Efficacy of Anti-anginal Drugs in the Treatment of Angina Pectoris Associated with Silent Myocardial Ischemia. Importance of Quantitative Holter ECG Data for Patient Activity.

Abstract

MethodsWe evaluated the clinical efficacy of transdermal nitroglycerin (NTG-TTS), a patch application of a nitrate, in the treatment of 27 patients with angina pectoris who had asymptomatic myocardial ischemic (SMI) attacks, using a double-blind cross-over method. Evaluation was made using Holter ECGand patient activity data.Results In frequency and duration of continuation of SMIepisodes, no significant differences were noted between the observation and placebo treatment periods, while the values of both these parameters were decreased significantly in the active drug treatment period compared with those in the observation and placebo treatment periods. Critical heart rate, the heart rate at the initiation of ST-segment depression, was significantly higher during the period of active drug treatment than during the placebo treatment and observation periods. In SMIfrequency index, which was determined by adjusting the SMIfrequency for the numberof steps taken, there were no significant differences between the 3 periods. The SMI time index was significantly lower in the active drug treatment period than in the observation period. Conclusions These results indicated that the clinical evaluation of the efficacy of anti-anginal drugs against SMI should take into consideration individual patient activity data.

Circadian Variation of the Myocardial Ischemic Threshold in Patients with Ischemic Heart Disease

“…A method was developed for counting characteristic walking motions using the accelerometer and converting these data into a walk rate per minute. A heart rate loop with the ST segment was recorded for each period of walking, and the myocardial ischemic threshold was defined as the HR at the point that ischemic ST depression began, with a simultaneous recording of the walking rate (13)(14)(15)(16). Variation of HR at the ischemic threshold over 24 hours was demonstrated by linear regression analysis of these data.…”

Involvement of Carotid Baroreceptor Function in Blood Pressure Control in the Chronic Phase: Effect on 24-Hour Ambulatory Blood Pressure

“…The resulting values were regarded as the parasympathetic or sympathetic tone, respectively. The number of steps taken over 15 minutes was determined by conversion of accelerometer sensor values into the number of steps using a method developed in-house (7,8). Hf, L/H, and the number of steps were plotted against systolic pressure on an X-Y co-ordinate, and the correlation coefficient was determined by the linear least squares method.…”

“…Therefore, the conventional concept requires re-examination, but clinical studies of this issue have yet to be reported. Here, we propose a new classification method based on the evaluation of ambulatory blood pressure using frequency analysis of the RR interval in simultaneous ambulatory blood pressure monitoring and Holter ECG recording, and we consider the clinical significance of data obtained from this new approach (6)(7)(8). We investigated the relationship between baroreceptor function and ambulatory blood pressure (as a method for measurement of blood pressure in the chronic phase), and evaluated the effect of baroreceptor function on blood pressure control in the chronic phase.…”