Rolf F. Veldkamp
Duke University
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Featured researches published by Rolf F. Veldkamp.
American Journal of Cardiology | 1993
Mitchell W. Krucoff; Martha A. Croll; James E. Pope; Karen S. Pieper; Prapti Kanani; Christopher B. Granger; Rolf F. Veldkamp; Beverly L. Wagner; Sharon T. Sawchak; Robert M. Califf
Early angiography may not adequately subgroup patients with myocardial infarction if cyclic changes in coronary flow occur frequently. From a pilot experience using a new 12-lead ST-segment monitor, a continuously updated, self-referenced ST-recovery analysis method was developed to quantify both instantaneous recovery, as a noninvasive marker of patency, and cumulative ST recovery over time, as a marker of the speed, stability and duration of reperfusion. In 22 patients with acute infarction in whom 44 observations of unique angiographic patency were noted within 6 hours of presentation, serial patency assessments simultaneous with all angiographic observations predicted coronary occlusion with 90% sensitivity and 92% specificity. Of the 22 patients, 11 (50%) had multiple ST trend transitions suggesting cyclic changes in coronary flow before catheterization. Speed, stability and duration of ST-segment recovery were defined by the time to first 50% ST recovery, total number of ST-trend transitions and patent physiology index (percentage of monitoring period showing ST recovery), respectively. Subgrouped angiographically, the median (interquartile range) for cumulative ST parameters with patent (n = 8) versus occluded (n = 14) arteries were, respectively--time to 50% recovery, 1.57 (1.16, 1.70) versus 0.17 (-0.47, 0.32) hours; number of reelevation/recovery events, 1.5 (1, 3) versus 3 (1, 3); and patent physiology index, 52 (47, 59) versus 50 (5, 73). Thus, continuous ST-segment recovery analysis appears to predict simultaneous angiographic patency over serial assessments, whereas cumulative parameters appear to contain independent information, probably because of patency changes before or after angiography.
Journal of the American College of Cardiology | 2000
Ron T. van Domburg; Karin Meeter; Dorien F.M van Berkel; Rolf F. Veldkamp; Lex A. van Herwerden; Ad J.J.C. Bogers
OBJECTIVES The goal of this study was to determine the influence of smoking cessation on mortality after coronary artery bypass graft surgery (CABG), which has still not been established clearly. BACKGROUND Cigarette smoking is one of the known major risk factors of coronary artery disease. METHODS One thousand and forty-one patients underwent CABG between 1971 and 1980. The preoperative and postoperative smoking habits of 985 patients (95%) could be retrieved and were analyzed in a multivariate Cox analysis. RESULTS The median follow-up was 20 years (range 13 to 26 years). Smoking status before surgery did not entail an increased risk of mortality: patients who had smoked before surgery and those who had not smoked in the year before surgery had a similar probability of survival. However, smoking cessation after surgery was an important independent predictor of a lower risk of death and coronary reintervention during the 20-year follow-up when compared with patients who continued smoking. In analyses adjusted for baseline characteristics, the persistent smokers had a greater relative risk (RR) of death from all causes (RR 1.68 [95% confidence interval 1.33 to 2.13]) and cardiac death (RR 1.75 [1.30 to 2.37]) as compared with patients who stopped smoking for at least one year after surgery. The estimated benefit of survival for the quitters increased from 3% at five years to 14% at 15 years. The quitters were less likely to undergo repeat CABG or a percutaneous coronary angioplasty procedure (RR 1.41 [1.02 to 1.94]). CONCLUSIONS Patients who continued to smoke after CABG had a greater risk of death than patients who stopped smoking. They also underwent repeat revascularization procedures more frequently. Cessation of smoking is therefore strongly recommended after CABG. Clinicians are encouraged to start or to continue smoking-cessation programs in order to help smokers to quit smoking, especially after CABG.
Journal of the American College of Cardiology | 1995
Anatoly Langer; Mitchell W. Krucoff; Peter Klootwin; Rolf F. Veldkamp; Maarten L. Simoons; Christopher B. Granger; Robert M. Califf; Paul W. Armstrong; Gusto Investigators
OBJECTIVES The ST segment monitoring substudy of the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial compared the speed and stability of ST segment recovery among four thrombolytic strategies for acute myocardial infarction. BACKGROUND Rapid resolution of ST segment elevation has been suggested as a noninvasive marker of infarct-related artery patency. We expected that patients treated with accelerated recombinant tissue-type plasminogen activator (rt-PA) would show a quicker recovery than that of other patients but that those treated with streptokinase would show greater stability of recovery. METHODS ST segment monitoring was initiated in 1,067 patients within 30 min of the start of thrombolysis and continued for > 18 h with the use of a three-channel continuous vectorcardiographic monitor, a 12-lead continuous electrocardiographic (ECG) monitor or a three-channel (V2, V5, aVF) Holter ambulatory ECG monitor. RESULTS Time to 50% recovery could be assessed in 618 patients and was similar in the four treatment groups: median 45 min with streptokinase/subcutaneous heparin, 45 min with streptokinse/intravenous heparin, 42 min with accelerated rt-PA and 47 min with combination therapy (p = 0.7). No significant difference among the thrombolytic regimens was shown with the three monitors used. Time to initiation of ST segment analysis was directly related to time to 50% recovery (p = 0.0001) and was its best predictor in a multiple regression model. ST segment elevation recurred equally in each treatment group (approximately 36%, p = 0.9) but was significantly more common in patients with a patent infarct-related artery (p = 0.033) or a low ejection fraction (p = 0.001). CONCLUSIONS The greater 90-min patency seen with accelerated rt-PA in the angiographic substudy did not correlate with a shorter time to 50% ST segment recovery, possibly because of technical limitations and study design. The similar rates of recurrent ischemia (as assessed by ST elevation) among the regimens support the similar infarction and reocclusion rates seen in the main trial and angiographic substudy.
