Effect of diltiazem on symptomatic and asymptomatic episodes of ST segment depression occurring during daily life and during exercise

BACKGROUND

Silent myocardial ischemia is an adverse prognostic marker in patients with coronary disease; however, controlled data on the effect of treatment are sparse and contradictory, and the relations among the occurrence of ST segment depression, drug efficacy, and heart rate are unclear.

METHODS AND RESULTS

Sixty patients with stable coronary artery disease, a positive treadmill exercise test and asymptomatic ST segment depression on ambulatory electrocardiographic recording were assessed in a multicenter, double-blind, placebo-controlled, cross-over trial. Treadmill exercise tests and 72-hour electrocardiographic recordings were obtained at the end of two 2-week treatment periods with sustained-release diltiazem 180 mg b.i.d. or equivalent placebo. Episodes of asymptomatic ST depression decreased by 50% or more in 70% of the patients from a median number of 4.5 (range, 0-19) to 1.5 (range, 0-13) (p = 0.0001); their cumulative duration also decreased from 78.5 (range, 0-60) to 24.5 (range, 0-411) minutes (p = 0.001). No circadian variation was found in the efficacy of diltiazem. The occurrence of ischemic type ST segment depression was modulated by changes in heart rate rather than by absolute heart rate. Diltiazem also improved exercise test end points but to a lesser extent. Time to ST segment depression increased to 341 +/- 148 from 296 +/- 154 seconds (p = 0.005). Although less frequent with diltiazem administration (45 versus 54 patients, p less than 0.03), exercise-induced ST depression was more often asymptomatic (98% versus 72% of patients, p less than 0.0001).

CONCLUSIONS

Diltiazem reduces the frequency and severity of ischemic type ST depression in patients with stable coronary artery disease.

Usefulness of sustained-release diltiazem for stable angina pectoris

Sustained-release diltiazem, 120 and 180 mg twice daily, was assessed in a multicenter, double-blind, randomized, placebo-controlled trial in 65 stable angina patients with exercise-induced ST depression. Exercise testing was performed 12 +/- 1 hours after the last dose at the end of each of the 3 treatment weeks. Both dose levels of drug reduced spontaneous angina (p less than 0.001) and increased exercise duration (p less than 0.01) and time to 1-mm ST depression (p less than 0.001). No differences were noted between the 2 dose levels. Rate-pressure product at maximal exercise was similar for the 3 groups. Only 1 patient terminated the study because of adverse drug effects; severe adverse effects occurred in 1 placebo and 1 low-dose period. Sustained-release diltiazem is safe and efficacious monotherapy for patients with stable angina.

Diagnostic accuracy and estimation of the severity of valvular regurgitation from the signal void on cine magnetic resonance images

Anomalous blood flow caused by valvular regurgitation can be visualized as a narrowly defined area of signal loss in contrast to the high intensity of the blood pool on repetitive gradient refocused magnetic resonance (MRI) (cine MRI) views. In order to assess the accuracy of identification and measurements of the signal void in the evaluation of mitral (MR) and aortic regurgitation (AR), the cine MRI studies of 62 patients with regurgitation and of 20 normal volunteers were retrospectively analyzed in a blinded study of three independent reviewers. Accuracy for detection of MR was greater than 0.96 and for AR was greater than 0.91 for all three reviewers. The total volume of the signal void associated with regurgitation was measured on cine MRI images of 58 patients by two independent observers. The patients were divided into three groups of severity based upon assessment of severity of regurgitation by two-dimensional echocardiography and/or angiography. The total volume of signal loss was 9.0 ml (+/- 0.94 SEE; n = 18) for mild MR, 30.7 ml (+/- 5.3 SEE; n = 11) for moderate MR, and 83.4 ml (+/- 17.4 SEE; n = 5) for severe MR. In patients with AR, the calculated signal void was 27.3 ml (+/- 3.2 SEE; n = 24) in mild, 49.7 ml (+/- 2.9 SEE; n = 7) in moderate, and 75.8 ml (+/- 5.7; n = 6) in severe cases. The differences in the volume of the signal void were significant among the three groups of severity (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Benefits of avoidance of induction immunosuppression in heart transplantation

Current immunosuppression protocols in heart transplantation commonly employ an inductive phase preoperatively, which often is followed by triple therapy (azathioprine, cyclosporine, and prednisone). From 1981 to June 1987, 119 heart transplants were performed in 114 patients. Group I (n = 19) received cyclosporine preoperatively and postoperatively, as well as steroid intraoperatively and postoperatively. Group II (n = 100) received antilymphocyte globulin postoperatively and interval cyclosporine orally 5 to 7 days postoperatively when the antilymphoblast globulin was discontinued. Methylprednisolone was given intraoperatively, and 1 mg/kg was given postoperatively. Steroid was tapered to 20 mg/day within 4 weeks. Cyclosporine was removed from the early postoperative regimen to reduce the deleterious renal effects. Steroid was used in low doses and tapered quickly to lessen steroid-related complications. There was one cyclosporine-related kidney failure in group I and none in group II. In no patient was cyclosporine discontinued because of adverse effects. The rate of rejection remains acceptable. There have been eight deaths as a result of rejection (three in group I and five in group II). Three patients have died of infection (one in group I and two in group II). Since January 1987 no postoperative protective isolation has been used. Overall survival is 77%, and no patient has exhibited late coronary atherosclerosis on follow-up coronary angiography. The regimen of immunosuppression that has evolved is safe and effective and has long-term benefits.

