Assessment of Nocturnal Blood Pressure: Importance of Determining the Time in Bed-A Pilot Study.

Objectives: Nocturnal blood pressure (BP) monitoring is essential for evaluating cardiovascular risk and guiding treatment decisions. However, the standardized narrow-fixed nighttime period between 10 p.m. and 6 a.m. may not accurately reflect individual sleep schedules. This pilot study aimed to investigate the comparability between the standardized nighttime period and actual time in bed (TIB) regarding BP assessment. Further, our goal was to evaluate the clinical relevance of the observed BP differences. Methods: A total of 30 participants underwent 24 h ambulatory blood pressure monitoring (ABPM). Patient-specific TIB was precisely assessed through an accelerometer and a position sensor from the SOMNOtouch NIBP™ (SOMNOmedics GmbH, Randersacker, Germany). We analysed the effect of considering individual TIB as nighttime instead of the conventional narrow-fixed interval on the resulting nocturnal BP levels and dipping patterns. Results: We observed differences in both systolic and diastolic BP between the standardized nighttime period and the TIB. Furthermore, a notable percentage of patients (27%) changed their dipping pattern classification as a function of the nighttime definition adopted. We found strong correlations between the start (r = 0.75, p < 0.01), as well as the duration (r = -0.42, p = 0.02) of TIB and the changes in dipping pattern classification. Conclusions: Definition of nocturnal period based on the individual TIB leads to clinically relevant changes of nocturnal BP and dipping pattern classifications. TIB is easily detected using a body position sensor and accelerometer. This approach may thus improve the accuracy of cardiovascular risk evaluation and enhance treatment strategies.

Impact of oscillometric measurement artefacts in ambulatory blood pressure monitoring on estimates of average blood pressure and of its variability: a pilot study.

OBJECTIVE: Ambulatory blood pressure monitoring (ABPM) plays an important role in the diagnosis of hypertension. However, methodological factors and the measurement conditions affect the results and may lead to incorrect classification of the patient. We performed a pilot study to evaluate the impact of oscillometric measurement artefacts on ABPM-derived variables. METHODS: Four classes of artefacts have been detected: motor activity artefacts, cuff errors, cardiovascular arousals, and arrhythmias. The data consisted of uncorrected measurements (all data), corrected measurements (all artefact free data), and artefact affected data. RESULTS: A total of 30 individuals (9 female/21 male), aged between 36 and 86 years, mean: 65.5 (standard deviation: 9.5) were included in the study. The average blood pressure (BP) was higher in artefacts-affected measurements compared the artefact-free measurements both for systolic (4.6 mmHg) and diastolic (1.3 mmHg) measurements. Further, artefact-affected systolic BP (SBP) was 6.4 mmHg higher than artefact-free measurements during daytime. Nocturnal measurements showed no artefact-depended differences. Individual comparisons yielded that 23% of the participants crossed the threshold for BP classification for either 24-h, daytime or nocturnal hypertension when comparing uncorrected and artefact-free measurements. Dipping classification changed within 24% of participants. BP variability was 21 and 12% higher for SPB and DBP, respectively, during daytime. These differences were even higher (27% for SBP and 21% for DPB) during night-time. CONCLUSION: The study reveals that measurement artefacts are frequently present during cuff-based ABPM and do relevantly affect measurement outcome. Exclusion of measurement artefacts is a promising approach to improving cuff-based ABPM accuracy.

Multislice spiral computed tomographic angiography of coronary arteries in patients with suspected coronary artery disease: an effective filter before catheter angiography?

BACKGROUND: Despite impressive image quality, it is unclear if noninvasive coronary angiography with multislice spiral computed tomography (CT) is powerful enough to act as a filter before invasive angiography (INV-A) in symptomatic patients. METHODS AND RESULTS: We therefore studied 133 consecutive symptomatic patients with suspected coronary artery disease (CAD) and an indication for INV-A (chest pain and signs of ischemia in conventional stress tests). Patients with known CAD, acute coronary syndrome, or a calcium volume score >1000 were excluded. In all patients, both INV-A and multislice CT angiography (MSCT-A) (Philips MX 8000 multislice spiral CT, scan time 250 milliseconds, slice thickness 1.3 mm, 120 mL of contrast agent, 4 mL/s, retrospective gating) were directly compared by 2 independent investigators using the American Heart Association 15-segment model. Altogether, we studied 1596 segments, 74% had diagnostic image quality. Multislice CT angiography correctly identified 68 significant stenoses of the 75 stenoses seen with INV-A (sensitivity 91%). In 945 of 1185 diagnostic segments, stenosis could correctly be ruled out with MSCT-A. There were 3 times more stenoses seen with MSCT-A compared with INV-A (positive predictive value 29%) mainly because of misclassification of nonobstructive plaques as stenosis. The per-patient analysis allowed to exclude significant CAD in 42 (32%) of 133 patients. In only 6 of 53 patients, MSCT-A failed to detect significant stenosis, 4 of those were in small segments not requiring intervention. Calcium scoring alone was less suited as a filter before angiography: 25 patients (18% of study group) had a calcium score = 0, and 8 of these patients turned out to have significant stenoses. CONCLUSION: Multislice CT angiography, but not calcium scoring alone, offers promise to reduce the number of INV-A in symptomatic patients with suspected CAD by up to one third with minimal risk for the patient.

