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P Block

Publications and source records attributed to P Block.

At least 19 recordsLinked to original sources
PubMed1999

Intravenous nitrates for pharmacological stimulation during head-up tilt testing in patients with suspected vasovagal syncope and healthy controls.

Nitrates may be used for pharmacological stimulation during tilt testing for the diagnosis of vasovagal syncope. In this study we assessed the diagnostic value of intravenous nitrates during tilt testing in patients with a typical history of vasovagal syncope. Twenty patients and 23 controls were tilted at 700 for a maximum duration of 30 minutes. After a 10-minute baseline supine phase, the test started with a continuous nitrate infusion at 1 microg/kg/min and increased every 5 minutes by 1 microg/kg/min, to a maximum of 6 microg/kg/min at the end of the test. The test was ended if the subjects developed a positive response (syncope or presyncope). Nineteen patients (95%) and 17 (74%) of the controls had a positive response. At test end sensitivity was 95%, but specificity was 26% and accuracy was 58%. Receiver operator characteristics (ROC) analysis revealed a maximum accuracy of 79% at 18 minutes, with a sensitivity of 80% and a specificity of 78%. Intravenous nitrates during tilt testing in patients with typical clinical criteria of vasovagal syncope is highly effective in provoking vasovagal syncope. Based on the ROC analysis, a maximum accuracy of 79% was attained at 18 minutes (at a dose of 4 microg/kg/min), suggesting a good diagnostic performance when tilt duration is limited to this point. A positive result requiring more than 18 minutes of stimulated tilting should be interpreted with caution, due to the accompanying considerable decrease of specificity.

Adult↗
PubMed1998

Contrast enhanced and functional magnetic resonance imaging for the detection of viable myocardium after infarction.

PURPOSE: Viable myocardium after acute myocardial infarction may be characterized by magnetic resonance imaging (MRI) either by demonstration of recovery of wall motion under dobutamine stress or by perfusion patterns after contrast medium administration. This study examines the relation between the two techniques. MATERIALS AND METHODS: Gradient-echo MRI at rest and under low-dose dobutamine stress was performed in 28 patients within the first 2 weeks after acute myocardial infarction. In addition, spin-echo MRI was performed after gadolinium-DOTA administration. Wall motion at rest and under stress was scored to assess the contractile reserve of the infarct regions. Infarct enhancement patterns were classified as subendocardial, transmural, or as a doughnut pattern. RESULT: Subendocardial or absent infarct enhancement was related to functional recovery under stress in 31 of 37 infarct segments. Transmural infarct enhancement was correlated with the absence of functional recovery in 10 of 17 infarct segments (p < 0.002), indicating nonviability. The doughnut pattern was exclusively associated with the absence of viability (five of five). CONCLUSION: Contrast enhancement patterns are related to residual myocardial viability.

Aged↗
PubMed1997

Randomised study of effect of ibopamine on survival in patients with advanced severe heart failure. Second Prospective Randomised Study of Ibopamine on Mortality and Efficacy (PRIME II) Investigators.

BACKGROUND: Drugs that improve symptoms in patients with heart failure must also be assessed for their effects on survival. Ibopamine stimulates DA-1 and DA-2 receptors and causes peripheral and renal vasodilatation; the drug improves symptoms of heart failure. We assessed the effect of ibopamine on survival in patients with advanced heart failure in a multicentre, randomised placebo-controlled study. METHODS: Patients with advanced severe heart failure (New York Heart Association classes III and IV) and evidence of severe left-ventricular disease, who were already receiving optimum treatment for heart failure, were randomly allocated oral ibopamine 100 mg three times daily or placebo. The primary endpoint was all-cause mortality. The study was designed to recruit 2200 patients, and the minimum duration of treatment would be 6 months. We did intention-to-treat and on-treatment analyses; a post-hoc subgroup analysis was also done. FINDINGS: After we had recruited 1906 patients the trial was stopped early, because of an excess of deaths among patients in the ibopamine group. 232 (25%) of 953 patients in the ibopamine group died, compared with 193 (20%) of 953 patients in the placebo group (relative risk 1.26 [95% CI 1.04-1.53], p = 0.017). The average length of follow-up was 347 days in the ibopamine group and 363 days in the placebo group. In multivariate analysis, only the use of antiarrhythmic drugs at baseline was a significant independent predictor of increased fatality in ibopamine-treated patients. INTERPRETATION: Ibopamine seems to increase the risk of death among patients with advanced heart failure who are already receiving optimum therapy, but the reasons for this increase are not clear. Our finding that antiarrhythmic treatment was a significant predictor of increased mortality in ibopamine-treated patients may be important, but exploratory analyses must be interpreted with caution.

