Jørgen Tobias Kühl

Left atrial volume and function in patients following ST elevation myocardial infarction and the association with clinical outcome: a cardiovascular magnetic resonance study

AIMS The left atrium (LA) transfers blood to the left ventricle in a complex manner. LA function is characterized by passive emptying (LA passive fraction), active emptying (LA ejection fraction), and total emptying (LA fractional change). Despite this complexity, the clinical relevance of the LA is based almost exclusively on LA maximal volume (LAmax), which may not glean the full prognostic potential. Cardiovascular magnetic resonance (CMR) is considered the most accurate method for studying LA function and size. The aim of the present study was to evaluate the prognostic importance of LA function in patients following ST elevation myocardial infarction (STEMI). METHODS AND RESULTS In 199 patients, a CMR scan was performed within 1-3 days after STEMI to measure LAmax and minimal volume (LAmin) and LA function. The incidence of death, re-infarction, stroke, and admission for heart failure [major adverse cardiac event (MACE)] were registered during the follow-up period [2.3 years (inter-quartile range: 2.0-2.5)]. A total of 40 patients (20%) met the clinical endpoint of MACE during follow-up. In a Cox regression analysis adjusting for known risk factors, LA fractional change remained independently associated with MACE [adjusted hazard ratio: 0.66 (95% confidence interval: 0.46-0.95)]. LAmax, LAmin, or LA passive fraction was not independently associated with MACE. Furthermore, LA fractional change provided incremental prognostic value to LAmax and other known predictors (Wald χ(2) 31.0 vs. 39.9, P= 0.016). CONCLUSION In STEMI patients, impaired LA fractional change is independently associated with outcome and provide incremental prognostic information to established predictors including LAmax.

P-wave duration and the risk of atrial fibrillation: Results from the Copenhagen ECG Study

BACKGROUND Results on the association between P-wave duration and the risk of atrial fibrillation (AF) are conflicting. OBJECTIVE The purpose of this study was to obtain a detailed description of the relationship between P-wave duration and the risk of AF. METHODS Using computerized analysis of electrocardiograms from a large primary care population, we evaluated the association between P-wave duration and the risk of AF. Secondary end-points were death from cardiovascular causes and putative ischemic stroke. Data on drug use, comorbidity, and outcomes were collected from administrative registries. RESULTS A total of 285,933 individuals were included. During median follow-up period of 6.7 years, 9550 developed AF, 9371 died of a cardiovascular cause, and 8980 had a stroke. Compared with the reference group (100-105 ms), individuals with very short (≤89 ms; hazard ratio [HR] 1.60, 95% confidence interval [CI] 1.41-1.81), intermediate (112-119 ms; HR 1.22, 95% CI 1.13-1.31), long (120-129 ms; HR 1.50, 95% CI 1.39-1.62), and very long P-wave duration (≥130 ms; HR 2.06, 95% CI 1.89-2.23) had an increased risk of incident AF. With respect to death from cardiovascular causes, we found an increased risk for very short (≤89 ms; HR 1.20, 95% CI 1.06-1.34), long (120-129 ms; HR 1.11, 95% CI 1.04-1.19), and very long P-wave duration (≥130 ms; HR 1.30, 95% CI 1.21-1.40) compared with the reference group (106-111 ms). Similar but weaker associations were found between P-wave duration and the risk of putative ischemic stroke. CONCLUSION In a large primary care population we found both short and long P-wave duration to be robustly associated with an increased risk of AF.

