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Firm myocardium in cardiopulmonary resuscitation
1Department of Traumatology and Critical Care Medicine, National Defense Medical College, Saitama, Japan.
Insights
Firm myocardium, or stiff heart muscle, is common during cardiopulmonary resuscitation (CPR). This condition indicates severe ischemia and is a grave prognostic factor for cardiac resuscitation success.
Area of Science:
- Cardiology
- Emergency Medicine
- Pathology
Background:
- Firm myocardium is a rarely described but potentially significant finding during cardiopulmonary resuscitation (CPR).
- Understanding myocardial consistency is crucial for assessing outcomes in cardiac arrest patients.
Purpose of the Study:
- To investigate the clinical characteristics and implications of firm myocardium in patients undergoing open-chest CPR.
- To determine the association between myocardial firmness and resuscitation outcomes.
Main Methods:
- Retrospective analysis of 59 adult patients with out-of-hospital cardiac arrest undergoing open-chest CPR.
- Recording of heart consistency, arterial blood gas analysis, end-tidal CO2 tension, and histopathological examination.
Main Results:
- Firm myocardium was observed in 36 patients (firm myocardium group), primarily in the left ventricle.
- The firm myocardium group exhibited greater base deficit and lower end-tidal CO2, suggesting more severe ischemic injury.
- Firm myocardium was associated with poor treatment response, lack of contraction, and a grave prognosis, while soft myocardium often regained pulse.
Conclusions:
- Firm myocardium is common in CPR patients and indicates ischemic contracture, reflecting the degree of ischemia.
- Myocardial firmness is a significant indicator of poor prognosis in cardiac resuscitation.
- The degree of myocardial firmness correlates with the severity of ischemic injury and resuscitation outcomes.
Abstract:
Firm myocardium in cardiopulmonary resuscitation (CPR) is a rarely described yet potentially important condition. To investigate the clinical nature and implications of firm myocardium in CPR, we retrospectively analyzed 59 adult patients with nontraumatic out-of-hospital cardiac arrest who underwent open-chest CPR in the emergency department and had heart consistency recorded. Consistency of the myocardium varied considerably between patients. Firm myocardium was noticed in 36 cases, mainly in the left ventricle (firm myocardium group). The remaining 23 hearts were not firm (soft myocardium group). Some hearts had an increase in their consistency during CPR. Patient characteristics were similar in the two groups. The firm myocardium group showed greater base deficit on arterial blood gas analysis, suggesting more severe ischemic injury. Very firm heart had a close association with an extremely low end-tidal CO2 tension. Histopathological examination revealed hypertrophy and fibrosis common to the two groups. Both groups received similar treatment except for a shorter duration of direct cardiac massage in the firm myocardium group, although a reasonably prolonged effort was made in most cases. The firm myocardium group responded poorly to treatment. Very firm myocardium never contracted, whereas less firm myocardium usually showed some, albeit insufficient, activity. Most cases in the soft myocardium group regained a pulse. Our results suggest that firm myocardium: (1) is common in patients who receive CPR in the emergency department, (2) indicates ischemic contracture, (3) is not uniform in firmness, reflecting the degree of ischemia and (4) is a grave prognostic factor in cardiac resuscitation.