Dobutamine Stress Magnetic Resonance Research Articles

Left ventricular contractile reserve as a determinant of adverse clinical outcomes: a systematic review.

An abnormal left ventricular contractile reserve is often seen in patients undergoing stress echocardiogram and may indicate the presence of obstructive coronary artery disease. The techniques and indexes used to identify abnormal left ventricular contractile response and its prognostic value in the absence of known causes has not been well studied. To describe the characteristics and clinical outcomes associated with an abnormal left ventricular contractile response, we performed a systematic review that identified 27 eligible studies. A diverse range of indices were utilised to measure left ventricular contractile reserve, most commonly Δleft ventricular ejection fraction in 11 studies. Dobutamine stress echocardiogram was the most commonly performed modality (19 studies) followed by exercise stress echocardiogram (4 studies), dipyridamole stress echocardiogram (2 studies), invasive hemodynamic measurement (1 study) and dobutamine stress magnetic resonance imaging (1 study). All but one study demonstrated a significant association between the absence of left ventricular contractile reserve and increased rate of cardiovascular events, cardiac death and all-cause mortality.

Multiparametric Rest and Dobutamine Stress Magnetic Resonance in Assessment of Myocardial Viability.

MR feature-tracking (FT) is a novel technique that quantitatively calculates myocardial strain and can assess myocardial viability. To evaluate the feasibility of FT at rest and with low-dose dobutamine (LDD), visual assessment of contractility with LDD and left ventricle (LV) end-diastolic wall thickness (EDWT) in the assessment of viability in ischemic cardiomyopathy (ICM) patients compared to delayed gadolinium enhancement (DGE). Prospective. Thirty ICM patients and 30 healthy volunteers. A 1.5 T with balanced steady-state free precession (bSSFP) cine and phase-sensitive inversion prepared segmented gradient echo sequences. LDD (5 μg/kg/min and 10 μg/kg/min) was administered in the patient group. LV was divided into 16 segments and MR-FT was derived from bSSFP cine images using dedicated software. Viable segments were defined as those with a dobutamine-induced increase in resting MR-FT values >20%, a dobutamine-induced increase in systolic wall thickening ≥2 mm by visual assessment, ≤50% fibrosis on DGE, and resting EDWT ≥5.5 mm. One-way analysis of variance (ANOVA), two-sampled t-test, paired samples t-test, and receiver operating characteristic (ROC) curve analysis. A P value < 0.05 was considered statistically significant. Resting peak global circumferential (Ecc) and radial (Err) strains were significantly impaired in patients compared to controls (-11.7 ± 7.9 vs. -20.1 ± 5.7 and 19.7 ± 13.9 vs. 32.7 ± 15.4, respectively). Segments with no DGE (n=354) and ≤ 50% (n=38) DGE showed significant improvement of both Ecc and Err with LDD while segments with >50% DGE (n=88) showed no improvement. In comparison to viable and nonviable segments identified by reference-standard DGE, the sensitivity, specificity, and diagnostic accuracy of the four methods were: 74%, 92%, and 89%, respectively, for Ecc; 70%, 89%, and 86%, respectively, for Err; 67%, 88%, and 84% for visual assessment; and 39%, 90%, and 80% for EDWT. Quantitative assessment of MR-FT, along with EDWT and qualitative visual assessment of myocardial contractility with LDD, are feasible alternative methods for the assessment of myocardial viability with moderate sensitivity and high specificity. 1 TECHNICAL EFFICACY: Stage: 2.

P2742Right ventricular stroke volume during dobutamine stress magnetic resonance compared to lung perfusion and peak oxygen uptake after arterial switch operation for transposition of the great arteries

