Lown Grade Research Articles

Application of novel QT interval correction and QT/RR assessment models to ECG 24-hour recordings in cardiac patients

The aim of the study was to apply different novel ventricular repolarization assessment models to clinical 24-hour ECG recordings for identification of patients with high level of myocardial electrical instability (MEI), i.e. those significantly predisposed to development of potentially life-threatening cardiac arrhythmias. In order to explore the ventricular repolarization inhomogeneity, Holter recordings of forty patients, divided into 4 groups according to their maximal Lown grade (Lown 0, 3A, 4A, 4B), were studied using six QT/RR regression models and six heart rate correction formulas. The algorithm developed during the study enables application of these novel models in routinely registered ECG 24-hour recordings in patients with various heart diseases and without overt heart condition. This approach assures heart rate correction optimization for every single person. The QTc deviation values, obtained with the linear correction model, differed significantly in patients with various MEI levels; thus, if further validated, they can be used as a method for arrhythmia risk stratification.

Atorvastatin might improve ventricular electrostability and decelerate the deterioration of renal function in patients with heart failure and diabetes mellitus

Previous studies suggested that statins have pleiotropic effects, such as improvements in endothelial function, as well as anti-inflammatory, anti-proliferative, and anti-oxidative effects. These effects might benefit patients with heart failure. In those patients, statins relieved symptoms, decreased the frequency of hospitalization, suppressed neurohumoral activation, and improved cardiac function. However, it remains unknown how statins impact pathophysiology of heart failure with diabetes mellitus. The aim of this study was to investigate the effects of atorvastatin on pathophysiology of heart failure with diabetes mellitus. We enrolled retrospectively 128 patients with heart failure with diabetes mellitus who were admitted from January 2003 to December 2005. Among these patients, 80 received atorvastatin (statin group) and the remaining patients served as controls (non-statin group). At study entry, there were no significant differences in the patient profiles between the two groups except for the low-density lipoprotein cholesterol level being higher in the statin group. After the follow-up period of two years, the frequency of re-hospitalization, brain natriuretic peptide, premature ventricular contractions, Lown grade, and deterioration of glomerular filtration rate were significantly less in the statin group. Atorvastatin might benefit patients with heart failure and diabetes mellitus by improving ventricular electrical stability and decelerating deterioration of renal function.

Prognostic Significance of the Lown Grades and Late Potentials in Patients after Myocardial Infarction

Background and Objectives: The aims of this study were to assess the long term overall survival of patients after an acute myocardial infarction (AMI), and to determine the association of survival with the occurrence of ventricular arrhythmia, as recorded by Holter electrocardiography (ECG) and signal-averaged electrocardiography (SAECG). Subjects and Methods: One hundred fifty two patients with an AMI were enrolled between January 2000 and August 2006. SAECG and Holter ECG were performed before hospital discharge (at range of 2-10 day). The grading system of Lown was used to evaluate the ventricular premature beats on Holter ECG. Three groups of patients were identified based on the seriousness of the ventricular arrhythmia, as identified by the Holter ECG: Lown grade 0, Lown grades 1, 2 and Lown grades 3, 4, 5. SAECG was performed with a high pass frequency of 25 Hz and 40 Hz. The presence of late potentials (LPs) recorded on SAECG was evaluated. The predictors for survival were assessed using Cox’s proportional hazard model and Kaplan-Meier analysis. Results: The mean duration of follow-up was 45.8±25.5 months. Twenty four patients (15.8%) died during follow-up. The multivariate predictors of all cause death included age [hazard ratio (HR)=1.25, 95% confidence interval (CI)=1.08-1.47, p=0.003] and Lown grades 3, 4 and 5 (HR=19.17, 95% CI=1.25-290.80, p=0.034). Survival analysis did not show a significant relationship between LPs and overall patient survival. The only predictors for overall mortality were age and the Lown grade. Conclusion: SAECG did not predict mortality for the patient with AMI. The ventricular arrhythmias recorded by conventional Holter before hospital discharge may be a useful noninvasive prognostic test after an AMI. (Korean Circ J 2008;38:17-22)

Prophylactic implantation of cardioverter-defibrillator in patients with severe cardiac amyloidosis and high risk for sudden cardiac death

