How long can an escalation of dose override tolerance to the hypotensive efficacy of nitroglycerin infusion in coronary care patients.

Tolerance to nitroglycerin infusion (NG) can be overridden by dose escalation. The aim of this study was to define for how long it can be done for hypotensive efficacy of NG, in a coronary care setting. A prospective trial with an intra-individual therapeutic comparison was performed in 60 patients with acute myocardial infarction or unstable angina. Initial efficacy of NG was confirmed by a 10% blood pressure decrease (measured by cuff). Seventy-two-hour NG infusion was interrupted, for 30 minutes, every 12 hours. If blood pressure increased by 10% after infusion interruption, the infusion was continued at the previous rate. If blood pressure did not increase (detected tolerance--weakened efficacy of NG), the dose was increased until pressure decreased by 10% and the infusion was continued at the new dose. Failure to achieve hypotensive response, despite a 5-fold dose increase, indicated onset of resistance--completely lost hypotensive efficacy of NG. The majority of patients (49 out of 55) who developed tolerance, developed it during the first 36 hours, while the majority of those who developed resistance (33 out of 40), developed it within 60 hours of the infusion. Tolerance was overridden by dose escalation in 41 out of 55 patients, which was repeated in 31 patients. Complete restoration of NG action was possible over 24 hours in half the patients, and over 48 hours in one third of the patients. Three out of 34 patients who developed tolerance before the 13th hour did not develop resistance during the following 60 hours of dose up-titration. The conclusion is that tolerance to NG can be overridden by dose escalation in the majority of patients for a significant period of time, which is useful in clinical practice.

Incidence and hospital mortality of acute coronary artery disease among civilians in Zagreb during air-raid alarms.

During the period of air-raid alarms in Zagreb (September 1991), the influence of war-induced stress on the incidence and mortality of acute coronary artery disease was investigated. Control periods were September 1989 and September 1990. Among 2903 patients admitted to Emergency Care Units, 369 (13%) were examined for suspect acute coronary artery disease. During the same periods in 1989 and 1990, 10% and 11% of acute coronary artery disease patients were recorded, respectively. The percentage of patients with myocardial infarction or unstable angina, admitted to Coronary Care Units during September 1989, 1990 and 1991, was 49%, 50% and 55%, respectively. The number of Q myocardial patients admitted during September 1991 was significantly higher than that recorded during the same period in 1990. The incidence and mortality patterns in acute coronary artery disease patients were also examined during August, September and October 1991. The peak incidence of acute coronary artery disease was found in the first half of September, while the peak mortality in these patients was found during the second half of September. During the second half of September of 1989, 1990 and 1991, the mortality in Q myocardial patients in Coronary Care Units, was 16.7%, 15.2% and 23.8%, respectively. Besides the war-induced stress, transportation of our patients to shelters or inner parts of the hospital caused additional stress, probably contributing to the development of refractory malignant arrhythmia or heart failure.

Dual photon absorptiometry for bone mineral measurements using a gamma camera.

A gamma camera was equipped with a special collimator and arm assembly for bone mineral measurements with dual photon absorptiometry (DPA). The system was evaluated in vitro and in vivo and compared both with a rectilinear DPA and a dual energy X-ray (DEXA) system. All 3 systems showed a linear response in measurements of 4 vials, containing different amounts of hydroxyapatite. Phantom measurements with the gamma camera system showed a precision of 1.6% to 2.8%. Results obtained in 8 healthy volunteers with rectilinear and gamma camera systems were well correlated (R2 = 0.78). With the photon beam directed from posterior to anterior, the separation of vertebrae was easy with the gamma camera system. We conclude that bone mineral measurements can be made with a gamma camera for assessment of fracture risk and in the decision process whether a patient needs treatment or not. For follow-up, the precision of DPA with a gamma camera is inadequate.

The value of the QRS scoring system in assessing regional and global left ventricular ejection fraction early after myocardial infarction.

In 71 patients with a myocardial infarction (MI) (anterior in 27, inferior in 44 patients) global (GEF) and regional (REF) left ventricular ejection fractions were determined by radionuclide ventriculography and estimated from a 12 lead electrocardiogram (ECG), using Selvester's QRS score, during the early phase of a MI (15 to 21 days following MI). Global ejection fractions determined by radionuclide ventriculography and from ECG using Palmeri's method were: for all MI 40.8 +/- 12.6% vs 39.6 +/- 11.4%; in the group of anterior MI 32.0 +/- 10.0% vs 30.0 +/- 9.7% and in the group of inferior MI 48.9 +/- 12.0% vs 45.1 +/- 8.2%. A good correlation was found between global ejection fractions determined by radionuclide ventriculography and ECG, as well as between radionuclide GEF and ECG score. A weaker correlation was found between radionuclide GEF and enzymes among all MIs and in the group of anterior MI, while in the group of inferior MI this correlation was insignificant. The analysis of REF determined by radionuclide ventriculography and ECG showed the greatest abnormalities in the infarct region, but in the group of anterior MI, dysfunction was present in the whole left ventricle. The comparison of infarct-related REF derived from radionuclide ventriculography, with the QRS score showed a significantly higher correlation than the comparison with enzymes. ECG estimation of REF from a modified Palmeri's equation showed a better correlation with radionuclide REF than did GEF derived from the standard Palmeri's equation: anterior MI; r = 0.90 vs r = 0.82, inferior MI; r = 0.84 vs r = 0.69, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Global and regional parameters of left ventricular performance in healthy subjects during rest and exercise assessed by radionuclide ventriculography.

