Physiologic or pathologic hypertrophy: how can we know?

Pathologic left ventricular hypertrophy due to hypertrophic cardiomyopathy is typically diagnosed based on compatible clinical and imaging findings. In a subset of patients however, the diagnosis is unclear, either due to the finding of concentric hypertrophy raising the possibility of physiologic hypertrophy due to athlete's heart or due to the potential of so-called hypertrophic cardiomyopathy 'phenocopies', which include Anderson-Fabry disease and cardiac amyloidosis. We review each of these diseases, highlighting important distinguishing features, the knowledge of which should permit the resolution of such diagnostic dilemmas.

Cardiac medication prescribing and adherence after acute myocardial infarction in Chinese and South Asian Canadian patients.

BACKGROUND: Failure to adhere to cardiac medications after acute myocardial infarction (AMI) is associated with increased mortality. Language barriers and preference for traditional medications may predispose certain ethnic groups at high risk for non-adherence. We compared prescribing and adherence to ACE-inhibitors (ACEI), beta-blockers (BB), and statins following AMI among elderly Chinese, South Asian, and Non-Asian patients. METHODS: Retrospective-cohort study of elderly AMI survivors (1995-2002) using administrative data from British Columbia. AMI cases and ethnicity were identified using validated ICD-9/10 coding and surname algorithms, respectively. Medication adherence was assessed using the 'proportion of days covered' (PDC) metric with a PDC ≥ 0.80 indicating optimal adherence. The independent effect of ethnicity on adherence was assessed using multivariable modeling, adjusting for socio-demographic and clinical characteristics. RESULTS: There were 9926 elderly AMI survivors (258 Chinese, 511 South Asian patients). More Chinese patients were prescribed BBs (79.7% vs. 73.1%, p = 0.04) and more South Asian patients were prescribed statins (73.5% vs. 65.2%, p = 0.001). Both Chinese (Odds Ratio [OR] 0.53; 95%CI, 0.39-0.73; p < 0.0001) and South Asian (OR 0.78; 95%CI, 0.61-0.99; p = 0.04) patients were less adherent to ACEI compared to Non-Asian patients. South Asian patients were more adherent to BBs (OR 1.3; 95%CI, 1.04-1.62; p = 0.02). There was no difference in prescribing of ACEI, nor adherence to statins among the ethnicities. CONCLUSION: Despite a higher likelihood of being prescribed evidence-based therapies following AMI, Chinese and South Asian patients were less likely to adhere to ACEI compared to their Non-Asian counterparts.

Modulation of arm stiffness in relation to instability at the beginning or the end of goal-directed movements.

In reaching to a target, stability near the target may be more critical for success than stability far from the target. Consequently, we postulated that high instability near the start would evoke less compensation than high instability near the target. Three stability conditions were implemented using a robot manipulandum: neutral stability everywhere (null field); high instability along the first half of the trajectory decreasing as the target was approached (start unstable); and instability increasing along the first half of the trajectory and remaining high as the target was approached (end unstable). Under the start unstable condition, the stiffness of the arm in the region of highest instability was significantly less than under the end unstable condition. Furthermore, the stability of the system (manipulandum plus arm) was much lower under the start unstable condition than under the null field condition whereas it was similar under the end unstable and null field conditions.