Tag: cardiac output

ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing

Abstract

Introduction: Mechanisms underlying exercise and orthostatic intolerance in myalgic encephalomyelitis/chronic
fatigue syndrome (ME/CFS) have been uncovered by invasive cardiopulmonary exercise testing (iCPET) and
autonomic function testing (AFT), but the relationships between the two are not known. This study aims to determine
if there is overlap of cardiovascular and respiratory pathophysiology in patients who have undergone both
tests.

Methods: Between January 2017 and April 2022, 62 patients were identified with a contemporary iCPET and
AFT. Key variables from the iCPET included peak oxygen uptake (pVO2), cardiac output (pQc), right atrial pressure
(pRAP), and systemic oxygen extraction (Ca-vOy/Hgb) at peak exercise. Key variables from the autonomic testing
included epidermal and sweat gland small fiber neurite density, electrochemical skin conductance, and change in
heart rate (AH) and end tidal carbon dioxide (AETCO2) from supine to upright during the tilt table test
(TTT).

Results: All 62 patients demonstrated preload failure (pRAP < 6.5mmHg). Of this group, 54 patients (87.1%) fulfilled NAM criteria for ME/CFS, with 32 testing positive (59.3%) for small fiber neuropathy (SFN) using either morphological and/or functional testing. Significant correlations were found between pVOg and both AH (r=-0.439. P<0.05) and AETCO, (r=0.474, P<0.05) during TTT. The same tilt table variables were found to be significantly correlated with pQc (r=-0.365, P<0.05 and r=0.351, P<0.05) from the iCPET. It should be noted that 8 of the ME/CFS SFN patients (25%) fulfilled diagnostic criteria for postural orthostatic tachycardia syndrome (POTS) based on the tilt table test.

Conclusion: Decreased oxygen uptake and cardiac output at peak exercise during iCPET correlated with a greater change in heart rate and ETCO from supine to upright during TTT. There appears to be significant overlap of cardiopulmonary pathophysiology in ME/CFS underlying exercise and orthostatic symptoms.

Source: J. Squires, K. Wichmann Madsen, M.C. Stovall, S. Al-Zayer, W. Xiao, C.-J. Chang, P. Novak, D.M. Systrom. ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing. American Journal of Respiratory and Critical Care Medicine 2023;207:A2996. https://www.atsjournals.org/doi/abs/10.1164/ajrccm-conference.2023.207.1_MeetingAbstracts.A2996

Comparison of the finger plethysmography derived stroke volumes by Nexfin CO Trek and suprasternal aortic Doppler derived stroke volume measurements in adults with myalgic encephalomyelitis/chronic fatigue syndrome and in healthy controls

Abstract:

Background: Finger plethysmography derived stroke volumes are frequently measured during tilt table testing. There are two algorithms to determine stroke volumes: Modelflow and NexfinCO Trek. Most tilt studies used Modelflow, while there are differences between the two algorithms.

Objective: To compare stroke volume indices by Nexfin CO Trek (SVINexfinCOTrek) with suprasternal Doppler derived SVI (SVIDoppler) in healthy controls (HC) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients during tilt testing. These patients may have a large SVI decrease during the tilt enabling a large range of SVI to be studied.

Methods: One hundred and fifty-four patients and 39 HC with a normal tilt test were included. Supine and end-tilt SVIDoppler and SVINexfinCOTrek were compared using the Bland-Altman analysis. Also, the effect of calibrating supine SVINexfinCOTrek to SVIDoppler was studiedRESULTS: Supine and end-tilt SVINexfinCOTrek were significantly higher than SVIDoppler: both P< 0.005. Bias, limits of agreement, and percent error (PE) were high with PE’s between 37 and 43%. The calibration procedure resulted in an acceptable variance with a PE of 29%.

Conclusions: SVINexfinCOTrek overestimates stroke volumes compared to SVIDoppler, leading to high PE’s. Calibration reduced variance to an acceptable level, allowing SVINexfinCOTrek to be used for assessment of SVI changes during tilt testing.

Source: van Campen CLMC, Verheugt FWA, Rowe PC, Visser FC. Comparison of the finger plethysmography derived stroke volumes by Nexfin CO Trek and suprasternal aortic Doppler derived stroke volume measurements in adults with myalgic encephalomyelitis/chronic fatigue syndrome and in healthy controls. Technol Health Care. 2021 Apr 25. doi: 10.3233/THC-202669. Epub ahead of print. PMID: 33998565. https://pubmed.ncbi.nlm.nih.gov/33998565/

The Abnormal Cardiac Index and Stroke Volume Index Changes During a Normal Tilt Table Test in ME/CFS Patients Compared to Healthy Volunteers, are Not Related to Deconditioning

Abstract:

1.1 Background. A small study in ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) patients undergoing tilt testing, showed that, despite a normal tilt test, stroke volumes and cardiac output were lower than in healthy volunteers. Moreover, it was suggested that this difference was related to deconditioning of patients. Aim of the study. We performed table testing in 150 ME/CFS patients. Stroke volumes and cardiac output were related to the severity of the disease.

1.2 Methods and results. In the patients the severity of the disease was clinically evaluated according to the ME criteria and scored as mild, moderate or severe disease. In a subgroup of 109 patients this clinical diagnosis was confirmed by the physical functioning score of the Rand-36 questionnaire. Significantly lower physical functioning scores (indicating worse functioning) were observed in the more severely affected patients. Stroke Volume Index (SVI) and Cardiac Index (CI) were measured by suprasternal aortic Doppler imaging in the supine position, prior to the tilt, and twice during the tilt. Thirty-seven healthy volunteers underwent the same tilt protocol. In all patients and all healthy volunteers, a normal heart rate and blood pressure response was observed during the tilt. The decreases in SVI and CI during the tilt was significantly larger in patients compared to the SVI and CI decrease in HV. The decrease in SVI and CI were similar and not significantly different between the mild, moderate, and severe ME groups.