The aim of our study was to analyze numerous global and regional parameters of left ventricular (LV) performance during rest and exercise, in the group of 14 healthy subjects, by quantitative gated equilibrium ventriculography in left anterior oblique view (45 degrees). The global LV parameters at rest vs. exercise in our study were: heart rate 68.9 +/- 18.4 vs. 137.5 +/- 38.6; systolic blood pressure (mmHg) 121.8 +/- 18.2 vs. 178.6 +/- 31.2; diastolic blood pressure (mmHg) 82.1 +/- 10.8 vs. 90.7 +/- 12.4; double product 8,368.6 +/- 2,308.8 vs. 24,589.3 +/- 8,357.8; global ejection fraction (%) 61.9 +/- 15.4 vs. 72.8 +/- 12.8, end-diastolic volume index (ml/m2) 82.5 +/- 23.2 vs. 96.9 +/- 27.8; end-systolic volume index (ml/m2) 31.8 +/- 19.8 vs. 26.9 +/- 15.4; stroke volume index (ml/m2) 50.6 +/- 17.6 vs. 70.0 +/- 22.6; peak emptying rate (EDV/s) 3.4 +/- 2.6 vs. 8.3 +/- 3.8 and peak filling rate (EDV/s) 3.6 +/- 2.6 vs. 9.6 +/- 3.8. A significant difference (p < 0.05) between rest and exercise was found for all parameters. The highest values of LV regional ejection fraction were found in anterolateral and posterolateral region, while the lowest values were observed in inferoseptal and inferior regions. During exercise a significant increase of regional ejection fraction was found in all regions. The highest percent of radius shortening during rest was in anterolateral and posterolateral regions, and lowest in inferoseptal and inferior regions. The same sequence was found during exercise, and the difference in percent of radius shortening, between rest and exercise was significant in all regions. The observed normal values of global and regional parameters of LV function during rest may serve as a contribution for referent values. Our results on regional ejection fraction and the percent of radius shortening in rest, and their change during exercise, offer the possibility of additional information in the investigation of cardiac patients by means of radionuclide ventriculography.

Hyperdynamic beta-adrenergic syndrome among Croatian soldiers engaged in battle.

A group of 1592 male Croatian soldiers (average age 32 +/- 9, ranging from 19 to 54) were examined by an internist at the war hospital. Elevated blood pressure was found in 80 men (5%); 61 of them had no history of hypertension (Group A), while in 19 patients hypertensive disease had been diagnosed before (Group B). In group A, systolic blood pressure (BPS in mm Hg), diastolic blood pressure (BPD in mm Hg) and heart rate (HR) were 182 +/- 13, 111 +/- 10, and 115 +/- 9; in group B, the values were 184 +/- 12, 108 +/- 8, 85 +/- 11. Electrocardiograms (ECG) and thorax roentgenograms of group A did not reveal any hypertension-caused signs, neither did the examination of the fundus, nor the serum creatinine values yield any abnormal results. The ECG test showed sinus tachycardia (heart rate > 100/min) but an otherwise normal function in group A. In group B, at least one of the laboratory examinations confirmed the previously diagnosed hypertension. Group A was treated with the cardioselective beta-blocker Atenolol (100 mg daily), while in group B, the previous antihypertensive medication was modified and/or increased. All patients were sent back to the front-line. Three days later, blood pressure and heart rate in group A were: BPS 139 +/- 9, BPD 87 +/- 6 and HR 77 +/- 8; and in group B: 156 +/- 11, 95 +/- 8, 75 +/- 7. A significant decrease in systolic and diastolic blood pressure (p < 0.0001) was found in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Regression of ECG signs of myocardial infarction related to infarct size and left ventricular function.

