Left ventricular hypertrophy: an overlooked cardiovascular risk factor.

Left ventricular hypertrophy (LVH) is common in hypertensive patients, and it increases the risk of myocardial infarction, stroke, and death. Recent evidence indicates it is a modifiable risk factor that is not entirely dependent on blood pressure control. The authors review its pathogenesis, diagnosis, and treatment.

Ischemic and viable myocardium in patients with non-Q-wave or Q-wave myocardial infarction and left ventricular dysfunction: a clinical study using positron emission tomography, echocardiography, and electrocardiography.

OBJECTIVES: We investigated whether patients with non-Q-wave myocardial infarction (NQMI) have more ischemic viable myocardium (IVM) than patients with Q-wave myocardial infarction (QMI). BACKGROUND: Non-Q-wave myocardial infarction is associated with higher incidences of cardiac events than QMI, suggesting more myocardium at risk in NQMI. METHODS: To identify myocardial ischemia, hibernation, and scar, the resting and stress (82)rubidium perfusion and F-18 fluorodeoxyglucose metabolic positron emission tomographic imaging (PET) was performed in 64 consecutive patients with NQMI (n = 21) or QMI (n = 43). Echocardiography was performed for assessment of left ventricular function and wall motion index (WMI). The relationships between PET, echocardiographic, and electrocardiographic findings were analyzed. RESULTS: There were no significant differences in left ventricular ejection fraction (LVEF) between NQMI and QMI groups (28 +/- 10% vs. 25 +/- 11%, p > 0.05). Ischemic and viable myocardium was more common in NQMI than in QMI (91% vs. 61%, p < 0.05). The total amount of IVM was significantly higher in NQMI than in QMI (6.5 +/- 5.2 vs. 2.9 +/- 2.8 segments, p < 0.001). Neither the number of Q waves, residual ST-segment depression of >or=0.5 mm or elevation of >or=1 mm, nor LVEF and WMI were significant predictors for IVM. Wall motion index correlated with scar segments (r = 0.54, p < 0.001) and LVEF (r = -0.67, p < 0.001). CONCLUSIONS: Ischemic and viable myocardium is common in patients with NQMI and left ventricular dysfunction, suggesting that aggressive approaches should be taken to salvage the myocardium at risk in such patients.

Signal-averaged P-wave analysis of normal controls and patients with paroxysmal atrial fibrillation: a study in gender differences, age dependence, and reproducibility.

BACKGROUND: Atrial fibrillation is often first recognized after a complication such as embolic stroke has occurred. Limited data are available for the prospective identification of patients at risk for developing atrial fibrillation. HYPOTHESIS: Demonstration of areas of slow conduction in the atrium by means of P-wave signal averaging may identify individuals at risk for atrial fibrillation. METHODS: P-wave signal averaging from the surface electrocardiogram was performed in 199 normal controls and 81 patients with paroxysmal atrial fibrillation using an automated, P-triggered, high-resolution signal for analysis. RESULTS: Of the variables measured, the filtered P-wave duration and P-wave integral were significantly different between controls and patients (filtered P-wave duration 120 +/- 9 vs. 145 +/- 21 and P-wave integral 666 +/- 208 vs. 868 +/- 352), whereas the terminal root-mean-square (RMS) voltages (RMS 20, RMS 30, RMS 40) showed no significant differences between the two groups. Regression analysis of the first and second measurement of the filtered P-wave duration obtained during consecutive tests showed excellent reproducibility (r and r2 of 0.96 and 0.92). The duration of the filtered P wave showed no age dependence but was shorter in women. CONCLUSION: Utilizing the 90th percentile value of the filtered P-wave duration of 133 ms in men and 130 ms in women, the sensitivity was 80 and 81%, the specificity 92 and 90%, the positive predictive value 84 and 73%, and the negative predictive value 90 and 93%, respectively.