Characterization and long-term prognosis of patients with effort-induced silent myocardial ischaemia

The aim of this study was to evaluate the anatomo-clinical correlations and the prognostic significance of silent myocardial ischaemia (SI) during exercise testing (ET). Four hundred and six patients with angiographically proven CAD and positive ET were studied. Patients were divided into two groups: 309 patients (Group A) with positive ET for both electrocardiographical findings and angina, and 97 patients (Group B) with positive ET for electrocardiographical findings but not for angina (SI). In Group A the following clinical characteristics differed significantly from Group B: incidence of diabetes mellitus (15.8% vs 27.8%, P less than 0.04); duration of disease (less than 1 month from its first manifestation) (30.4% vs 54.6%, P less than 0.001) and a positive ET at low work-load (41.7% vs 50.5%, P less than 0.05). Mortality during follow-up (mean 72 +/- 11 months) was 8.6% in Group A and 8.2% in Group B (NS). Incidence of sudden death was similar in the two groups (2.9% vs 2.06%; NS). The multivariate analysis shown as independent variables, related significantly with a poor prognosis in both groups: left ventricular function (P less than 0.0001); prior myocardial infarction (P less than 0.0001); and multivessel disease (P less than 0.001). In conclusion, patients with a recent onset of symptoms, a positive ET at low workload and diabetes mellitus are more likely to present SI during ET. The long-term prognosis and the incidence of sudden death are similar in patients with painful and painless myocardial ischaemia during ET.

Sudden death during pregnancy in hypertrophic cardiomyopathy

A 27-year-old asymptomatic woman became pregnant 6 months after a diagnosis of hypertrophic cardiomyopathy and was well until 28 weeks' gestation when she died suddenly while running up stairs. The potential pathophysiological mechanisms of sudden death during pregnancy in hypertrophic cardiomyopathy, as well as the diagnostic and therapeutic implications, are discussed.

Nonrandom association of atrioventricular canal and del (8p) syndrome

We describe a patient with partial deletion of the short arm of chromosome 8 with an atrioventricular canal. This type of congenital heart defect was found in 4 of the 7 previously reported del (8p) children with a congenital heart defect in which the cardiac assessment was complete. The prevalence of an atrioventricular canal in this aneuploidy is high and suggests a nonrandom association of the 2 anomalies.

Effects of slow-release verapamil and nitrendipine on office and 24-hour ambulatory blood pressure in hypertensive patients

The aim of the present study was to compare the effects of slow-release verapamil (V), 240 mg and nitrendipine (N), 20 mg, administered once daily, on office (OBP) and 24-h ambulatory blood pressure (ABP) in patients with mild-to-moderate hypertension. Twenty patients were entered into this open, randomized, two-group (V, N) parallel study. The study groups had similar age and sex distribution. The OBP (V, 155/103 +/- 19/8 mm Hg; N, 141/98 +/- 13/4 mm Hg), heart rate (HR) (V, 74 +/- 7 beats/min; N, 77 +/- 10 beats/min), daytime systolic ABP (V, 149 +/- 14 mm Hg; N, 147 +/- 13 mm Hg), and nighttime ABP of the two groups were not statistically different after a 2-week washout period. The daytime diastolic ABP (V, 99 +/- 6 mm Hg; N, 93 +/- 6 mm Hg) was slightly lower (p less than 0.05) in group N. Both the OBP (V, 136/90 +/- 19/9 mm Hg; N, 135/85 +/- 10/4 mm Hg) and daytime ABP (V, 132/85 +/- 14/4 mm Hg; N, 136/87 +/- 13/8 mm Hg) dropped in the two groups after 8 weeks of treatment. Nonparametric analysis did not show statistical differences between the groups in OBP and ABP percentage drop. There was no significant change in nighttime ABP, HR (V, 73 +/- 10 beats/min; N, 74 +/- 12 beats/min), ECG, and laboratory exams. We conclude that both verapamil SR and nitrendipine are effective in reducing blood pressure in hypertensive patients without altering the HR.

[Partial deletion of the long arm of chromosome 17. Presentation of a clinical case]

A partial deletion of the long arm of chromosome 17 has been found in a liveborn infant. The clinical findings of the propositus are compared with those of a previously reported case allowing delineation of a hitherto unrecognized partial deletion (17q) syndrome.

