Biomedical subjects
Publications and source records attributed to F Arrigo.
The authors report three cases in which the dipyridamole test provoked: (1) junctional rhythm with AV dissociation; (2) sinus arrest; (3) 2:1 AV block. The three cases described above draw attention to the possible effect of dipyridamole on the AV conduction, which is not yet completely known. This unwanted effect suggests that careful ECG monitoring should be performed during the dipyridamole test.
The electrical resistivity of intracardiac blood is less than the resistivity of the surrounding tissues. This affects the transmission of cardiac forces to the body surface: the radial forces are enhanced, whereas the transmission of tangential forces is diminished (the Brody effect). Blood resistivity is directly related to haematocrit, hence, haematocrit changes are expected to affect the transmission of cardiac forces, resulting in changes in QRS complex voltage. To assess this hypothesis, a 12-lead electrocardiogram was recorded in 40 patients affected by thalassaemia before and after a transfusion of concentrated red cells. The voltage of each QRS component was carefully measured in every lead, and the sum of all R wave amplitudes (sigma R) was calculated. The post-transfusional electrocardiogram reflected a significant decrease in the R wave amplitude in every lead. sigma R also decreased, whereas S wave amplitude in lead V6 increased. A negative correlation between the ratio of haematocrit pre/post transfusion and that of the corresponding sigma R values was also observed (r = -0.434; P less than 0.01). An increase in haematocrit is therefore associated with a decrease in R wave amplitude. These findings explain why several patients with high haematocrit manifest relatively low voltage QRS complexes.
This study was aimed at assessing coronary reperfusion in patients with acute myocardial infarction (AMI) undergoing systemic thrombolysis with SK and rtPA. The occurrence of reperfusion was related to the time of treatment. The evaluation of reperfusion was performed by monitoring ST segment changes. 56 patients with AMI were studied. 22 out of these (39.2%) showed a significant decrease (greater than 50%) in ST segment sum (sigma ST) at 100 minutes from the beginning of the treatment. Analysis of the relationship between reperfusion and elapsed time between the onset of symptoms and the treatment, reveals that the reperfusion is less frequent (p less than 0.05) in patients treated at 180 minutes or later. The standard electrocardiogram appears as the most useful method to evaluate indirectly coronary reperfusion in acute myocardial infarction. A further refinement of this method is desirable to recommend its widespread clinical use. The assessment of reperfusion by means of ECG in large series of patients will permit the evaluation of the benefits of reperfusion, in terms of survival, complications and incidence of ventricular dysfunction.
The Authors describe a case of a patient showing, during an episode of chest pain, an ecg-pattern of wide and tall "Q" wave simulating inferior myocardial infarction. In fact, a further ecg recorded during sinus rhythm denotes that the "Q" wave was a retrograde P wave generated by a nodal rhythm. The other known causes of "pseudonecrosis" are discussed.
This study was aimed to evaluate if the time-course of creatinkinase MB in acute myocardial infarction (AMI) is influenced by therapy and which index, derived from the enzymatic curve, is the most reliable marker of successful coronary artery recanalization. We studied the enzymatic curves in 38 patients with transmural myocardial infarction, 19 treated with streptokinase (SK) and 19 with tissue plasminogen activator (rtPA). Blood samples were obtained every 2 hours for the first 12 hours and every 6 hours until the level of serum CK returned to baseline. Three indexes were calculated: peak serum enzyme level, time to peak enzyme level and maximal enzyme rise velocity. Time to peak did not differ significantly between SK and rtPA groups. Peak levels were significantly higher (414 +/- 40 vs 249 +/- 33; p = 0.004) in rtPA groups, as well as maximal enzyme rise velocity (1.7 +/- 0.4 vs 0.8 +/- 0.1; p = 0.02). However, infarct size evaluated by the total release of CK-MB in 28 patients was greater in rtPA group (10949 +/- 1097 vs 6346 +/- 869; p = 0.002). These findings suggest that differences in peak level and in maximal velocity of rise observed between SK and rtPA are due to differences in infarct size and not to a different recanalization rate. Thus, enzymatic estimate of infarct size significantly correlates to peak enzyme (r = 0.894, p less than 0.001), and to maximal rise velocity (r = 0.518, p = 0.007) but not to time to peak (r = 0.208, NS).