Respiratory muscle dysfunction in congestive heart failure—The role of pulmonary hypertension

doi:10.1016/j.ijcard.2010.04.006

International Journal of Cardiology

Volume 150, Issue 2, 15 July 2011, Pages 182-185

https://doi.org/10.1016/j.ijcard.2010.04.006 Get rights and content

Abstract

Background

Inspiratory muscle weakness has been described in patients with congestive heart failure (CHF), and only recently in patients with idiopathic pulmonary arterial hypertension. However, the relationship between pulmonary hemodynamics and respiratory muscle function has not been investigated in patients with CHF.

Methods and results

In two tertial referral centers for CHF patients, 532 consecutive CHF patients (159 female, age 59 ± 12 years, NYHA I–IV) were studied by right heart catheterization, maximal inspiratory mouth occlusion pressure (Pi_max) and pressure 0.1 s after beginning of inspiration during tidal breathing at rest (P_0.1). There was a significant correlation between Pi_max and mean pulmonary artery pressure (PAPm) (r = − 0.65, p = 0.0023), mean pulmonary capillary wedge pressure (PCWPm) (r = − 0.56; p = 0.0018), PVR (r = − 0.73; p = 0.0031), and cardiac output (r = 0.51; p = 0.0022). Moreover, the ratio P_0.1/Pi_max showed a linear correlation with PAPm (r = 0.54; p = 0.0019), and with TPG (r = 0.64; p = 0.0014) respectively. Vital capacity was reduced in relation to increased PAPm (r = − 0.54; p = 0.0029). Pi_max and P_0.1/Pi_max were independent from VC.

Conclusions

This study provides the first evidence of a close relation between inspiratory muscle dysfunction, increased ventilatory drive and pulmonary hypertension in a large patient cohort with CHF. Pi_max and P_0.1 can easily be measured in clinical routine and might become an additional parameter for the non-invasive monitoring of the hemodynamic severity of disease.

Introduction

In patients with congestive heart failure (CHF), exercise intolerance and dyspnoea have been attributed partially to the dysfunction of the skeletal and possibly of the respiratory musculature [1], [2], [3], [4]. Moreover, the inspiratory muscle strength was assessed by static maximal inspiratory mouth occlusion pressure (Pi_max) or using tests more independent from patients aptitude; and Pi_max serving as a significant and independent prognostic marker [5], [6]. Several pathomechanisms have been suggested to contribute to respiratory muscle dysfunction in CHF. In severe CHF, a general atrophic loss of skeletal muscle mass in patients has been reported [3], [7]. Moreover, even in early stages of CHF, peripheral muscle function is impaired due to structural and metabolic abnormalities of skeletal myocytes [7]. Hammond et al. [8] reported on respiratory muscle weakness in patients with congestive heart failure and proposed blood flow reduction to be responsible for the inspiratory muscle weakness. Moreover, in CHF the increase in ventilatory drive has been an inconsistent finding. Its potential contribution to respiratory muscle dysfunction remains a matter of debate [4], [11], [12]. However, no data were provided as for the relationship between respiratory muscle strength and pulmonary hemodynamics. The relation between hemodynamics and respiratory muscle strength was first studied by Nishimura et al. [9] who showed an inverse relationship between cardiac index and maximal inspiratory mouth occlusion pressure (Pi_max). Recently, additional data were reported on the association of respiratory muscle dysfunction with the severity of idiopathic pulmonary arterial hypertension [10]. However, comprehensive data on respiratory muscle strength in relation to pulmonary hemodynamics in a large CHF population is lacking.

Therefore, the present study was designed to investigate the relationship between pulmonary hypertension, respiratory muscle dysfunction, and ventilatory drive in CHF patients with a wide range in disease severity.

Section snippets

Study population

This study enrolled 532 consecutive CHF patients (159 female, age 59 ± 12 years, NYHA functional classes I–IV) from two tertial referral centers in Germany (German Heart Institute, Berlin, and University Hospital, Heidelberg). All patients were electively short-term hospitalized for comprehensive invasive and non-invasive evaluation.