Histones and DNA methylation in mammalian chromatin. II. Presence of non-inhibitory tightly-bound histones

After removal, by high-salt extraction, of the loosely-bound components present in human placenta chromatin, tightly-bound cationic proteins could be solubilized, by acid extraction, from the 'stripped' chromatin, as well as from the 'stripped' loops or from the 'digested matrix'. These acid-soluble tightly-bound proteins are, in terms of apparent molecular mass and immunoreactivity, quite similar to the 'typical', loosely-bound histones, and, similarly to their 'loosely-bound' counterparts, they can be subdivided in distinct H1-, H2A-, H2B-, H3- and H4-like components, the 'digested matrix' being however characterized by the absence of tightly-bound H1. These tightly-bound histones, at variance from the 'typical' ones, readily find a right-handed helical conformation upon renaturation by progressive dialyses. The H1 components strongly differ also in their effects on enzymic DNA methylation: while 'typical' H1 has a strong inhibitory effect, its tightly-bound counterpart exerts a slight but definite stimulation.

Spontaneous left atrial echocardiographic contrast in mitral stenosis: early disappearance after valve replacement

We describe a patient with mitral stenosis and severely enlarged left atrium. Transthoracic echocardiography showed a false image of intraatrial thrombus, whereas transesophageal echocardiography showed massive spontaneous left atrial contrast. Intraoperative transesophageal echocardiography was performed. During cardioplegic arrest the contrast was enhanced, but it gradually and completely cleared 15 minutes after cardiopulmonary by-pass arrest. Transesophageal echocardiography is a useful technique for the study of intraatrial masses and may bring a new dimension to tissue characterization studies.

ST/HR slope and improved exercise ECG detection of myocardial ischemia in patients with suspected coronary artery disease

Predictive values of ST/HR slope and ST-segment displacement during symptom-limited exercise were determined in 85 patients who underwent coronary angiography for suspected coronary artery disease, using perfusional and functional radionuclide images with 99mTc-2-methoxy-isobutil-isonitrile as an index of stress-induced myocardial ischemia. ST/HR slope showed a better sensitivity than conventional stress-induced changes of ST-segment displacement (96% vs. 73%, respectively). In patients with clinical suspicion of coronary artery disease, the main result was the negative predictive value of ST/HR slope when compared with conventional ST-segment displacement (98% vs. 41%). ST/HR slope was unable to perfectly separate patients with different degrees of ischemia, however, subjects without scintigraphic signs of stress-induced ischemia and patients with ischemic impairment in three myocardial regions were correctly identified as distinct populations. In patients with a previous myocardial infarction, no difference was found between the two criteria and a wide overlap of ST/HR slope values was present. The authors conclude that ST/HR slope is useful to detect the rate of change in electric parameters during exercise and might therefore more adequately be used to separate normal from definitely abnormal responses to exercise.

Ventricular conduction defects and atrial fibrillation after coronary artery bypass grafting. Multivariate analysis of preoperative, intraoperative and postoperative variables

Preoperative, intraoperative and postoperative variables, which might play a role in the development of ventricular conduction defects (VCD) and atrial fibrillation (AF) following coronary artery bypass grafting (CABG), were evaluated in 236 consecutive patients. VCD and AF developed postoperatively in 15.5% of patients: 4.5% had VCD (subgroup A), 11.0% had AF (subgroup B). In 84.5% of patients VCD and AF did not occur (subgroup C). Univariate analysis showed statistically significant differences between subgroups A and C with respect to: left main significant stenoses and number of diseased vessels. Bypass pump time and aortic cross-clamp time were significantly longer in subgroup B. Multivariate analysis showed a significantly greater incidence of left main disease and of right coronary artery occlusion associated with significant stenosis of the proximal left anterior descending artery in subgroup A. In subgroup B, the duration of aortic cross-clamp time was significantly higher. Ischaemic injury, with increasing duration of cardioplegic arrest, seems to play a key role in the development of AF. Nonhomogeneous cardioplegic delivery to critical areas of myocardium, and particularly to the specialized conducting system, may cause VCD after CABG.