Cardiac light-chain amyloidosis carries a high risk for death predominantly from progressive cardiomyopathy or sudden death (SCD). Independent risk factors for SCD are syncope and complex nonsustained ventricular arrhythmias. The purpose of this study was to test whether prophylactic placement of an implantable cardioverter-defibrillator (ICD) reduces SCD in patients with cardiac amyloidosis. Nineteen patients with histologically proven cardiac amyloidosis and a history of syncope and/or ventricular extra beats (Lown grade IVa or higher) received an ICD. During a mean follow-up of 811 +/- 151 days, two patients with sustained ventricular tachyarrhythmias were successfully treated by the ICD. Two patients underwent heart transplantation, and seven patients died due to electromechanical dissociation (n = 6) or glioblastoma (n = 1). Nonsurvivors more often showed progression of left ventricular wall thickness, low-voltage pattern, ventricular arrhythmias (Lown grade IVa or higher), and higher N-terminal pro-brain natriuretic peptide levels than did survivors. Bradycardias requiring ventricular pacing (VVI 40/min <1%, DDD 60/min 6% +/- 1%) occurred only rarely. Patients with cardiac amyloidosis predominantly die as a result of electromechanical dissociation and other diagnoses not amenable to ICD therapy. Selected patients with cardiac amyloidosis may benefit from ICD placement. Better predictors of arrhythmia-associated SCD and randomized trials are required to elucidate the impact of ICD placement in high-risk patients with cardiac amyloidosis.

Arrhythmias and conduction abnormalities in children after repair of tetralogy of Fallot

To find out types and frequency of cardiac arrhythmias and conduction abnormalities in the group of children who underwent surgery for tetralogy of Fallot (TOF). Forty-six pedicatric patients who underwent a complete repair of TOF at the age of 1 to 13 (mean 2.89+/-2.36) were studied Thirty-eight (82.60%) had total correction and 8 (17.40%) had palliative operation first, and total correction afterwards. Twenty-four-hour Holter ECG monitoring was performed in all 46 pediatric patients aged from 1 to 16 yrs (mean 6.48+/-4.04) after surgery as follows: in 1 patient (2.17%) after a year, in 20 patients (43.477%) after 2 to 5 years and in 25 patients (54.34%) after 5 years. Mean age of patients on Holter monitoring was 9.25+/-4.39 (range 4-19). Twenty of them (43.47%) were girls and 28 (56.53%) were boys. All the patients were evaluated by standard methods (clinical signs, clinical findings, ECG before surgery, ECG before Holter monitoring and 2D Doppler echocardiography. Types of heart rhythm found out by Holter monitoring were: sinus nodus dysfunction in 1 child (2.17%), significant premature atrial contraction (PAC) in 8 (17.39%), supraventricular paroxysmal tachycardia in 3 (6.535), transient nodal rhythm in 2 (4.34%), premature ventricular contraction (PVC) Lown grade 1-III in 9 (19.56%) and Lown grade IV in 2 (4.34), atrioventricular (AV) block grade I in 2, right bundle branch block (RBBB) in all 46 (100%) and RBBB + left anterior hemiblock (LAH) in 4 (8.96%). There was no presence of atrial flutter, ventricular tachycardia or complete A V block. None of them experienced sudden death. Using cross procedure statistical methods, it was found that all the patients with PVC had right ventricular dilatation. There was no relation of other types of arrhythmia found on Holter monitoring to the other parameters from echocardiography, neither to the other standard methods. Children did not need the pace-maker, but 36.95% of the them required antiarrhythmic drugs. Twenty-four hour Holter ECG is a noninvasive and very sensitive method for discovering heart rhythm disturbances in children after the repair of tetralogy of Fallot, especially in asymptomatic patients. The patients after the repair of this congenital heart disease needed a long-term follow-up for early recognition of serious heart rhythm disturbances and their treatment.

