Uwe K.H. Wiegand

Independent Prognostic Value of Cardiac Troponin T in Patients With Confirmed Pulmonary Embolism

BACKGROUND Cardiac troponin T (cTnT) is a sensitive and specific marker, allowing the detection of even minor myocardial cell injury. In patients with severe pulmonary embolism (PE), myocardial ischemia may lead to progressive right ventricular dysfunction. It was therefore the purpose of this study to test the presence of cTnT and its prognostic implications in patients with confirmed PE. METHODS AND RESULTS Fifty-six consecutive patients with confirmed PE were enrolled in this prospective study. PE was confirmed by pulmonary angiography, lung scan, or echocardiography and subsidiary analyses. Severity of PE was assessed by a clinical scoring system, and cTnT was measured within 12 hours after admission. cTnT was elevated (>/=0.1 microg/L) in 18 (32%) patients with massive and moderate PE but not in patients with small PE. In-hospital death (odds ratio 29. 6, 95% CI 3.3 to 265.3), prolonged hypotension and cardiogenic shock (odds ratio 11.4, 95% CI 2.1 to 63.4), and need for resuscitation (odds ratio 18.0, 95% CI 2.6 to 124.3) were more prevalent in patients with elevated cTnT. cTnT-positive patients more often needed inotropic support (odds ratio 37.6, 95% CI 5.8 to 245.6) and mechanical ventilation (odds ratio 78.8, 95% CI 9.5 to 653.2). After adjustment, cTnT remained an independent predictor of 30-day mortality (odds ratio 15.2, 95% CI 1.22 to 190.4). CONCLUSIONS cTnT may improve risk stratification in patients with PE and may aid in the identification of patients in whom a more aggressive therapy may be warranted.

Long‐Term Complication Rates in Ventricular, Single Lead VDD, and Dual Chamber Pacing

A higher incidence of pacemaker related complications has been reported in DDD systems as compared to VVI devices. The implantation of single lead VDD pacemakers might reduce the complication rate of physiological pacing in patients with AV block. In a retrospective study, the data records of 1,214 consecutive patients with pacemaker implantation for AV block between 1990 and 2001 (VVI 36.5%, DDD 32.9%, VDD 30.6%) were analyzed. Complications requiring surgical interventions were compared during a follow‐up period of 64 ± 31 months. Operation and fluoroscopic times were longer in DDD pacemaker implantation compared to VDD and VVI devices: 58 ± 23 versus 39 ± 10 and 37 ± 13  minutes   (P < 0.001), 9.2 ± 5.2 versus 4.1 ± 2.4 and 3.5 ± 2.3  minutes , respectively. Differences remained significant after correction for covariates. In a multivariate Cox regression model, the corrected complication hazard of a DDD pacemaker implantation was increased by 3.9 (1.4–11.3) compared to VVI and increased by 2.3 (1.1–4.5) compared to VDD pacing. Higher complication rates in DDD pacing were mainly due to a higher incidence of early reoperation for atrial lead dysfunction, whereas the long‐term complication rate was not different from VDD or VVI pacing. Early and long‐term complication rates did not differ between VDD and VVI pacemaker systems. In conclusion, operation time and complication rates of physiological pacing are reduced by VDD pacemaker implantation achieving values comparable to VVI pacing. Thus, single lead VDD pacing can be recommended for patients with AV block. (PACE 2003; 26:1961–1969)

Course and prognostic implications of QT interval and QT interval variability after primary coronary angioplasty in acute myocardial infarction

