Heart rate variability in the early hours of an acute myocardial infarction.

The occurrence of an autonomic disturbance early in acute myocardial infarction (AMI) has been reported: signs of sympathetic activation were mainly observed in relation to an anterior localization, whereas signs of vagal overactivity were more frequent in inferior wall AMI. Information is limited in relation to the persistence of these alterations during the early hours of AMI. We studied 33 patients with an AMI within 188 +/- 16 minutes from the onset of symptoms and 1 week after hospital admission. From a 20-minute Holter recording, we computed with autoregressive methodology, time and frequency domain indexes of heart rate variability. At admission, patients with an anterior wall AMI exhibited a smaller RR variance (593 +/- 121 ms2) than did those with an inferior wall AMI (1,122 +/- 191 ms2). In both groups the spectral profile was characterized by a predominant (73 +/- 4 and 61 +/- 4 normalized units) low frequency and by a small (13 +/- 2 and 22 +/- 3 normalized units) high-frequency component, indicating the presence of a sympathetic excitation and of a diminished vagal modulation. Although signs of sympathetic activation were more evident in patients with anterior wall AMI, no evidence of a vagal hyperactivity was observed in patients with inferior wall AMI. In the latter group, we noticed 1 week after the acute event an increase in the low-frequency component, which reached the values observed in patients with anterior wall AMI. Thrombolysis did not affect heart rate variability parameters. Thus, this study suggests the presence of an autonomic disturbance characterized by signs of sympathetic excitation and of a reduced vagal modulation, which was more evident in patients with an anterior localization early after AMI.

Results of total correction of tetralogy of Fallot performed in adults.

Today, total correction of tetralogy of Fallot is rarely performed in adults. In a 10-year period, 40 patients aged 20 to 67 years underwent intracardiac repair in our institution. Twenty-eight of them had had a palliative procedure 11 to 30 years earlier. Preoperatively, 23 patients were in New York Heart Association (NYHA) Functional Class II, 14 were in Class III, and 3 were in Class IV. Operative mortality was 2.5% (1/40). Follow-up ranged from 1 year to 11 years (average, 3 years). One patient died of a noncardiac cause 4 years after operation. Residual cardiac defects were observed in 4 patients. Postoperatively, 30 patients were in NYHA Functional Class I, 8 were in Class II, and 1 was in Class III. Major ventricular arrhythmias were recorded in 7 (35%) of 20 patients. Radionuclide angiography demonstrated impaired right ventricular function in 8 patients. Left ventricular impairment was present in 2. Total correction of tetralogy of Fallot can be performed safely in adults with low mortality and good functional improvement. The incidence of residual cardiac defects is low. The long-term importance of impaired ventricular function and arrhythmias remains to be ascertained.

Value of exercise stress test, radionuclide angiography and coronary angiography in predicting new coronary events in asymptomatic patients after a first episode of myocardial infarction.

One-hundred-and-fifty-five consecutive symptom-free patients underwent maximal treadmill exercise testing, rest and stress radionuclide angiography at least two months after an uncomplicated acute myocardial infarction; of these, 90 underwent coronary angiography. All patients were followed-up for a mean of 32 +/- 13 months regarding the prediction of hard (death and reinfarction) and soft (angina and coronary surgery) coronary events. The specificity, sensitivity, positive and negative predictive value of exercise stress test were 47%, 76% and 41% for any coronary events; none of the patients who incurred a hard coronary event showed ischemia during electrocardiographic exercise tests. Sensitivity, specificity and positive predictive value for failure to increase the ejection fraction of at least 5% were 60%, 45% and 30% for any coronary event and 25%, 49% and 2% for any hard coronary event. The presence of multivessel disease at coronary angiography showed a sensitivity of 62% for any coronary event and of 67% for hard coronary events; specificities were 66% and 57%, and predictive values were 52% and 10%, respectively. It is concluded that electrocardiographic exercise testing, radionuclide angiography and coronary angiography are not helpful two months after an episode of uncomplicated myocardial infarction in order to identify patients who will suffer a new coronary event.