Adult↗
PubMed1997

Clinical one-year outcomes after stenting in acute myocardial infarction.

We retrospectively review our results of 96 stent placements in 64 patients identified from our data base who received stents acutely and within 48 hr of acute myocardial infarction. The average age was 60 years; 77% were male. The average length of stay was 6.75 days. Three patients needed coronary artery bypass grafting (CABG) before discharge: 2 for stent occlusion and 1 for papillary muscle rupture. Need for CABG, further percutaneous transluminal coronary angioplasty (PTCA), myocardial infarction, and death defined outcome. Mean patient follow-up was 10.3 (+/-5.3) months. Seventy-two percent of patients were free of outcome events at 1 year, 17% needed CABG, and 11% required further PTCA. There were 2 myocardial infarctions and 1 death. Presence of left bundle branch block on admission electrocardiogram and angina in hospital after stent placement predicted worse outcome (P < 0.01).

Adult↗
PubMed1997

Sublingual nitrates during head-up tilt testing for the diagnosis of vasovagal syncope.

Pharmacologic stimulation during head-up tilt test (HUT) is used to increase the diagnostic yield of the test to detect vasovagal syncope. Reported lack of specificity of stimulation with intravenous isoproterenol has made a pharmacologic alternative desirable. Because nitrates are known to cause syncope of a vasovagal origin, we administered sublingual nitrates after classic tilt test in 32 patients with a history of typical vasovagal syncope and 20 healthy volunteers to assess the sensitivity, specificity, and accuracy of this new HUT technique. During the classic HUT four (13%) patients had syncope; after administration of sublingual nitrates, this number increased to 28 (87%). In the control group no subject had syncope during classic HUT, whereas during nitrate administration six (30%) had syncope. Sublingual nitrate stimulated HUT revealed a maximum accuracy of 83% at a cutoff point of 11 minutes, giving a sensitivity of 81% and specificity of 85%. Sublingual nitrate administration increased the accuracy of HUT in diagnosing vasovagal syncope in patients with a history of typical vasovagal syncope.

Administration, Sublingual↗
PubMed1997

Dipyridamole-induced angina pectoris during sestamibi stress test in patients with significant coronary artery disease: clinical, angiographic, and nuclear determinants.

Intravenous dipyridamole induces angina pectoris (AP) in some patients with significant coronary artery disease (CAD). The aim of this prospective study was to identify the angiographic, nuclear, and clinical determinants. The authors examined 50 patients consecutively with significant CAD on coronary angiography. All antiischemic medications were stopped twenty-four hours (nitrates only 6 hours) before injection of dipyridamole (0.84 mg/kg). ECGs were taken before, during, and after this injection. The regional myocardial activity of Tc-99m-Sestamibi at rest and after dipyridamole injection was measured with single-photon emission computed tomography (SPECT). During dipyridamole injection 20 patients had AP, of whom 15 had ST segment depression on ECG (P < 0.001). The only significant difference on coronary angiography between patients with dipyridamole-induced AP and those without AP was the presence of collaterals (P < 0.05). In patients with AP and collaterals, ECG and SPECT changes were always noted in the collateralized territory. Subgroup analysis showed that patients without previous myocardial infarction (MI, n = 17, P < 0.05) or nontransmural MI (n = 17, P < 0.05) had a good correlation between collaterals and AP, whereas patients with a history of transmural MI (n = 16) did not. No further significant variables could be found as a predictor of AP after dipyridamole injection. These findings suggest that AP during dipyridamole stress test is due to ischemia, which is not related to the severity of CAD. Ischemia is probably due to coronary steal to the collateralized territory in patients without transmural MI. Dipyridamole-induced angina pectoris is predictive for collaterals and may indicate viability in patients with MI.

Angina Pectoris↗
PubMed1996

Prediction of functional outcome after myocardial infarction using BMIPP and sestamibi scintigraphy.

