Novel insights into diminished cardiac reserve in non-obstructive hypertrophic cardiomyopathy from four-dimensional flow cardiac magnetic resonance component analysis.

AIMS: Hypertrophic cardiomyopathy (HCM) is characterized by hypercontractility and diastolic dysfunction, which alter blood flow haemodynamics and are linked with increased risk of adverse clinical events. Four-dimensional flow cardiac magnetic resonance (4D-flow CMR) enables comprehensive characterization of ventricular blood flow patterns. We characterized flow component changes in non-obstructive HCM and assessed their relationship with phenotypic severity and sudden cardiac death (SCD) risk. METHODS AND RESULTS: Fifty-one participants (37 non-obstructive HCM and 14 matched controls) underwent 4D-flow CMR. Left-ventricular (LV) end-diastolic volume was separated into four components: direct flow (blood transiting the ventricle within one cycle), retained inflow (blood entering the ventricle and retained for one cycle), delayed ejection flow (retained ventricular blood ejected during systole), and residual volume (ventricular blood retained for >two cycles). Flow component distribution and component end-diastolic kinetic energy/mL were estimated. HCM patients demonstrated greater direct flow proportions compared with controls (47.9 ± 9% vs. 39.4 ± 6%, P = 0.002), with reduction in other components. Direct flow proportions correlated with LV mass index (r = 0.40, P = 0.004), end-diastolic volume index (r = -0.40, P = 0.017), and SCD risk (r = 0.34, P = 0.039). In contrast to controls, in HCM, stroke volume decreased with increasing direct flow proportions, indicating diminished volumetric reserve. There was no difference in component end-diastolic kinetic energy/mL. CONCLUSION: Non-obstructive HCM possesses a distinctive flow component distribution pattern characterised by greater direct flow proportions, and direct flow-stroke volume uncoupling indicative of diminished cardiac reserve. The correlation of direct flow proportion with phenotypic severity and SCD risk highlight its potential as a novel and sensitive haemodynamic measure of cardiovascular risk in HCM.

Factors contributing to poor compliance with anti-TB treatment among tuberculosis patients.

Tuberculosis (TB) has made a comeback. It has become a resurgent public health problem in developing countries in the tropics and is the leading cause of death from any single infectious agent. Non-compliance to anti-tuberculosis treatment is the most serious problem in TB control. A cross-sectional study was conducted to investigate the determinants of poor compliance with anti-tuberculosis treatment among tuberculosis patients in Kota Bharu, Kelantan, Malaysia in 1999. A total of 390 patients were included in the study of which 130 were tuberculosis patients who defaulted treatment and 260 were those compliant to treatment. Data collection was done by interviewing the patients and collecting clinical and laboratory data from their medical records. Using multiple logistic regression analysis, patients who were not on direct observed therapy (DOT) lived distant to the health facility, were non-intravenous drug users (IVDU) and were HIV positive had statistically significant higher odds of being non-compliant. Patients should be given treatment under direct supervision with special attention to IVDU and HIV positive groups. Anti-TB treatment should be accessible to patients at the nearest health center from their residence. Interventions with health education programs emphasizing the benefits of treatment compliance should be implemented by further large-scale multicentered studies.