American Journal of Cardiology | 1994
Rolf F. Veldkamp; Cynthia L. Green; Michelle L. Wilkins; James E. Pope; Sharon T. Sawchak; Jill A. Ryan; Robert M. Califf; Galen S. Wagner; Mitchell W. Krucoff
Continuous ST-segment recovery analysis and 5 static methods using ST-segment comparison between a pre- and post-treatment electrocardiogram were compared for their ability to predict infarct-related artery patency in 82 patients with acute myocardial infarction who underwent angiography a median of 124 minutes after onset of thrombolytic treatment. Accuracy at the moment of angiography was 85% (95% confidence interval [CI] 77% to 93%) for the continuous method, and 68% (CI 57% to 78%), 78% (CI 69% to 87%), 83% (CI 74% to 91%), 82% (CI 73% to 90%), and 80% (CI 71% to 89%) for the static methods. At the moment of angiography the most accurate static method and the continuous method agreed in patency assessment in 90% of the patients (CI 84% to 97%). Agreement was reduced to 83% (CI 75% to 91%) of patients when a patency assessment was performed earlier at 90 minutes after treatment onset, and was only 77% (CI 68% to 86%), at 60 minutes. Early disagreement was mainly seen when the continuous ST recording showed ST recovery from a delayed peak ST elevation after the pretreatment static electrocardiogram or when dynamic ST changes suggesting cyclic reperfusion occurred. Continuous ST-segment recovery analysis appears to be as accurate as the most accurate static methods. Continuously updated reference points appear to give important additional information when ST recovery follows a delayed peak ST elevation or when re-elevation occurs, suggesting cyclic flow changes. Such findings appear to affect about half of patients with acute myocardial infarction treated with intravenous thrombolysis, particularly early after administration of therapy.
Journal of Electrocardiology | 1996
Rolf F. Veldkamp; Sharon T. Sawchak; James E. Pope; Robert M. Califf; Mitchell W. Krucoff
Continuously updated ST-segment recovery analysis has been shown to accurately predict infarct-related artery patency. Salient principles were converted into algorithms and incorporated into a portable ST monitor for optimal application. This study tested the automated programs ability to detect occlusion and reperfusion during balloon angioplasty. ST-segment recordings during 78 balloon occlusions in 31 patients were analyzed. The program requires at least one electrocardiogram with ST elevation of 200 microV or greater in the recording, caused by the current occlusion or by a previous occlusion, before it will yield a patency prediction. All 35 inflations causing peak ST elevation of 200 microV or more were indeed detected. All five inflations causing less than 200 microV ST elevation preceded by an inflation causing 200 microV or higher ST elevation were also detected. Occlusion was detected a median of 40 seconds after inflation, and reperfusion a median of 17 seconds after deflation. Peak ST elevation greater than 200 microV occurred in 19 of 26 left anterior descending artery inflations (73%), 1 of 22 left circumflex artery LCX inflations (5%), and 15 of 30 right coronary artery inflations (50%). Five different leads identified peak ST elevation through 12-lead surveillance. In this model of coronary occlusion during angioplasty balloon inflation, the automated patency assessment program appears to detect coronary angioplasty balloon occlusion and reperfusion within seconds in all occlusions causing a peak ST elevation of 200 microV or greater. Testing this automated patency assessment program as a noninvasive triage tool in myocardial infarction patients seems warranted.
Journal of Electrocardiology | 1992
Rolf F. Veldkamp; James R. Bengtson; Sharon T. Sawchak; James E. Pope; James R. Mertens; David Mortara; Robert M. Califf; Mitchell W. Krucoff
Patients in whom early and stable reperfusion through the infarct artery fails after thrombolytic treatment might benefit from further revascularization therapy. A reliable noninvasive technique able to detect both reperfusion and reocclusion would be useful to test this hypothesis. However, no such technique presently exists. ST-segment recovery analysis using continuous digital 12-lead ST monitoring has been shown to be an accurate predictor of infarct artery patency in real time. This method was dependent on a trained clinicians analysis of the recordings on a personal computer. For optimal bedside application, salient principles of this ST-segment recovery analysis were converted into algorithms and built into the ST monitor software. The essentials of these algorithms are described in this report.
European Heart Journal | 1996
Peter Klootwijk; Anatoly Langer; Simon Meij; Cynthia L. Green; Rolf F. Veldkamp; A. M. Ross; Paul W. Armstrong; M. L. Simoons
European Heart Journal | 1996
Peter Klootwijk; Anatoly Langer; Simon Meij; Cynthia L. Green; Rolf F. Veldkamp; A. M. Ross; Paul W. Armstrong; M. L. Simoons
European Heart Journal | 2000
Rolf F. Veldkamp; Suzanne Valk; R.T. van Domburg; L.A. van Herwerden; Karin Meeter
Journal of Electrocardiology | 1994
Mitchell W. Krucoff; Cynthia L. Green; Anatoly Langer; Kathleen Trollinger; Sharon T. Sawchak; Nancy Wilderman; Rolf F. Veldkamp; James E. Pope; Maarten L. Simoons; Christopher B. Granger; Peter Klootwijk; Paul W. Armstrong