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

2016 ◽  
Vol 121 (4) ◽  
pp. 885-892 ◽  
Author(s):  
Daniel Gagnon ◽  
Steven A. Romero ◽  
Hai Ngo ◽  
Satyam Sarma ◽  
William K. Cornwell ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Heat Stress ◽  
Stroke Volume ◽  
Cardiac Function ◽  
Healthy Aging ◽  
Filling Pressure ◽  
Volume Loading ◽  
Cardiac Filling Pressure ◽  
Chronotropic Response ◽  
Cardiac Filling

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.

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

2007 ◽  
Vol 292 (6) ◽  
pp. R2292-R2298 ◽  
Author(s):  
Erik Sandblom ◽  
Michael Axelsson
Keyword(s):  
Cardiac Output ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Temperature Increase ◽  
Venous Return ◽  
Filling Pressure ◽  
Venous Capacitance ◽  
Cardiac Filling Pressure ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Cardiac Filling

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.

Different hemodynamic effects of atrial natriuretic factor and nitroglycerin in rats with congestive heart failure

1989 ◽  
Vol 257 (6) ◽  
pp. R1481-R1487
Author(s):  
Y. W. Chien ◽  
N. C. Trippodo ◽  
E. D. Frohlich
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Atrial Natriuretic Factor ◽  
Filling Pressure ◽  
Fluid Migration ◽  
Hemodynamic Effects ◽  
Cardiac Filling Pressure ◽  
Cardiac Filling

Atrial natriuretic factor (ANF) decreases cardiac filling pressure, suggesting that diminished venous return is an important mechanism for the associated reduction in cardiac output. To determine whether ANF reduces cardiac preload through venodilation in congestive heart failure (CHF), we compared the hemodynamic effects of ANF-(99-126) with those of the venodilator nitroglycerin in conscious rats with CHF induced by coronary artery ligation previously. Depending on the extent of myocardial infarction, rats were subdivided into two groups: 1) mild or 2) severe CHF. Incremental intravenous infusions of ANF (0.1, 0.25, 0.5 micrograms.kg-1.min-1) or nitroglycerin (2, 5, 10 micrograms.kg-1.min-1) were administered for 20 min at each dose. Both agents reduced cardiac filling pressures. There was no change in cardiac output or arterial pressure at any dose of ANF in rats with severe CHF, but cardiac output decreased at higher ANF doses in rats with mild CHF. In contrast, nitroglycerin produced no change in cardiac output at any dose in either CHF group, although it decreased arterial pressure at the higher doses in rats with severe CHF. ANF increased whereas nitroglycerin decreased hematocrit in both CHF groups. The ANF-induced hematocrit increase also occurred in those rats with vesicovenous shunts designed to prevent volume contraction induced by diuresis. These data suggest that ANF and nitroglycerin decreased cardiac filling pressure through different hemodynamic mechanisms. The known venodilator action of nitroglycerin was associated with decreased hematocrit, suggesting enhanced transcapillary fluid migration. However, ANF produced an opposite effect on fluid migration as demonstrated by an increased hematocrit, suggesting a mechanism other than venodilation must be operative in reducing cardiac filling pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of blood volume on forearm venous and cardiac stroke volume during exercise

1983 ◽  
Vol 55 (3) ◽  
pp. 884-890 ◽  
Author(s):  
S. M. Fortney ◽  
C. B. Wenger ◽  
J. R. Bove ◽  
E. R. Nadel
Keyword(s):  
Stroke Volume ◽  
Blood Volume ◽  
Filling Pressure ◽  
Isotonic Solution ◽  
O2 Uptake ◽  
Deep Body Temperature ◽  
Cardiac Filling Pressure ◽  
Cardiac Filling ◽  
Deep Body ◽  
Cardiac Stroke Volume

Five healthy men exercised at 65-70% of maximum O2 uptake (VO2 max) for 30 min in an ambient temperature of 30 degrees C. Duplicate experiments were conducted at three levels of plasma volume:control, hypovolemia, in which blood volume (BV) was reduced an average of 490 ml (9.7%) with diuretics, and hypervolemia, in which BV was increased an average of 440 ml (7.8%) by infusing an isotonic solution containing 5% human serum albumin. Marked venoconstriction occurred during exercise in all conditions and persisted despite large increases in deep body temperature. The degree of venoconstriction was similar during control and hypervolemic conditions, but was potentiated during hypovolemia. The observed venoconstriction appeared to consist of two components: an early one related to autonomic adjustments at the onset of exercise, and a later one possibly related to progressive decreases in cardiac filling. Heart rate, cardiac stroke volume (SV), and cardiac output during exercise were significantly affected by changes in BV. During hypovolemia the average differences from control values were 10 beats X min-1, -14 ml, and -2.2 l X min-1, respectively; during hypervolemia the differences from control were -7 X min-1, 10 ml, and 1.0 l X min-1, respectively. The pattern of SV over the course of exercise indicates that pooling of blood in veins may be quantitatively more important than plasma water loss in reducing cardiac filling pressure in the heat.

