Nonradiative excitation energy transport in one-component disordered systems

High-accuracy Monte Carlo simulations of the time-dependent excitation probabilityG (s) (t) and steady-state emission anisotropyr M /r 0M for one-component three-dimensional systems were performed. It was found that the values ofr M /r 0M obtained for the averaged orientation factor[Formula: see text] only slightly overrate those obtained for the real values of the orientation factor κ ik (2) . This result is essentially different from that previously reported. Simulation results were compared with the probability coursesG (s) (t) andR(t) obtained within the frameworks of diagrammatic and two-particle Huber models, respectively. The results turned out to be in good agreement withR(t) but deviated visibly fromG (s) (t) at long times and/or high concentrations. Emission anisotropy measurements on glycerolic solutions of Na-fluorescein and rhodamine 6G were carried out at different excitation wavelengths. Very good agreement between the experimental data and the theory was found, with λex≈λ0-0 for concentrations not exceeding 3.5·10(-2) and 7.5·10(-3) M in the case of Na-fluorescein and rhodamine 6G, respectively. Up to these concentrations, the solutions investigated can be treated as one-component systems. The discrepancies observed at higher concentrations are caused by the presence of dimers. It was found that forλ ex <λ0-0 (Stokes excitation) the experimental emission anisotropies are lower than predicted by the theory. However, upon anti-Stokes excitation (λex>λ0-0), they lie higher than the respective theoretical values. Such a dispersive character of the energy migration can be explained qualitatively by the presence of fluorescent centers with 0-0 transitions differing from the "mean" at λ0-0.

How often pulmonary embolism mimics acute coronary syndrome?

BACKGROUND

The clinical picture of acute pulmonary embolism (APE) is often uncharacteristic and may mimic acute coronary syndrome (ACS) or lung diseases, leading to misdiagnosis. In 50% of patients, APE is accompanied by chest pain and in 30-50% of the patients markers of myocardial injury are elevated.

AIM

To perform a retrospective assessment of how often clinical manifestations and investigations (ECG findings and elevated markers of myocardial injury) in patients with APE may be suggestive of ACS.

METHODS

We included 292 consecutive patients (109 men and 183 women) from 17 to 89 years of age (mean age 65.4 ± 15.5 years) with APE diagnosed according the ESC guidelines.

RESULTS

Among the 292 patients included in the study 33 patients died during hospitalisation (mortality rate 11.3%) and 73 (25.0%) patients developed complications. A total of 75 (25.7%) patients were classified as high risk according to the ESC risk stratification, 163 (55.8%) as intermediate risk and 54 (18.5%) as low risk. Chest pain on and/or before admission was reported by 128 (43.8%) patients, including 73 (57.0%) patients with chest pain of coronary origin, 52 (40.6%) patients with chest pain of pleural origin and 3 patients with pain of undeterminable origin based on the available documentation. A total of 56 (19.2%) patients had a history of ischaemic heart disease and 5 (1.7%) had a history of myocardial infarction. A total of 8 (2.7%) patients were admitted with the initial diagnosis of ACS. The high-risk group consisted of 15 (20.6%) patients with a typical retrosternal chest pain and 60 (27.3%) patients without the typical anginal pain. Elevated troponin was observed in 103 (35.3%) patients. The ECG changes suggestive of myocardial ischaemia (inverted T waves, ST-segment depression or elevation) were observed in 208 (71.2%) patients. The following findings were significantly more common in high-risk versus non-high-risk patients: ST-segment depression in V4-V6 (42.6% vs 23.9%, p = 0.02), ST-segment elevation in V1 (46.7% vs 20.0%, p = 0.0002) and aVR (70.7% vs 40.1%, p = 0.0007).

CONCLUSIONS

One third of patients with APE may present with all the manifestations (pain, elevated troponin and ECG changes) suggestive of ACS. The ECG changes suggestive of myocardial ischaemia are observed in 70% of the patients with ST-segment depression in V4-V6 and ST-segment elevation in V1 and aVR being significantly more common in high-risk vs non-high-risk patients.

Acute pulmonary embolism registry in the Małopolska region - clinical course

BACKGROUND

Acute pulmonary embolism (APE) is a life-threatening disease. Mortality in APE still remains very high in spite of progress in diagnostic tools. Mortality rate is about 30% in patients with unrecognised APE. APE is one of the main causes of in-hospital mortality.

AIM

To asses management of patients with APE in the Małopolska region.

METHODS

This registry consists of 205 consecutive patients who were hospitalised in 6 cardiology departments between 1 January 2005 and 30 September 2007, with the mean age of 65.1 +/- 15.3 years (124 females and 81 males). Mean hospitalisation duration 14.6 days (1-52 days).

RESULTS

During hospitalisation 23 (11.2%) patients died. Complications (death, cardiogenic shock, cardiac arrest, use of catecholamines, respiratory therapy and ventilation) during in-hospital stay were observed in 57 (27.8%) patients. Fifty-three patients were haemodynamically unstable (cardiogenic shock or hypotension). The troponin I or T level was assessed in 147 (71.7%) patients and in 50 (34.0%) was positive. In patients with positive troponin we observed 11 (22.0%) deaths, while in patients with normal troponin T or I level 6 (6.2%) deaths occurred. In patients with normal blood pressure we observed a significant difference in mortality in patients with elevated vs. normal troponin level (14.3 vs. 2.5%, p = 0.02). Thrombolytic therapy was used in 20 (9.8%) patients. In patients treated with thrombolytic therapy 9 (45%) deaths were observed. We divided patients according to the ESC 2008 guidelines risk stratification. The 'non-high risk' group consisted of 152 (74.1%) patients, and mortality was 3.9%. The 'high-risk' group consisted of 53 (26.8%) patients. The 'non-high risk' group was divided into the following subgroups: 1. moderate-high (with 2 risk factors: both RV dysfunction and positive injury markers) mortality - 8.1%; 2. moderate subgroup with one risk factor, mortality - 3.6%; 3. low risk - no risk factors - 0% mortality.

CONCLUSIONS

1. In our registry mortality rate in patients with APE was 11%. 2. In about 30% of patients APE was under mask of acute coronary syndrome or syncope, 34% of patients had elevated troponin level, and 30% of patients had complication during hospitalisation. 3. In patients treated with thrombolytics mortality rate was 45%. 4. Reperfusion strategy (trombolysis or embolectomy) in the high risk group was used in only 41% of patients. 5. Elevated troponin level in normotensive patient was associated with 4-fold times higher risk of death. 6. New risk stratification according to the ESC guidelines 2008 correctly predicts prognosis in everyday clinical practise.