OBJECTIVES The aim of this study was to determine the influence of early reperfusion on the course of QT interval and QT interval variability in patients undergoing primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI) and its prognostic implications on major arrhythmic events during one-year follow-up. BACKGROUND Although early coronary artery recanalization by primary angioplasty is an established therapy in AMI, a substantial number of patients is still threatened by malignant arrhythmias even after early successful reperfusion, which may be caused by an inhomogeneity of ventricular repolarization despite reperfusion. METHOD Temporal fluctuations of ventricular repolarization were studied prospectively in 97 consecutive patients with a first AMI by measurements of QT interval and QT interval variability during and after successful PTCA (Thrombolysis in Myocardial Infarction flow grades 2 and 3). Continuous beat-to-beat QT interval measurement was performed from 24-h Holter monitoring, which was initiated at admission before PTCA. RESULTS Reperfusion caused a significant continuous increase of mean RR interval (738 +/- 98 to 808.5 +/- 121 ms; p < 0.001) and a significant decrease of parameters of QT interval (QTc: 440 +/- 32 to 416.5 +/- 37ms; p < 0.001) and QT interval variability (QTcSD: 27.5 +/- 3 to 24.9 +/- 6 ms; p < 0.001) in the majority of patients. However, in patients with major arrhythmic events at the one-year follow-up (sudden cardiac death, ventricular fibrillation or sustained ventricular tachycardia, n = 15), parameters of QT interval remained unaltered after successful reperfusion (QTc: 447.3 +/- 41 to 432.9 +/- 45 ms, p = NS; QTcSD: 35.1 +/- 13.4 to 29.0 +/- 9.1 ms, p = NS). CONCLUSIONS Reduction of QT interval and QT interval variability after timely reperfusion of the infarct-related artery may be a previously unreported beneficial mechanism of primary PTCA in AMI, indicating successful reperfusion.

Prothrombin fragments F1+2, thrombin–antithrombin III complexes, fibrin monomers and fibrinogen in patients with coronary atherosclerosis

We determined the plasma levels of prothrombin fragment F1+2, thrombin-antithrombin III complexes (TAT), fibrin monomers (FM), D-dimers (DD) and fibrinogen in 57 patients with angiographically verified graded coronary artery disease (CAD) free of concomitant peripheral atherosclerosis, cerebrovascular disease or diabetes mellitus and a group of 21 apparently healthy controls. Blood was collected from the antecubital vein through atraumatic venipuncture prior to the angiographic procedure. Plasma levels of hemostatic markers were related to the presence and graded severity of CAD. The levels of prothrombin fragment F1+2 (1.74+/-0.11 vs. 1.0+/-0.07 nmol/l, P<0.001), FM (41.6+/-5.5 vs. 7.42+/-3.05 nmol/l, P<0.001), TAT (15.6+/-2.7 vs. 2.96+/-0.32 microg/l, P<0.001) and fibrinogen (3.64+/-1.3 vs. 3.08+/-0.33 g/l, P<0.01) were significantly higher in patients with CAD compared to controls, while there was no difference regarding the fibrinolytic system represented by DD (441.6+/-58.9 vs. 337.4+/-42.05 microg/l, n.s.). Within the CAD group, patients with extensive coronary atherosclerosis (> or =2 vessel disease) had significantly higher values for prothrombin fragment F1+2 (1.89 vs. 1.57 nmol/l, P = 0.04), FM (50.7 vs. 29.8 nmol/l, P = 0.03), and a trend to significance was noted for fibrinogen (3.9 vs. 3.3 g/l, P = 0.07) suggesting that blood coagulability was related to the severity of the disease and that hemostatic markers of thrombin activity represent a useful tool to identify patients with a latent hypercoagulable state with a higher susceptibility to sustain coronary thrombosis.

Atrial sensing and AV synchrony in single lead VDD pacemakers: a prospective comparison to DDD devices with bipolar atrial leads.

Atrial Sensing and AV Synchrony in VDD and DDD Devices, Introduction: Single lead VDD pacing has offered an alternative to DDD systems in patients with isolated AV block. Up to now, however, the relative performance of these pacemaker systems was not systematically compared.