Prognosis of hibernating myocardium is independent of recovery of function: evidence from a routine based follow-up study.

Revascularization of hibernating segments improves both ventricular function (VF) and survival. In this study, we determined whether this relation is true in a routine based patients population with mildly reduced VF. Two to 6 years after undergoing 201Tl scintigraphy to detect hibernation, 153 patients were interviewed in order to collect medical information. This population was divided into four groups, according to the presence or absence of myocardial hibernation and of revascularization. Age, gender and left ventricular ejection fraction (LVEF) were similar in the four groups. Hard cardiac events (HEs) were noted in 14/33 (41%) patients with uncorrected hibernation, while in the other three groups HEs were recorded in fewer than 3% of patients. Univariate analysis indicated that the presence of hibernation, regardless of its extension, was the highest significant predictor of HEs. Multivariate analysis indicated that hibernation, stress ischaemia, age and absence of revascularization were significant predictors of HEs. These findings were not related to changes in LVEF or to New York Heart Association (NYHA) class during follow-up. In this routine based patient population, with mildly reduced VF, the rate of HEs seems to be related to uncorrected hibernation regardless of its extension. In these patients revascularization of hibernating segments is effective in reducing the risk of HEs while its role in improving VF or NYHA class is negligible.

[Reciprocating tachycardias in pregnancy. A clinical case report]. / Tachicardie reciprocanti in gravidanza. Descrizione di un caso clinico.

The paper describes the case of a patients suffering from a pre-excitation syndrome who underwent numerous episodes of reciprocal tachycardia during pregnancy. The clinical implications and various methods of therapy used are discussed.

Two-dimensional echocardiographic method for the estimation of cardiac output independent of left ventricular geometry. Comparison with cardiac catheterization in mitral stenosis.

An hydraulic formula for the estimation of cardiac output independent of the geometric status of the left ventricle was studied by comparing the predictions based upon echographic and catheterization data with the results of the standard Fick principle method for cardiac output. The formula tested specifies cardiac output as Q = (1/21) RAT2, where Q is the cardiac output in ml, R is the heart rate, A is the mitral valve area in cm2 and T is the diastolic filling period in seconds per minute. Cardiac output estimated by this equation corresponds with cardiac output as determined by the Fick principle method at a level characterized by a correlation coefficient of r = 0.92 and a standard error of SE = 0.15 L/min for N = 26. The results suggest that the new expression may be useful for estimating cardiac output from echographic data.

[Ion channels in cardiac tissue. Validity and limits of cellular electrophysiology in the interpretation of clinical data]. / I canali ionici nel tessuto cardiaco. Validità e limiti della elettrofisiologia cellulare nell'interpretazione dei dati clinici.

New experimental methods in cellular electrophysiology allowed the identification and characterization of specific "ion channels" in the plasma membrane of cardiac cells in different regions of the heart. Function and implication of the "ion channels" have been considered in 1) the initiation of the heart-beat, 2) the chronotropic and inotropic effects of neurotransmitters (nor-epinephrine-acetylcholine), 3) the action mechanism of the steroid cardioactive drugs, 4) the cardiac repolarization, 5) the physiopathology of several arrhythmias. Moreover clinical data useful for the indirect evaluation of the ion channels function have been pointed out, stressing the ion channels models contribution for the cardiac pathology interpretation, particularly in the cardiac arrhythmias field.

[Physical and psychological future of patients with coronary disease. To whom should ambulatory rehabilitation be proposed? (author's transl)]. / Evolution physique et psychologique des malades coronariens. A qui proposer la réadaptation ambulatoire?

To ambulatory rehabilitation programme was proposed to 91 patients during their stay in hospital for myocardial infarction or aortocoronary bypass surgery. A retrospective study showed that 51 patients did follow the programme, whereas 40 patients preferred their own method of self-rehabilitation. Serial exercise tests demonstrated progressive and considerable improvement in physical aptitude among those who followed the programme, but the psychological, socio-familial and professional outcome was globally the same in both groups. The present study therefore confirms the numerous advantages of the rehabilitation programme but also shows that many of the potential candidates to such programmes are capable of returning by themselves to a normal and active life.

