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Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formula are indirect estimates of renal function which have been widely accepted, though their accuracies have been scarcely validated in advanced chronic renal failure. The purpose of this study was to determine the accuracy (bias and precision) of these formulas in advanced CRF patients. The study group consisted of 99 unselected patients (62 +/- 15 years, 59 females) with advanced CRF. The glomerular filtration rate (GFR) was measured by Tc(99m) DTPA. Simultaneously, estimates of GFR by CG corrected for 1.73 m2 and MDRD (formula 7) were calculated. Agreement was evaluated graphically, bias was assessed by mean and median difference, and precision by median absolute differences and Bland-Altman plots. Mean GFR by DTPA, CG and MDRD were: 16.24 +/- 4.38 and 16.77 +/- 4.65 and 13.58 +/- 4.27 ml/min/1.73 m2, respectively. MDRD equation significantly underestimated GFR-DTPA (p = 0.0001). Both CG and MDRD correlated significantly with GFR-DTPA (R = 0.53 and R = 0.62, respectively). CG formula performed better than the MDRD equation with respect to bias (0.30 vs -3.24 ml/min/1.73 m2, p = 0.0001), and precision (0.58 vs. -3.11 ml/min/1.73 m2, p = 0.0001). By multiple linear regression, the best determinants of the error of the estimation by CC formula were: serum creatinine (beta = -0.58; p < 0.0001), age (beta = -0.62; p < 0.0001), and body mass index (beta = 0.26, p = 0.004), and by MDRD formula were: serum creatinine (beta = -0.38; p < 0.0001), and body mass index (beta = -0.20, p = 0.03). In conclusion, in unselected patients with advanced chronic renal failure, estimates by CC formula were more accurate than those obtained by MDRD formula. Serum creatinine was the main source of error of the estimation of GFR by both formulas, though demographic and anthropometric characteristics influenced as well on their accuracies.

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Las ecuaciones de Cockcroft-Gault (CG) y MDRD son estimaciones indirectasde la función renal de amplia aceptación, pero que han sido escasamente validadasen los estadios más avanzados de la insuficiencia renal crónica (IRC). Elobjetivo del presente estudio fue establecer la exactitud (sesgo y precisión) deestas estimaciones en pacientes con IR avanzada.Se estudiaron 99 pacientes (59 mujeres, edad media 62 ± 15 años), con IRCavanzada prediálisis. Se recogieron datos demográficos, comorbilidad, peso, talla,creatinina, urea, y albúmina. El filtrado glomerular (FG) se midió con Tc99m DTPA(FG-DTPA). Simultáneamente se estimó el FG con las fórmulas de CG corregidoa 1,73 m2 y MDRD (fórmula 7). Se determinó la exactitud de cada una delas fórmulas analizando el grado de correlación, sesgo (diferencia de media ymediana), y precisión (mediana de las diferencias absolutas y método de Bland-Altman).El FG-DTPA, y los estimados por CG y MDRD fueron respectivamente: 16,24± 4,38; 16,77 ± 4,65 y 13,58 ± 4,27 ml/min/1,73 m2. FG-MDRD infraestimó significativamenteel FG-DTPA (p < 0,0001). La diferencia de la mediana fue másamplia con FG-MDRD (-3,24 frente 0,30 ml/min/1,73 m2, p = 0,0001), al igualque la mediana de las diferencias absolutas (-3,11 frente 0,58 ml/min, p = 0,0001).Los mejores determinantes del error FG-CG fueron: la creatinina (beta = -0,58; p< 0,0001), la edad (beta = -0,62; p < 0,0001), y el índice masa corporal (beta= -0,26; p = 0,004). Los mejores determinantes del error FG-MDRD fueron: creatinina(beta = -0,38; p < 0,0001), y el índice masa corporal (beta = -0,20; p =0,035).En conclusión, en pacientes no seleccionados con IRC avanzada la estimacióndel FG con CG corregida a 1,73 m2 fue menos sesgada y más precisa que conMDRD. La creatinina sérica fue la principal fuente de error en la estimación delFG con ambas fórmulas, aunque las características demográficas y antropométricastambién influyeron

Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulaare indirect estimates of renal function which have been widely accepted,though their accuracies have been scarcely validated in advanced chronic renalfailure. The purpose of this study was to determine the accuracy (bias and precision)of these formulas in advanced CRF patients.The study group consisted of 99 unselected patients (62 ± 15 years, 59 females)with advanced CRF. The glomerular filtration rate (GFR) was measured byTc99m DTPA. Simultaneously, estimates of GFR by CG corrected for 1.73 m2 andMDRD (formula 7) were calculated. Agreement was evaluated graphycally, biaswas assessed by mean and median difference, and precision by median absolutedifferences and Bland-Altman plots.Mean GFR by DTPA, CG and MDRD were: 16.24 ± 4.38 and 16.77 ± 4.65 and13.58 ± 4.27 ml/min/1.73 m2, respectively. MDRD equation significantly underestimatedGFR-DTPA (p = 0.0001). Both CG and MDRD correlated significantly withGFR-DTPA (R = 0.53 and R = 0.62, respectively). CG formula performed better thanthe MDRD equation with respect to bias (0.30 vs –3.24 ml/min/1.73 m2, p = 0.0001),and precision (0.58 vs –3.11 ml/min/1.73 m2, p = 0.0001). By multiple linear regression,the best determinants of the error of the estimation by CG formula were:serum creatinine (beta = -0.58; p < 0.0001), age (beta = -0.62; p < 0.0001), andbody mass index (beta = 0.26, p = 0.004), and by MDRD formula were: serum creatinine(beta = -0.38; p < 0.0001), and body mass index (beta = -0.20, p = 0.03).In conclusion, in unselected patients with advanced chronic renal failure, estimatesby CG formula were more accurate than those obtained by MDRD formula.Serum creatinine was the main source of error of the estimation of GFR byboth formulas, though demographic and anthropometric characteristics influencedas well on their accuracies