Reflex Cardiac Activity in Ischemia and Reperfusion Heart Rate Turbulence in Patients Undergoing Direct Percutaneous Coronary Intervention for Acute Myocardial Infarction

Background—Abnormal heart rate turbulence (HRT) is associated with an increased risk of mortality in the chronic phase of myocardial infarction (MI) in the prethrombolytic and thrombolytic eras. However, the impact of direct percutaneous coronary intervention (PCI) on HRT in the acute phase of MI and its association to the epicardial infarct-related arterial flow has not been examined. Methods and Results—We investigated HRT in 126 patients undergoing direct PCI for a first MI. Turbulence onset and turbulence slope were determined before reperfusion, during the initial 2 hours after reperfusion, and during hours 6 to 24 after reperfusion. HRT significantly improved after PCI. There were no significant differences in baseline clinical characteristics between Thrombolysis in Myocardial Infarction Trial classification (TIMI) 2 (n=28) and TIMI 3 (n=98) flow. After PCI, turbulence slope increased (13.2±11 to 18.1±12 ms/beat, P <0.001) and turbulence onset decreased (−0.008±0.04% to −0.023±0.04%, P <0.01) in patients with TIMI 3 flow after PCI, whereas there were no significant alterations of turbulence slope (12.2±10 to 12.8±6.5 ms/beat) and turbulence onset (−0.009±0.05% to −0.003±0.03%) in patients with TIMI 2 flow. Conclusions—The improvement of HRT after successful reperfusion is a previously unreported effect of direct PCI for acute MI, reflecting rapid restoration of baroreceptor response. The persistent impairment of HRT after PCI in patients with TIMI 2 flow indicates a sustained blunted baroreflex response and may reflect a more severe microvascular dysfunction.

Heart Rate Variability in Patients With Acute Myocardial Infarction Undergoing Primary Coronary Angioplasty

Depressed heart rate variability (HRV) has been associated with adverse outcome during and after acute myocardial infarction (AMI). The effects of reperfusion in AMI on the course of HRV have not been well characterized as yet. We analyzed 123 consecutive patients with a first AMI who underwent successful reperfusion (Thrombolysis In Myocardial Infarction grades 2 and 3) by primary percutaneous transluminal coronary angioplasty (PTCA). Time- and frequency-domain HRV was measured from 24-hour Holter monitoring, which began at hospital admission. Mean RR interval increased significantly after successful PTCA. Reperfusion immediately caused an immediate transient depression of HRV, which was followed by a significant increase of HRV. Quantitative markers of sympathetic activity and sympathovagal balance, such as SD of the averages of NN intervals in all 5-minute segments, and low- and/or high-frequency ratio continuously decreased within the observation period. Patients with anterior AMI exhibited the same pattern of temporal changes of HRV, with, however, lower absolute values for HRV and mean RR interval than patients with non-anterior AMI. Subgroup analysis in 21 patients with reperfusion > 12 hours after onset of pain showed that the biphasic profile of HRV and the marked increase of mean RR interval was absent. Furthermore, in patients with late reperfusion, HRV was significantly lower compared with those with early reperfusion. Thus, timely reperfusion in AMI leads to a biphasic effect on autonomic tone, characterized by a transient suppression, followed by a significant activation of the vagal tone, as well as an attenuation of sympathetic activity. Recovery of HRV may contribute to the benefits of early reperfusion in AMI.

Risk Stratification in Patients With Inferior Acute Myocardial Infarction Treated by Percutaneous Coronary Interventions The Role of Admission Troponin T

