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A pharmacological analysis of the possible role of vasoactive mediators in compensatory coronary blood flow.

Exp Clin Cardol. 2008;13(1):7-14

Authors: Parratt JR, Végh A

BACKGROUND: Coronary blood flow in one (circumflex) branch of the left coronary artery increases when an adjacent (left anterior descending [LAD]) branch is occluded for periods of between 1 min and 25 min. OBJECTIVE: To examine the possible role of the myocardial release of vasoactive substances in such 'compensatory blood flow' increase by the classical pharmacological approach of inhibition of synthesis, or blockade at the receptor level, of the most likely mediators. METHODS: In pentobarbitone anesthetized, thoracotomized dogs, coronary blood flow changes were measured in both the LAD (using a Doppler flow probe) and the left circumflex (using an electromagnetic flow probe) coronary arteries. RESULTS: The flow increase during 5 min occlusions of the LAD coronary artery was unaffected by blockade of adenosine receptors by 8-sulfophenyltheophylline, inhibition of prostanoid synthesis by sodium meclofenamate or celecoxib, blockade of bradykinin B(1) receptors by icatibant, inhibition of nitric oxide synthesis by N(omega)-nitro-L-arginine methyl ester (L-NAME), inhibition of guanylyl cyclase by methylene blue, or opening (using diazoxide) and closing (using glibenclamide or 5-hydroxydecanote) of ATP-dependent K(+) channels. Neither dual blockade with L-NAME and glibenclamide, or meclofenamate and 5-hydroxydecanote, nor triple blockade with L-NAME, glibenclamide and 8-sulfophenyltheophylline, modified the blood flow response. However, it was greatly reduced (60%) by metoprolol. CONCLUSIONS: These results suggest that coronary vascular beta(1)-adrenoceptors are involved in 'compensatory' vasodilation, whereas bradykinin, nitric oxide, prostanoids and ATP-dependent K(+) channels are seemingly not required for this flow increase.

PMID: 18650966 [PubMed - in process]

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QRS voltages are transiently increased at the superacute stage of experimental myocarditis.

Exp Clin Cardol. 2008;13(1):15-8

Authors: Kishimoto C, Ohmae M, Tomioka N

BACKGROUND: There are few reports on the precise electrocardiographic characteristics of acute myocarditis. The present study was focused on QRS voltage changes at the superacute stage of murine myocarditis. METHODS: Serial electrocardiograms were recorded during the acute stage of viral myocarditis in mice, and then the cardiac pathology was examined. After recording baseline electrocardiograms, mice (n=235) were inoculated intraperitoneally with the encephalomyocarditis virus, resulting in severe myocarditis. Electrocardiograms were serially recorded until nine days after virus inoculation (superacute stage, days 3 to 6; acute stage, days 7 to 9). Changes in heart rate and QRS voltages were analyzed. RESULTS: Serial electrocardiograms revealed that heart rates began to increase after day 3, and that the sum of the QRS voltages increased on day 3 and then decreased on days 7 to 9. Trivial mononuclear cell infiltrations and interstitial edema were most frequently found in mice at the superacute stage. CONCLUSIONS: Transient increase of the QRS voltages at the superacute stage of myocarditis was demonstrated, which may be due to an increase in ventricular mass caused by interstitial edema at this stage.

PMID: 18650967 [PubMed - in process]

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Reaching target lipid levels and the natural history of diabetes mellitus in patients surviving acute coronary syndrome: A retrospective cohort study from a tertiary care outpatient clinic.