[M-mode and two-dimensional echocardiography in evaluating mitral stenosis before and after commissurotomy]. / L'échocardiographie uni- et bidimensionnelle dans l'évaluation des sténoses mitrales avant et après commissurotomie.

A first group of 51 patients with pure or predominant mitral stenosis underwent M-mode (M) and two-dimensional (2D) echocardiography and cardiac catheterization (cath). After elimination of 3 incomplete cases, the series consists of 48 patients. 20 later underwent surgery. Quantitative correlations between M and cath are poor (r = 0.34, p less than 0.05); however, correlations between 2D and cath were excellent (r = 0.89, p less than 0.001). There were 4 major discrepancies between 2D and cath: 3 of these patients were operated upon and surgery confirmed 2D mitral valve area in all of them. 2D had served to diagnose all 6 cases of mitral calcifications seen at surgery; however, M provided 1 false negative and 5 false positive results with regard to diagnosis of calcifications. A second group consisted of 18 patients who had undergone mitral commissurotomy, 8 of these had a pre- and postoperative echocardiography. 10 also underwent postoperative cath. M appeared to be unable to predict correctly the presence or absence of a recurrence of mitral stenosis. Quantitative correlations between diastolic slope and mitral valve area at cath were poor. However, excellent correlations were found between 2D and cath, showing that 2D also serves to measure mitral valve area after commissurotomy.

[M-mode and two dimensional echocardiography for evaluation of mitral stenosis (author's transl)]. / L'ecocardiografia mono e bidimensionale nella valutazione della stenosi mitralica.

M-mode and two-dimensional echocardiography (echo) were performed in 51 patients with pure or predominant mitral stenosis. Echocardiographic assessment of the severity of the stenosis was compared to the results of cardiac catheterization (cath); surgical evaluation of the mitral valve area was also obtained in 20 patients. M-mode is an excellent method for the diagnosis of mitral stenosis. However two-dimensional echo is much better for the assessment of its severity; in the present study correlations with cardiac catheterization have been excellent (r = 0.89, p less than 0.001). Major disagreement between echo and cath were found in 4 patients; 3 of them have been operated on and surgery has confirmed the echo results in all 3. Two-dimensional echo has also allowed correct prediction in the presence of mitral calcifications in 6 of the operated patients, whereas several false positive and negative diagnosis was made on M-mode. Two-dimensional echocardiography is therefore an excellent non-invasive technique for the diagnosis of mitral stenosis, measurement of mitral valve area and identification of mitral calcifications.

Regional sympathetic denervation after myocardial infarction: a follow-up study using [123I]MIBG.

Previous studies in dogs have shown that experimental infarction produces myocardial sympathetic denervation not only in the infarcted area, but also in a region apical to the infarction. In these dogs MIBG myocardial scintigraphy detected denervation but returned to normal in a few months at which time reinnervation was shown to have occurred. Myocardial sympathetic denervation was studied with MIBG scintigraphy in ten patients after their first acute transmural myocardial infarction; scans were repeated at 4 months, one year and 30 months to follow the time course of possible reinnervation. Except during the first 48 hours following the infarction, no therapy except for antiaggregants was administered to the patients; during this follow-up period no cardiac events were seen. One week after infarction, comparison of MIBG images with perfusion scans revealed that the denervated area was larger than the infarcted area; no difference in MIBG uptake by the infarcted myocardium was found during the 30 months follow-up.

[Comparison of two-dimensional echocardiography, angiocardioscintigraphy and cineventriculography in the study of left ventricular wall motion in ischemic cardiopathy]. / Confronto tra ecocardiografia bidimensionale, angiocardioscintigrafia e cineventricolografia nello studio della motilità di parete del ventricolo sinistro nella cardiopatia ischemica.

