P1648Prevalence of increased filling pressure assessed by echocardiography in acute dyspnoea cohort

Introduction Acute heart failure (AHF) is frequently associated with congestion leading to elevation of cardiac filling pressure. The present study investigates echocardiographic parameters of diastolic function in patients with AHF or non-AHF aetiology of acute dyspnoea. Purpose To determine the patterns of diastolic dysfunction in different profiles of acute dyspnoea. Methods Prospective multicentre observational study included 1455 acutely dyspnoeic patients in emergency departments from 2015 to 2017. Echocardiography was performed during the first 48 hours in 452 (31%) patients assessing left ventricular (LV) parameters. They were compared in four patient profiles based on dyspnoea cause and history of chronic HF (CHF): 1) AHF; 2) acute coronary syndrome without adjudicated AHF (Non-AHF+ACS); 3) non-AHF with CHF (Non-AHF+CHF); 4) other non-AHF patients (Non-AHF+other). Data were analysed using R statistical package. Results Significant differences in LV morphology and function were observed in the groups (Table 1). Increased LV filling pressure (E/E' >13) was found in most of AHF and Non-AHF+ACS patients, and in around 1/4 of Non-AHF+CHF group. Furthermore, more pronounced left-sided remodelling was observed in the first two groups. 1/3 of AHF patients had restrictive pattern of LV filling. Normal filling pressure dominated in Non-AHF+CHF and Non-AHF+other subgroups. LV parameters in acute dyspnoea profiles Parameter AHF (n=291) Non-AHF + ACS (n=43) Non-AHF + CHF (n=44) Non-AHF + other (n=74) p value Age, years 71 [62–78] 72 [64–78] 71 [65–80] 68 [56–74] 0.045 LVEF, % 38 [25–55] 47 [32–55] 55 [45–55] 55 [50–55] <0.001 LV MMI, g/m2 126 [104.6–150.4] 99.1 [82.9–124] 94.4 [78.3–108.6] 79.6 [70.7–99.4] <0.001 LAVi, cm3 61.7 [50.9–81.1] 40.4 [35.5–46.8] 43.2 [39.8–58.9] 37.2 [32.6–43.8] <0.001 E/E' >13, % 57.7% 57.1% 23.1% 2.9% <0.001 E/E' <10, % 23.4% 38.1% 76.9% 70.6% <0.001 E/A >2, % 34.4% 14.8% 12.5% 3.9% <0.001 E/A <1, % 30.3% 59.3% 66.7% 74.5% <0.001 LVEF, left ventricular ejection fraction; LVdd, left ventricular diastolic diameter; LV MMI, left ventricular myocardial mass index; LAVi, left atrial volume index; AHF, acute heart failure; ACS, acute coronary syndrome; CHF, chronic heart failure. Conclusions Our data confirm the predominance of an increased cardiac filling pressure in acute heart failure patients, differently from chronic heart failure patients admitted due to other causes of dyspnoea. Patients with dyspnoea due to acute coronary syndrome frequently demonstrate elevated left-sided filling pressure. Acknowledgement/Funding The work was supported by the Research Council of Lithuania, grant Nr. MIP-049/2015 and approved by Lithuanian Bioethics Committee, Nr. L-15-01.

Healthy aging does not compromise the augmentation of cardiac function during heat stress

During heat stress, stroke volume is maintained in young adults despite reductions in cardiac filling pressures. This is achieved by a general augmentation of cardiac function, highlighted by a left and upward shift of the Frank-Starling relation. In contrast, healthy aged adults are unable to maintain stroke volume during heat stress. We hypothesized that this would be associated with a lack of shift in the Frank-Starling relation. Frank-Starling relations were examined in 11 aged [69 ± 4 (SD) yr, 4 men/7 women] and 12 young (26 ± 5 yr, 6 men/6 women) adults during normothermic and heat stress (1.5°C increase in core temperature) conditions. During heat stress, increases in cardiac output were attenuated in aged adults (+2.5 ± 0.3 (95% CI) vs. young: +4.5 ± 0.5 l/min, P < 0.01) because of an attenuated chronotropic response (+30 ± 4 vs. young: +42 ± 5 beats/min, P < 0.01). In contrast to our hypothesis, a leftward shift of the Frank-Starling relation maintained stroke volume during heat stress in aged adults (76 ± 8 vs. normothermic: 74 ± 8 ml, P = 0.38) despite reductions in cardiac filling pressure (6.6 ± 1.0 vs. normothermic: 8.9 ± 1.1 mmHg, P < 0.01). In a subset of participants, volume loading was used to return cardiac filling pressure during heat stress to normothermic values, which resulted in a greater stroke volume for a given cardiac filling pressure in both groups. These results demonstrate that the Frank-Starling relation shifts during heat stress in healthy young and aged adults, thereby preserving stroke volume despite reductions in cardiac filling pressures.

Finger photoplethysmography during the Valsalva maneuver reflects left ventricular filling pressure

It is often challenging to assess cardiac filling pressure clinically. An improved system for detecting or ruling out elevated cardiac filling pressure may help reduce hospitalizations for heart failure. The blood pressure response to the Valsalva maneuver reflects left heart filling pressure, but its underuse clinically may be due in part to lack of continuous blood pressure recording along with lack of standardization of expiratory effort. In this study, we tested whether Valsalva-induced changes in the pulse amplitude of finger photoplethysmography (PPG), a technology already widely available in medical settings, correlate with invasively measured left ventricular end-diastolic pressure (LVEDP). We tested 33 subjects before clinically scheduled cardiac catheterizations. A finger photoplethysmography waveform was recorded during a Valsalva effort of 20 mmHg expiratory pressure sustained for 10 s, an effort most patients can achieve. Pulse amplitude ratio (PAR) was calculated as the PPG waveform amplitude just before release of expiratory effort divided by the waveform amplitude at baseline. PAR was well correlated with LVEDP ( r = 0.68; P < 0.0001). For identifying LVEDP > 15 mmHG, PAR > 0.4 was 85% sensitive [95% confidence interval (95CI): 54–97%] and 80% specific (95CI: 56–93%). In conclusion, finger PPG, a technology already ubiquitous in medical centers, may be useful for assessing clinically meaningful categories of left heart filling pressure, using simple analysis of the waveform after a Valsalva maneuver effort that most patients can achieve.

Venous hemodynamic responses to acute temperature increase in the rainbow trout (Oncorhynchus mykiss)

Many ectotherms regularly experience considerable short-term variations in environmental temperature, which affects their body temperature. Here we investigate the cardiovascular responses to a stepwise acute temperature increase from 10 to 13 and 16°C in rainbow trout ( Oncorhynchus mykiss). Cardiac output increased by 20 and 31% at 13 and 16°C, respectively. This increase was entirely mediated by an increased heart rate (fH), whereas stroke volume (SV) decreased significantly by 20% at 16°C. The mean circulatory filling pressure (MCFP), a measure of venous capacitance, increased with temperature. Central venous pressure (Pven) did not change, whereas the pressure gradient for venous return (MCFP-Pven) was significantly increased at both 13 and 16°C. Blood volume, as measured by the dilution of 51Cr-labeled red blood cells, was temperature insensitive in both intact and splenectomized trout. This study demonstrates that venous capacitance in trout decreases, but cardiac filling pressure as estimated by Pven does not change when cardiac output increases during an acute temperature increase. SV was compromised as fH increased with temperature. The decreased capacitance likely serves to prevent passive pooling of blood in the venous periphery and to maintain cardiac filling pressure and a favorable pressure gradient for venous return.