Volumetric evaluation of coronary plaque in patients presenting with acute myocardial infarction or stable angina pectoris—a multislice computerized tomography study

BACKGROUND We hypothesized that unstable clinical presentation of coronary artery disease is associated with distinct characteristics of culprit lesions identifiable by multislice computed tomography (MSCT). METHODS Patients with non-ST-elevation myocardial infarction (NSTEMI) (n = 57) or stable angina (SA) pectoris (n = 19) were studied. Coronary culprit lesions in patients with NSTEMI and symptomatic lesions in patients with SA were evaluated with 64-slice MSCT and a volumetric plaque imaging tool. Plaque volumes of lipid, fibrous tissue, or calcification according to signal intensity were determined. Plaque burden, mean signal intensity of the lesions, relative volumetric distribution of plaque components, and remodeling index were measured. RESULTS Volumetric plaque burden of study lesions were similar in the 2 patient groups (P = .38). Mean signal intensity of study lesions were lower in patients with NSTEMI compared with patients with SA (74 [66-97] Hounsfield units vs 99 [77-154] Hounsfield units, P = .02). The volume of plaque occupied by calcified material was lower in patients with NSTEMI compared with patients with SA (15 mm(3) [3-58 mm(3)] vs 42 mm(3) [18-82 mm(3)], P = .045). In patients with NSTEMI, the lipid-rich plaque subtype was more frequent than in patients with SA, and the calcified plaque subtype was less frequent in patients with NSTEMI than in patients with SA (P = .032). Positive remodeling was observed in 19% of patients with NSTEMI, whereas this was absent in patients with SA (P = .04). CONCLUSION Volumetric measurements with MSCT revealed that coronary culprit lesions in acute coronary syndrome frequently display low mean plaque signal intensity values, lipid-rich plaque subtype, and positive remodeling.

Assessment of left atrial volume and function in patients with permanent atrial fibrillation: comparison of cardiac magnetic resonance imaging, 320-slice multi-detector computed tomography, and transthoracic echocardiography

AIMS Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with substantial morbidity and mortality. AF is associated with enlargement of the left atrium (LA), and the LA volume has important prognostic implications for the disease. The objective of the study was to determine how measurements of LA volume and function obtained by transthoracic echocardiography (TTE), cardiac magnetic resonance (CMR), and 320-slice multi-detector computed tomography (MDCT) correlate in patients with permanent AF. METHODS AND RESULTS Thirty-four patients with permanent AF participated in the study. TTE, CMR, and 320-slice MDCT imaging procedures were performed within 7 ± 4 days. 320-slice MDCT overestimated maximal LA volume (LAmax) and minimal LA volume (LAmin) compared with CMR (LAmax: 80 vs. 73 mL/m(2), P = 0.0017; LAmin: 69 vs. 64 mL/m(2), P = 0.0217), whereas TTE underestimated these parameters compared with CMR (LAmax: 60 vs. 73 mL/m(2), P < 0.0001; LAmin: 50 vs. 64 mL/m(2), P < 0.0001), and also compared with MDCT (LAmax: 60 vs. 80 mL/m(2), P < 0.0001; LAmin: 50 vs. 69 mL/m(2), P < 0.0001). Measurements of LA volumes by MDCT and CMR closely correlated, and both MDCT and CMR had excellent intra- and inter-observer agreement with correlation coefficients of >0.90. The correlation between TTE-derived measurements and CMR/MDCT was fair to moderate. Intra- and inter-observer agreement for LA volume measurements by TTE were inferior to CMR and MDCT. CONCLUSION Measurements of LA volumes by CMR and 320-slice MDCT correlate closely in patients with permanent AF, and both modalities improve the reproducibility of measurements of LA volumes and function compared with 2D TTE.

Long-Term Clinical Impact of Coronary CT Angiography in Patients With Recent Acute-Onset Chest Pain: The Randomized Controlled CATCH Trial.