UNLABELLED: We determined the predictive value of combined beta-methyl iodophenyl pentadecanoic acid (BMIPP) and sestamibi scintigraphy for the functional outcome after myocardial infarction and compared the value of this approach with dobutamine echocardiography. METHODS: Rest BMIPP, rest sestamibi and low-dose dobutamine echocardiographic studies were obtained in 18 patients 4 to 10 days after infarction (mean 6.7 +/- 2.0 days). Six months later, a rest echocardiographic study was performed to assess functional outcome. RESULTS: Wall motion improved in 27/33 segments (82%) which showed mismatching but not in 19/21 segments (90%) with matched defects (p < 0.001). The accuracy of combined BMIPP and sestamibi SPECT in predicting segmental functional outcome was higher (85%) than that of sestamibi uptake alone (77%). Wall motion improved in 16/20 segments (80%) showing contractile reserve and not in 21/34 segments (63%) with the negative dobutamine test, giving an accuracy of 69% for dobutamine echocardiography. Combination of the two techniques resulted in higher positive (94%) and negative predictive values (94%). CONCLUSION: Mismatching of BMIPP and sestamibi uptake is predictive for long-term functional recovery after acute myocardial infarction. In contrast, segments with matched defects contain only scar tissue. Combined BMIPP and sestamibi scintigraphy offers increased accuracy compared to dobutamine echocardiography.

Coronary Angiography↗
PubMed1996

Clinical nuclear cardiology: flow tracers and free fatty acid analogs to detect viable myocardium after infarction.

Among the available invasive and noninvasive modalities, nuclear cardiology techniques utilizing single photon emission computerized tomography (SPECT) have achieved a preeminent position for the assessment of myocardial viability. This arises from the rather unique potential of scintigraphic methods to assess myocardial perfusion, cell membrane integrity, and metabolic activity. The purpose of this article is to review the relative merits and limitations of myocardial flow tracers (thallium and sestamibi) and metabolic tracers (fatty acid analogs) to identify residual myocardial viability in patients with coronary artery disease and left ventricular dysfunction.

Cell Survival↗
PubMed1995

European postmarketing surveillance of ramipril in hypertension. 1. Feasibility and study cohort.

A prospective observational cohort study of the angiotensin inhibitor, ramipril, was undertaken in four countries within the European Community-Netherlands, United Kingdom, Germany and Belgium. A total of 10,377 consecutive patients with essential hypertension were recruited to the study with the aim of follow-up for one year. Overall 37% of doctors who agreed to participate in the study actually enrolled at least one patient. One third of the doctors who enrolled patients in the study entered two thirds of patients studied. Some 15% of participating males and 27% of females were aged over 70 years. Newly diagnosed hypertensives comprised 22% of the study cohort, the proportion being highest in UK and Netherlands, whereas 53% were established hypertensives of two or more years' duration, the proportion being highest in Germany and Belgium. There were substantial differences among the participating countries in the concurrent treatment these patients were receiving for hypertension, with two or more co-therapies being most frequent in Germany and Belgium. There were also substantial differences in co-therapies for concurrent diseases among the participating countries, reflecting both standard therapeutic practices in local areas and differences in marketing of drugs in the different countries. This report describes the initial findings of this multinational study and emphasises the need to consider several major potentially confounding variables in the analysis of the outcome events both in this study and in other collaborative observational international monitoring schemes for adverse drug reactions.

Aged↗
PubMed1995

Patient compliance and therapeutic coverage: comparison of amlodipine and slow release nifedipine in the treatment of hypertension. The Belgian Collaborative Study Group.

To study patient compliance in hypertensive outpatients amlodipine (5 mg once daily) and slow release nifedipine (20 mg twice daily) were compared in an open, crossover study in general practices. Four methods of assessment for patient compliance (pill count, taking compliance, days with correct dosing, timing compliance) were used in both study arms. For the latter three assessment a special device, the medication event monitoring system, was used to record the time and date of each opening and closure of the container. The compliance of the 320 hypertensive patients with once-daily amlodipine was markedly superior to twice-daily slow release nifedipine. Therapeutic coverage was also significantly better for amlodipine in the hypertensive patients. Amlodipine was better tolerated than nifedipine slow release. Patient compliance and therapeutic coverage with the calcium antagonist amlodipine given once daily was superior to slow release nifedipine b.d. in hypertensive outpatients recruited in general practice.

Amlodipine↗
PubMed1994

Magnetic resonance imaging of the heart in a case of hepatocellular carcinoma extending into the right atrium.

Hepatocellular carcinoma is the most common primary malignant liver tumor occurring in more than 1 million cases a year all over the world. Vascular invasion is known to occur in 30% of patients at initial presentation [1]. An extension of the tumor into the right atrium is well described in the literature [2], with surgical resection as the only procedure available. But the diagnosis is often difficult before death. We report a case in which magnetic resonance imaging of liver and heart shows the extension of this tumor into the right atrium.

