The effect of left ventricular longitudinal strain on left atrial function and ventricular filling in hypertension

AIM

To assess the relationship of global longitudinal strain during left atrial (LA) and left ventricular (LV) filling and emptying.

MATERIALS AND METHODS

Using magnetic resonance imaging in 47 hypertensive patients, biplane global LV longitudinal strain was evaluated and related to LA and LV filling and emptying (by volumetric analysis), and to pulmonary vein and trans-mitral flow (by phase-contrast imaging). The results were compared to normal subjects.

RESULTS

In hypertensive patients, reduced global longitudinal LV strain was associated with reduced LA reservoir (47 ± 10 versus 53 ± 9%, p<0.05), reduced LA conduit function (21 ± 9 versus 32 ± 11%, p<0.004), reduced LA early peak emptying rate (150 ± 77 versus 230 ± 88 ml/s, p=0.007), and slower early LV filling (373 ± 141 versus 478 ± 141 ml/s, p=0.03). LA peak filling rate showed a positive correlation to LV peak emptying rate (R=0.331, p=0.02).

CONCLUSION

In hypertensive heart disease, impaired LV longitudinal systolic function causes reduced LA filling and emptying, and this leads directly to impaired LV filling and diastolic dysfunction.

Electrocardiographic detection of hypertensive left atrial enlargement in the presence of obesity: re-calibration against cardiac magnetic resonance

Left atrial enlargement (LAE) has adverse prognostic implications in hypertension. We sought to determine the accuracy of five electrocardiogram (ECG) criteria for LAE in hypertension relative to cardiac magnetic resonance (CMR) gold standard and investigate the effect of concomitant obesity. One hundred and thirty consecutive patients (age: 51.4±15.1 years, 47% male, 51% obese, systolic blood pressure (BP): 171±29 mm Hg, diastolic BP: 97±15 mm Hg) referred for CMR (1.5 T) from a tertiary hypertension clinic were included. Patients with concomitant cardiac pathology were excluded. ECGs were assessed blindly for the following: (1) P-wave >110 ms, (2) P-mitrale, (3) P-wave axis <30°, (4) area of negative P-terminal force in V1 >40 ms.mm and (5) positive P-terminal force in augmented vector left (aVL) >0.5 mm. Left atrial volume ≥55 ml m^-2, measured blindly by CMR, was defined as LAE. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy and area under the receiver operator curve were calculated. The prevalence of LAE by CMR was 26%. All the individual ECG LAE criteria were more specific than sensitive, with specificities ranging from 70% (P-axis <30^o) to 99% (P-mitrale). Obesity attenuated the specificity of most of the individual ECG LAE criteria. Obesity correlated with significant lower specificity (48% vs 65%, P<0.05) and a trend towards lower sensitivity (59 vs 43%, P=0.119) when ≥1 ECG LAE criteria were present. Individual ECG criteria of LAE in hypertension are specific, but not sensitive, at identifying LAE. The ECG should not be used to excluded LAE in hypertension, particularly in obese subjects.

The effect of obesity on electrocardiographic detection of hypertensive left ventricular hypertrophy: recalibration against cardiac magnetic resonance

Electrocardiograph (ECG) criteria for left ventricular hypertrophy (LVH) are a widely used clinical tool. We recalibrated six ECG criteria for LVH against gold-standard cardiac magnetic resonance (CMR) and assessed the impact of obesity. One hundred and fifty consecutive tertiary hypertension clinic referrals for CMR (1.5 T) were reviewed. Patients with cardiac pathology potentially confounding hypertensive LVH were excluded (n=22). The final sample size was 128 (age: 51.0±15.2 years, 48% male). LVH was defined by CMR. From a 12-lead ECG, Sokolow–Lyon voltage and product, Cornell voltage and product, Gubner–Ungerleidger voltage and Romhilt–Estes score were evaluated, blinded to the CMR. ECG diagnostic performance was calculated. LVH by CMR was present in 37% and obesity in 51%. Obesity significantly reduced ECG sensitivity, because of significant attenuation in mean ECG values for Cornell voltage (22.2±5.7 vs 26.4±9.4 mm, P<0.05), Cornell product (2540±942 vs 3023±1185 mm • ms, P<0.05) and for Gubner–Ungerleider voltage (18.2±7.1 vs 23.3±1.2 mm, P<0.05). Obesity also significantly reduced ECG specificity, because of significantly higher prevalence of LV remodeling (no LVH but increased mass-to-volume ratio) in obese subjects without LVH (36% vs 16%, P<0.05), which correlated with higher mean ECG LVH criteria values. Obesity-specific partition values were generated at fixed 95% specificity; Cornell voltage had highest sensitivity in non-obese (56%) and Sokolow–Lyon product in obese patients (24%). Obesity significantly lowers ECG sensitivity at detecting LVH, by attenuating ECG LVH values, and lowers ECG specificity through changes associated with LV remodeling. Our obesity-specific ECG partition values could improve the diagnostic performance in obese patients with hypertension.

