Selective Heart Rate Inhibition Improves Single-Ventricular Stroke Volume, Function, and Efficiency During Exercise

Author(s):  
Bram Ruijsink ◽  
Mari N. Velasco Forte ◽  
Phuoc Duong ◽  
Esther Puyol-Antón ◽  
Kuberan Pushparajah ◽  
...  
2012 ◽  
Vol 40 (3) ◽  
pp. 1175-1181 ◽  
Author(s):  
J Li ◽  
Fh Ji ◽  
Jp Yang

OBJECTIVE: The accuracy of stroke volume variation (SVV) obtained by the FloTrac™/Vigileo™ system in otherwise healthy patients undergoing brain surgery was assessed. METHODS: Anaesthesia was induced in 48 patients with minimal fluid infusion. Before surgery, fluid volume loading was performed by infusion with Ringer's lactate solution in 200 ml steps over 3 min, repeated successively if the patient responded with an increase in stroke volume of ≥ 10%, until the increase was < 10% (nonresponsive). RESULTS: A total of 157 volume loading steps were performed in the 48 patients. Responsive and nonresponsive steps differed significantly in baseline values of blood pressure, heart rate and SVV. Significant correlations were found between the change in stroke volume after fluid loading and values of blood pressure, heart rate and SVV before fluid loading, with SVV the most sensitive variable. CONCLUSION: Stroke volume variation obtained using the FloTrac™/Vigileo™ system is a sensitive predictor of fluid responsiveness in healthy patients before brain surgery.


1977 ◽  
Vol 22 (1) ◽  
pp. 64-68 ◽  
Author(s):  
H. Åström ◽  
B. Jonsson

Beta-blocking agents with partial agonist activity seem to reduce heart rate at rest slightly less than those without this property. Cardio-selective drugs have no effect on stroke volume at rest contrary to the non-selective ones which will reduce it somewhat. This difference is abolished during exercise. The only difference seen during work between different beta-blockers is the effect on the peripheral vascular resistance. The selective drugs lower the arterial pressure with unchanged resistance.


2000 ◽  
Vol 99 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Stephan SCHMIDT-SCHWEDA ◽  
Christian HOLUBARSCH

In the failing human myocardium, both impaired calcium homoeostasis and alterations in the levels of contractile proteins have been observed, which may be responsible for reduced contractility as well as diastolic dysfunction. In addition, levels of a key protein in calcium cycling, i.e. the sarcoplasmic reticulum Ca2+-ATPase, and of the α-myosin heavy chain have been shown to be enhanced by treatment with etomoxir, a carnitine palmitoyltransferase inhibitor, in normal and pressure-overloaded rat myocardium. We therefore studied, for the first time, the influence of long-term oral application of etomoxir on cardiac function in patients with chronic heart failure. A dose of 80 mg of etomoxir was given once daily to 10 patients suffering from heart failure (NYHA functional class II–III; mean age 55±4 years; one patient with ischaemic heart disease and nine patients with dilated idiopathic cardiomyopathy; all male), in addition to standard therapy. The left ventricular ejection fraction was measured echocardiographically before and after a 3-month period of treatment. Central haemodynamics at rest and exercise (supine position bicycle) were defined by means of a pulmonary artery catheter and thermodilution. All 10 patients improved clinically; no patient had to stop taking the study medication because of side effects; and no patient died during the 3-month period. Maximum cardiac output during exercise increased from 9.72±1.25 l/min before to 13.44±1.50 l/min after treatment (P < 0.01); this increase was mainly due to an increased stroke volume [84±7 ml before and 109±9 ml after treatment (P < 0.01)]. Resting heart rate was slightly reduced (not statistically significant). During exercise, for any given heart rate, stroke volume was significantly enhanced (P < 0.05). The left ventricular ejection fraction increased significantly from 21.5±2.6% to 27.0±2.3% (P < 0.01). In acute studies, etomoxir showed neither a positive inotropic effect nor vasodilatory properties. Thus, although the results of this small pilot study are not placebo-controlled, all patients seem to have benefitted from etomoxir treatment. Etomoxir, which has no acute inotropic or vasodilatory properties and is thought to increase gene expression of the sarcoplasmic reticulum Ca2+-ATPase and the α-myosin heavy chain, improved clinical status, central haemodynamics at rest and during exercise, and left ventricular ejection fraction.