Aged↗
PubMed1994

Abnormal free fatty acid uptake in subacute myocardial infarction after coronary thrombolysis: correlation with wall motion and inotropic reserve.

UNLABELLED: Iodine-123-free fatty acid analogs, such as beta-methyliodophenylpentadecanoic acid (BMIPP), allow for myocardial metabolic studies with SPECT. The goal of this investigation was to determine whether BMIPP uptake can be used to differentiate viable myocardium from scar tissue soon after coronary thrombolysis for acute myocardial infarction. METHODS: BMIPP and 99mTc-sestamibi (MIBI) myocardial distribution after injection at rest were analyzed in 22 patients 4 to 10 days after coronary thrombolysis. The relative uptake of the two tracers was compared on a segmental basis to the regional wall motion and to the inotropic reserve assessed by two-dimensional echocardiography and low-dose dobutamine stimulation. RESULTS: Three segmental patterns were identified in the infarct-related coronary artery territory. Segments with normal BMIPP and MIBI uptake showed normal wall motion. Segments with more reduced BMIPP uptake than MIBI uptake (mismatching) showed either normal wall motion or demonstrated inotropic reserve during dobutamine stimulation. Segments with matched defects always showed abnormal wall motion and did not demonstrate inotropic reserve, regardless of the MIBI uptake. CONCLUSION: In patients with subacute myocardial infarction, combined imaging of BMIPP and MIBI at rest might be more sensitive than MIBI or wall motion at rest alone to demonstrate myocardial areas that have been acutely ischemic. Mismatching is due to more severely depressed fatty acid metabolism than expected on the basis of the flow and is indicative of jeopardized, but viable myocardium. In dysfunctional segments, mismatching may correspond either to stunned or to hibernating myocardium. Matched defects are associated with scar tissue.

Coronary Angiography↗
PubMed1993

Regional distribution of 123I-(ortho-iodophenyl)-pentadecanoic acid and 99Tcm-MIBI in relation to wall motion after thrombolysis for acute myocardial infarction.

To characterize the myocardium after thrombolytic therapy for infarction single photon emission computed tomographic (SPECT) studies with 123I-(ortho-iodophenyl)-pentadecanoic acid (oPPA) and 99Tcm-methoxyisobutyl isonitrile (MIBI) were obtained at rest in nine patients within a fortnight after the acute event. A decreased oPPA activity compared to MIBI was observed in 15/45 segments (7/9 patients). The segments with discordant oPPA/MIBI activities showed less severe wall motion abnormalities than the segments with concordant decreased oPPA and MIBI activities (P = 0.004). A significant association was found between discordant oPPA/MIBI activities and the early evolution of wall motion following thrombolysis: discordant oPPA/MIBI activities were present in nine of the 11 segments (82%) with improved wall motion, while the wall motion of the seven segments with similar decreased oPPA and MIBI activities was unchanged or had deteriorated (P = 0.018). It is concluded that metabolic abnormalities often persist longer than perfusion and wall motion abnormalities soon after thrombolysis, and that 123I-oPPA in combination with 99Tcm-MIBI is useful to demonstrate myocardial areas which have been salvaged by thrombolysis.

Aged↗
PubMed1993

Survival at 15 to 18 years after coronary bypass surgery for angina in women.

