Present Substudy Research Articles

795 Electrocardiogram after successful primary angioplasty: does it still matter?

@Background: elevated heart rate preceding the onset of ventricular tachycardia (VT), suggesting an increased sympathetic tone, has been reported to reduce the success of antitachycardia pacing (ATP) therapy in patients with implantable cardioverter defibrillators (ICD). Based on the data of the Variability Learned from Implantable Defibrillators (VALID) study, we aimed to assess the impact of autonomic tone on ATP effectiveness in ICD recipiens. Methods and results: a total of 36 out of 226 VALID-study patients implanted with a Biotronik ICD(Phylax XM or Microphylax+) were considred for the present sub-study. These devices have extended memory capacities (18000 RR intervals) that offerred the ability of analyzing heart rate variability (HRV) before the begening of the arrythmia. All the patients had ischemic heart disease. ATP programming was standardized within VT zones. During follow-up, 106 VTs recurred in these patients, 95 were terminated by ATP (ATP+) and ATP was unseccessful in 11 VTs (ATP-). HRV parameters were analyzed during the 30 minutes preceding VT onset. Two time- and three frequency-domain indices were derived semi-automatically: the standard deviation of normal RR intervals (SDNN), the proportion of adjacent normal RR intervals differing by > 50 ms (pNN50), the low-frequency (LF) power reflecting sympathetic tone, the high-frequency (HF) power reflecting parasympathetic activity, and the LF/HF power ratio. The following table summarizes the main

Ambulatory Blood Pressure Monitoring (ABPM) in the VALUE Trial

The VALUE Trial evaluated the cardiac outcomes in a large group of high-risk, elderly hypertensive patients randomized to either a valsartan-based (VAL) or amlodipine-based (AML) antihypertensive regimen. During the entire 4.2 year study period office blood pressure (BP) at trough remained significantly lower in the AML group. The present substudy aimed to demonstrate similar BP reductions in the two groups over 24 hours. ABPM was performed after one year of randomized treatment in 47 centres in Italy, USA and Denmark. Measurements were carried out with Spacelab 90202 or 90207 monitors hooked up before the morning dose of medicine. 659 patients were available for ITT analysis. The two treatment groups were generally well balanced concerning BP and other demographic data at baseline. However, ECG-verified left ventricular hypertrophy was more prevalent in patients randomized to valsartan (15.7 vs. 8.0%, p=0.002). The mean doses of VAL and AML employed were 131±36 and 8±2 mg respectively. 34% were on monotherapy with VAL and 43% had AML alone. The average 24-SBP difference at one year was 1.1 mmHg in favour of AML (131.8 vs. 132.9 mmHg, ns), and the DBP difference was 0.4 mmHg in favour of VAL (75.0 vs. 75.4 mmHg, ns). Similar trends were seen both during day- and nighttime with a tendency for AML to be more effective during the late night hours. The number of combined cardiovascular endpoints (cardiac morbidity, mortality and stroke) were not different in the two groups, but correlated significantly with the level of 24-h SBP and DBP. Thus for the ITT-population a 10 mmHg increase in 24-h SBP translated into a 37% increase in combined risk (p<0001). The difference between office DBP at trough and mean 24-h DBP tended to be less pronounced in the AML group than in the VAL treated patients (4.2 vs.5.4 mmHg). A tendency to more advanced BP-dipping during nighttime was observed in the VAL-treated patients. After one year 24-h BP was similarly reduced by the valsartan and the amlodipine based regimen. Endpoints were strongly related to 24-h BP levels. Night BP during the last hours of the dosing interval tended to be lower on amlodipine.

Usefulness of ventricular repolarization dynamicity in predicting arrhythmic deaths in patients with ischemic cardiomyopathy (from the European Myocardial Infarct Amiodarone Trial)

The European Myocardial Infarct Amiodarone Trial (EMIAT) investigated the effects of amiodarone versus placebo in patients after myocardial infarction who had left ventricular ejection fraction </=40% and were </=75 years of age. The present substudy examined whether ventricular repolarization (VR) dynamicity could differentiate patients who died from cardiac death from their matched survivors in this EMIAT population. In addition, we assessed whether VR dynamicity could differentiate patients who died from arrhythmic cardiac death (ACD) and from non-ACD. VR dynamicity (determined from Holter's recordings at baseline) was compared before antiarrhythmic therapy in 118 patients who had cardiac death and 118 matched survivors according to age, gender, left ventricular ejection fraction, and subsequent administration or nonadministration of amiodarone. VR dynamicity was compared within the cardiac death group between the 59 patients who died from ACD and the 59 who died from non-ACD. VR dynamicity was expressed as the slope of the linear regression between QTo (measured automatically) and stable RR intervals. Patients who died were found to have a significant steeper rate dependence of QTo intervals during the 3 periods than their matched survivors. In multivariate analysis, the QTo/RR nocturnal interval appeared to be the best independent predictor of cardiac death. In addition, patients who died from ACD were found to have a significant steeper rate dependence of QTo intervals during the morning period than those who died from non-ACD. In the multivariate analysis, the QTo/RR morning interval remained the best independent predictor of ACD. Thus, in the EMIAT trial, evaluation of QT dynamicity is a strong predictor of cardiac death. In addition, QT dynamicity could predict the occurrence of ACD in cases of cardiac death.

