Estimation of subjective stress in acute myocardial infarction.

BACKGROUND AND AIMS: Mental stress is considered to be a precipitating factor in acute coronary events. We aimed to assess the association of subjective or 'perceived' mental stress with the occurrence of acute coronary events. SETTINGS AND DESIGN: Prospective case-control survey was carried out in a referral teaching hospital. SUBJECTS & METHODS: Consecutive patients with acute myocardial infarction and ST elevation on electrocardiogram who were admitted to the Coronary Care Unit of a referral teaching hospital were enrolled in the study as cases. Controls were unmatched and were enrolled from amongst patients with coronary artery disease who did not have recent acute coronary events. Subjective Stress Functional Classification (SS-FC) for the preceding 2-4 weeks was assessed and assigned four grades from I to IV as follows: I - baseline, II - more than usual but not affecting daily routine, III - significantly high stress affecting daily routine and IV - worst stress in life. STATISTICAL ANALYSIS: Proportions of different characteristics were compared using chi-square test with Yates continuity correction. Student's unpaired t test was applied for mean age. 'p' value of < 0.05 was considered statistically significant. RESULTS: SS-FC could be reliably (99%) and easily assessed. Eighty (53%) of the total 150 patients with acute MI reported 'high' levels of stress (stress class III and IV). This is in contrast to only 30 (20%) of 150 healthy controls reporting high stress for the same period (p value < 0.001). CONCLUSION: Patients with acute myocardial infarction report a higher subjective mental stress during 2 to 4 weeks preceding the acute coronary event.

Muscular training through localized in vivo electrical stimulations.

In vivo electrical stimulations were applied to the gastrocnemius muscles of intact frogs for prolonged periods which lead to improved muscular efficiency and delayed onset of fatigue. The muscular strength improvement was correlated to increased tissue contractile proteins and decreased collagen content. Elevated levels of muscular fuels, mitochondrial content, oxidative metabolism in the stimulated muscles were suggested to be responsible for the delayed onset of fatigue. In view in these characteristics regarding the improvement at physical and metabolic levels, the muscles exposed to chronic electrical stimulations were termed as trained muscles. The applicability of electrical stimulations to induce the training effects into the muscles in atrophic and dystrophic conditions to avert the muscle wastings was suggested.

Pattern of skeletal muscle chemical composition during in vivo electrical stimulations.

Electrical stimulations of low voltage, frequency and short duration of time are suitable for amphibian muscle to induce localized muscular exercise in an intact animal. The pattern of changes in the muscle chemical components on chronic exposure to repeated electrical stimulations suggested the onset of regulation on muscle metabolism leading to carbohydrate sparing process and muscular hypertrophy. The applicability of this procedure to prevent the muscle wasting in atrophic and dystrophic muscles is suggested.