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This survey presents the results of a poll sent to all Spanish nuclear medicine departments between July 1999 and March 2000, with the aim of clarifying the current situation of nuclear medicine in Spain. This survey is believed to be the first of its kind, and it is anticipated that the data will be of assistance to health authorities in ensuring that the needs of the population with regard to nuclear medicine facilities are met.

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Catheter ablation of the atrioventricular node is a therapeutic technique for the treatment of patients with drug-refractory supraventricular tachyarrhythmias. In our Arrhythmia Unit 25 patients (8 women, 17 men) aged (mean +/- DE) 56 +/- 10 years have undergone fulguration of the atrioventricular junction since 1986. The more frequent treated rhythm disturbance was atrial flutter or fibrillation, with uncontrolled rapid ventricular response. Absence of organic heart disease was diagnosed in 9 patients; the remainder had valvular heart disease (2), cor pulmonale (2), cardiomyopathy (7), hypertensive heart disease (2) and Wolff-Parkinson-White syndrome (3). Under general anesthesia 1.8 +/- 0.8 shocks/patients were delivered along 1.2 +/- 0.7 sessions/patient. In 23 of 25 patients (92%) complete atrioventricular block was achieved, and a pacemaker was implanted. There were no complications. The other 2 patients were referred to surgery for cryoablation of the atrioventricular junction. Patients were followed for an average of 21 +/- 12 months. Four patients have died: two due to congestive heart failure, which was present prior to the ablation procedure, the third because of a metastatic carcinoma, and the fourth had a sudden death 14 months after the procedure (he had dilated cardiomyopathy and Wolff-Parkinson-White syndrome). The remainder in chronic stable complete atrioventricular block are asymptomatic for arrhythmias and without antiarrhythmic medication.

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Ten patients underwent endocardial catheter ablation of the atrioventricular junction for atrioventricular nodal reentrant tachycardias. Unipolar cathodic discharges at the distal electrode were administered against an external plate. Bipolar His and atrial deflections showed a mean of 0.15 mv and 0.5 mv respectively. Mean total energy used per patient was 195 J (range: 50-750), with a mean number of ablating discharges of 2.0 per patient, (range: 1-5). Complete atrioventricular block was achieved, but conduction reappeared in all except one patient, after a mean interval of 19.9 min. Electrophysiological evaluation was assessed 3-8 days after ablation. Sustained atrioventricular nodal reentrant tachycardias were no longer inducible in any patient. Retrograde conduction was abolished in six, and was slow and decremental in four. First-degree atrioventricular block, with intranodal delay was diagnosed in six, with an AH interval that ranged from 240 to 130 ms. Mean cycle length for appearance of Wenckebach atrioventricular block was 390 ms after ablation. One patient developed complete atrioventricular block after two discharges of 50 J, another required a repeat ablation for recurrence of intranodal tachycardia and also developed complete anterograde block in a new session of ablation with a 150 J discharge. In these two patients permanent pacing was needed. Eight patients were cured after a mean follow-up of 20 months. Less energy and fewer discharges should be administered to abolish functional dissociation of the atrioventricular node, without complete interruption of anterograde conduction.

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Fibrinolysis and lipid disturbances have been considered as independent risk factors for coronary artery disease. Besides this, lipoprotein(a), which is characterized by its homology with plasminogen may interfere with the fibrinolytic function. To evaluate the eventual correlation between fibrinolytic parameters, lipoprotein (a) and other risk factors, 46 patients with coronary artery disease (34 with chronic angina pectoris and 12 with myocardial infarction) were studied. Increased basal values of t-PA antigen (8.2 and 6.6 vs. 4.2 ng/ml) but decreased response after stimulus (2.2 and 1.8 vs. 3.8 ng/ml) and increased levels of lipoprotein(a) (24.7 and 35.9 vs. 10.5 mg/dl) were the most relevant differences between coronary artery disease patients and controls. No correlation between lipoprotein(a) and fibrinolytic parameters was found. Therefore plasma concentration of the main plasma fibrinolytic parameters and lipoprotein(a) seem to be unrelated though the relevance of this interaction at a local level needs to be studied.

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We report two cases of cardiac amyloidosis. The echocardiographic features of this infrequent disease, and the doppler study of the ventricular diastolic function in these patients, together with its possible prognostic significance, is revised.