Exp Clin Cardol. 2008;13(1):25-8

Authors: Málek F, Dvorák IJ, Strieborná H, Kocvarová V, Spacek R

BACKGROUND: Despite the known benefits of lipid-lowering therapy, only a minority of high-risk subjects are reaching defined lipid targets. Impaired fasting glucose and diabetes mellitus are associated with poor short- and long-term outcomes in subjects with acute coronary syndromes (ACSs). OBJECTIVES: To determine the proportion of patients surviving five years of ACS who met recommended lipid targets, and to determine the proportion of subjects with impaired fasting glucose and diabetes mellitus. METHODS: A retrospective cohort study of 101 patients surviving at least five years of ACS and having at least three visits to a tertiary care outpatient clinic was conducted. Fasting lipid and glucose profiles were extracted from records of each patient's visit. RESULTS: The mean change in lipid values between visits 1 and 3 was significant. Only 34% of the patients met the target level for low-density lipoprotein cholesterol, and 63% met the target ratio for total cholesterol to high-density lipoprotein cholesterol at visit 3. The mean glucose level increased, and the proportion of subjects with diabetes mellitus increased (P<0.0001 between visits 1 and 3). The predictors for diabetes mellitus at visit 3 were a high lipid level and a high fasting glucose level at visit 1 (P<0.05 for both). CONCLUSIONS: Despite a significant improvement in mean lipid levels in the patients surviving at least five years of ACS, the majority of high-risk patients are not meeting defined lipid levels for low-density lipoprotein cholesterol. The mean fasting glucose level and the proportion of subjects with diabetes mellitus significantly increased during follow-up. Patients with higher glucose and lipid levels at baseline were found to be associated with a higher risk for new diabetes mellitus.

PMID: 18650969 [PubMed - in process]

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Analysis of atrial fibrillatory activity from high-resolution surface electrocardiograms: Evaluation and application of a new system.

Exp Clin Cardol. 2008;13(1):29-35

Authors: Grubitzsch H, Modersohn D, Leuthold T, Konertz W

BACKGROUND: Algorithms of signal processing allow the estimation of atrial fibrillation (AF) activity from surface electrocardiograms (ECGs). OBJECTIVE: To evaluate a new commercially available ECG system for AF analysis from surface potentials. METHODS: Patients (n=52, mean [+/- SD] age of 68+/-9.6 years) with persistent AF (mean duration 44+/-52.2 months), referred for cardiac surgery, underwent high-gain, high-resolution ECG preoperatively. After QRST cancellation, the frequency content of AF was identified by fast Fourier transformation. Epicardial potentials were registered at the right atrial appendage, the right atrium (RA), the left atrium (LA) and the left atrial appendage intraoperatively (nine patients). RESULTS: Mean (+/- SD) fibrillatory rate (MFR) in lead V(1) (393+/-40.4 fibrillations/min [fpm]) correlated significantly with V(2) (391+/-43.3 fpm, r=0.976; P<0.05) and II (379+/-41.1 fpm, r=0.878; P<0.05), and was stable within an interval of 13.6+/-3.8 min (27 patients). In the right atrial appendage, RA, LA and left atrial appendage, the relative difference in MFR was small (5.6%, 6.6%, 6.8% and 5.7%, respectively, compared with V(1)). The mean peak frequency component at 75% of the maximum power was significantly smaller in the LA than in the RA (13+/-4.2 fpm versus 22+/-7.2 fpm, respectively; P<0.01), and in patients with high (more than 390 fpm) compared with low (390 fpm or fewer) fibrillatory activity (14+/-7.6 fpm versus 22+/-13.3 fpm, respectively; P<0.05). There was a nonsignificant trend to higher fibrillatory activity with longer AF duration. Other characteristics (age, sex, LA size, ejection fraction, type of heart disease and medication) were not associated with the MFR. CONCLUSIONS: Using the CardioLink system, AF analysis from surface ECG is reliable and equivalent to epicardial measurements. By noninvasive assessment of individual electrical remodelling, this system certainly supports clinical AF research.

PMID: 18650970 [PubMed - in process]

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Stenting of unprotected left main stem stenosis: Results from a German single-centre registry.