Electrocardiographic correlates with left ventricular morphology in idiopathic dilated cardiomyopathy

The purpose of the present study was to verify whether the electrocardiographic pattern of patients with idiopathic dilated cardiomyopathy (IDC) might be useful in predicting measurements of left ventricular (LV) morphology. A total of 12 electrocardiographic criteria for LV enlargement were evaluated in 67 patients with IDC, aged 14 to 68 years (mean 48), and were correlated to LV wall thickness, volume and mass, as assessed at angiography (all patients) and echocardiography (50 patients). Linear regression analysis showed weak correlations between multiple electrocardiographic criteria and LV wall thickness, volume and mass. Multiple logistic regression analysis showed that total 12-lead QRS amplitude, voltage criteria of Sokolow and Lyon, overshoot and U-wave inversion were the variables significantly related to LV wall thickness, as assessed by angiography (r = 0.55, p less than 0.005) and echocardiography (r = 0.43, p less than 0.025). The sum of T/R-wave ratios, the RV6/RV5 ratio and the Romhilt-Estes score were predictors of LV end-diastolic volume, as determined by angiography (r = 0.83, p less than 0.001) and echocardiography (r = 0.77, p less than 0.005). Total 12-lead QRS amplitude and the sum of T/R-wave ratios were the only independent predictors of LV mass, either angiographically (r = 0.81, p less than 0.001) or echocardiographically measured (r = 0.71, p less than 0.025). It is concluded that a single electrocardiographic criterion for prediction of LV morphology in patients with IDC is barely effective. Multiple electrocardiographic criteria should be utilized to better predict LV mass and distinguish reliably between LV wall thickening and dilatation.

Histones and DNA methylation in mammalian chromatin. Differential inhibition by histone H1

Histones (from calf thymus or from human placenta), if renatured in the presence of EDTA, caused a severe inhibition of in vitro methylation of double-stranded DNA (from Micrococcus luteus) by human placenta DNA methyltransferase. The absence of EDTA during the histone renaturation procedure abolished--at least in the 'physiological' range of the histones/DNA ratio--the inhibition. The H1 component was responsible for this inhibition, no effect being exerted by the other histones. H1 preparations were more effective if renatured in the presence of EDTA--90% inhibition being reached at a 0.3:1 (w/w) H1/DNA ratio. It seems likely that the requirement for the presence of EDTA during the renaturation process is correlated to its ability to induce a fairly stable ordered conformation of the histones, although this effect could also be shown with the 'inactive' H2a, H2b and H3 components, and was instead less evident with histone H1. The restriction to histone H1 of the ability to inhibit enzymic DNA methylation may account for the lower methylation levels present in the internucleosomal DNA of mammalian chromatin.

Correlation between angiographic success and functional improvement assessed by exercise test following percutaneous transluminal coronary angioplasty

Sixty-one consecutive patients with stable effort angina and single vessel disease underwent successful (reduction of coronary stenoses by greater than or equal to 20%) percutaneous transluminal coronary angioplasty (PTCA). Anatomical results were analysed on the basis of functional evaluation obtained by exercise test (ET) 1 week before (pre-PTCA) and within 1 month after (post-PTCA) PTCA. Total exercise duration and maximal double product significantly increased after PTCA (4.5 +/- 1 min vs 6.9 +/- 1.5 min, p less than 0.001 and 14.1 +/- 3.6 x 1000 mmHg x bpm vs 18 +/- 4.2 x 1000 mmHg x bpm, p less than 0.001). Pre-PTCA ET was positive in 43 patients (70%) and post-PTCA ET in 15 (24%). In patients with post-PTCA positive ET, mean stenosis diameter reduction was significantly lower than that obtained in patients with negative post-PTCA ET (29.6 +/- 8.9% vs 61.1 +/- 18.8%, p less than 0.001). In conclusion, PTCA improved exercise tolerance in the majority of patients with myocardial ischemia, however the definition of anatomical success used in this study appears to be poorly correlated with functional improvement as assessed by ET.

[The transcatheter modulation of the AV node as a possible treatment of choice in nodal re-entrant tachycardia]

Transcatheter modification of the AV node with radiofrequency energy (RF) was performed in 6 patients (mean age 24 years) with inducible AV node reentry tachycardia (AVNRT). Although tachycardia could be controlled with antiarrhythmic drugs in each patient, the option was offered to eliminate the arrhythmia by means of RF catheter technique. A 7F catheter with 2 mm interelectrode distance and a large tip electrode was positioned to record the maximal His deflection, then withdrawn until the smallest possible His and ventricular potentials with a large atrial signal could be recorded. RF energy was delivered at this site in unipolar mode in incremental steps, until AVNRT was no longer inducible or VA block occurred. The procedure resulted in non-inducibility of tachycardia in 5/6 patients. The fast and the slow pathways were abolished in 2 and 1 patients, respectively, while the AV node duality persisted in 2 in spite of non-inducibility. VA block occurred in 2 patients, while the anterograde conduction was preserved in all. During the follow-up (mean 4.5 months) 5/6 patients remained free of AVNRT without drugs. It is concluded that transcatheter RF modulation of the AV node can be advised, provided that similar results will be obtained in larger series with longer follow-up, as the first line therapy in patients with AVNRT.

