QT dispersion ratio in patients with unstable angina pectoris (a new risk factor?).

BACKGROUND: QT dispersion has been shown to be associated with fatal arrhythmias and sudden death in coronary artery disease. A recent study indicated that marked QT dispersion in electrocardiograms (ECGs) obtained during acute ischemia demonstrated a significant correlation with ventricular fibrillation. HYPOTHESIS: This study investigated the ECG parameters for repolarization (QT dispersion, corrected QT, corrected QT dispersion, and QT dispersion ratio) and their interrelation with acute ischemia. METHODS: QT parameters as well as a newly developed repolarization index, QT dispersion ratio [(QT dispersion/RR interval) x 100] were calculated digitally during rest and ischemia in 32 patients with coronary artery disease (rest angina, Braunwald class III). Results were correlated with clinical consequences, mainly arrhythmias, within a follow-up period of 5 +/- 2 days. RESULTS: While most patients had an increase in all four parameters, only the QT dispersion ratio showed a significant difference when correlated with ventricular arrhythmias (p < 0.001, F ratio = 38). CONCLUSION: QT dispersion ratio appears to be a new and promising parameter in predicting ventricular arrhythmias in patients with acute ischemia.

Relationship between QRS score and the extent of coronary artery disease.

We studied 92 patients to determine the relationship between the QRS treadmill score (QTS) and extent of coronary artery disease. The results were compared to those of ST segment deviation in a < (+)QRS score > population. A cut off point of < 5 mm was used for mild to moderate risk patients whereas a QTS of < 3 was considered high risk for the patients. 43% of the patients had high risk QTS and 57% mild to moderate QTS. A highly significant correlation was observed between the extent of coronary artery disease and the high risk group of patients, whereas nonsignificant changes were observed in the control group (p < 0.001). Finally, the results indicate that in patients with a (+) QTS score (< 5 mm), coronary artery disease was significant and accordingly extensive during coronary angiography. On the other hand, a (+) QRS score proved to be superior to ST deviation in predicting critical coronary stenoses in the same population (F ratio; 41 vs 24).

The effects of nisoldipine on carotid artery stiffness and left ventricular functions.

Doppler echocardiographic determination, left ventricular (LV) fractional shortening (FS), cardiac output (CO), diastolic function parameter (E/A ratio) and carotid artery pulse wave velocity and stiffness were evaluated in 36 patients with essential hypertension before and after nisoldipine treatment. Blood pressure decreased significantly, and carotid artery width and fractional shortening increased significantly following nisoldipine administration (p < 0.0001). Carotid artery pulse wave peak velocity did not change following the treatment period (p > 0.05). In conclusion, short term nisoldipine administration improved blood pressure and LV systolic function, whereas LV diastolic function and carotid artery stiffness did not change. Nisoldipine did not alter serum biochemical parameters, including cholesterol, triglyceride, HDL-cholesterol, and LDL-cholesterol (p > 0.05). Only one patient manifested symptoms of hypotension as an adverse effect of the drug.

The use of the handgrip maneuver to identify left ventricular diastolic function abnormalities by Doppler echocardiography in patients with coronary artery disease.

Doppler echocardiography accurately identifies diastolic dysfunction through the assessment of transmitral flow patterns during the application of the handgrip (HG) maneuver. In this study, 45 normal control patients (mean age 46 +/- 9, group A) and 13 patients with coronary artery disease (CAD) (mean age 51 +/- 6, group B) were involved. The effects of handgrip maneuver on transmitral flow patterns were studied by Doppler echocardiography. Group B patients had higher peak late diastolic filling velocities (A), lower peak early (E) to late diastolic filling velocity ratios (E/A) and longer isovolumic relaxation times (IVRT) compared to group A. On the other hand, systolic blood pressure (SBP), heart rate (HR) and peak E velocity (E) did not change significantly (p > 0.05) in either group, at rest. During the supine handgrip maneuver, NR (mean +/- standard error of mean, +21 +/- 13%, p < 0.05) and SBP (+21 +/- 9%, p < 0.05) increased significantly in both group A and group B (+21 +/- 13%, p < 0.05, +22 +/- 15%, p < 0.05, respectively). In group B, E/A ratio (-28 +/- 7%) decreased significantly (p < 0.05) compared to group A (-20 +/- 6%), as a consequence of significantly increased peak A velocity in group B (+7 +/- 5%) compared to group A (+6 +/- 3%, p < 0.05). Deceleration time decreased significantly in both groups (-10 +/- 6% vs -9 +/- 6%, p < 0.05). Isovolumic relaxation time (IVRT) significantly increased in both groups (+18 +/- 7% vs +16 +/- 6%, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)