Relationship Between Brain Natriuretic Peptide, Myocardial Wall Stress, and Ventricular Arrhythmia Severity

We previously demonstrated that the severity of arrhythmias is reflected by circulating brain natriuretic peptide (BNP) concentrations in patients without signs of congestive heart failure. In the present study, we evaluated the relationships between the severity of the arrhythmia, BNP concentration, and echocardiographic findings. The subjects consisted of 52 patients with ventricular premature contractions (VPC) but no manifestations of heart failure and no digoxin or beta-blocker therapy. Patients underwent Holter monitoring, plasma sampling for BNP measurement, and transthoracic echocardiography (TTE). We scored the motion of 16 left ventricular segments, deriving a wall-motion score index (WMSI) by totaling the scores and dividing by the number of segments scored. Twenty-three patients with Lown grade I to II arrhythmias constituted group A while group B consisted of 29 Lown III to IV patients. Group B had BNP concentrations triple those in group A (57.2 versus 18.1 pg/mL, P < 0.01). Left ventricular ejection fraction (LVEF) was similar in groups A and B (65.2% versus 62.1%, NS). Although left ventricular end-diastolic dimension (LVEDD) was normal in both groups, group B exhibited a larger LVEDD than group A (50 versus 46 mm, P < 0.005). The correlation (r) between BNP and interventricular septum thickness (IVST) was 0.27 (P = 0.013) in group A and 0.37 (P < 0.0001) in group B. Between BNP and posterior wall thickness (PWT), the correlation was 0.23 (P = 0.014) in group A versus 0.33 (P < 0.0001) in group B. The WMSI in group B was higher than in group A (1.34 versus 1.11, P < 0.05). We believe that besides the changes in echocardiographic parameters, the BNP elevation in group B could be a response to abnormal wall stress from the severe ventricular arrhythmias.

Late ventricular potentials in risk assessment of the occurrence of complex ventricular arrhythmia in patients with myocardial infarction and heart failure

To determine the prognostic significance of late ventricular potentials on signal-averaged electrocardiogram and left ventricular ejection fraction for the occurrence of complex ventricular arrhythmia in patients treated with accelerated tissue-type plasminogen activator, using the rapid protocol, within six months of acute myocardial infarction. In this analytic observational prospective study patients were divided into four groups: patients with left ventricular ejection fraction bellow 40% and late ventricular potentials, patients with left ventricular ejection fraction bellow 40% and without late ventricular potentials, patients with left ventricular ejection fraction over 40% and late ventricular potentials, and patients with left ventricular ejection fraction over 40% and without late ventricular potentials. Complex ventricular arrhythmias (Lown grade IVa, IVb, and V) were recorded using standard electrocardiography and 24-hour Holter monitoring 21, 60, and 90 days after acute myocardial infarction, respectively. Serial recordings of signal-averaged electrocardiogram were obtained 30, 90, and 180 days after acute myocardial infarction. Left ventricular ejection fraction was determined by echocardiography between 15 and 21 days after acute myocardial infarction. Multivariant logistic regression analysis was used to evaluate the relation between late ventricular potentials and left ventricular ejection fraction with the occurrence of complex ventricular arrhythmias. Sensitivity, specificity, positive and negative predictive values of late ventricular potentials and left ventricular ejection fraction for the occurrence of complex ventricular arrhythmias were determined. The prospective study included 80 patients (73% men), mean age 64 +/- 3.5 years. Complex ventricular arrhythmias were recorded in 34 (42.5%) of patients, all 17 (50%) of which were from the first group (p < 0.01). Complex ventricular arrhythmias were recorded in 25 (73.5%) patients with late ventricular potentials, and in 23 (67.6%) patients with left ventricular ejection fraction bellow 40%. Left ventricular ejection fraction bellow 40% and late ventricular potentials represented independent predictors for the occurrence of complex ventricular arrhythmias (RR = 14.33, p < 0.01). When combined with left ventricular ejection fraction bellow 40%, late ventricular potentials had sensitivity (0.50), specificity (0.93), and positive predictive accuracy (0.85) higher than late ventricular potentials alone (0.44, 0.67, and 0.37, respectively) for the occurrence of complex ventricular arrhythmias following acute myocardial infarction. In this study, late ventricular potentials in patients with left ventricular ejection fraction bellow 40% represented the independent predictor for the occurrence of complex ventricular arrhythmias in the first six months after the first myocardial infarction treated with accelerated tissue-type plasminogen activator, using the rapid protocol.

Magnetocardiographic and magnetic resonance imaging for noninvasive localization of ventricular arrhythmia origin in a model of nonischemic cardiomyopathy.