[Relations between ACE inhibition with captopril and atrial natriuretic factor during an acute hemodynamic study]

Aim of this study was to evaluate if captopril treatment may directly alter the trial natriuretic factor (ANF) concentration. Six patients (2 male and 4 female) aged 53 +/- 11 years, with mitral stenosis, and atrial fibrillation, underwent cardiac catheterization in our Institution. The following parameters were evaluated: heart rate, right atrial and pulmonary capillary wedge pressure, aortic and pulmonary pressure, cardiac index, pulmonary and systemic resistances and ANF concentration in coronary sinus, pulmonary, artery, aorta, peripheral vein. All these parameters were measured before and 30 and 60 min after captopril administration (50 mg orally). No hemodynamic changes occurred after captopril administration. No changes in ANF concentration occurred in comparison with baseline levels, after 30 and 60 min in coronary sinus (199.8 +/- 151.5 vs 181.9 +/- 102.5 fmol/ml; 178.4 +/- 95.2 vs 181.9 +/- 102.5 fmol/ml), in pulmonary artery (58.3 +/- 36.6 vs 51.4 +/- 48.8 fmol/ml; 35.5 +/- 16.9 vs 51.4 +/- 48.8 fmol/ml), in aorta (29.7 +/- 22.7 vs 37.5 +/- 26.3 fmol/ml; 25.2 +/- 9.8 vs 37.5 +/- 26.3 fmol/ml); and in peripheral vein (14.6 +/- 7.9 vs 17.3 +/- 9.7 fmol/ml; 16.2 +/- 12.2 vs 17.3 +/- 9.7 fmol/ml). In conclusion our data show that, providing no hemodynamic changes occur, captopril administration does not alter ANF concentration.

Exponential fit of QT interval-heart rate relation during exercise used to diagnose stress-induced myocardial ischemia

The aim of this study was to analyze the dynamic changes of QT interval--heart rate relation during exercise, fitting their reciprocal variations to an exponential formula (QT = A - B.exp(-k.RR], in order to see whether diagnostic contributions might so be derived. The authors studied 139 patients who underwent a simultaneous assessment of regional myocardial perfusion and ventricular function by means of two injections of 99mTc-methoxy-isobutyl-isonitrile at rest and at peak of a submaximal exercise test, using first pass radionuclide angiography with multielement gamma-camera and single photon emission computerized tomography, in order to detect and localize the presence of stress-induced myocardial ischemia. According to radionuclide results, patients were divided into three groups: group A, 7 individuals with no sign of stress-induced myocardial ischemia; group B, 79 patients with evidence of ischemia in 1 (16.5%), 2 (65.5%), or 3 (17.7%) main coronary territories; and group C, 53 patients with previous infarction and evidence of ischemia in other territories. Conventional analysis of the exercise test (greater than or equal to 0.1 mV ST depression) showed a pathological response in no individual of group A, in 34 patients of group B (43%), and in 27 patients of group C (50.9%); overall sensitivity was 46.2%, specificity 100%, and diagnostic accuracy 48.9%. Exponential coefficients A, B, and k showed wide overlap of values among the three groups, although a significant difference was present in mean k values between groups A and B (p less than 0.001), and group C (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of left ventricular ejection fraction by magnetic resonance imaging and radionuclide ventriculography in idiopathic dilated cardiomyopathy

To assess the validity of gated magnetic resonance imaging (MRI) in determining left ventricular (LV) ejection fraction (EF), MRI (Spin Echo, multislice-multiphase technique on the short-axis plane) was compared with equilibrium radionuclide ventriculography in 32 patients with idiopathic dilated cardiomyopathy. All patients underwent MRI and radionuclide ventriculography, performed consecutively on the same day (mean time interval between the 2 examinations: 40 minutes). Comparison with LVEF showed a high correlation (y = 0.79 X +3.51, r = 0.91; p less than 0.001). Mean difference between radionuclide ventriculography and MRI data was 1.7, with the 95% confidence interval 0.71 to 2.68: MRI slightly underestimated LVEF. MRI interobserver and intrapatient variability (assessed in 15 of 32 patients) showed a high correlation (r = 0.91, r = 0.98). In conclusion, data suggest that MRI, using the short-axis approach and the multislice-multiphase technique, is an accurate, noninvasive, highly reproducible method of evaluating LVEF in patients with idiopathic dilated cardiomyopathy.

