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Inspiratory muscle weakness in diastolic dysfunction
Marc H Lavietes1, Christine M Gerula, Kristin G Fless
1University Hospital #I354, 100 Bergen St, Newark, NJ 07103, USA. lavietmh@umdnj.edu
Chest
|September 15, 2004
Summary
Patients with diastolic dysfunction (DD) experience inspiratory muscle weakness and a rapid, shallow breathing pattern during exercise, leading to increased dyspnea. This study confirms these findings, highlighting a significant difference compared to healthy individuals.
Area of Science:
- Cardiology
- Pulmonology
- Exercise Physiology
Background:
- Respiratory muscle weakness is documented in systolic heart failure.
- The presence of similar findings in diastolic dysfunction (DD) is not well-established.
- Investigating respiratory mechanics in DD is crucial for understanding patient limitations.
Purpose of the Study:
- To determine if patients with diastolic dysfunction (DD) exhibit inspiratory muscle weakness.
- To assess if DD patients experience dyspnea and tachypnea during exercise.
- To compare respiratory parameters in DD patients versus healthy controls.
Main Methods:
- 14 patients with confirmed DD and 7 matched controls underwent pulmonary function tests.
- Maximal inspiratory pressure (Pimax) and handgrip strength (Hgr) were measured.
- Graded exercise tests monitored ventilation, gas exchange, and heart rate, with dyspnea rated on the Borg scale.
Main Results:
- Patients with DD showed significantly diminished Pimax compared to controls (p=0.013).
- DD patients reported higher dyspnea scores (2.6 vs 0.5 Borg units) at submaximal exercise.
- A rapid, shallow breathing pattern was observed in DD patients during exercise.
Conclusions:
- Diastolic dysfunction is associated with reduced inspiratory muscle strength (Pimax).
- Patients with DD develop a rapid, shallow breathing pattern during exertion.
- Dyspnea occurs at lower exercise workloads in individuals with DD.