Ventricular arrhythmia may in myocardial failure arise as a consequence of remodeling related to hypertrophy and dilatation. In surgically repaired tetralogy of Fallot (TOF), which carries a substantial risk for ventricular arrhythmias and sudden death, the situation is even more complex and several potential arrhythmia mechanisms exist. The authors wanted to test a completely noninvasive localization technique, magnetocardiography (MCG) and magnetic resonance imaging (MRI), to define the origin of ventricular ectopic beats (VEBs) in this model of nonischemic cardiomyopathy. The study included 84 patients with surgically repaired TOF, all 11 subjects with VEBs Lown grade > or = 2 on a 24-hour Holter were included. From 37-channel MCG registrations, the underlying current dipole was computed for the VEBs, and for anatomic correlation MRIs were produced. Eight patients had VEBs of altogether 11 morphologies during the MCG recording. The RVOT was the origin of 6 VEBs, while 4 originated from the RV free wall, and 1 VEB could not be localized. Applying this completely noninvasive technique, it was possible to define different origins of RV ectopies in a complex heart model. Thus, VEBs originated from the RVOT, suggesting a relation to surgical scars and from the nonoperated parts of the RV, supporting that ventricular remodeling might be of equal importance for arrhythmogenesis in this model of cardiomyopathy. This technique can assist in answering the important question of whether there is any difference in prognostic information depending on the origin and related mechanism of VEBs in this and other high risk conditions.

The D Allele of the Angiotensin-Converting Enzyme Gene and Reperfusion-Induced Ventricular Arrhythmias in Patients With Acute Myocardial Infarction

The renin-angiotensin system may play a pivotal role in reperfusion ventricular arrhythmias (RVA). The purpose of this study was to investigate the association between angiotensin-converting enzyme (ACE) gene polymorphism and RVA in patients with acute myocardial infarction (AMI) in a case-control study. Patients who had undergone successful coronary intervention for AMI were enrolled (n= 127, male/female: 97/30, mean age, 62.6 years). The incidence of RVA was continuously monitored by ECG at a coronary care unit. The severity of ventricular arrhythmias was evaluated in terms of the Lown's grade and patients with a high risk of ventricular arrhythmias that may cause sudden cardiac death (Lown's grade > or =2) within 5 h of coronary intervention were defined as cases (n=59), and otherwise as controls (n=68). A receiver operating characteristic curve was used to determine the discriminatory ability of continuous variables and to produce dummy variables for use in a logistic regression analysis. Cases had a significantly higher body mass index, higher maximal levels of serum creatine kinase, and a shorter time preceding coronary intervention than controls. The severity of coronary atherosclerosis was similar between the 2 groups. The frequency distribution of ACE genotypes in cases differed from that in controls (II/ID/DD: 22.0%/52.6%/25.4% vs 44.1%/41.4%/14.7%, p<0.05, by the Mantel-Haenzel chi-square test). The ACE-D allele had additive and dominant effects with regard to the occurrence of significant ventricular arrhythmias after adjusting for other risk factors. The ACE-D allele may play a pivotal role in sudden cardiac death in patients with AMI.

Dispersion of ventricular repolarization is determined by the presence of myocardial viability in patients with old myocardial infarction. A dobutamine stress echocardiography study.

The study sought to investigate the relationship of myocardial viability detected by dobutamine stress echocardiography to changes of QT dispersion and to the presence of arrhythmias during dobutamine infusion in patients with old myocardial infarction. We also examined whether patency of the infarct-related artery is associated with the presence of myocardial viability and QT dispersion. QT dispersion and myocardial variability have been associated with the presence of arrhythmias during late post infarction but not during dobutamine stress. Restoration of anterograde coronary flow has beneficial effects on ventricular systolic function and repolarization, suggesting that the extent of viable myocardium may determine ventricular repolarization. Seventy five patients with previous myocardial infarction were studied in a low dose (up to 20 microg(-1) x kg(-1) x min(-1)) dobutamine stress echocardiography study. ECGs were obtained at rest and peak stress for measurement of QT intervals. The presence of ventricular arrhythmias (Lown grade >lb) during stress was noted. A reduction in the total wall motion score of the left ventricle at peak stress confirmed the presence of myocardial viability. Dobutamine infusion increased QT dispersion in all patients (P<0.01). Patients with myocardial viability had a lower resting QT dispersion (P<0.05) and a greater increase in QT dispersion% (P<0.01) than patients without. The combination of a resting QT dispersion <65 ms or an increase in QT dispersion >30% predicted viability with a sensitivity of 67%, a specificity of 96%, and an accuracy of 78%. A patent infarct-related artery, as well as ventricular arrhythmias, were more commonly observed in patients with evidence of viable myocardium (P<0.05). Patients with arrhythmias had a higher QT dispersion than patients without (P<0.05). The combination of a resting QT dispersion +/-65 ms or an increase in QT dispersion >30% predicts the presence of viable myocardium and thus, may represent a simple index for the assessment of viability in everyday clinical practice. Myocardial viability is related to a patent coronary artery and to a high incidence of arrhythmias accompanied by a greater increase in QT dispersion at peak dobutamine infusion.