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There is a wide spectrum of changes in the resting electrocardiograms of athletes. We here present a case of third-degree atrioventricular block in an asymptomatic young athlete.

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UNLABELLED: To evaluate the reliability of Holter monitoring in reproducing myocardial ischemic changes, 110 patients (90 males, 20 females; age range: 14-74 years) underwent a Bruce protocol treadmill exercise test. An electrocardiogram was recorded simultaneously with a two-channel modulated Holter recorder (frequency response: 0.05-100 Hz) with bipolar CM-V3 and CM-V5 leads and by a conventional 12-lead system. An ischemic ST-segment change was defined as 1 mm or more ST-segment depression lasting more than 0.08 sec after the J point. Results were concordant in 101 patients, 36 with both positive and 65 with both negative responses. Eight false negative and one false positive Holter ischemic episodes occurred. This yielded an accuracy (expressed as sensitivity, specificity, positive and negative predictive values) of 81.8%, 98.5%, 97.3% and 89.0%, respectively. There was a good correlation between the maximal ST-segment depression (r = 0.57; p less than 0.001), duration of ischemia (r = 0.89; p less than 0.001), heart rate at the onset of the ischemic episode (r = 0.91; p less than 0.001) and maximal heart rate (r = 0.98; p less than 0.001). CONCLUSIONS: Two-channel amplitude modulated Holter recording system with bipolar CM-V3 and CM-V5 leads can reliably reproduce ST-segment changes.

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To evaluate the prognostic significance of silent ischemia during exercise testing, 152 consecutive patients (143 males, 9 females) with a mean SD of 55 +/- 7 years (age range 32-73) who underwent exercise testing and coronary arteriography within 3 months were studied. All patients had the following characteristics: 1) a positive electrocardiographic exercise test response; 2) significant coronary artery disease on the arteriography; 3) uninterrupted clinical follow-up for a minimum of 6 months. The 152 patients were divided in 2 groups: group I: 56 patients (37%) with ischemic ST-segment depression during exercise testing without angina (silent ischemia); group II: 96 patients (63%) with ischemic ST-segment depression and angina (symptomatic ischemia). Patients in group I and group II showed similar time to ST-segment depression (3.6 +/- 1.5 min vs 3.2 +/- 1.4 min; p = NS), maximal ST-segment depression and peak heart rate-systolic pressure product (21,151 +/- 7,124 vs 20,456 +/- 6,024; p = NS). Exercise duration was longer in group I than in group II (5.6 +/- 2.1 min vs 4.8 +/- 1.5 min; p less than 0.001). The extent of coronary artery disease defined by the number of significant narrowed coronary vessels, left ventricular end diastolic pressure and ejection fraction were similar in the 2 groups. Sixty six patients who underwent coronary bypass surgery were not included in the analysis. The remaining 86 patients (40 in group I and 46 in group II) were medically treated. The mean follow-up period was 43,5 +/- 25 months (range 6-101).2+ myocardial ischemia during exercise testing.

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UNLABELLED: To evaluate the prevalence and characteristics of silent myocardial ischemia in asymptomatic patients with non insulin dependent diabetes mellitus, 50 diabetic patients (24 males, 26 females; mean age +/- SD = 58.3 +/- 6.4 years) with a normal resting electrocardiogram were prospectively studied. The total group underwent 48 hours electrocardiographic Holter monitoring, medical history, physical examination an a test for cardiac autonomic neuropathy. Serum levels of total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and Hb A1c were determined. An ischemic episode was defined as asymptomatic ST-segment depression greater than or equal to 1 mm, greater than or equal to 1 min. Day-to-day variability was studied. Six hundred and forty one episodes with a total duration of 1,014 minutes of ischemia were recorded in 29 patients (58%). The mean number of episodes in 48 hours per patients was 19.2 +/- 21.9 and the mean time of ischemia over this period was 149 +/- 374 minutes. The average heart rate at the onset of the episodes was 95.2 +/- 8.4 beats per minute. Two hundred and ninety two (45.6%) episodes occurred without heart rate changes and in 349 (54.4%) episodes an increase in heart rate was detected at the onset of the episode. An important day-to-day variability in the number of episodes (73.8 +/- 29.5%) and ischemia duration (76.9 +/- 88.8%) was found. Fifteen patients had no ischemic episodes in either the first or second monitoring day. Silent ischemia was related to higher levels of total cholesterol (p less than 0.05), LDL-cholesterol (p less than 0.05) and Hb A1c (p less than 0.01) and was associated to diabetes complications: retinopathy (p less than 0.001), peripheral vascular disease (p less than 0.01), polyneuropathy (p less than 0.05), nephropathy (p less than 0.05), and impotence (p less than 0.01). Silent ischemia was not associated to abnormal test for cardiac autonomic neuropathy. CONCLUSIONS: prevalence of silent myocardial ischemia during daily activities in asymptomatic diabetic patients is very high (58%). Both an increase in oxygen demand and a decrease in oxygen supply may be involved in its pathophysiology. In diabetic patients silent ischemia is related to the presence of other risk factors for coronary artery disease and to diabetes complications and shows a marked day-to-day variability.

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