Abstract Objectives Abnormal pulmonary perfusion due to stenosis of the central pulmonary arteries is common after neonatal arterial switch operation (ASO) for transposition of the great arteries (TGA). We conducted a monocentric prospective study in young adults after neonatal ASO for TGA to evaluate the effects of abnormal pulmonary perfusion on the increase of the right ventricular stroke volume (RVSV) during dobutamine stress magnetic resonance (DSMR) and on cardiopulmonary exercise capacity. Methods 68 unselected patients (age 18–29 years) underwent CMR at rest and under dobutamine stress (10 to 40 μg/kg/min). RVSV, pulmonary blood flow distribution (PBFD) and peak flow velocity were derived from phase contrast mapping in the main, right and left pulmonary artery (PA) at rest and each stress level. A cardiopulmonary exercise test (CPET) was performed at the same day. All patients reached maximal exercise effort according to heart rate and respiratory exchange rate. Results PBFD at rest: 9/68 patients (13%, ASO-S) had abnormal pulmonary perfusion at rest, defined as PBFD &gt;2:1 (right/left or left/right) and/or relevant stenosis of the main PA (Vmax &gt;2.5 m/s). 59/68 patients (87%, ASO-N) had normal pulmonary perfusion. PBFD under DSMR: (1) In the whole patient group, there was no increase of PBFD under stress compared to PBFD at rest. On an individual patient level, no relevant worsening of abnormal PBFD was found. (2) Under low dose dobutamine, ASO-S had a significantly lower RVSV-increase (RVSVstress/RVSVrest) compared to ASO-N (see figure). However, under high dose dobutamine, this effect was no longer significant (see figure). (3) The RVSV-increase under low and high dose dobutamine did not correlate with peak oxygen uptake during CPET, neither in the total group nor in the subgroups (see table). Peak oxygen uptake was not significantly different between ASO-N and ASO-S (p=0,72). RVSV-increase compared to CPET peak VO2% ASO-total ASO-S ASO-N RVSV-increase/peak VO2% RVSV-increase/peak VO2% RVSV-increase/peak VO2% low dose dobu high dose dobu low dose dobu high dose dobu low dose dobu high dose dobu Pearson correlation coefficient −0.02 −0.05 0.01 −0.22 −0.05 −0.04 p-value 0.90 0.71 0.98 0.56 0.71 0.78 Figure 1 Conclusion (1) Patients with relevant stenosis of main PA and/or abnormal peripheral blood flow distribution (ASO-S) exhibit a reduced RVSV-increase under low dose dobutamine compared to patients without stenosis (ASO-N). This effect was not present under high dose dobutamine stress. (2) These findings did not correlate with peak oxygen uptake during CPET, an objective parameter of cardiopulmonary exercise capacity. (3) Therefore, a conservative proceeding rather than surgery or catheter intervention should be considered, especially in asymptomatic adult patients. Acknowledgement/Funding Supported by Kinderherzen, Fördergemeinschaft Deutsche Kinderherzzentren e.V.

High-dose dobutamine stress steady-state free precession (SSFP) cine MRI at 3T with patient adaptive local radiofrequency (RF) shimming using dual-source RF transmission.

To prospectively assess the feasibility, image quality, and diagnostic accuracy of high-dose dobutamine stress magnetic resonance imaging (DSMR) using steady-state free precession (SSFP) cine imaging at 3T applying a dual-source radiofrequency (RF) excitation magnetic resonance imaging (MRI) system with parallel transmission and patient adaptive local RF shimming. DSMR using SSFP cine imaging was performed in 44 patients at 3T scheduled for a clinically indicated coronary angiography. The effect of conventional versus dual-source RF transmission was assessed regarding homogeneity of the B1 field, contrast-to-noise ratios (CNRs) at rest, image quality, and diagnostic accuracy of DSMR using long and short axis. The mean percentage of the intended flip angle within the heart increased from 88 ± 9.1% with single-source to 103 ± 5.6% (P < 0.001) dual-source RF transmission. CNR increased for dual-source particularly at the apex (63.4 ± 24.2 vs. 36.5 ± 16.5, P < 0.001) but also at the base of the left ventricle (LV) (50.1 ± 14.8 vs. 39.3 ± 15.8, P < 0.001). Image quality of dual-source was higher both at rest (2.8 ± 0.5 vs. 2.6 ± 0.7, P < 0.001) and stress (2.5 ± 0.7 vs. 2.0 ± 1.0, P < 0.001). The number of segments with severe artifacts or nondiagnostic image quality at stress was lower with dual-source RF transmission (8% vs. 27%, P < 0.001). The diagnostic accuracy of DSMR in coronary territories using dual-source RF transmission was significantly higher (77% vs. 65%, P = 0.04). Patient adaptive local RF shimming using dual-source RF transmission provided significantly improved image quality and higher diagnostic accuracy of SSFP during DSMR at 3T compared to conventional RF transmission.

Magnetic Resonance for Noninvasive Detection of Microcirculatory Disease Associated With Allograft Vasculopathy: Intracoronary Measurement Validation