QT intervals and heart rate variability in hypertensive patients.

Low heart rate variability and increased QT dispersion are risk factors for cardiac mortality in various patient populations. We studied dispersion of QT interval, i.e. an index of inhomogeneity of repolarization, and heart rate variability (HRV) i.e., a measure of cardiac autonomic modulation in 76 essential hypertension cases (45 women, 53.0 +/- 11.1 years, body mass index: 25.1 +/- 1.4 kg/m2) and 70 healthy cases (42 women, 54.0 +/- 10.2 years, body mass index: 25.5 +/- 1.6 kg/m2, p > 0.05). QT-corrected QT intervals and their dispersions were significantly higher in the hypertensive group (p < 0.0001), all showing a direct relation with the level of systolic and diastolic blood pressures, ventricular mass index and high Lown grade ventricular rhythm problems. Time domain measures like standard deviation of RR intervals, standard deviation of the means of all corrected RR intervals calculated at 5 min intervals (p < 0.0001), proportion of adjacent RR intervals differing by > 50 msec (p = 0.005), HRV triangular index (p = 0.007), the square root of the mean squared differences of successive RR intervals (p = 0.011), and the high frequency (HF, 0.16-0.40 Hz, p < 0.0001) part of the frequency domain measure of HRV were all decreased, whereas the low frequency (LF, 0.04-0.15 Hz, p = 0.013) part of the frequency domain measures and LF / HF ratio (p < 0.0001) were increased in hypertensive cases. Time domain and the HF part of frequency domain measures of heart rate variability showed an inverse relation with the increased levels of both systolic and diastolic blood pressures and Lown grading system of ventricular rhythm problems, whereas LF and LF / HF showed direct relations with high levels of systolic and diastolic blood pressures and high Lown grade ventricular rhythm problems. The measures of heart rate variability apart from LF and LF / HF were inversely related with the QT intervals and dispersions, whereas LF / HF was directly related with them. Therefore, we conclude that the levels of both systolic and diastolic blood pressures are related to the generation of ventricular rhythm problems either via increasing left ventricular mass which results in an increase in QT parameter measurements, or by altering heart rate variability measures indicating a disturbance in cardiac autonomic balance in essential hypertension.

Ventricular arrhythmia suppression by magnesium treatment after coronary artery bypass surgery

Ventricular arrhythmias occur frequently shortly after coronary artery bypass grafting (CABG), and their occurrence coincides with the postoperative decline in serum magnesium (Mg) levels. To examine if this decline causes ventricular arrhythmias and if their appearance could be reduced by intravenous Mg administration, 140 consecutive CABG patients were randomized to receive 70 mmol of Mg sulphate (N=69) or placebo (N=71) over two days. Serum Mg concentration fell to 0.77 mmol/l in the control group but rose to 1.09 mmol/l in the Mg group (p < 0.001). On 48 h Holter, the number of ventricular premature complexes (VPC) on the third postoperative day was reduced in the Mg group (4 ± 5 vs 12 ± 21 VPCs/h; p < 0.05) and the incidence of complex ventricular arrhythmias (Lown grade 2–5) was significantly diminished (19% vs 41% of the patients; p < 0.05). In multivariate analysis, high risk ventricular arrhythmias (repetitive polymorphic ventricular complexes, couplets, R-on-T complexes or operative tachycardia) were independently predicted by high number of bypassed vessels (p = 0.01), poor NYHA functional class (p = 0.06), preoperative diuretic use (p = 0.07), and low postoperative Mg levels (p = 0.08). In conclusion, correction of the postoperative decline in serum Mg concentration decreases the occurrence of early VPCs and complex ventricular arrhythmias. Patients with extensive underlying coronary artery disease and prior diuretic therapy appear to benefit greatest from Mg treatment.