Thirty-two patients with non acute myocardial infarction (inferior in twenty, anterior in ten, anterior and inferior in two) were studied with contrast left ventriculography, two-dimensional echocardiography and radionuclide angiography to assess left ventricular wall motion. We adopted the CASS criteria for the standard left ventriculography, and the Mayo Clinic classification for the echocardiographic study. Radionuclide angiography studies were obtained in left anterior oblique view; the images were evaluated with the use of Walsh-Hadamard transform; the left ventricle was divided in basal and apical septal, apical, posterolateral, posterobasal and two central segments. We tried to correlate the findings of the three techniques both for single segments and larger regions made of contiguous segments. Left ventricular angiography and two-dimensional echocardiography showed a fair concordance for both anterobasal and posterolateral left ventricular wall, whereas for the septal, apical and posterolateral regions contrast and radionuclide angiography had the best correlation. Compared to left ventricular angiography two-dimensional echocardiography shows better sensitivity than radionuclide angiography; the latter is more specific in defining left ventricular wall motion. The two non invasive techniques are therefore helpful in the evaluation of wall motion and their role is complementary.

Evidence of functional alterations in sympathetic activity after myocardial infarction.

To assess whether the presence of areas of efferent sympathetic denervation might contribute to alterations in sympathetic and vagal neural regulatory activities observed after myocardial infarction, we attempted to correlate the changes in the spectral components of RR variability with the I-123 MIBG and Thallium-201 uptake defects. Ten patients with first and uncomplicated myocardial infarction were studied. Thallium-201 and I-123 MIBG scintigraphy as well as spectral analysis of heart rate variability were performed 7 days, 4, 12 and 30 months after the acute event. Regional abnormalities in I-123 MIBG uptake were more extensive than the perfusion defects indicated by Thallium-201 images and remained constant throughout the entire period of observation. In the early post-infarction period, spectral analysis of RR variability was characterized by a predominant LF (74 +/- 6 nu) and a smaller HF (16 +/- 3 nu) component indicating a sympathetic predominance. Thereafter, we observed a progressive reduction in LF and a gradual increase in HF which were consistent with a normalization of sympatho-vagal balance. These data indicate that after a myocardial infarction, the presence and persistence of areas of sympathetic functional denervation do not seem to play a major role in determining the changes in sympathetic and vagal neural regulatory activities directed to the heart.

Use of radionuclide angiography and an electrocardiographic stress test to diagnose multivessel disease after a first episode of uncomplicated myocardial infarction.

Sixty consecutive patients who were symptom free 2-12 months after an uncomplicated acute myocardial infarction underwent maximal treadmill exercise testing, radionuclide angiography before and during submaximal bicycle stress test, and coronary angiography. The results of the non-invasive procedures were compared with those of coronary angiography. The sensitivity and specificity of electrocardiogram stress test for detection of multivessel disease were 40% and 77% respectively. Failure of left ventricular ejection fraction to increase at least 5% with exercise identified 20 of the 25 patients with multivessel disease (sensitivity 80%) and 23 of the 35 patients with no additional coronary artery stenosis (specificity 66%). In patients with anterior Q waves the sensitivity was 78% and the specificity 50%, whereas in the presence of inferior Q waves these values were 81% and 87% respectively. Loss of left ventricle synchronicity during effort, as indicated by failure of the standard deviation of the phases to decrease during exercise, demonstrated a radionuclide angiography sensitivity of 80% (77% for anterior myocardial infarction and 81% for inferior myocardial infarction) and a specificity of 50% (33% for anterior myocardial infarction and 64% for inferior myocardial infarction). When the test was considered to be positive if either the ejection fraction or the standard deviation of the phases criteria were positive, the sensitivity was 100% and specificity 46% (30% for anterior myocardial infarction and 65% for inferior myocardial infarction). It is concluded that in patients who are free from angina 2-12 months after an episode of uncomplicated myocardial infarction, a simple exercise electrocardiogram cannot be relied upon to detect residual ischaemia. An abnormal ejection fraction response or an increased standard deviation of the phases during exercise nuclear angiography or both identified all the patients with multivessel disease. None of the patients in whom radionuclide angiographic criteria were negative had multivessel disease.