De novo coronary artery grafting in a heart transplant recipient

The current organ shortage prompts reassessment of donor selection. This article describes a patient who underwent heart transplantation with an internal mammary artery graft to the left anterior descending artery beyond a single stenotic lesion in the transplanted heart.

[Left ventricular function and intra-cardiac blood flow: study using dynamic magnetic resonance tomography]

Cardiac function can be assessed using conventional spin-echo magnetic resonance imaging. However, long imaging times and poor temporal resolution have limited the clinical applicability of this technique. A new dynamic magnetic resonance pulse sequence avoids these shortcomings using lower flip angles, shorter repetition and echo times and gradient refocused echoes. The entire heart can thus be imaged with a temporal resolution of 60 ms within 20 min. Display of 15 images of the cardiac cycle in a movie loop allows excellent visual assessment of cardiac motion and intracardiac blood flow. Applications of this new technique include blood flow measurements, visualization of regurgitant or shunt blood flow in patients with valvular regurgitation or ventricular septal defect, assessment of regional wall thickening in patients with myocardial disease, and three-dimensional determination of ventricular and atrial volumes.

Functional evaluation of the heart with magnetic resonance imaging

This review examines the capability of cine MRI for evaluation of cardiovascular function and shows early results in valvular, ischemic, and congenital heart disease. MR assessment of left and right ventricular volumes is independent of geometrical models; dimensional values have been defined for normal individuals. Noninvasive measurement of peak and end systolic pressure along with cine MR imaging can be used to calculate left ventricular meridional wall stress which can be used for monitoring of myocardial diseases and evaluation of therapeutic intervention. Cine MR may be more accurate than angiography for identifying regional LV dysfunction since it can measure wall thickening as well as inward wall motion. Regurgitant jets due to valvular lesions are readily seen and their characteristics may be used to define the severity of aortic or mitral regurgitation. Calculation of the regurgitant volume separates patients with mild, moderate, or severe disease. Likewise, the shunt flow across ventricular and atrial septal defects has been visualized in cine MR images and shunt flow calculated. Cine MRI serves as a three-dimensional imaging technique with high temporal resolution. It extends the capability of MRI in cardiac disease beyond the depiction of anatomy and renders a comprehensive cardiac imaging technique for quantitation of cardiac anatomy and function.

Quantification of cardiac function by conventional and cine magnetic resonance imaging

Magnetic resonance imaging (MRI) has been effective for depicting cardiac anatomy and is already established as a technique for the evaluation of some structural abnormalities of the heart and pericardium. With recent advances, MRI can now be used to quantitate cardiac function. Multiphasic ECG-gated spin-echo imaging has been used to quantitate right and left ventricular volumes and ejection fraction, left ventricular mass, and regional myocardial wall thickening. The new technique of cine MRI acquires frames during the cardiac cycle with a time resolution corresponding to 20 msec up to approximately 40 frames for an average cardiac cycle. This technique uses narrow flip angle (30 degrees) and gradient refocused echoes. Cine MRI has been used to measure ventricular volumes and ejection fraction and regional myocardial wall thickening. It is also sensitive to the detection of valvular regurgitation and can provide quantitation of regurgitant volume. This article reviews the current status of MRI for quantitating cardiac function.

Ventricular septal defect: visualization of shunt flow and determination of shunt size by cine MR imaging

Cine MR imaging is a new, fast technique that employs low flip angles, short repetition and echo times, and gradient-refocused echoes. This technique was used in three patients with documented ventricular septal defects (VSDs) to obtain transverse and oblique sections of the heart spanning the cardiac cycle. In all patients, cine MR imaging showed high-velocity turbulent blood flow across the defect as areas of low signal intensity extending from the left ventricle to the right ventricle. In the oblique sections oriented parallel to the interventricular septum it was possible to identify the cross-sectional area of the VSD. Quantification of the left-to-right shunt was performed by comparing left and right ventricular stroke volumes determined from end-diastolic and end-systolic volumes of both ventricles. Cine MR imaging provides important functional information and anatomic detail in patients with VSD and may be useful for diagnosis, determination of severity, and noninvasive monitoring of the disease.

Comparative effects of calcium entry-blocking drugs, beta-blocking drugs, and their combination in patients with chronic stable angina

For monotherapy, beta-blockers and calcium-entry blockers are effective and safe antianginal medications. For prophylaxis of myocardial ischemia, a different mechanism of action for each class of drugs is reflected by the different heart rate and rate-pressure product during exercise. In patients who continue to have anginal symptoms despite adequate beta-blockade, further alleviation of symptoms together with an increase in exercise tolerance may be observed with the addition of a calcium-entry blocker. Of note is the individual patient response to the various calcium-entry blockers when combined with propranolol. Although of theoretic concern with combination therapy, no deleterious effect on left ventricular function or increased adverse clinical effects were noted in our studies. Combination therapy with beta-blockers and calcium-entry blockers is well tolerated, effective, and safe both over the short and long term in patients with exertional angina.

Predicting mortality after elective abdominal aortic aneurysmectomy in the elderly

40 non-emergency cases of abdominal aortic aneurysmectomy were reviewed. Of the 20 cases who died during the follow-up period, a significant number had more evidence of pre-existing multiple diseases than had the survivors. The results of the study suggest that there is an association between the amount of coincident disease, length of survival, and mortality following elective abdominal aortic aneurysmectomy.