Exp Clin Cardol. 2008;13(1):37-41

Authors: Hertting K, Härle T, Krause K, Reimers J, Boczor S, Kuck KH

OBJECTIVE: To elucidate the influence of drug-eluting stents (DESs) on interventional therapy of de novo unprotected left main stem (LMS) lesions in a hospital with on-site cardiac surgery. METHODS AND RESULTS: A retrospective study of all patients with unprotected LMS angioplasty from 1999 to 2005 was conducted with regard to clinical and procedural data, and follow-up data. Fifty-four patients with unprotected LMS stenosis were treated inter-ventionally. Of these patients, 16 were treated with DESs. Seven patients presented with cardiogenic shock. During their hospital stay, four patients died (all treated with bare metal stents [BMSs], three initially presenting with cardiogenic shock). Follow-up data for 53 patients (98%) were obtained. Median follow-up time was 24 months (25th percentile, 12 months; 75th percentile, 35 months). Survival after nine months was 87% (81% from the BMS-treated group, and 100% from the DES-treated group). Control angiography had been performed in 36 patients (67%). Patients with unprotected LMS with an angiographic follow-up had a higher nine-month survival rate than patients without (36 of 36 patients [100%] versus 10 of 17 patients [59%], respectively; P<0.0001). Target lesion revascularization rate was 19% in both the BMS and the DES groups. Methods of revascularization did not vary significantly between the groups. CONCLUSIONS: In the present study of selected patients with LMS stenosis, the use of DESs showed a low mortality rate but did not have a clear effect on target lesion revascularization rate compared with BMSs. A close follow-up appears to be mandatory to achieve acceptable results.

PMID: 18650971 [PubMed - in process]

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The role of the sizing balloon in selection of the patent foramen ovale closure device size.

Exp Clin Cardol. 2008;13(1):42-6

Authors: Alibegovic J, Bonvini R, Sigwart U, Dorsaz P, Camenzind E, Verin V

OBJECTIVES: To find a correlation between the patent foramen ovale (PFO) size measured by the sizing balloon and the appropriate closure device size. METHODS: The PFO of 57 patients was closed using a sizing balloon. A mathematical model was introduced to relate the PFO balloon waist diameter to the closure device size based on the PFO transformation from a slit-like to a circular form during balloon inflation. According to this model, PFOs smaller than 8 mm should be closed with a 25 mm device, PFOs 8 mm to 11 mm with a 35 mm device, and PFOs larger than 11 mm with an Amplatzer septal occluder. In the first group, 36 patients (63.2%) received an appropriately sized device and six patients (10.5%) received an oversized device. In the second group, 15 patients (26.3%) received an undersized device. RESULTS: A comparison of the PFO dimensions in two views showed that the PFO slit was circular when the balloon was inflated. A six-month echocardiography follow-up was obtained in 46 patients (80.7%). Five patients (13.9%) in the group with an appropriately sized device had a discrete residual shunt during Valsalva. In the second group, five patients (33.3%) had a residual shunt (P = 0.06), of which one was considered large. CONCLUSION: The sizing balloon is helpful in selecting the PFO closure device size. Consequently, the incidence of residual shunt and recurrent events may be reduced.

PMID: 18650972 [PubMed - in process]

Patterns of USPIO deposition in murine atherosclerosis.

Arterioscler Thromb Vasc Biol. 2008 Sep;28(9):E157; author reply E158-9

Authors: Klug G, Bauer L, Bauer WR

PMID: 18716317 [PubMed - in process]

Patterns of USPIO Deposition in Murine Atherosclerosis.

Arterioscler Thromb Vasc Biol. 2008 Sep;28(9):e158-e159

Authors: Morris JB, Olzinski AR, Jucker BM

PMID: 18716318 [PubMed - as supplied by publisher]

VEGF-B taken to our hearts: specific effect of VEGF-B in myocardial ischemia.

Arterioscler Thromb Vasc Biol. 2008 Sep;28(9):1575-6

Authors: Claesson-Welsh L

PMID: 18716319 [PubMed - in process]

Targeted increases in endothelial cell superoxide anion production stimulate eNOS-dependent nitric oxide production, not uncoupled eNOS activity.

Arterioscler Thromb Vasc Biol. 2008 Sep;28(9):1580-1

Authors: Xu H, Pritchard KA

PMID: 18716321 [PubMed - in process]

Is LDL-C passed its prime? The emerging role of non-HDL, LDL-P, and ApoB in CHD risk assessment.

Arterioscler Thromb Vasc Biol. 2008 Sep;28(9):1582-3

Authors: Davidson MH

PMID: 18716322 [PubMed - in process]

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