Evaluation of the AccuTnI cardiac troponin I assay for risk assessment in acute coronary syndromes.

Effective risk assessment guides appropriate triage and therapy for patients with suspected unstable angina or non-ST-elevation myocardial infarction (MI) (1)(2). Cardiac biomarkers play a valuable role in risk stratification in non-ST-elevation acute coronary syndromes (NSTE ACS). In particular, the cardiac troponins have been identified as the preferred biomarkers for this purpose (1). Clinical application of cardiac troponin I (cTnI) has been complicated by a lack of standardization across the multiple commercially available assays, which has produced substantial variation in the reported clinical decision limits. As such, clinical appraisal of the prognostic performance of each cTnI assay is important to providing an evidence-based guide to its use for risk assessment. The most recent generation cTnI assay from Beckman Coulter (AccuTnITM) uses antibodies directed at a stable region (amino acids 30–110) of the NH2 terminus of cTnI and delivers very good analytic performance (3)(4). We evaluated this assay for the assessment of the short-term risk of death and recurrent ischemic events among patients with suspected NSTE ACS enrolled in the Orbofiban in Patients with Unstable Coronary Syndromes (OPUS)-Thrombolysis in Myocardial Infarction (TIMI) 16 trial. OPUS-TIMI 16 was a multicenter, randomized, parallel-group trial comparing an oral glycoprotein IIb/IIIa inhbitor with placebo for patients with ACS. The design and results of OPUS-TIMI 16 have been reported (5). The protocol was approved by the Institutional Review Board of each participating hospital, and all patients signed written informed consent. Patients were included if they presented within 72 h of symptom onset and had at least one of the following: dynamic electrocardiographic changes; increased cardiac markers; history of coronary artery disease; or age ≥65 with diabetes or vascular disease. Patients were randomized to placebo or one of two orbofiban doses. The present substudy was conducted in all patients with NSTE ACS …

Analysis of Recent Papers in Hypertension

Analysis of Recent Papers in Hypertension

Comparison of Home and Office Blood Pressure in Treated Hypertensives in the Nordic Diltiazem (NORDIL) Study

The aim of the Nordic Diltiazem (NORDIL) Study was to compare cardiovascular morbidity and mortality in calcium-antagonist-based treatment with diltiazem and conventional diuretic/beta-blockerbased treatment in essential hypertension. The objective of the present sub-study was to compare self-measured home blood pressure with office blood pressure at a time-point in the study when the patients' blood pressures had been treated to the level that the investigators conceived to be the blood pressure target. The NORDIL study was prospective, randomized, open and endpoint-blinded. It enrolled 10881 patients aged 50-74 years at health centers in Norway and Sweden who had diastolic blood pressure (BP) of 100 mmHg or more. The present sub-study group ( n = 87) was small but fairly representative for the entire study population regarding baseline characteristics. Both systolic (4.0 mmHg, p = 0.01) and diastolic blood pressures (3.1 mmHg, p < 0.001) were significantly lower at home than in the office. Pearson correlation coefficients between the respective office and home readings were statistically highly significant ( p >< 0.001), but of moderate strength ranging from r = 0.41 for heart rate to r = 0.46 and r = 0.58 for diastolic and systolic blood pressures, respectively. Altman plots also gave statistical support to some inconsistency between the two methods of measurements. Pearson correlation coefficients between afternoon and morning measurements showed strong relationships with r -values >0.9 for both blood pressures and heart rate. The Altman plots also suggested excellent consistency between afternoon and morning measurements. Thus, motivated and trained hypertensive patients can perform home recordings of blood pressure and heart rate with precision; however, there are differences between recordings at home and in the investigators' offices that suggest some degree of "white coat effect" in these treated hypertensives.

Collaborative WHO xylitol field studies in Hungary VI. Changes in the carbohydrate to protein ratio of dental plaque

The carbohydrate to protein ratio of dental plaque was analyzed in a field study assessing the effect of partial substitution of dietary sucrose by xylitol (X group) in comparison with systemic fluoride (F group) and restorative treatment solely (C group). The biochemical analysis was supplemented by quantitative assessment of plaque through the visible plaque index (VPI). The present substudy was carried out cross-sectionally and longitudinally (n = 83) in initially 6- to 11-year-old children. Missing base-line values for the carbohydrate to protein ratio were partly compensated for through reexamination of the carbohydrate to protein ratio 15 months after termination of the trial. The latter series served as reference to indicate the base-line situation. A lower carbohydrate to protein ratio was measured in the X and F groups than in the C group. Improvement of the VPI values was obtained only in the X group. Our results suggest the potential value of parallel quantitative and qualitative assessment of plaque.