OBJECTIVES The aim of the CATCH (CArdiac cT in the treatment of acute CHest pain) trial was to investigate the long-term clinical impact of a coronary computed tomographic angiography (CTA)-guided treatment strategy in patients with recent acute-onset chest pain compared to standard care. BACKGROUND The prognostic implications of a coronary CTA-guided treatment strategy have not been compared in a randomized fashion to standard care in patients referred for acute-onset chest pain. METHODS Patients with acute chest pain but normal electrocardiograms and troponin values were randomized to treatment guided by either coronary CTA or standard care (bicycle exercise electrocardiogram or myocardial perfusion imaging). In the coronary CTA-guided group, a functional test was included in cases of nondiagnostic coronary CTA images or coronary stenoses of borderline severity. The primary endpoint was a composite of cardiac death, myocardial infarction (MI), hospitalization for unstable angina pectoris (UAP), late symptom-driven revascularizations, and readmission for chest pain. RESULTS We randomized 299 patients to coronary CTA-guided strategy and 301 to standard care. After inclusion, 24 patients withdrew their consent. The median (interquartile range) follow-up duration was 18.7 (range 16.8 to 20.1) months. In the coronary CTA-guided group, 30 patients (11%) had a primary endpoint versus 47 patients (16%) in the standard care group (p = 0.04; hazard ratio [HR]: 0.62 [95% confidence interval: 0.40 to 0.98]). A major adverse cardiac event (cardiac death, MI, hospitalization for UAP, and late symptom-driven revascularization) was observed in 5 patients (2 MIs, 3 UAPs) in the coronary CTA-guided group versus 14 patients (1 cardiac death, 7 MIs, 5 UAPs, 1 late symptom-driven revascularization) in the standard care group (p = 0.04; HR: 0.36 [95% CI: 0.16 to 0.95]). Differences in cardiac death and MI (8 vs. 2) were insignificant (p = 0.06). CONCLUSIONS A coronary CTA-guided treatment strategy appears to improve clinical outcome in patients with recent acute-onset chest pain and normal electrocardiograms and troponin values compared to standard care with a functional test. (Cardiac-CT in the Treatment of Acute Chest Pain [CATCH]; NCT01534000).

Assessment of left atrial volume and mechanical function in ischemic heart disease: A Multi Slice Computed Tomography study

UNLABELLED Left atrial (LA) maximal volume contains prognostic information in patients with heart failure and acute myocardial infarction. However, only few studies have investigated the detailed mechanical function of the LA in these patients. We assessed the feasibility of evaluating LA volume and mechanical function with Multi Slice Computed Tomography (MSCT) in patients with ischemic heart disease. Furthermore, the LA and left ventricular (LV) function was evaluated in relation to signs of clinical heart failure. METHODS AND RESULTS MSCT was performed in 40 patients with sinus rhythm and ischemic heart disease. We enrolled 20 patients with reduced LV ejection fraction (LVEF≤45%) and 20 with preserved LVEF (>45%). LA volumes, reservoir, channel and pump function were measured. Interobserver variation for LA volume measures was 1.5% (SD: 6.6%). In patients with reduced LVEF, LA volumes were larger throughout the cardiac cycle (LA-max 66.8 ml/m(2) vs 57.4 ml/m(2) and LA-min: 45.8 ml/m(2) vs 31.6 ml/m(2), p<0.05) and LA reservoir and pump function were all significantly impaired (Fractional change: 43% vs 31%, LAEF 31% vs 19%, p<0.05). Patients with clinical signs of heart failure during hospitalisation had significantly lower LAEF than patients without (16(9)% vs. 30(17)% p<0.05). In a multivariate linear regression analyses the presence of clinical signs of heart failure and reduced LVEF were independent determinants of impaired LA reservoir and pump function (p<0.05). CONCLUSION Reproducible assessment of LA size and mechanical function throughout the cardiac cycle using MSCT is feasible and potentially useful clinically.

