Prognostic value of dipyridamole stress echocardiography in hypertensive patients with left ventricular hypertrophy, chest pain and resting electrocardiographic repolarization abnormalities.

BACKGROUND: Hypertension is a major cardiovascular risk factor in the development of coronary artery disease (CAD); therefore, evaluating the presence of CAD is a primary clinical goal. However, the noninvasive tests that are commonly used have poor diagnostic specificity, particularly in patients with left ventricular hypertrophy. OBJECTIVES: To assess the prognostic value of dipyridamole stress echocardiography (DET) for ischemic events in a subset of patients with hypertension with left ventricular hypertrophy, chest pain and resting electrocardiographic repolarization abnormalities. PATIENTS AND METHODS: Eighty-two patients (48 men and 34 women; average age 65+/-7.2 years with left ventricular hypertrophy documented echocardiographically (left ventricular mass index greater than 50 g/h(2.7)), and resting ST segment shift of 0.1 mV or more from baseline at 80 ms after J point in at least two contiguous leads, were submitted to DET according to high-dosage protocol and coadministered with atropine. RESULTS: The follow-up period was 25.11+/-8.3 months. The stress test produced positive results in 30 patients (36.5%); 16 (53%) and three (5%) cardiac events occurred in positive and negative stress test groups, respectively. At multivariate analysis, only positive DET response (P=0.000002), left ventricular mass index (P=0.028) and a family history of CAD (P=0.037) were independent predictors. The two-year event-free survival rates were 95% and 47% (log-rank 21.093, P=0.00001) for negative and positive stress test results, respectively. CONCLUSIONS: DET is a useful tool in the prognostic assessment of coronary events in this particular subgroup of patients with hypertension.

Oscillations in a chloroplast suspension system.

Results of experimental and theoretical study of a photosynthetic system presented with rather complicated temporal behaviour are shown. Experimental results are comparable with those obtained previously by using the electrical method, and thus provide a support to the applicability of the more convenient spectrophotometric method. A possible explanation of a multimode nature of the oscillations observed is presented.

Noninvasive tests for risk stratification in major vascular surgery.

BACKGROUND: The predictive values of noninvasive tests versus perioperative cardiac events in patients undergoing major vascular surgery has not been definitively established. PATIENTS AND METHODS: According to clinical markers and left ventricular function at rest, 188 patients were assigned to the following groups: 40 low, 115 moderate and 33 high risk. They were then randomly submitted to dipyridamole (n = 64), dobutamine (n = 63) stress echocardiography and dipyridamole perfusion scintigraphy (n = 61). RESULTS: No events were observed in low-risk patients, whereas 12 (10.4%) and 8 (24%) events in moderate- and high-risk categories occurred, respectively. Only the high-risk category, as a predictive variable, was significantly related to the onset of cardiac complications (p < 0.05). A positive dipyridamole/dobutamine stress test was related to cardiac events, but multivariate analysis showed that only severity and extent of ischemia were the best predictors of events (p < 0.01 for dipyridamole and p < 0.005 for dobutamine). The presence of reversible, but not fixed, perfusion defects at scintigraphy was significantly related to perioperative events; at multivariate analysis, only > 3 reversible perfusion defects represented a strong predictor of events (p < 0.05). CONCLUSIONS: Among subjects undergoing major vascular surgery, severity and extent of ischemia during dipyridamole/dobutamine stress echocardiography and presence of > 3 reversible perfusion defects are strong predictors of cardiac events, particularly in moderate-risk category of patients.

The effect of patient sex on the incidence of early adverse effects in a population of elderly patients.

Patient sex is known to influence the response to general and regional anaesthesia and recovery after surgery. However, most studies come from analyses carried out on middle-aged patients. As most of the patients admitted to the post-anaesthesia recovery room in our institution are elderly, we took the opportunity to investigate the association between sex and incidence of early adverse events in this older population of patients after major surgery. Consecutive patients undergoing general, orthopaedic, urological and gynaecological surgery, admitted to the recovery room of our institution over a 15-month period, were retrospectively studied. The following adverse events were considered in the analysis: shivering, postoperative nausea and vomiting, hypotension and hypertensive responses, new arrhythmias requiring treatment, acute respiratory failure and desaturation. A total of 1347 patients (mean age 73.3±15.1 years, 61.4% women) were included. Women showed a higher incidence of shivering (relative difference +48%, P=0.0003), postoperative nausea and vomiting (+91%, P<0.0001), hypotension (+32%, P=0.044) and desaturation (+60%, P=0.0030) than men. The incidence of hypertensive response, arrhythmias and acute respiratory failure were not statistically significantly different. The findings of this exploratory study suggest that women have a higher risk of early postoperative adverse events even in a more elderly population.

