A case of Crush syndrome with giant negative T waves and reversible left ventricular dysfunction

β1-Blocker improves survival and ventricular remodelling in rats with lethal crush injury

BACKGROUND

Crush injury/crush syndrome (CI/CS) is the second most common cause of death during earthquakes. Most studies of CI/CS have mainly focused on kidney injury after decompression. Few studies have focused on myocardial injury caused by crush injury and its potential mechanisms.

METHODS

We first verified cardiomyocyte injury during compression in rats with a crush injury. The survival rate, electrocardiographic results, histological results, catecholamine changes and cardiac β1-AR expression were evaluated. Next, we explored the effects of pretreatment with a selective β1-blocker (bisoprolol) with or without fluid resuscitation on rats with a crush injury. In addition to evaluating the survival rates, biochemical and histological analyses and echocardiographic measurements were also performed.

RESULTS

Reduced heart rates, elevated ST segments, and tall-peaked T waves were observed in the rats with a crush injury. The changes in the myocardial enzymes and pathological results demonstrated that myocardial damage occurred during compression in rats with a crush injury. The levels of the catecholamine norepinephrine in both the serum and myocardial tissue were elevated during compression. Pretreatment with a selective β1-blocker combined with fluid resuscitation significantly improved the survival rates of the rats with lethal crush injury. The myocardial enzymes and pathological results showed that the combined therapy decreased myocardial damage. The echocardiography measurements showed that the rats that received the combined therapy exhibited decreased left ventricular mass (LVM), left ventricular volume at end-systole (LVVs) and left ventricular internal diameter (LVID) compared with the rats with a crush injury.

CONCLUSIONS

Our findings demonstrated the presence of myocardial injury in the early stage of compression in rats with a crush injury. Pretreatment with a β1-blocker (bisoprolol) with fluid resuscitation significantly reduced mortality, decreased myocardial tissue damage, and improved ventricular remodelling in rats with a lethal crush injury.

Reversible left ventricular apical ballooning associated with jet lag in a Taiwanese woman: A case report

Reversible left ventricular apical ballooning, without coronary artery stenosis, is a novel heart syndrome mimicking acute myocardial infarction, and is very rare in Taiwan. A 74-year-old Taiwanese woman returned from travelling abroad for one week and suffered from persistent, severe jet lag with sleep disturbance. She had a cold exacerbated by bronchial asthma for three days. She presented with sudden onset of chest pain after drinking three cups of coffee and taking a sauna for more than 1 h. On admission, an electrocardiogram showed ST segment elevation in leads II, III, aVF and V(3-6), and cardiac enzyme tests revealed minimal elevation. An echocardiogram showed apical ballooning and basal hyperkinesias of the left ventricle (LV) in systole. A coronary angiogram on the second day was normal, while the ST segment was still elevated, and the patient continued to experience chest pain. A negative T wave developed three days later. The electrocardiogram abnormality and LV dysfunction resolved completely six months later. A takotsubo (ampulla) cardiomyopathy was diagnosed. The activated myocardial adrenergic nervous system, stimulated by acute and marked stress in this patient, with more adrenergic innervations distributed in the apex of the LV, may be the trigger for this novel cardiac syndrome.

Surviving collapsed structure entrapment after earthquakes: a "time-to-rescue" analysis

INTRODUCTION

Massive earthquakes often cause structures to collapse, trapping victims under dense rubble for long periods of time. Commonly, this spurs resource intensive, dangerous, and frustrating attempts to find and extricate live victims. The search and rescue phase usually is maintained for many days beyond the last "save," potentially diverting critical attention and resources away from the pressing needs of non-trapped survivors and the devastated community. This recurring phenomenon is driven by the often-unanswered question "Can anyone still be alive under there?" The maximum survival time in entrapment is an important issue for responders, yet little formal research has been conducted on this issue. Knowing the maximum survival time in entrapment helps responders: (1) decide whether or not they should continue to assign limited resources to search and rescue activities; (2) assess the safety risks versus the benefits; (3) determine when search and rescue activities no longer are indicated; and (4) time and pace the important transition to community recovery efforts.