T wave spectral variance for noninvasive identification of patients with idiopathic dilated cardiomyopathy prone to ventricular fibrillation even in the presence of bundle branch block or atrial fibrillation.

Conventional methods using Holter ECG recordings for noninvasive risk stratification are limited in patients with idiopathic dilated cardiomyopathy (IDC) prone to ventricular fibrillation (VF) having atrial fibrillation (AF) or bundle branch block (BBB). We therefore investigated, whether spectral assessment of beat-to-beat alternations of repolarization is associated with VF in these patients. Twenty-four-hour Holter ECG recordings in 462 patients with IDC were used. The VF group comprised of 64 consecutive patients who survived cardiac arrest, the no VF group consisted of 398 consecutive patients without a history of malignant ventricular arrhythmia. One hundred patients with ischemic cardiomyopathy (ICM) served as a control group. In each patient, 1,024 consecutive T waves were aligned using cross correlation methods. Two-dimensional Fourier transform (2D FFT) used the data matrix of 1,024 consecutive 200-ms segments centered to the T wave peak. Power spectra of the 2D FFT revealed the frequency content of the T wave in the first dimension and the periodicity of this frequency content in the second dimension. The ratio between periodic frequency contents and the sum of nonperiodic and periodic frequency contents between 0.5 and 50 Hz is equal to the T wave spectral variance (TWSV) index. Thus, TWSV index = 0 would mean that all 1,024 T waves are identical and TWSV index = 1 would mean that the 1,024 T waves are totally variable. The TWSV index was significantly higher in the VF group (0.93 +/- 0.14) than in the no VF group (0.53 +/- 0.13, P < 0.01). The best cutoff between the VF and the no VF group was achieved by using a TWSV index of 0.75 (sensitivity = 89%, specificity = 78%). No significant differences were observed between patients with and without AF or with and without BBB, and between patients with IDC and ICM. Even in the presence of BBB or AF spectral assessment of T wave alternations by TWSV index using 2D FFT in Holter ECG recordings, allows the identification of patients with IDC at risk for VF.

Relation of coronary vasoreactivity and coronary calcification in asymptomatic subjects with a family history of premature coronary artery disease.

Electron-beam computed tomography (EBCT) allows non-invasive imaging of coronary calcification and has been promoted as a screening tool for coronary artery disease (CAD) in asymptomatic high-risk subjects. This study assessed the relation of coronary calcifications to alterations in coronary vascular reactivity by means of positron emission tomography (PET) in asymptomatic subjects with a familial history of premature CAD. Twenty-one subjects (mean age 51+/-10 years) underwent EBCT imaging for coronary calcifications expressed as the coronary calcium score (CCS according to Agatston) and rest/adenosine-stress nitrogen-13 ammonia PET with quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR). The mean CCS was 237+/-256 (median 146, range 0-915). The CCS was <100 in eight subjects and >100 units in 13. As defined by age-related thresholds, 15 subjects had an increased CCS (>75th percentile). Overall mean resting and stress MBF and CFR were 71+/-16 ml 100 g(-1) min(-1), 218+/-54 ml 100 g(-1) min(-1) and 3.20+/-0.77, respectively. Three subjects with CCS ranging from 114 to 451 units had an abnormal CFR (<2.5). There was no relation between CCS and resting or stress MBF or CFR ( r=0.17, 0.18 and 0.10, respectively). In asymptomatic subjects a pathological CCS was five times more prevalent than an abnormal CFR. The absence of any close relationship between CCS and CFR reflects the fact that quantitative myocardial perfusion imaging with PET characterises the dynamic process of vascular reactivity while EBCT is a measure of more stable calcified lesions in the arterial wall whose presence is closely related to age.

[Invasive versus noninvasive (MSCT) coronary angiography. Importance of cardiac diagnostics with multislice computed tomography]. / Invasive versus nichtinvasive (MSCT) Koronarangiographie. Stellenwert der kardialen Diagnostik mittels Multislice-Computertomographie.

Cardiac imaging with fast computed tomography (CT) is a quickly evolving field starting to become established in the cardiac routine work-up. The exclusion of coronary calcification is the most accurate noninvasive method to exclude significant coronary stenosis whereas the detection of calcification identifies coronary arteriosclerosis. The total calcium load correlates with the risk of coronary stenosis, but there is not a 1 : 1 relationship. CT angiography with contrast enhancement offers promises to increase diagnostic accuracy. 4-slice scanners acquire data with a slide width down to 1 mm. The spatial resolution of invasive coronary angiography cannot be achieved yet. Severe coronary stenosis may be excluded with 90% specificity if image quality is not impaired by artifacts, severe calcification, arrhythmia, and a heart rate > 70 beats/min. With present technology, about 26% of segments may not be adequately assessed. Despite these limitations CT angiography is a useful tool to reduce the number of invasive diagnostic angiography. In patients with known coronary artery disease (CAD), progression as well as stent occlusion can be assessed. Instent stenosis can only be diagnosed indirectly. The patency of arterial and venous grafts can be assessed very well including also the bypass insertion site. Actual studies on the significance of noncalcified plaques are in progress.A CT angiography should take place in order to avoid further exposure to radiation. Therefore, patients with typical angina or significant signs of coronary ischemia have to be investigated by invasive methods and do not profit from a CT scan. Preparation and implementation of this method should only be applied in cooperation with radiologists and cardiologists in an experienced center.