(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this study, designed as an open multicenter trial, was to test the antihypertensive efficacy, patient acceptability, and side effects of long-term treatment with slow-release nifedipine in a large population. The drug was studied in 330 outpatients with essential hypertension, WHO stage 1-2, recruited in 20 hospital centers. After washout period was completed, nifedipine (20 mg bid) was given for 1 month (phase 1). Then, the treatment was extended for 4 months (phase 2) with variable doses (range 20-80 mg daily). No other antihypertensive drugs were administered during phase 1. However diuretics, beta blockers, or captopril were added to nifedipine during phase 2 in 11 patients. Seventy patients did not meet criteria for inclusion at washout. During phase 1 and 2, 66 additional patients were excluded due to side effects, the need of other antihypertensive drugs, or non-compliance. Systolic blood pressure significantly lowered (10% or more) in 84% patients in phase 1 and in 76% in phase 2. No responders were 6.1% and 3.6%, respectively. Diastolic blood pressure was normalized in 60% of patients after 5 months of therapy. Effects on blood pressure were equal in young patients and in the elderly, but a minimal rise in heart rate was recorded in younger patients. At least one side effect occurred in 46.6% patients, mainly headache (15.4%), hot flashes (13.3%), ankle edema (12.8%), or palpitation (6.6%). Sixteen patients (8.2%) were obliged to stop nifedipine treatment due to the severity of the side effects. This trial confirms the efficacy of nifedipine in hypertension, both in young and in aged patients.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this study was to evaluate if the occurrence of acute myocardial infarction (AMI) follows a regular pattern during the day and, if so, to assess any difference according to sex and patients' age. To determine 24-hour trend of AMI onset, clinical recordings of patients admitted to the CCU for AMI over a period of 8 years were reviewed: 427 patients (310 men and 117 women, aged 24-95 years), with a first AMI and in whom the time of onset of cardiac pain due to MI could be accurately established by history, were selected. Analysis of hourly distribution of the event was performed using a mathematical model based on Whittaker's method for periodic phenomena. It showed the occurrence is cyclic with 2 waves with periods of 6 and 12 hours in all age groups in men an women. No statistical differences were found between observed figures of periods and values calculated by Fourier analysis. The overall occurrence of MI showed a regular pattern with 4 peaks at 4.00 am, 10.00 am, 4.00 am and 10.00 pm. This periodic behaviour is nearly the same both in men and in women. The occurrence of MI is maximal in the morning (34.2% in men, and 35.9% in women); the minimum was recorded during the evening in male patients over 70 years and during the night in the other age groups; it was recorded during the afternoon and the night in women.(ABSTRACT TRUNCATED AT 250 WORDS)
The authors present a case of trifascicular block: complete right bundle branch block, tachycardia-dependent left anterior hemiblock, and bradycardia-dependent left posterior hemiblock. There is, in addition, a complicating independent AV junctional rhythm that is in most instances not affected by the conducted sinus impulses. Occasionally, however, this focus is discharged by very early sinus impulses that are unexpectedly conducted to the ventricles (a manifestation of "supernormal" conduction). A complex electrocardiographic pattern results from the interplay of the aforementioned mechanisms.
A clinical, electrocardiographic and echocardiographic (M-Mode, 2D) study was performed to explain the causal relationship between mitral annular calcification and cardiac conduction disturbances. Forty-seven patients, 28 women and 19 men (mean age 69) with mitral annular calcification were studied. In 18 patients A-V and/or intraventricular conduction disturbances were present. In this study we have found: a greater incidence of posterior than anterior mitral annular calcification; the anterior mitral annular calcification is often associated with aortic valve calcification and ultimately the common association between anterior mitral annular calcification and conduction disturbances.
Intravenous propafenone (1 mg/Kg in 3 min) has been administered to 14 patients with recent atrial fibrillation. The sinus rhythm was restored in 7 patients within 30 min after the injection. The left atrial size, evaluated by M-mode echocardiography, was no different in the group of responders, with respect to the non-responders. No adverse effect has been observed. One single patient manifested a long asystolic pause (3860 ms), at the restoration of sinus rhythm. Propafenone appears to be useful in the treatment of recent atrial fibrillation.
Fifteen cases of ventricular parasystole were analyzed to determine whether the interectopic intervals were regular, as expressed by long intervals being exact multiples of the short ones, or not. The regularity of the interectopic intervals was assessed by means of the variation index: the ratio of the maximal difference between various measurements of the parasystolic cycle length and the mean parasystolic cycle length. Three out of 15 cases had a variation index less than 5, and were classified as "regular parasystole." Twelve cases were associated with a variation index greater than 7.5, and were classified as "irregular parasystole." The cases of irregular parasystole were then analyzed to determine whether the variability of the interectopic intervals was casual or dependent on action of the sinus beats. A parasystolic resetting by critically timed sinus impulses (a form of intermittent parasystole) was evident in three cases. The irregularity in the remaining nine cases was due to modulation (viz., due to electrotonic influence exerted by the sinus beats on the parasystolic focus). In every case of modulated parasystole a phase-response curve was constructed, which enabled an analysis of all the interectopic intervals on the basis of a time-dependent effect exerted by the sinus impulses on an otherwise rhythmic parasystolic focus.