Prediction of clinical outcome by myocardial CT perfusion in patients with low-risk unstable angina pectoris

The prognostic implications of myocardial computed tomography perfusion (CTP) analyses are unknown. In this sub-study to the CATCH-trial we evaluate the ability of adenosine stress CTP findings to predict mid-term major adverse cardiac events (MACE). In 240 patients with acute-onset chest pain, yet normal electrocardiograms and troponins, a clinically blinded adenosine stress CTP scan was performed in addition to conventional diagnostic evaluation. A reversible perfusion defect (PD) was found in 38 patients (16 %) and during a median follow-up of 19 months (range 12–22 months) 25 patients (10 %) suffered a MACE (cardiac death, non-fatal myocardial infarction and revascularizations). Accuracy for the prediction of MACE expressed as the area under curve (AUC) on receiver-operating characteristic curves was 0.88 (0.83–0.92) for visual assessment of a PD and 0.80 (0.73–0.85) for stress TPR (transmural perfusion ratio). After adjustment for the pretest probability of obstructive coronary artery disease, both detection of a PD and stress TPR were significantly associated with MACE with an adjusted hazard ratio of 39 (95 % confidence interval 11–134), p < 0.0001, for visual interpretation and 0.99 (0.98–0.99) for stress TPR, p < 0.0001. Patients with a PD volume covering >10 % of the LV myocardium had a worse prognosis compared to patients with a PD covering <10 % of the LV myocardium, p = 0.0002. The optimal cut-off value of the myocardial PD extent to predict MACE was 5.3 % of the left ventricle [sensitivity 84 % (64–96), specificity 95 % (91–97)]. Myocardial CT perfusion parameters predict mid-term clinical outcome in patients with recent acute-onset chest pain.

Clinical feasibility of myocardial computed tomographic perfusion imaging in patients with recent acute-onset chest pain

imaging in patients with recent acute-onset chest pain☆ Jesper James Linde ⁎, Jens Dahlgaard Hove , Jørgen Tobias Kühl , Mathias Sørgaard , Henning Kelbæk , Walter Bjørn Nielsen , Klaus Fuglsang Kofoed b,c a Department of Cardiology, Hvidovre Hospital, University of Copenhagen, Denmark b Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Denmark c Department of Radiology, The Diagnostic Centre, Rigshospitalet, University of Copenhagen, Denmark

Endocardial-epicardial distribution of myocardial perfusion reserve assessed by multidetector computed tomography in symptomatic patients without significant coronary artery disease: insights from the CORE320 multicentre study.

AIM Previous animal studies have demonstrated differences in perfusion and perfusion reserve between the subendocardium and subepicardium. 320-row computed tomography (CT) with sub-millimetre spatial resolution allows for the assessment of transmural differences in myocardial perfusion reserve (MPR) in humans. We aimed to test the hypothesis that MPR in all myocardial layers is determined by age, gender, and cardiovascular risk profile in patients with ischaemic symptoms or equivalent but without obstructive coronary artery disease (CAD). METHODS AND RESULTS A total of 149 patients enrolled in the CORE320 study with symptoms or signs of myocardial ischaemia and absence of significant CAD by invasive coronary angiography were scanned with static rest and stress CT perfusion. Myocardial attenuation densities were assessed at rest and during adenosine stress, segmented into 3 myocardial layers and 13 segments. MPR was higher in the subepicardium compared with the subendocardium (124% interquartile range [45, 235] vs. 68% [22,102], P < 0.001). Moreover, MPR in the septum was lower than in the inferolateral and anterolateral segments of the myocardium (55% [19, 104] vs. 89% [37, 168] and 124% [54, 270], P < 0.001). By multivariate analysis, high body mass index was significantly associated with reduced MPR in all myocardial layers when adjusted for cardiovascular risk factors (P = 0.02). CONCLUSION In symptomatic patients without significant coronary artery stenosis, distinct differences in endocardial-epicardial distribution of perfusion reserve may be demonstrated with static CT perfusion. Low MPR in all myocardial layers was observed specifically in obese patients.

Semi-quantitative myocardial perfusion measured by computed tomography in patients with refractory angina: a head-to-head comparison with quantitative rubidium-82 positron emission tomography as reference

Computed tomography (CT) is a novel method for assessment of myocardial perfusion and has not yet been compared to rubidium‐82 positron emission tomography (PET). We aimed to compare CT measured semi‐quantitative myocardial perfusion with absolute quantified myocardial perfusion using PET and to detect stenotic territories in patients with severe coronary artery disease.