Influence of lipid-lowering therapy on the progression of coronary artery calcification: a prospective evaluation.

BACKGROUND: Coronary calcification measured by fast computed tomography techniques is a surrogate marker of coronary atherosclerotic plaque burden. In a cohort study, we prospectively investigated whether lipid-lowering therapy with a cholesterol synthesis enzyme inhibitor reduces the progression of coronary calcification. METHODS AND RESULTS: In 66 patients with coronary calcifications in electron beam tomography (EBT), LDL cholesterol >130 mg/dL, and no lipid-lowering treatment, the EBT scan was repeated after a mean interval of 14 months and treatment with cerivastatin was initiated (0.3 mg/d). After 12 months of treatment, a third EBT scan was performed. Coronary calcifications were quantified using a volumetric score. Cerivastatin therapy lowered the mean LDL cholesterol level from 164+/-30 to 107+/-21 mg/dL. The median calcified volume was 155 mm3 (range, 15 to 1849) at baseline, 201 mm3 (19 to 2486) after 14 months without treatment, and 203 mm3 (15 to 2569) after 12 months of cerivastatin treatment. The median annualized absolute increase in coronary calcium was 25 mm3 during the untreated versus 11 mm3 during the treatment period (P=0.01). The median annual relative increase in coronary calcium was 25% during the untreated versus 8.8% during the treatment period (P<0.0001). In 32 patients with an LDL cholesterol level <100 mg/dL under treatment, the median relative change was 27% during the untreated versus -3.4% during the treatment period (P=0.0001). CONCLUSIONS: Treatment with the cholesterol synthesis enzyme inhibitor cerivastatin significantly reduces coronary calcium progression in patients with LDL cholesterol >130 mg/dL.

Computed tomography-fluoroscopy guided drainage of pericardial effusions: experience in 11 cases.

RATIONALE AND OBJECTIVES: The purpose of the study was to evaluate feasibility and safety of CT-fluoroscopy in the drainage of pericardial effusion in cases not accessible by sonography. METHODS: Eleven drainages were performed in Seldinger-technique under CT-fluoroscopy on eight patients suffering from pericardial effusion. The inclusion criterion was a sonographically proved pericardial effusion not drainable under sonographic surveillance. In seven procedures the catheter was positioned using a medial, in four procedures a lateral approach from the apex was chosen. RESULTS: All catheters could be placed successfully (11/11) in the pericardial effusion and allowed for draining of the effusion in 10 of 11 cases. One epicardial laceration necessitated a surgical approach. The elapsed total procedure time for the drainage was on average 18:23 +/- 8:58 minutes. CONCLUSIONS: Visual surveillance by CT-fluoroscopy is a feasible method in the drainage of pericardial effusions even in cases not accessible by ultrasound.

Postinfarction risk assessment for sudden cardiac death using late potential analysis of the digital Holter electrocardiogram.

INTRODUCTION: Noninvasive postinfarction risk assessment for sudden cardiac death is limited. Standard analysis of the signal-averaged QRS complex can identify patients at risk for monomorphic ventricular tachycardia, but its value for discriminating patients at risk for sudden death is low. METHODS AND RESULTS: The aim of this study was to prospectively investigate repeated late potential analysis of digital Holter ECG and compare it with standard analysis of the signal-averaged QRS complex within a short ECG period and with common clinical risk factors for sudden cardiac death in 756 consecutive patients after acute myocardial infarction. Digital Holter ECG were subdivided into 5-minute segments, and late potential analysis was performed on each 5-minute segment. During follow-up of 32 +/- 15 months, 35 patients died of sudden cardiac death and 50 patients died of nonsudden cardiac death. Sudden cardiac death was associated with ejection fraction < 40%, nonsustained ventricular tachycardia, creatine kinase > 1,000 IU/L, and late potentials in > 75% of analyzed Holter ECGs (abnormal LP75), but not with late potentials determined by only a short ECG period. According to multivariate analysis, the best independent significant predictor of sudden cardiac death was abnormal LP75 (P = 0.002, sensitivity 29%, specificity 96%, positive predictive value 40%, negative predictive value 97%). Nonsudden cardiac death was associated with ejection fraction < 40% (P = 0.001). CONCLUSIONS: Late potential analysis of digital Holter ECG is a powerful tool that can be used to determine postinfarction patients at risk for sudden cardiac death and is optimized when combined with determination of ejection fraction.