Quantitative and qualitative analyses of Q waves and QRS scores were performed on 69 patients during the early phase of first myocardial infarction (MI) and 6 months subsequently. The regression of ECG signs of MI were compared with the enzymatically estimated size of MI, the location of MI, and with the changes of global ejection fraction (GEF) assessed by radionuclide ventriculography. Among 57 patients with Q wave MI a complete disappearance of ECG signs of MI was found in 9 (15.7%). Patients with MI of inferior location showed a significantly higher reduction of Q waves (p < 0.001) and QRS scores (p < 0.001) than the anterior MI group. In the group of 12 patients with non Q wave MI, 11 demonstrated complete regression of MI signs. Among all Q wave and non Q wave MIs, the authors found no significant difference in the size of MI between patients with and without complete regression of ECG signs of MI. The median of the percent of change of the QRS score was significantly higher (p = 0.04) in the group of patients with improved GEFs than in the group of patients with decreased or unchanged GEFs 6 months following acute MI. The sensitivity, specificity, and predictive values for improved left ventricular function according to the change of Q waves and ECG scores were 91%, 32%, and 62%; for changes of Q waves, 81%, 40%, and 63%; and for changes of ECG scores, 91%, 36%, and 64%, respectively. In the group of patients with non Q wave MI these values were 100%, 50%, and 91% as a result of ST-T disappearance.

[The effect of war-induced stress in Croatia on the incidence and mortality of acute ischemic heart disease]. / Der Einfluss des kriegsbedingten Stresses in Kroatien auf die Häufigkeit und Mortalität der akuten ischämischen Herzkrankheit.

During war operations in Croatia and air alarms in Zagreb, a significantly higher incidence of patients with acute coronary artery disease was registered. Higher incidence of patients with acute myocardial infarction was present and the incidence of hospital mortality among patients with myocardial infarction was significantly higher than earlier. Significant difference was not found between various study periods neither for sex ratio, localization of myocardial infarction (anterior vs. inferior) nor in the ECG form of myocardial infarction (Q vs. Non-Q).

Self-poisonings with psychopharmacological agents in Zagreb.

1. A 5-year retrospective study of 1743 episodes of self-poisoning in 1608 adult patients, was undertaken to determine the frequency of self-poisoning with psychopharmacological agents, the frequency of each toxic agent usage and the epidemiological characteristics of the poisoned population. 2. The annual incidence of self-poisoning in Zagreb was 38.7 per 100,000 adult inhabitants. The anxiolytic-antipsychotic-antidepressant usage ratio was 8.8:1.5:1.0 in total self-poisoning, whereas it was 4.9:1.5:1.0 in patients with a previous history of self-poisoning. The use of anxiolytics decreased and the use of antidepressants increased during the 5 years. 3. The female-male ratio was 3.8:1 and 77% of self-poisoned persons were aged 15-44 years. The incidence of self-poisoning was 74% higher in the urban than in the rural population. The proportion of self-poisoned persons was 204% higher among the unemployed than in the population as a whole. There were 76% more repetitors among highly educated and 43% fewer repetitors among students than in the general population. The use of antipsychotics was 120% higher in males than in females. The use of antidepressants was 107% higher in the highly educated. 4. The increased use of antidepressants in self-poisoning is an alarming signal and caution in their prescription seems to be indicated.

Right ventricle wall motion abnormalities in patients treated with chemotherapy.

Doxorubicin is a cytotoxic agent used in the treatment of patients with various malignancies. Its clinical value is limited by a dose-related cardiotoxicity. Wall motion was analyzed in 52 patients during different stages of treatment. Eleven patients were studied once, and in 41 patients serial radionuclide ventriculography was performed from 2 to 5 times. Abnormal wall motion was found in 96 out of 1,062 segments (9.0%), of which 33 out of 735 (4.5%) were in the left ventricle (LV) and 65 out of 327 (19.9%) were in the right ventricle (RV). The number of abnormalities in the RV was significantly higher than in the LV (P less than 0.001). Regional analysis of LV and RV in 109 40 degrees LAO studies and in 102 75 degrees LAO studies showed abnormal wall motion in the following segments: LV--posterobasal 6 (5.9%), inferior 2 (2.0%), anterior 5 (4.9%), anteroseptal 11 (10.1%), apical 5 (4.6%), posterolateral 4 (3.7%); RV--septal 44 (40.4%), apex 15 (13.8%), and the free wall 6 (5.5%). The left ventricular ejection fraction decreased from 74% median (M) in baseline studies to 54% (M) in the highest dose group (greater than 650 mg/m2). The present data show an increased number of wall motion abnormalities in the RV compared with the LV, particularly in the RV septum (P less than 0.001).

Role of radionuclide ventriculography in evaluating cardiac function.

The role of nuclear cardiology techniques for evaluating cardiac function has become increasingly important among other diagnostic techniques. The current status of radionuclide imaging of left and right ventricular function allows accurate diagnosis of cardiac patients with both coronary and noncoronary disease. The combination of gated first-pass and equilibrium radionuclide ventriculography makes it possible to assess more completely cardiac function than by either technique alone. Of particular interest to most imaging physicians is the current position of exercise ventriculography in the diagnostic setting, especially since this test has undergone new scrutiny in its application to broader patient segments. This technique and issues related to its place in the diagnostic environment are discussed in this review article, with emphasis on relevance to the clinical laboratory.