QT dispersion in patients with Duchenne-type progressive muscular dystrophy

Background A high degree of QT dispersion is a risk factor for arrhythmic sudden death in patients with myocardial infarction and cardiomyopathy. Duchenne-type progressive muscular dystrophy (DMD) is also associated with the development of ventricular arrhythmias. The purpose of this study was to determine the relationship between QT interval dispersion and ventricular arrhythmias in patients with DMD. Methods Sixty-seven patients with DMD were studied. Standard 12-lead electrocardiograms and 24-hour Holter electrocardiograms were recorded, and the QT interval was determined in every lead of the standard electrocardiogram to determine the QT dispersion. QT dispersion was compared with the frequency of ventricular arrhythmias and the severity of skeletal muscle damage on the basis of the Swinyard and Deaver 8-stage scale. Results QT dispersion in all 67 patients averaged 54 ± 18 ms. The QT dispersion was 49 ± 16 ms in stage 5 patients, 61 ± 22 ms in stage 6 patients, 52 ± 17 ms in stage 7 patients, and 56 ± 17 ms in stage 8 patients. Ventricular arrhythmias of Lown grade III or higher were observed in 3 of 35 patients with QT dispersion <60 ms and in 14 of 32 patients with QT dispersion ≥60 ms. Logistic regression analysis demonstrated that QT dispersion is an independent risk factor for ventricular arrhythmias of grade III or higher in patients with DMD. Conclusions The incidence of ventricular arrhythmias of Lown grade III or higher was greater in patients with QT dispersion ≥60 ms than in patients with QT dispersion >60 ms. QT dispersion therefore is a risk factor for serious ventricular arrhythmias in patients with DMD. (Am Heart J 1999;137:672-7.)

Relation between QT dispersion and ventricular arrhythmias in uncomplicated isolated mitral valve prolapse.

Complications of mitral valve prolapse (MVP), among which serious ventricular arrhythmia and sudden death are of major importance, affect many individuals due to the high incidence of MVP itself in the community despite the actual low incidence of these complications. The present study investigated the incidence and distribution of ventricular arrhythmias according to their severity and relationship with the QT interval and dispersion of repolarization in uncomplicated isolated MVP (IMVP) cases. Fifty-eight uncomplicated IMVP patients, 33 patients with accompanying tricuspid valve prolapse (TVP), to compare its relationship with ventricular arrhythmia, and 60 age- and sex-matched control subjects were enrolled in the study. Individuals with accompanying cardiac or systemic disease, or who were on drug therapy that could potentially affect QT characteristics, were excluded. The incidence of ventricular arrhythmia was 48% in the IMVP group and 64% in the TVP group; the difference was statistically insignificant. In addition, the differences of the QT and Q peak T values were insignificant, whereas QT dispersion (QTd) and Q peak T dispersion (QpeakTd) values were significantly higher in the patient group (60+/-14, 54+/-14 ms, respectively) compared with the control group (42+/-10, 38+/-10 ms, respectively, p<0.001). Complex ventricular arrhythmias (Lown Grade > or =III) in the IMVP group had a significant relationship with QTd and QpeakTd (p<0.001), but not with QT or QpeakT. As a result of the study, it is concluded that TVP accompanying MVP does not increase the incidence of ventricular arrhythmia, that ventricular arrhythmia is related to QT dispersion rather than QT interval in IMVP, that the QT dispersion is a fairly good marker for identifying the high-risk group for serious ventricular arrhythmia and sudden death, and that QpeakT dispersion measurement is an additional indicator that could be an alternative when QT is difficult to determine in conditions such as high heart rate or the presence of U wave.