BackgroundCardiac troponin T (cTnT) elevations on admission indicate a high-risk subgroup of patients with ST-segment elevation acute myocardial infarction (AMI). This finding has been attributed to less effective reperfusion after thrombolytic therapy. The aim of this study was to determine the role of admission cTnT on the efficacy of percutaneous coronary interventions (PCIs) in inferior AMI. Methods and ResultsOne hundred fifty-nine consecutive patients with inferior ST-segment AMI were enrolled and followed up for a mean of 448 days. Patients were stratified by cTnT on admission. A cTnT ≥0.1 &mgr;g/L was found in 58% of patients. These patients had longer time intervals from onset of symptoms to therapy (P <0.001) and higher 30-day (10.8% versus 1.5%, P =0.027) and long-term (17.2% versus 4.5%, P =0.023) cardiac mortalities. Rates of the combined end point of death, nonfatal reinfarction, and need for repeated target vessel revascularization procedures were not different in cTnT groups (log rank, 0.69;P =0.41). PCI was attempted in 93.3% of cTnT-positive and 98.5% cTnT-negative patients (P =0.24) but was less frequently successful in patients with cTnT ≥0.1 &mgr;g/L (77.9% versus 96.9%, P <0.001). Coronary stenting reduced 30-day and long-term cardiac mortality, particularly among cTnT-positive patients. In a multivariate analysis, cTnT indicated an ≈5-fold-higher risk (adjusted OR, 4.6; 95% CI, 0.79 to 27.11;P =0.089) and was a strong albeit not independent risk predictor. ConclusionsIn inferior AMI, a positive admission cTnT is associated with lower success rates of direct PCI and higher rates of cardiac events over the short and long term. These patients benefit from coronary stenting.

An Optimized AV Delay Algorithm for Patients with Intermittent Atrioventricular Conduction

Detection and promotion of an intermittent atrioventricular (A V) conduction is the objective of an AV delay hysteresis algorithm in dual chamber pacemaker (DDDj pacing. The AV delay following an atrial event is automatically extended by a programmable interval (AV hysteresis interval) if the previous cycle showed spontaneous AV conduction, i.e., a ventricular event was detected within the previous AV delay. An automatic search mode scans for spontaneous ventricular events during the hysteresis interval: a single AV delay extension (equal to the programmed AV delay hysteresis) will occur after a successive, programmable number of AV cycles with ventricular pacing. If a spontaneous AV conduction is present, the AV delay will remain extended by the hysteresis interval. Our first results in 17 patients with intermittent AV block disclosed a satisfactorily working algorithm with effective reduction of ventricular stimuli. In relation to the underlying conduction disturbance and pacemaker settings, the majority of our patients showed a reduction of ventricular pacing events up to 90% without any adverse hemodynamic or electrophysiological changes. Based on clinical (promotion of a physiological activation and contraction sequence) and technical (reduction of power consumption) advantages, the AV hysteresis principle could be of incremental value for future dual chamber pacing in patients with intermittent complete heart block.

Circadian Profile of QT Interval and QT Interval Variability in 172 Healthy Volunteers

BONNEMEIER, H., et al.: Circadian Profile of QT Interval and QT Interval Variability in 172 Healthy Volunteers. The limited prognostic value of QT dispersion has been demonstrated in recent studies. However, longitudinal data on physiological variations of QT interval and the influence of aging and sex are few. This analysis included 172 healthy subjects (89 women, 83 men; mean age 38.7 ± 15 years). Beat‐to‐beat QT interval duration (QT, QTapex [QTa], Tend[Te]), variability (QTSD, QTaSD), and the mean R‐R interval were determined from 24‐hour ambulatory electrocardiograms after exclusion of artifacts and premature beats. All volunteers were fully active, awoke at approximately 7:00 am, and had 6–8 hours of sleep. QT and R‐R intervals revealed a characteristic day‐night‐pattern. Diurnal profiles of QT interval variability exhibited a significant increase in the morning hours (6–9 am; P < 0.01) and a consecutive decline to baseline levels. In female subjects the R‐R and Tend intervals were significantly lower at day‐ and nighttime. Aging was associated with an increase of QT interval mainly at daytime and a significant shift of the T wave apex towards the end of the T wave. The circadian profile of ventricular repolarization is strongly related to the mean R‐R interval, however, there are significant alterations mainly at daytime with normal aging. Furthermore, the diurnal course of the QT interval variability strongly suggests that it is related to cardiac sympathetic activity and to the reported diurnal pattern of malignant ventricular arrhythmias. (PACE 2003; 26[Pt. II]):377–382)