METHODS

The time period of 1985-2004 was selected for investigation. Medline and Lexis-Nexis databases were searched for earthquake events that occurred within this timeframe. Medical literature articles providing time-torescue data for victims of earthquakes were identified. Lexis-Nexis reports were scanned to select those with time-to-rescue data for victims of earthquakes. Reports from both databases were examined for information that might contribute to prolonged survival of entrapped individuals.

RESULTS

A total of 34 different earthquake events met study criteria. Forty-eight medical articles containing time-to-rescue data were identified. Of these, the longest time to rescue was "13-19 days" post-event (secondhand data and the author is not specific). The second longest time to rescue in the medical articles was 8.7 days (209 hours). Twenty-five medical articles report multiple rescues that occurred after two days (48 hours). Media reports describe rescues occurring beyond Day 2 in 18 of 34 earthquakes. Of these, the longest reliably reported survival is 14 days after impact, with the next closest having survived 13 days. The average maximum times reported from these 18 earthquakes was 6.8 days (median = 5.75 days). The event with the most media reports of distinct rescue events was the 1999 Marmara, Turkey earthquake (43 victims). Times range from 0.5 days (12 hours) to 6.2 days (146 hours) for this event. Both databases provide little formal data to develop detailed insight into factors affecting survivability during entrapment.

CONCLUSIONS

A thorough search of the English-language medical literature and media accounts provides a provocative picture of numerous survivors beyond 48 hours of entrapment under rubble, with a few successfully enduring entrapment of 13-14 days. These data are not necessarily applicable to non-earthquake collapsed-structure events. For incident managers and their medical advisors, the study findings and discussion may be useful for post-impact decision-making and in establishing and/or revising incident priorities as the response evolves.

Reversible myocardial dysfunction in critically ill, noncardiac patients: a review

OBJECTIVE

To review reversible myocardial dysfunction affecting critically ill patients without cardiac pathology.

DATA SOURCES

The bibliography for the study was compiled through a search of different databases for the period 1966-2001. References cited in the selected articles also were reviewed.

STUDY SELECTION

The selection criteria included all articles published on reversible myocardial dysfunction in critically ill patients.

CONCLUSIONS

Reversible myocardial dysfunction may develop in a situation of critical pathology, but the etiology of reversible myocardial dysfunction is not fully understood. This dysfunction may be accompanied by increases in enzyme concentrations and electrocardiographic changes. Reversible myocardial dysfunction probably is underdiagnosed, although its presence is associated with a worsening of the prognosis and with more specific therapeutic options. Further studies are necessary to define its true incidence and clinical implications.

Emotional stress-induced 'ampulla cardiomyopathy': discrepancy between the metabolic and sympathetic innervation imaging performed during the recovery course

Four patients had the clinical features of 'ampulla cardiomyopathy', consisting of acute-onset transient left ventricular apical akinesis with basal normokinesis, normal coronary angiogram, ST-segment elevation and subsequent giant T wave inversion, which mimicked acute coronary syndrome, the onset of which occurred shortly after extreme mental stress. Myocardial necrosis was minimal, although 2 patients showed elevated serum catecholamine levels in the acute phase. Each patient underwent serial cardiac radionuclide single-photon emission computed tomography of myocardial functional sympathetic innervation, fatty acid metabolism and perfusion using I-123-metaiodobenzyl-guanidine (MIBG), I-123-beta-metyl-iodophenyl pentadecanoic acid (BMIPP) and thallium-201 (201Tl), respectively. In the acute phase, MIBG and BMIPP imaging showed an uptake defect in the apical region, whereas 201Tl uptake was mildly decreased. When assessed semi-quantitatively, the MIBG images had higher defect scores from the acute phase throughout the year of observation compared with BMIPP, and 201Tl. These observations suggest that the primary cause of ampulla cardiomyopathy is related to a disturbance of the cardiac sympathetic innervation.