up (21.0 [14.0-21.0] years), a total of 136 (39%) deaths occurred, of which 100 (68%) of cardiovascular cause. The low 24h-HR SD group had a higher risk for both cardiovascular (adjusted hazard ratio [aHR] 2.00, 95%CI 1.30-3.08, p=0.002) and all-cause mortality (aHR 1.61, 95%CI 1.13-2.29, p=0.009), compared with high 24h-HR SD. Similarly, patients with blunted nocturnal HR dip had a higher risk for cardiovascular (aHR 1.63, 95%CI 1.08-2.46, p=0.019) and all-cause mortality (aHR 1.69, 95%CI 1.20-2.38, p=0.003), compared with those with preserved nocturnal HR dip. Impaired circadian HR fluctuations are associated with microvascular disease and long-term cardiovascular and all-cause mortality in diabetes. ABPM-derived HR measures may provide a widely available and inexpensive risk stratification tool in this high-risk population.

Impact of targeted neonatal echocardiography consultations for critically sick preterm neonates

RationalePreterm neonates needing rescue treatments with inotropes and/or inhaled nitric oxide (iNO) (acute critical illnesses, ACIs) in neonatal intensive care units (NICUs) are at high risk of mortality. While targeted...

Abstract P210: IDENTIFICATION OF ALAMANDINE-(1-5) AS A NEW ANTI-HYPERTENSIVE PEPTIDE OF THE RENIN-ANGIOTENSIN SYSTEM

It is currently accepted that angiotensin-(1-7) [Ang-(1-7)] and alamandine [Ala 1 -Ang-(1-7)] are members of the counterregulatory axis of the renin-angiotensin system (RAS). Both peptides can undergo hydrolysis by angiotensin-converting enzyme and form Ang-(1-5) and Alamandine-(1-5), respectively. Recently, we have shown that Alamandine-(1-5) is present in human and mice circulation. Here, we evaluated the cardiovascular effects induced by intravenous (i.v.) administration of these peptides in conscious normotensive Wistar (n=6 for each peptide) and spontaneously hypertensive rats (SHR) (n=6 for each peptide). After a period of one hour for stabilization of the cardiovascular parameters, Alamandine-(1-5) or Ang-(1-5) were injected at a dose of 3µg/ 100g of b.w. A similar volume (0.1 ml/ 100g b.w.) of sterile saline was injected into SHR and Wistar rats for control. Alamandine-(1-5) injection produced a progressive decrease in systolic blood pressure (SBP, SHR, reaching -33±3.0 mmHg six hours after injection (Baseline SBP: 208±8 mmHg before and 175±10 mmHg, six hours after the injection). In contrast, SBP did not significantly change after the administration of Ang-(1-5) (Baseline SBP: 198±13 mmHg before and 199±8 mmHg six hours after injection). There was no significant change in heart rate (HR) in SHR after Alamandine-(1-5) (Baseline HR: 342±14 beats/min before and 341±18.8 beats/min after six hours) or after Ang-(1-5) (Baseline HR: 333±18 beats/min before and 326±19 beats/min after six hours). Alamandine-(1-5) injection in Wistar rats produced only small changes in BP (Baseline SBP: 109±10 mmHg before injection and 99±11 mmHg six hours after injection, p&lt;0.05). No differences were observed for Ang-(1-5) injection in Wistar rats (Baseline SBP: 118±8 mmHg before injection and 115±9 mmHg six hours after injection) or in HR for Alamandine-(1-5) or Ang-(1-5). Saline injection did not change BP or HR in SHR or in Wistar rats. These results show that Alamandine-(1-5), but not Ang-(1-5), triggers a long-lasting fall in BP in hypertensive animals. These data indicate that we have identified a new vasodilatory peptide of the RAS, increasing our understanding of the complexity of this system and opening a possibility for future development of a new pharmacological target for hypertension treatment.

Beta-blocker use and outcomes in patients with heart failure and mildly reduced and preserved ejection fraction.

In the absence of randomized trial evidence, we performed a large observational analysis of the association between beta-blocker (BB) use and clinical outcomes in patients with heart failure (HF) and mildly reduced (HFmrEF) and preserved ejection fraction (HFpEF). We pooled individual patient data from four large HFmrEF/HFpEF trials (I-Preserve, TOPCAT, PARAGON-HF, and DELIVER). The primary outcome was the composite of cardiovascular death or HF hospitalization. Among the 16 951 patients included, the mean left ventricular ejection fraction (LVEF) was 56.8%, and 13 400 (79.1%) had HFpEF (LVEF ≥50%). Overall, 12 812 patients (75.6%) received a BB. The median bisoprolol-equivalent dose of BB was 5.0 (Q1-Q3: 2.5-5.0) mg with BB continuation rates of 93.1% at 2 years (in survivors). The unadjusted hazard ratio (HR) for the primary outcome did not differ between BB users and non-users (HR 0.98, 95% confidence interval [CI] 0.91-1.05), but the adjusted HR was lower in BB users than non-users (0.81, 95% CI 0.74-0.88), and this association was maintained across LVEF (pinteraction = 0.88). In subgroup analyses, the adjusted risk of the primary outcome was similar in BB users and non-users with or without a history of myocardial infarction, hypertension, or a baseline heart rate <70 bpm. By contrast, a better outcome with BB use was seen in patients with atrial fibrillation compared to those without atrial fibrillation (pintreraction = 0.02). In this observational analysis of non-randomized BB treatment, there was no suggestion that BB use was associated with worse HF outcomes in HFmrEF/HFpEF, even after extensive adjustment for other prognostic variables.