Noninvasive methods for detecting elevated left-sided cardiac filling pressure

2000 ◽  
Vol 6 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Gregory P. Sanders ◽  
Lisa A. Mendes ◽  
Wilson S. Colucci ◽  
Michael M. Givertz
Keyword(s):  
Filling Pressure ◽  
Noninvasive Methods ◽  
Cardiac Filling Pressure ◽  
Cardiac Filling

scholarly journals Non-Invasive Scale Measurement of Cardiac Output Compared with the Gold-Standard Direct Fick Method: A Feasibility Study

2021 ◽  
Author(s):  
Daniel Yazdi ◽  
Sarin Patel ◽  
Suriya Sridaran ◽  
Evan Wilson ◽  
Sarah Smith ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Cardiac Function ◽  
Exercise Test ◽  
Gold Standard ◽  
Cardiopulmonary Exercise Test ◽  
Cardiac Monitoring ◽  
Non Invasive ◽  
Cardiopulmonary Exercise ◽  
The Mean

AbstractBackgroundObjective markers of cardiac function are limited in the outpatient setting and may be beneficial for monitoring patients with chronic cardiac conditions.ObjectiveWe assess the accuracy of a scale, with the ability to capture ballistocardiography, electrocardiography, and impedance plethysmography signals from a patient’s feet while standing on the scale, in measuring stroke volume and cardiac output compared to the gold-standard direct Fick method.MethodsThirty-two patients with unexplained dyspnea undergoing level 3 invasive cardiopulmonary exercise test at a tertiary medical center were included in the final analysis. We obtained scale and direct Fick measurements of stroke volume and cardiac output before and immediately after invasive cardiopulmonary exercise test.ResultsStroke volume and cardiac output from a cardiac scale and the direct Fick method correlated with r = 0.81 and r = 0.85, respectively (P < 0.001 each). The mean absolute error of the scale estimated stroke volume was -1.58 mL, with a 95% limits of agreement (LOA) of -21.97 mL to 18.81 mL. The mean error for the scale estimated cardiac output was -0.31 L/min, with a 95% LOA of -2.62 L/min to 2.00 L/min. The change in stroke volume and cardiac output before and after exercise were 78.9% and 96.7% concordant, respectively between the two measuring methods.ConclusionsThis novel scale with cardiac monitoring abilities may allow for non-invasive, longitudinal measures of cardiac function. Using the widely accepted form factor of a bathroom scale, this method of monitoring can be easily integrated into a patient’s lifestyle.

Hindlimb unweighting affects rat vascular capacitance function

2001 ◽  
Vol 281 (3) ◽  
pp. H1170-H1177 ◽  
Author(s):  
Stacey L. Dunbar ◽  
Laleh Tamhidi ◽  
Dan E. Berkowitz ◽  
Artin A. Shoukas
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Arterial Compliance ◽  
Filling Pressure ◽  
Right Atrial ◽  
Orthostatic Stress ◽  
Venous Compliance ◽  
Reservoir Volume ◽  
Venous Filling ◽  
And Control

Microgravity is associated with an impaired stroke volume and, therefore, cardiac output response to orthostatic stress. We hypothesized that a decreased venous filling pressure due to increased venous compliance may be an important contributing factor in this response. We used a constant flow, constant right atrial pressure cardiopulmonary bypass procedure to measure total systemic vascular compliance (CT), arterial compliance (CA), and venous compliance (CV) in seven control and seven 21-day hindlimb unweighted (HLU) rats. These compliance values were calculated under baseline conditions and during an infusion of 0.2 μg · kg−1 · min−1norepinephrine (NE). The change in reservoir volume, which reflects changes in unstressed vascular volume (ΔV0) that occurred upon infusion of NE, was also measured. CT and CV were larger in HLU rats both at baseline and during the NE infusion ( P < 0.05). Infusion of NE decreased CT and CV by ∼20% in both HLU and control rats ( P < 0.01). CA was also significantly decreased in both groups of rats by NE ( P < 0.01), but values of CA were similar between HLU and control rats both at baseline and during the NE infusion. Additionally, the NE-induced ΔV0 was attenuated by 53% in HLU rats compared with control rats ( P < 0.05). The larger CV and attenuated ΔV0 in HLU rats could contribute to a decreased filling pressure during orthostasis and thus may partially underlie the mechanism leading to the exaggerated fall in stroke volume and cardiac output seen in astronauts during an orthostatic stress after exposure to microgravity.

scholarly journals Finger photoplethysmography during the Valsalva maneuver reflects left ventricular filling pressure

2012 ◽  
Vol 302 (10) ◽  
pp. H2043-H2047 ◽  
Author(s):  
Harry A. Silber ◽  
Jeffrey C. Trost ◽  
Peter V. Johnston ◽  
W. Lowell Maughan ◽  
Nae-Yuh Wang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Amplitude Ratio ◽  
Valsalva Maneuver ◽  
Pulse Amplitude ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Left Heart ◽  
Cardiac Filling Pressure ◽  
Cardiac Filling ◽  
Waveform Amplitude

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.

Estimating cardiac filling pressure in mechanically ventilated patients with hyperinflation

2000 ◽  
Vol 28 (11) ◽  
pp. 3631-3636 ◽  
Author(s):  
Jean-Louis Teboul ◽  
Michael R. Pinsky ◽  
Alain Mercat ◽  
Nadia Anguel ◽  
Gilles Bernardin ◽  
...  
Keyword(s):  
Filling Pressure ◽  
Mechanically Ventilated ◽  
Cardiac Filling Pressure ◽  
Mechanically Ventilated Patients ◽  
Cardiac Filling ◽  
Ventilated Patients
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