BACKGROUND: Coronary bypass surgery in women is associated with lower survival than in men. We need to know whether this is because of patient-related factors and whether the lower survival is present in all subgroups of patients and for all time periods during which the surgery was performed. METHODS AND RESULTS: Using actuarial techniques, we determined the outcome of coronary bypass surgery performed for chronic stable and unstable angina in 1979 women and 6927 men. The operative mortality was 2.7% for women and 1.9% for men (P = .02). The higher operative mortality in women was seen in those with three-vessel disease or greater and abnormal left ventricular function (5.4% versus 2.8%, P = .009) and those with stable angina (2.6% versus 1.5%, P = .006). The 5-, 10-, 15-, and 18-year survival for women was 86 +/- 0.9%, 70 +/- 1.5%, 50 +/- 2.5%, and 37 +/- 6.4%, respectively, and for men, 88 +/- 0.4%, 73 +/- 0.7%, 54 +/- 1.2%, and 42 +/- 1.9%, respectively (P = .03). The lower survival in women compared with men was seen in those with three-vessel disease or greater and abnormal left ventricular function (at 10 years, 69 +/- 1.8% versus 73 +/- 0.8%, P = .005). At 15 years, the incidence of reoperation was 26 +/- 2.4% versus 28 +/- 1.2% and of myocardial infarction, 30 +/- 2.8% versus 32 +/- 1.3%, P = NS for either. The incidence of no angina or mild angina was 70% in women and 78% in men, P < .0001. The operative mortality and late survival of those operated on in different time periods for either women or men was not significantly different. Women were older (64 +/- 9.4 versus 61 +/- 9.9 years, P < .0001) and smaller (body surface area, 2.0 +/- 0.2 versus 1.7 +/- 0.2 m2, P < .0001), had a higher incidence of diabetes, systemic hypertension, and unstable angina, and had a smaller lumen of the left anterior descending coronary artery (1.7 +/- 0.4 versus 1.9 +/- 0.4 mm, P < .0001), right coronary artery, and diagonal arteries. More men were smokers, and men had a higher incidence of prior myocardial infarction, previous coronary bypass surgery, and extent of coronary disease and of abnormal left ventricular function. The Cox regression model of survival showed that independent risk factors for lower survival were older age, previous coronary bypass surgery, previous myocardial infarction, and diabetes. Sex was not an independent risk factor for poorer survival. CONCLUSIONS: Women have a higher operative mortality and lower long-term survival than men after coronary bypass surgery for angina. However, the differences are small, even if statistically significant. Importantly, patient-related factors and not sex are independent predictors of poorer survival. Therefore, coronary bypass surgery should not be delayed or denied to women who have the usual indications for surgery.

Actuarial Analysis↗
PubMed1992

Sociotropy and autonomy: relationship to antidepressant drug treatment response and endogenous-nonendogenous dichotomy.

This study evaluated the relationship of sociotropic and autonomous personality traits with response to pharmacotherapy for 217 depressed outpatients using the Sociotropy-Autonomy Scale. Sociotropy was related to nonendogenous depression, whereas autonomy was related to endogenous depression. Subjects who had high autonomous-low sociotropic traits showed greater response to antidepressants (and greater drug-placebo differences) than those who had high sociotropic-low autonomous traits (who showed no drug-placebo differences). Hierarchical multiple regression analysis showed that the sociotropy-autonomy, but not the endogenous-nonendogenous, distinction was a predictor of drug treatment response. The combination of endogeneity and autonomy predicted response to placebo. If replicated, these findings may enable better matching of patient traits to various treatment modalities for depression.

Adult↗
PubMed1991

Measurement and interrelations of psychiatric symptomatology in inpatients.

For 152 psychiatric inpatients scores on the Beck Depression Scale, State form of the State-Trait Anxiety Inventory, the Self-report Inventory, Hopelessness Scale and 3 MMPI scales, Hypochondriasis, Schizophrenia, and Hypomania, were factor analyzed. The two factors appeared to confirm Gotlib's 1984 suggestion that such questionnaires measure general distress, as responding endorses negative affect.

Adult↗
PubMed1991

Late potentials and ejection fraction at hospital discharge: prognostic value in thrombolyzed and non-thrombolyzed patients. A preliminary report. The Belgian Working Group for Signal Averaging.

The prognostic value of the use of thrombolytic therapy (TL), the ejection fraction (EF) and the presence of late potentials (LP) in the signal-averaged ECG (filter less than 40 Hz) at the time of hospital discharge was assessed in a multicenter prospective study. This report presents the follow-up at 4 months of the first 263 patients. Thrombolytic therapy was given to 41%. The mean ejection fraction was 45%. The average duration of the high frequency QRS complex (HFQRS) was 104 ms. The mean duration of the terminal signal under 40 microV (D40) was 31 ms. The combination of both HFQRS greater than 110 ms and a D40 greater than 40 ms was considered as presence of LP. The cardiac mortality at 4 months was 5.7% (15 patients). Late ventricular tachycardia or fibrillation occurred in 2.3% (6 patients). The relative risk (RR) for cardiac death or late events was 5.14 with a 95% confidence interval (CI) of 1.2 to 22.0 when no thrombolytic therapy was used. The RR was 3.39 (CI: 1.4 to 8.4) for patients with an EF lower than 30%. The single most important electrocardiographic parameter was a D40 greater than 40 ms (RR: 3.14, CI: 1.3 to 7.8). The presence of LP had a RR of 4.28 (CI: 1.7 to 10.5). With stepwise regression analysis it was evident that cardiac function and information obtained by signal averaging offered independent prognostic information. The presence of LP at hospital discharge after acute infarction offers additional prognostic information to EF for the risk of later cardiac death, especially in patients without thrombolysis.

Aged↗