1.3 Conclusions. During a normal tilt table test decreases in SVI and CI decrease are significantly greater in ME/CFS patients than in HV, consistent with previous work. The absence of differences between patients with mild, moderate, and severe ME/CFS suggests that the decreases in stroke volumes and cardiac output are not related to deconditioning. Other factors like decreased blood volumes and autonomic dysfunction may cause this difference in the hemodynamic response between ME/CFS patients and HV.

3. Abbreviations

BMI : Body Mass Index

BSA : Body Surface Area

CFS : Chronic Fatigue Syndrome

CI : Cardiac Index

DBP : Diastolic Blood Pressure

HR : Heart Rate

HUT : Head-Up Tilt Test

HV : Healthy Volunteers

IOM : Institute of Medicine

MAP : Mean Blood Pressure

ME : Myalgic Encephalomyelitis

NMH : Neurally Mediated Hypotension

Normal BPHR : normal Blood Pressure and Heart Rate Response During HUT

OI : Orthostatic Intolerance

R36 Phys Funct : Rand-36 Physical Functioning Score

SBP : Systolic Blood Pressure

SVI : Stroke Volume Index

SVRI : Systemic Vascular Resistance Index

VTI : Time-Velocity Integral

Source: van Campen CMC, Visser FC (2018) The Abnormal Cardiac Index and Stroke Volume Index Changes During a Normal Tilt Table Test in ME/CFS Patients Compared to Healthy Volunteers, are Not Related to Deconditioning. J Thrombo Cir: JTC -107. DOI: 10.29011/ JTC -107. 000007 https://www.gavinpublishers.com/articles/Research-Article/Journal-of-Thrombosis-and-Circulation/The-Abnormal-Cardiac-Index-and-Stroke-Volume-Index-Changes-During-a-Normal-Tilt-Table-Test-in-ME-CFS-Patients-Compared-to-Healthy-Volunteers-are-Not-Related-to-Deconditioning (Full article)

Cardiovascular dysfunction with low cardiac output due to a small heart in patients with chronic fatigue syndrome

Abstract:

OBJECTIVE: Little attention has been paid to possible cardiovascular involvement in patients with chronic fatigue syndrome (CFS), although many of their symptoms and signs suggest cardiovascular dysfunction. Possible cardiovascular symptoms and cardiac function were investigated in CFS patients.

METHODS: Cardiovascular symptoms were intensively investigated and cardiac function was evaluated echocardiographically.

PATIENTS: Fifty-three patients (23 men and 30 women, mean age: 31+/-7 years) with CFS under 50 years were studied.

RESULTS: Slender build (body mass index <20 kg/m(2)) was common (47%). Possible cardiovascular symptoms including shortness of breath (32%), dyspnea on effort (28%), rapid heartbeat (38%), chest pain (43%), fainting (43%), orthostatic dizziness (45%) and coldness of feet (42%), were all frequent complaints. Hypotension (28%) was occasionally noted. Electrocardiograms frequently revealed right axis deviation (21%) and severe sinus arrhythmia (34%) suggesting accentuated parasympathetic nervous activity. Small heart shadow (cardiothoracic ratio <or=42%) was noted on the chest roentgenogram in 32 patients (60%). Echocardiographic examination demonstrated low cardiac indexes (<2 L/min/m(2)) with low stroke volume indexes (<30 mL/m(2)) due to a small left ventricular chamber in 19 (36%, p<0.05 vs. 8% in 36 controls). None had reduced left ventricular ejection fraction.

CONCLUSION: Cardiovascular symptoms are common in CFS patients. Cardiac dysfunction with low cardiac output due to small left ventricular chamber may contribute to the development of chronic fatigue as a constitutional factor in a considerable number of CFS patients.

 

Source: Miwa K, Fujita M. Cardiovascular dysfunction with low cardiac output due to a small heart in patients with chronic fatigue syndrome. Intern Med. 2009;48(21):1849-54. Epub 2009 Nov 2. https://www.ncbi.nlm.nih.gov/pubmed/19881233

 

Abnormal impedance cardiography predicts symptom severity in chronic fatigue syndrome

Abstract:

BACKGROUND: Findings indicative of a problem with circulation have been reported in patients with chronic fatigue syndrome (CFS). We examined this possibility by measuring the patient’s cardiac output and assessing its relation to presenting symptoms.

METHODS: Impedance cardiography and symptom data were collected from 38 patients with CFS grouped into cases with severe (n = 18) and less severe (n = 20) illness and compared with those from 27 matched, sedentary control subjects.

RESULTS: The patients with severe CFS had significantly lower stroke volume and cardiac output than the controls and less ill patients. Postexertional fatigue and flu-like symptoms of infection differentiated the patients with severe CFS from those with less severe CFS (88.5% concordance) and were predictive (R2 = 0.46, P < 0.0002) of lower cardiac output. In contrast, neuropsychiatric symptoms showed no specific association with cardiac output.

CONCLUSIONS: These results provide a preliminary indication of reduced circulation in patients with severe CFS. Further research is needed to confirm this finding and to define its clinical implications and pathogenetic mechanisms.

 

Source: Peckerman A, LaManca JJ, Dahl KA, Chemitiganti R, Qureishi B, Natelson BH. Abnormal impedance cardiography predicts symptom severity in chronic fatigue syndrome. Am J Med Sci. 2003 Aug;326(2):55-60. http://www.ncbi.nlm.nih.gov/pubmed/12920435