Effects of cilazapril on ventricular arrhythmia in patients with congestive heart failure

Angiotensin-converting enzyme (ACE) inhibitors reduce mortality and morbidity in patients with congestive heart failure. These effects may be mediated, at least in part, by suppression of lethal ventricular tachycardia (VT). The aims of this study were to examine whether the ACE inhibitor cilazapril reduces ventricular arrhythmia in patients with congestive heart failure and, if cilazapril does reduce ventricular arrhythmia, to determine whether this reduction is associated with suppression of sympathetic nerve activity in these patients. Thirty-two congestive heart failure patients (left ventricular ejection fraction, 35 ± 6%; New York Heart Association class II or III) with VTs (Lown grade IVa or IVb) were randomly assigned to receive either conventional therapy, consisting of diuretics and digitalis (control group), or conventional therapy plus cilazapril (cilazapril group). Twenty-four-hour ambulatory electrocardiographic monitoring was performed at baseline and after 2 months of therapy. Plasma norepinephrine levels and heart rate variability (standard deviation about the mean RR interval) were compared at baseline and after 2 months of treatment. The control group demonstrated no significant change in arrhythmia frequency after 2 months of treatment. In the cilazapril group, however, the number of ventricular couplets and VT runs was significantly decreased. In association with this reduction, plasma norepinephrine levels were decreased, and heart rate variability was increased. These results suggest that cilazapril has antiarrhythmic effects, which may be produced by suppressing high sympathetic activity, in patients with congestive heart failure. It should be noted that the study group was small and that, although ventricular dysrhythmia was reduced with therapy, it remained substantial. Further study is needed to verify these results and to determine the exact causes of the reduction.

Prognostic Factors for Late Ventricular Arrhythmias after Repair of Tetralogy of Fallot

During a median follow-up period of 9 years (ranging from 9 months to 25 years), 24-hour ambulatory electrocardiographic studies were undertaken in 155 patients after repair of tetralogy of Fallot. The patients were divided into two groups. Group A consisted of 76 patients in whom the right ventricular approach was used and group B comprised 79 patients whose repair was through the right atrium. A transannular patch was employed in all patients in group A and in none of the patients in group B. Age at surgery was between 1 and 37 years (median age 4.8 years). During follow-up, 37 patients (48.6%) in group A had significant ventricular arrhythmias (Lown grade 2 or higher) and 13 patients (15.4%) in group B had significant ventricular arrhythmias. A close relationship was observed between age at surgery and Lown grade (R2 = 0.374, p &lt; 0.001) and between follow-up duration and Lown grade (R2 = 0.514, p &lt; 0.001), especially when the two groups were analyzed separately (R2 = 0.502, 0.476, p &lt; 0.001). In contrast, no significant relationship was observed between the ratio of right ventricular to left ventricular pressure and Lown grade or between right ventricular systolic pressure and Lown grade. Discriminant analysis revealed risk factors associated with postoperative ventricular arrhythmias are follow-up duration (partial F = 3.22, p &lt; 0.01), right ventricular to pulmonary artery pressure gradient (partial F = 3.35, p &lt; 0.01), and operative method (partial F = 2.4, p &lt; 0.05). Despite antiarrhythmic therapy, 11 of 22 late postoperative deaths occurred suddenly, presumably from ventricular arrhythmias. In this series of patients, the right atrial and pulmonary artery approach significantly reduced the risk of life-threatening ventricular arrhythmias after repair of tetralogy of Fallot.

Long-term results of surgical treatment for mitral regurgitation with severe left ventricular dysfunction after myocardial infarction caused by Kawasaki disease

Cardiovascular involvement is the major cause of morbidity and mortality among children with Kawasaki disease. 1 Mitral regurgitation (MR) is one of the major determinants of long-term survival after myocardial infarction caused by Kawasaki disease. 2 Only a few reports discuss surgical treatment for this cardiac abnormality, however, and its long-term results have been unknown, 3-4 especially in patients with severe left ventricular (LV) dysfunction. In this report, we describe two cases of Kawasaki disease with refractory congestive heart failure caused by massive MR after myocardial infarction, as well as long-team results of surgical treatment (Table I).