Severity of aortic stenosis predicts early post-operative normalization of left atrial size and function detected by myocardial strain.

BACKGROUND: Aortic stenosis (AS) causes significant disturbances in left ventricular (LV) and left atrial (LA) function irrespective of the extent of myocardial hypertrophy which associates the increased afterload. We hypothesize that aortic valve replacement (AVR) and removal of LV outflow tract obstruction should result in LA size and function recovery, even partial, and were set to study this in a group of patients with AVR for AS. METHODS: Peak atrial longitudinal strain (PALS) was evaluated in 43 patients with severe isolated AS and normal EF (56.6 ± 3.8%) and no obstructive coronary artery disease candidates for AVR, pre-operatively and then 40 days and 3 months after surgery. Results were compared with those from 34 age- and gender-matched healthy controls. RESULTS: LVEF remained unchanged and LV mass regressed after AVR. Global PALS was reduced pre-operatively and increased 40 days after surgery (p=0.002) and showed only a slight further increase at 3 months follow-up (p<0.0001). Indexed LA volume was increased before surgery, but significantly fell 40 days after surgery (p<0.0001) and showed only a slight further reduction after 3 months (p<0.0001). Trans-aortic mean gradient change after surgery was the only independent predictor of the recovery of LA size and function. CONCLUSIONS: AVR reverses LA abnormalities and regains normal atrial function, a behavior which is directly related to the severity of pre-operative LV outflow tract obstruction. Early identification of LA size enlargement and functional disturbances might contribute to better patient's recruitment for AVR.

Mitral annular longitudinal function preservation after mitral valve repair: the MARTE study.

BACKGROUND: In patients with chronic mitral regurgitation (MR), undergoing surgical mitral valve repair, current Guidelines only recommend standard echocardiographic indices i.e. left ventricular (LV) ejection fraction (EF), and LV end-systolic and end-diastolic diameters as preoperative variables. However LV EF is often preserved until advanced stages of the valve disease. Aim of this study was to evaluate changes in LV systolic longitudinal function, 3 months after mitral valve repair in patients with chronic degenerative MR and normal preoperative EF. METHODS: We measured M-mode mitral lateral annulus systolic excursion (MAPSE) and Tissue Doppler (TD) peak systolic annular velocity (S(m)) in 31 patients with moderate to severe MR and normal EF (59.9 ± 4.7%) candidates for mitral valve repair, preoperatively and 3 months after surgery. RESULTS: After mitral valve repair, S(m) increased from 7.8 ± 1.4 to 9.6 ± 2.2 cm/s (p<0.0001) and MAPSE increased from 1.33 ± 0.26 to 1.55 ± 0.25 cm (p=0.0013). EF decreased from 59.9 ± 4.7 to 51.3 ± 5.9% (p<0.0001). As expected, LV diameters and volumes, wall thicknesses, midwall fractional shortening (mFS), and left atrial (LA) size were all reduced after surgery. CONCLUSIONS: This study suggests that assessment of LV long axis systolic velocity and amplitude of excursion by echocardiography is more sensitive than simple determination of EF for revealing the beneficial impact of MR surgery on overall systolic function.

Periodicity and chaos in a photosynthetic system.

In this paper experimental results of investigation of the oscillations in a photosynthetic system are presented and a model for their interpretation is suggested. Periodicities in photosynthetic systems detected in earlier studies by physical chemical methods can be also detected by means of recording the potential difference between two point electrodes. The observed dependences demonstrate a wide range of various types of behaviour of the system, working, e.g. in periodic, quasiperiodic, chaotic or 'pulse' regimes. Since the until-now-used 2-dimensional theoretical model, based on the existence of two dominant autocatalytical processes, appeared not to be sufficient for explaining such types of the regimes, a generalized 3-dimensional autocatalytical model is suggested, which is able to explain all the above mentioned photosynthetic regimes.