The optimal imaging strategy for patients with stable chest pain: a cost-effectiveness analysis

BACKGROUND

The optimal imaging strategy for patients with stable chest pain is uncertain.

OBJECTIVE

To determine the cost-effectiveness of different imaging strategies for patients with stable chest pain.

DESIGN

Microsimulation state-transition model.

DATA SOURCES

Published literature.

TARGET POPULATION

60-year-old patients with a low to intermediate probability of coronary artery disease (CAD).

TIME HORIZON

Lifetime.

PERSPECTIVE

The United States, the United Kingdom, and the Netherlands.

INTERVENTION

Coronary computed tomography (CT) angiography, cardiac stress magnetic resonance imaging, stress single-photon emission CT, and stress echocardiography.

OUTCOME MEASURES

Lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios.

RESULTS OF BASE-CASE ANALYSIS

The strategy that maximized QALYs and was cost-effective in the United States and the Netherlands began with coronary CT angiography, continued with cardiac stress imaging if angiography found at least 50% stenosis in at least 1 coronary artery, and ended with catheter-based coronary angiography if stress imaging induced ischemia of any severity. For U.K. men, the preferred strategy was optimal medical therapy without catheter-based coronary angiography if coronary CT angiography found only moderate CAD or stress imaging induced only mild ischemia. In these strategies, stress echocardiography was consistently more effective and less expensive than other stress imaging tests. For U.K. women, the optimal strategy was stress echocardiography followed by catheter-based coronary angiography if echocardiography induced mild or moderate ischemia.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to changes in the probability of CAD and assumptions about false-positive results.

LIMITATIONS

All cardiac stress imaging tests were assumed to be available. Exercise electrocardiography was included only in a sensitivity analysis. Differences in QALYs among strategies were small.

CONCLUSION

Coronary CT angiography is a cost-effective triage test for 60-year-old patients who have nonacute chest pain and a low to intermediate probability of CAD.

PRIMARY FUNDING SOURCE

Erasmus University Medical Center.

Explosibility boundaries for fly ash/pulverized fuel mixtures

Incomplete combustion and subsequent fuel contamination of a waste stream can pose a serious explosion hazard. An example of this type of incident is the contamination of fly ash with unburned pulverized coal. The coal, if present in sufficient quantities in the mixture, can act as a fuel source for a potential explosion. Experiments were conducted in a 20l Siwek explosibility test chamber to determine the minimum fuel contamination of fly ash required to form an explosible mixture. A sample of fly ash from Ontario Power Generation (OPG) (Ont., Canada) was artificially contaminated with Pittsburgh pulverized coal dust (the surrogate used to represent unburned fuel dust). Additionally, the influence of fly ash particle size on the amount of fuel contaminant required to form an explosible mixture was examined. Fine and coarse size fractions of fly ash were obtained by screening the original sample of OPG fly ash. The results show that at least 21% Pittsburgh pulverized coal (or 10% volatile matter) was required to form an explosible mixture of the original fly ash sample and coal dust. The results also illustrate that fly ash particle size is important when examining the explosibility of the mixture. The fine size fraction of fly ash required a minimum of 25% coal dust (12% volatile matter) in the mixture for explosibility, whereas the coarse fly ash required only 10% coal dust (7% volatile matter). Thus, the larger the particle size of the inert fly ash component in the mixture, the greater the hazard.

An epidemiological survey of carcinoma cervix in north Bengal zone

Correlation between various epidemiological factors and carcinoma cervix patients in North Bengal zone has been studied for the first time. Significant correlation between elderly women (41-50 years age group), low socio-economic status (SES), first coitus before 17 years of age, low literacy rate and this illness has been established. Suggestion has been made for improvement of the picture. Oncology and radiotherapy department of North Bengal Medical College and Hospital should be utilised as the centre for National Cancer Registration Project in North Bengal zone.

Bronchogenic carcinoma in young adults

Clinicopathological features of 26 cases of bronchogenic carcinoma in patients below the age of 40 years have been studied and compared with 271 cases of bronchogenic carcinoma occurring in elderly patients. There was female preponderance (19.23%) in the younger study group compared to the elderly group (6.6%) and increased incidence of smokers in the younger group (57.6% versus 79.3%) and had achieved statistical significance (p < 0.001). Majority (20 out of 26) had a rural background. All the patients were symptomatic at the time of diagnosis and all the 26 cases except one belonged to advanced stage. The incidence of squamous cell carcinoma was almost same for both the age groups. Eighteen of the 26 cases had received antituberculosis chemotherapy by general practitioners before referral to the specialists. Twenty patients were treated initially by palliative radiotherapy and then by chemotherapy.

Creatine of tenotomised muscle under influence of prednisolone treatment

The prednisolone has got a devastating effect on the creatine content of muscle when it is tenotomised. In non-tenotomised muscle, prednisolone reduces the creatine content. The reduction of creatine content in prednisolone treated muscle which are tenotomised is due to perhaps the catabolic effect of glucocorticoid analogue on muscle protein together with inactivity of the muscle.