Explore the source record for details and available documents.
A case of non-sustained, recurrent ventricular tachycardia, manifesting with irregular R-R intervals, is described. Analysis of a long electrocardiographic recording reveals that the arrhythmia is generated by a regularly discharging ectopic ventricular focus, the R-R interval variations being due to a Wenckebach form of exit block.
The study was carried out on 60 consecutive patients (23 males and 37 females) aged between 20 and 83 years (means +/- SD, 40.7 +/- 16) who arrived at our Cardiologic Unit with paroxysmal supraventricular arrhythmias (PSVA) including junctional paroxysmal tachycardia (n = 32), atrial fibrillation (n = 13), atrial flutter (n = 1), premature beats (n = 13) and with no obvious cardiovascular causes. Serum thyroxine and triiodothyronine were normal in all patients and thyroid scintiscan revealed normal shape and size thyroids without autonomously functioning nodule(s). Thyrotropin (TSH) response to thyrotropin releasing hormone (TRH) was normal in 44 subjects in whom normal serum free T4 (FT4) and free T3 (FT3) levels were measured. Six patients with normal FT4 and FT3 levels did not respond to TRH. Abnormalities in thyrotropin response to TRH were observed in 10 patients all exhibiting increased FT4 or also FT3 levels. Among these, 5 patients did not respond to TRH, whereas the remaining 5 exhibited a blunted TSH response to TRH. These results suggest that only in a small proportion (5/60) of consecutive patients with PSVA it is possible to recognize a status of "occult thyrotoxicosis" on the basis of the combined evaluation of free thyroid hormones and TSH response to TRH.
A patient with 2:1 AV block underwent temporary ventricular pacing. All the paced stimuli resulted in ventricular capture, but a marked variability in morphology of the paced QRS complexes occurred. Two different types of paced QRS complex (labeled A and B) were recognized. Type B complexes were manifest only when the pacing stimulus was preceded by a sinus P wave within a time interval ranging from 0.15 to 0.52 sec. The P wave-induced changes in morphology of the paced QRS complexes were interpreted as due to displacement of the pacing ventricular lead caused by atrial systole.
Explore the source record for details and available documents.
A series of 4260 consecutive echocardiographic examinations, performed in 5 Cardiological Centers was examined, identifying 125 intraventricular false tendons (FTs) in 100 cases (55 normals and 45 with heart disease) of whom 31 were female and 69 male, aged 3 to 82 years. An anatomo-morphological study was possible in 9 cases, dead for stroke or heart failure, on autopsy, and in 7, on heart surgery. A phonocardiogram was performed in all normals and in 20 patients. On echocardiography, FTs appeared as an echo-producing string-like structure, straight between the septum and the ventricular free wall, mobile during the cardiac cycle, without systolic thickening and any relation with the atrioventricular valvular apparatus. The prevalence of FTs was 2.3%; it was 3.2% to 5.3% in younger people. FTs were located in the right ventricle (4 cases), left ventricle (95 cases) or in both (1 case). Their site was left apical (45 FTs), right apical (2 FTs), right (3 FTs) and left (20 FTs), upper septum-to-free wall (55 cases). In 1 case hypertrophy of trabeculae of the left ventricle was detected. FTs were single (79 cases), double (19 cases), multiple (2 cases), short (42 cases), long (58 cases), thick (45 cases) and thin (55 cases). They showed a membrane-like motion (thick FTs-45 cases) and a valve-like motion (thin FTs-55 cases). Innocent murmur was detected in 50 of 55 normals and related to thin FTs. Of 16 cases examined anatomically and histologically, FTs were fibrous in their distal portion and fibro-muscular in the proximal one in 12 cases, whereas they were entirely fibrous-muscular in 4 cases. The site and location of FTs detected by echo were confirmed by anatomy in all cases. In 4 cases other 9 FTs, not detected on echocardiography, were found. These data suggest that echocardiography is a useful tool to detect intraventricular FTs and differentiate them from other echo-producing structures. Although a relationship between FTs and heart disease has not been found, their presence could be responsible of innocent murmur in many normal subjects.
The efficacy of Propafenone to prevent exercise-induced ventricular arrhythmias (EIVA) has been studied in eleven patients affected by ischemic heart disease. None of the patients manifested any arrhythmia at rest, but ventricular arrhythmias occurred in every case during a treadmill test. EIVA disappeared after Propafenone in nine patients, while a reduction by 90% was achieved in the remaining two patients. A further treadmill test carried out five days after withdrawal of the drug induced again the same ventricular arrhythmias in all the patients. Thus, Propafenone appears effective to prevent EIVA in patients with ischemic heart disease.