The diagnostic classification of underlying cardiac disorder was based on left heart catheterization and coronary angiography. As inclusion criteria, left ventricular

Results

Invasive hemodynamic assessment was compatible with CHF (Table 1). In 65% of the 532 CHF patients, PAPm was > 25 mm Hg at rest (Table 1). The close correlation between PAPm and PCWPm (r = 0.61; p = 0.0015), together with the PVR (6.2 ± 4.5 WU) and the TPG (9 ± 6 mm Hg) indicates a postcapillary component of PH.

Discussion

The present study provides first evidence of a close relation between respiratory muscle dysfunction, increased ventilatory drive and pulmonary hypertension in 532 patients with various degrees of chronic left ventricular failure.

The major findings are:

1.
Inspiratory muscle dysfunction (reduction in Pi_max) is more pronounced in patients with severe CHF.
2.
There is a close inverse correlation between inspiratory muscle strength and PAPm as well as PCWP. This occurs in parallel with a reduction in VC.
3.

Acknowledgement

The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology [29].

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Inspiratory dysfunction occurs in patients with heart failure with reduced ejection fraction (HFrEF) in a manner that depends on disease severity and by mechanisms that are not fully understood. In the current study, we tested whether HFrEF effects on diaphragm (inspiratory muscle) depend on disease severity and examined putative mechanisms for diaphragm abnormalities via global and redox proteomics. We allocated male rats into Sham, moderate (mHFrEF), or severe HFrEF (sHFrEF) induced by myocardial infarction and examined the diaphragm muscle. Both mHFrEF and sHFrEF caused atrophy in type IIa and IIb/x fibers. Maximal and twitch specific forces (N/cm²) were decreased by 19 ± 10% and 28 ± 13%, respectively, in sHFrEF (p < .05), but not in mHFrEF. Global proteomics revealed upregulation of sarcomeric proteins and downregulation of ribosomal and glucose metabolism proteins in sHFrEF. Redox proteomics showed that sHFrEF increased reversibly oxidized cysteine in cytoskeletal and thin filament proteins and methionine in skeletal muscle α-actin (range 0.5 to 3.3-fold; p < .05). In conclusion, fiber atrophy plus contractile dysfunction caused diaphragm weakness in HFrEF. Decreased ribosomal proteins and heighted reversible oxidation of protein thiols are candidate mechanisms for atrophy or anabolic resistance as well as loss of specific force in sHFrEF.
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Respiratory muscle dysfunction in congestive heart failure—The role of pulmonary hypertension

Abstract

Background

Methods and results

Conclusions

Introduction

Section snippets

Study population

Results

Discussion

Acknowledgement

Respiratory muscle function in congestive heart failure

Chest

Respiratory muscle function and dyspnea in patients with chronic congestive heart failure

Circulation

The “muscle hypothesis” of chronic heart failure

J Mol Cell Cardiol

Inefficient ventilation and reduced respiratory muscle capacity in congestive heart failure

Basic Res Cardiol

Respiratory muscle dysfunction in congestive heart failure: clinical correlation and prognostic significance

Circulation

Diaphragm strength in chronic heart failure

Am J Respir Crit Care Med.

Wasting as independent risk factor for mortality in chronic heart failure

Lancet

Respiratory muscle function in congestive heart failure

Chest

Respiratory muscle strength and hemodynamics in chronic heart failure

Chest

Respiratory muscle dysfunction in idiopathic pulmonary arterial hypertension

Eur Respir J

Breathing pattern, ventilatory drive and respiratory muscle strength in patients with chronic heart failure

Eur Respir J

Respiratory muscle weakness and normal ventilatory drive in dilative cardiomyopathy

Eur Heart J

Is the six minutes walk test a reliable substitute for peak oxygen uptake in patients with dilated cardiomyopathy?

Eur Heart J

Guidelines for the diagnosis and treatment of chronic heart failure: executive summary (update 2005): the Task Force for the Diagnosis and Treatment of Chronic Heart Failure of the European Society of Cardiology

Eur Heart J.