1997 ◽  
Vol 200 (11) ◽  
pp. 1695-1702 ◽  
Author(s):  
J M Jones ◽  
A K Gamperl ◽  
A P Farrell ◽  
D P Toews

Flow from the posterior lymph hearts of Bufo marinus was measured using Doppler flow probes. These probes were placed on the posterior vertebral vein and recorded flow as lymph was ejected from the heart. In resting, hydrated toads, mean lymph flow from one of the paired posterior lymph hearts was 25.9 +/- 4.9 ml kg-1 h-1, stroke volume was 8.9 +/- 1.4 microL kg-1 and lymph heart rate was 47.5 +/- 3.7 beats min-1. We estimate that, together, the paired posterior lymph hearts are capable of generating flows that are approximately one-sixtieth of the resting cardiac output. Mean peak systolic pressure developed by the posterior lymph hearts was 1.62 +/- 0.08 kPa. Simultaneous measurements of lymph heart pressure development and flow revealed that the outflow pore of the heart opened at a pressure of 0.71 +/- 0.04 kPa, approximately 113 +/- 5 ms into systole. When toads were moderately disturbed, stroke volume increased by as much as fourfold with little change in lymph heart rate (&lt; 5 beats min-1). When toads were dehydrated, lymph flow decreased by 70% at 12h and by 80% and 24h. Since there was only a modest non-significant decrease in lymph heart rate (30%), this reduction in flow was attributed to decreases in stroke volume (approximately 80%). Lymph heart flow and stroke volume returned to control values 30 min after adding water back into the experimental chamber. Stroke volume was clearly more important in regulating lymph flow than lymph heart rate under these conditions in Bufo marinus.


1976 ◽  
Vol 230 (4) ◽  
pp. 893-900 ◽  
Author(s):  
ER Powers ◽  
Foster ◽  
Powell WJ

The modification by aortic pressure and stroke volume of the response in cardiac performance to increases in heart rate (interval-force relationship) has not been previously studied. To investigate this interaction, 30 adrenergically blocked anesthetized dogs on right heart bypass were studied. At constant low aortic pressure and stroke volume, increasing heart rate (over the entire range 60-180) is associated with a continuously increasing stroke power, decreasing systolic ejection period, and an unchanging left ventricular end-diastolic pressure and circumference. At increased aortic pressure or stroke volume at low rates (60-120), increases in heart rate were associated with an increased performance. However, at increased aortic pressure or stroke volume at high rates (120-180), increases in heart rate were associated with a leveling or decrease in performance. Thus, an increase in aortic pressure or stroke volume results in an accentuation of the improvement in cardiac performance observed with increases in heart rate, but this response is limited to a low heart rate range. Therefore, the hemodynamic response to given increases in heart rate is critically dependent on aortic pressure and stroke volume.


1989 ◽  
Vol 66 (2) ◽  
pp. 949-954 ◽  
Author(s):  
A. M. Rivera ◽  
A. E. Pels ◽  
S. P. Sady ◽  
M. A. Sady ◽  
E. M. Cullinane ◽  
...  

We examined the hemodynamic factors associated with the lower maximal O2 consumption (VO2max) in older formerly elite distance runners. Heart rate and VO2 were measured during submaximal and maximal treadmill exercise in 11 master [66 +/- 8 (SD) yr] and 11 young (32 +/- 5 yr) male runners. Cardiac output was determined using acetylene rebreathing at 30, 50, 70, and 85% VO2max. Maximal cardiac output was estimated using submaximal stroke volume and maximal heart rate. VO2max was 36% lower in master runners (45.0 +/- 6.9 vs. 70.4 +/- 8.0 ml.kg-1.min-1, P less than or equal to 0.05), because of both a lower maximal cardiac output (18.2 +/- 3.5 vs. 25.4 +/- 1.7 l.min-1) and arteriovenous O2 difference (16.6 +/- 1.6 vs. 18.7 +/- 1.4 ml O2.100 ml blood-1, P less than or equal to 0.05). Reduced maximal heart rate (154.4 +/- 17.4 vs. 185 +/- 5.8 beats.min-1) and stroke volume (117.1 +/- 16.1 vs. 137.2 +/- 8.7 ml.beat-1) contributed to the lower cardiac output in the older athletes (P less than or equal 0.05). These data indicate that VO2max is lower in master runners because of a diminished capacity to deliver and extract O2 during exercise.


Radiology ◽  
1984 ◽  
Vol 153 (1) ◽  
pp. 235-240 ◽  
Author(s):  
M Schwaiger ◽  
O Ratib ◽  
E Henze ◽  
R Grossman ◽  
K Dracup ◽  
...  

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