Right Ventricular Dysplasia: The Mayo Clinic Experience

To determine the initial clinical manifestations and echocardiographic features of right ventricular dysplasia as encountered in a major cardiovascular referral center in the United States. We conducted a retrospective study of cases of right ventricular dysplasia diagnosed at the Mayo Clinic between January 1978 and January 1993. In an institutional data-base search, we identified 20 patients with right ventricular dysplasia. Echocardiographic, electrophysiologic, Holter monitoring, cardiac catheterization, and endomyocardial biopsy results were analyzed. The mean duration of follow-up was 7 years. In the 12 female and 8 male patients (mean age, 30 years; range, 3 to 60), the initial manifestations of right ventricular dysplasia included ventricular arrhythmia (45%), congestive heart failure (25%), heart murmur (10%), asymptomatic (10%), complete heart block (5%), and sudden death (5%). First-order relatives were affected in 30% of the patients. Ventricular tachycardia with morphologic features of left bundle branch block was inducible in seven of nine patients. On Holter monitoring, all but 2 of 15 patients studied had frequent ventricular ectopic activity (Lown grade 2 or more). Characteristic fatty infiltration of the myocardium was present in 7 of 13 right ventricular biopsy specimens. Inordinate right ventricular enlargement was present in 60% of the patients at first echocardiographic assessment and in two other patients on follow-up assessment. Variable left ventricular involvement was noted in 50% of the cases. During the follow-up period, four patients died: two died suddenly, one died of congestive heart failure, and one died of respiratory failure after a coronary artery bypass operation. Of the 16 living patients, 8 are doing well, 3 have an implanted cardiac defibrillator, 3 are receiving antiarrhythmic agents, and 2 have undergone cardiac transplantation because of progressive biventricular failure. Patients with right ventricular dysplasia have varied initial manifestations and a high frequency of serious cardiovascular symptoms and complications.

Magnesium sulfate prophylaxis after cardiac operations

One hundred patients undergoing elective cardiac operations were randomized into placebo (n = 54) and magnesium (n = 46) groups. The magnesium group received six doses of 2.4 g (19.2 mEq) magnesium sulfate intravenously in the first 24 hours after the cardiac operation. The magnesium group had higher serum magnesium concentrations postoperatively (1.09 +/- 0.20 versus 0.75 +/- 0.13 mmol/L; p < 0.0001), postoperative day 1 (1.49 +/- 0.34 versus 0.70 +/- 0.12 mmol/L; p < 0.0001) and postoperative day 2 (0.96 +/- 0.19 versus 0.76 +/- 0.07 mmol/L; p < 0.0001). Patients in the magnesium group had a lower incidence of ventricular tachyarrythmias (VTs) (17.3% versus 51.9%; p = 0.0006), less need for treatment (6.5% versus 20.3%; p < 0.0001), fewer VT episodes/patient (0.3 +/- 0.8 versus 1.39 +/- 1.9; p < 0.0001), and a reduction in the severity of VTs as measured by the modified Lown grade (p = 0.0002). No differences were demonstrated with respect to supraventricular tachyarrythmias. The magnesium group had reduced absolute creatine kinase-MB levels (5.3 +/- 4.2 versus 28.4 +/- 28 IU/L; p = 0.001) as well as creatine kinase-MB fraction (0.01 +/- 0.02 versus 0.05 +/- 0.04; p = 0.001) on postoperative day 1. Serum magnesium concentrations were lower during VTs than during periods of sinus rhythm (0.75 +/- 0.75 versus 1.02 +/- 0.35 mmol/L; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Late Sudden Deaths after Repair of Tetralogy of Fallot:Electrocardiographic Findings Associated with Survival

Of 141 hospital survivors after intracardiac repair of tetralogy of Fallot, eight died suddenly 6-23 years later. Compared with the other 133 patients, these eight were older at operation, with higher post-repair systolic right ventricular pressure and more often complete atrioventricular block; ventricular arrhythmia was diagnosed before death in three cases. In follow-up totalling 2255 patient years, the linearized rate of sudden death was 0.35%/year. The instantaneous risk of sudden death showed continuous increase with the length of follow-up. Of 80 survivors electrocardiographically evaluated 13-26 (median 20) years postoperatively, none had complete block, but 79 had complete right bundle branch block, including seven with left anterior hemiblock. Ventricular extrasystoles were recorded in 1% at rest, in 34% during exercise and in 83% during 24-hour ambulatory monitoring, with Lown Grade > or = II in 27%. Old age and possibly presence of fibrosis and/or fibroelastosis in right ventricular outflow Lown Grade. A patient with Lown grade III died suddenly 2 years after our follow-up. Old age at repair thus was associated with increased risk of late sudden death and with frequent ventricular arrhythmia in long-term survivors.