Natural history of hypertrophic cardiomyopathy in the elderly

To assess the natural history of hypertrophic cardiomyopathy (HC) in the elderly, we reviewed clinical, electrocardiographic and hemodynamic data from 21 patients over 60 years of age at diagnosis who were studied since 1970. Comparison with 95 younger patients (less than 60 years) showed that a greater proportion of older patients had exertional angina and atrioventricular conduction delay at time of diagnosis. During a mean follow-up of 9 +/- 6 years, mortality from cardiac causes was 33% (7 out of 21) in patients over 60 years of age and 23% (22 out of 95) in younger patients (NS). Univariate analysis showed that functional class and hemodynamic indices of right- and left-sided heart impairment were associated with a poor prognosis in the elderly. We conclude that: (1) presenting features and outcome of patients with HC over 60 years of age do not differ significantly from those of younger patients; (2) functional class and measurements of cardiac function are significant predictors of death in the elderly.

Hypertrophic cardiomyopathy: long-term effects of propranolol versus verapamil in preventing sudden death in "low-risk" patients

The aim of this study was to evaluate retrospectively the outcome of 101 patients who were assigned to long-term therapy with propranolol (55 patients) or verapamil (46 patients) between 1980 and 1988. Baseline clinical, electrocardiographic, and echocardiographic data were similar in both groups. Exclusion criteria were the evidence of complex ventricular arrhythmias, a family history of the disease and/or sudden death, previous syncopal episodes, or left ventricular dysfunction. During a mean follow-up of 4 +/- 3 years (range: 1-9 years), side effects were more commonly recorded in patients who were treated with verapamil rather than in propranolol-treated patients (8 vs. 3, respectively), though the difference was not statistically significant. Sixteen patients (13 propranolol-treated patients and three verapamil-treated ones, p less than 0.05) died suddenly while on treatment. In addition, three patients who stopped verapamil because of adverse reactions died from heart failure after withdrawal, but before the end of the follow-up period. The assessment of total mortality on the intention-to-treat basis showed that death due to cardiac causes occurred in 13 propranolol-treated patients and in six verapamil-treated patients (ns). Thus, verapamil was more effective than propranolol in preventing sudden death during long-term therapy of "low-risk" patients with hypertrophic cardiomyopathy, though its administration was associated with the occurrence of non-sudden cardiac deaths and a high incidence of side effects.

[Primary pulmonary hypertension: a retrospective study of 13 patients]

Twenty-four patients (9M and 15F, mean age 28 years) with primary pulmonary hypertension underwent cardiac catheterization in our institution from 1955 to 1989. The prevalence of the disease in our population was lower (0.2%) than that reported by other Authors (1%). Thirteen of these patients (4 M and 9 F, mean age 32 years) evaluated between January 1979 and December 1989, were followed. Five were alive after 52 +/- 30 months (Group A) while 8 died after 11 +/- 9 months (Group B). In Group B mean pulmonary pressure was significantly higher than in Group A (66.7 +/- 17.2 vs 41.2 +/- 19.0 mmHg, p less than 0.05, respectively). Cardiac index and systolic volume index were lower in Group B than in Group A (2.07 +/- 0.85 vs 3.72 +/- 1.32 l/min/m2, p less than 0.01 and 24.43 +/- 10.25 vs 41.08 +/- 16.97 ml/m2, p less than 0.05, respectively). Pulmonary resistance index and systemic resistance index were higher in Group B than in Group A (3039 +/- 1519 vs 1181 +/- 1236 dyne x s x cm-5/m2, p less than 0.01; 4277 +/- 1794 vs 2309 +/- 1238 dyne x s x cm-5/m2, p less than 0.01). One patient underwent repeated cardiac catheterization after 2 years. This patient showed a deterioration of the hemodynamic parameters, consistent with the worsening of the clinical conditions. In conclusion, in our population of patients with primary pulmonary hypertension, an increase in pulmonary artery pressure and pulmonary resistances, as well as a decrease in cardiac index, are associated with a reduced life expectancy. On the other hand, right atrial pressure does not affect mortality.