How well can the fetal heart rate baseline be assessed by intrapartum intermittent auscultation? An interrater reliability and agreement study.

We aimed to examine the inter-reliability and agreement among midwives when assessing the fetal heart rate (FHR) using the handheld Doppler. The primary aim was to measure the reliability and agreement of FHR baseline (baseline) as beats per minute (bpm). The secondary aims were to measure fluctuations from the baseline, defined as increases and decreases, and classifications (normal or abnormal) of FHR soundtracks. This is the first interrater reliability and agreement study on intermittent auscultation (IA) to our knowledge. The participant population consisted of 154 women in labor, from a mixed-risk population and admitted to hospital for intrapartum care. The rater population were 16 midwives from various maternity care settings in Norway. A total of 154 soundtracks were recorded with a handheld Doppler device, and the 16 raters assessed 1-min soundtracks once, through an online survey (Nettskjema). They assessed the baseline, FHR increase or decrease, and the FHR classification. The primary outcome, baseline, was measured with intraclass correlation coefficient (ICC). The secondary outcomes were measured with kappa and proportion of agreement. The interrater reliability for the baseline (bpm) was ICC(A,1) 0.74 (95% CI 0.69-0.78). On average, an absolute difference of 7.9 bpm (95% CI 7.3-8.5 bpm) was observed between pairs of raters. Our results demonstrate an acceptable level of reliability and agreement in assessing the baseline using a handheld Doppler.

How to give a spider a heart attack: Evaluating cardiac stress reactions of Trichonephila and Argiope spiders

AbstractAll animal species, from arthropods to vertebrates, must deal with occasional stressors in their lives, though most research on this has been focused on vertebrates. Meanwhile, our understanding of stress reactions in arthropod species like spiders is nascent. In the United States, a non‐native orb‐weaving spider, Trichonephila clavata (‘jorō’ spider), is spreading as is its already‐established cousin in the United States, T. clavipes (golden silk spider). Prior study has revealed how these two species have a unique behavioural reaction to physical stressors, whereby they remain in a thanatosis state for a prolonged period compared with other species. Here, we investigate the physiological stress reactions of these Trichonephila spiders by evaluating how each species' dorsal vessel contractions (heart rates) become elevated after being subjected to a non‐lethal stressor. For comparison, we also evaluate two similarly‐sized orb weavers, Argiope aurantia (garden spider) and A. trifasciata (banded garden spider). We record baseline heart rates of inactive, resting, spiders in our lab, then restrain them under an electronic, ‘optocardiographic’, sensor for 10 min, to record their ‘stressed’ heart rates. Argiope aurantia has a pronounced heart rate elevation, for reasons unknown. We observe that all spider heart rates increase during restraint, though each has a species‐specific pattern of elevation over time under restraint. Notably, heart rates of both Trichonephila spiders are less variable under stress, since they tend not to struggle during restraint. Meanwhile, both Argiope spiders frequently struggle, leading to marked fluctuations in cardiac output. The stress reactions of Trichonephila spiders could be characterized as ‘even‐tempered’, which may factor into their ability to live in habitats with frequent disturbances.

2289 The association of heart rate and cholinesterase inhibitor use among elders living with dementia: a retrospective cohort study

Abstract Introduction Cholinesterase inhibitors (ChEIs) are the primary medication for dementia treatment. Bradycardia is a potential adverse effect associated with ChEIs. However, the relationship between ChEIs and bradycardia has not been definitively established, particularly in the Asian population. We conducted a study investigating the association between ChEIs and heart rate. Methods We retrieved data from electronic medical records (EMR) of patients aged over 60 who were diagnosed with mild cognitive impairment or dementia at Ramathibodi Hospital between January 2009 and December 2022. These patients had outpatient records at 3, 6, and 12 months after the diagnosis. After filtering out by eligibility criterias, patients were categorised into ChEIs and non-ChEIs use, and then were 1:1 matched by baseline characteristics. We compared heart rate changes between the groups using Student’s t-tests or Mann Whitney U test depending on their distribution and Bayesian linear regression. Bradycardia was analysed using Kaplan–Meier Estimates and Cox proportional hazards model. Results 790 eligible patients were included, with 395 patients in each group. The median of difference of changes from baseline heart rate between group were − 0.5 BPM (p = 0.06), −1.5 BPM (p = 0.12), and − 1.5 BPM (p = 0.002) at 3, 6, and 12 months, respectively. The bradycardia incidence was higher in the ChEIs group (38.5%) compared with the non-ChEIs group (30.6%) at 12 months, but this difference was not statistically significant (p = 0.2). Among all regarded variables, baseline heart rate, age and beta-blocker usage associated with bradycardia, with adjusted hazard ratios (aHR) = 0.888 (95% CI 0.873–0.904, p &amp;lt; 0.001), 1.019 (95% CI 1.001–1.037, p = 0.035) and 1.334 (95% CI 1.045–1.703, p = 0.021). Conclusions The use of ChEIs was found to be associated with a decrease in heart rate. However, the changes were minimal and may not have had clinical implications for the patient.