Introduction and objectivesCardiac allograft vasculopathy affects both epicardial and microcirculatory coronary compartments. Magnetic resonance perfusion imaging has been proposed as a useful tool to assess microcirculation mostly outside the heart transplantation setting. Instantaneous hyperemic diastolic flow velocity-pressure slope, an intracoronary physiology index, has demonstrated a better correlation with microcirculatory remodelling in cardiac allograft vasculopathy than other indices such as coronary flow velocity reserve. To investigate the potential of magnetic resonance perfusion imaging to detect the presence of microcirculatory remodeling in cardiac allograft vasculopathy, we compared magnetic resonance perfusion data with invasive intracoronary physiological indices to study microcirculation in a population of heart transplantation recipients with macrovascular nonobstructive disease demonstrated with intravascular ultrasound. MethodsWe studied 8 heart transplantation recipients (mean age, 61 [12] years, 100% male) with epicardial allograft vasculopathy defined by intravascular ultrasound, nonsignificant coronary stenoses and negative visually-assessed wall-motion/perfusion dobutamine stress magnetic resonance. Quantitative stress and rest magnetic resonance perfusion data to build myocardial perfusion reserve index, noninvasively, and 4 invasive intracoronary physiological indices were determined. ResultsPostprocessed data showed a mean (standard deviation) myocardial perfusion reserve index of 1.22 (0.27), while fractional flow reserve, coronary flow velocity reserve, hyperemic microvascular resistance and instantaneous hyperemic diastolic flow velocity-pressure slope were 0.98 (0.02), cm/s/mmHg, 2.34 (0.55) cm/s/mmHg, 2.00 (0.69) cm/s/mmHg and 0.91 (0.65) cm/s/mmHg, respectively. The myocardial perfusion reserve index correlated strongly only with the instantaneous hyperemic diastolic flow velocity-pressure slope (r=0.75; P=.033). ConclusionsMyocardial perfusion reserve index derived from a comprehensive dobutamine stress magnetic resonance appears to be a reliable technique for noninvasive detection of microcirculatory coronary disease associated with cardiac allograft vasculopathy.

Resonancia magnética para la detección no invasiva de la enfermedad microcirculatoria asociada a la vasculopatía de alotrasplante: validación de la determinación intracoronaria

Introduction and objectivesCardiac allograft vasculopathy affects both epicardial and microcirculatory coronary compartments. Magnetic resonance perfusion imaging has been proposed as a useful tool to assess microcirculation mostly outside the heart transplantation setting. Instantaneous hyperemic diastolic flow velocity-pressure slope, an intracoronary physiology index, has demonstrated a better correlation with microcirculatory remodelling in cardiac allograft vasculopathy than other indices such as coronary flow velocity reserve. To investigate the potential of magnetic resonance perfusion imaging to detect the presence of microcirculatory remodeling in cardiac allograft vasculopathy, we compared magnetic resonance perfusion data with invasive intracoronary physiological indices to study microcirculation in a population of heart transplantation recipients with macrovascular nonobstructive disease demonstrated with intravascular ultrasound. MethodsWe studied 8 heart transplantation recipients (mean age, 61 [12] years, 100% male) with epicardial allograft vasculopathy defined by intravascular ultrasound, nonsignificant coronary stenoses and negative visually-assessed wall-motion/perfusion dobutamine stress magnetic resonance. Quantitative stress and rest magnetic resonance perfusion data to build myocardial perfusion reserve index, noninvasively, and 4 invasive intracoronary physiological indices were determined. ResultsPostprocessed data showed a mean (standard deviation) myocardial perfusion reserve index of 1.22 (0.27), while fractional flow reserve, coronary flow velocity reserve, hyperemic microvascular resistance and instantaneous hyperemic diastolic flow velocity-pressure slope were 0.98 (0.02) cm/s/mmHg, 2.34 (0.55) cm/s/mmHg, 2.00 (0.69) cm/s/mmHg, and 0.91 (0.65) cm/s/mmHg, respectively. The myocardial perfusion reserve index correlated strongly only with the instantaneous hyperemic diastolic flow velocity-pressure slope (r = 0.75; P = .033). ConclusionsMyocardial perfusion reserve index derived from a comprehensive dobutamine stress magnetic resonance appears to be a reliable technique for noninvasive detection of microcirculatory coronary disease associated with cardiac allograft vasculopathy.Full English text available from:www.revespcardiol.org/en

Impact of diastolic wall stress on the diagnostic value of visually interpreted dobutamine stress MR imaging

Dobutamine stress magnetic resonance (DSMR) is a valuable tool for the detection of myocardial ischemia in a wide spectrum of patients [1]. However, previous studies indicated that patients with distinct left ventricular (LV) geometries (i.e., concentric hypertrophy or concentric remodeling) exhibited surprisingly low sensitivity regarding the detection of significant coronary artery disease (CAD) [2]. In a subset of patients with such LV geometries, we frequently encountered uncompromised segmental wall motion (normal endocardial inward motion/systolic thickening) during dobutamine stress testing even in the presence of angiographically severe CAD (≥70% luminal stenosis).

Value of strain analysis with feature tracking in dobutamine stress cardiac magnetic resonance imaging for detecting coronary artery disease

Background Dobutamine stress magnetic resonance (DSMR) has been established for the detection of coronary artery disease (CAD) due to its high diagnostic accuracy and prognostic value. The novel technique feature tracking (FT) analyses regional myocardial strain and thereby offers detailed information about myocardial deformation. The purpose of this study was to examine how FT based circumferential strain (CS) compares to visually detected wall motion abnormalities (WMA) during DSMR and whether it adds beneficial information for detecting CAD. Methods A total of 25 patients (72% male; mean age 64 ± 8) with suspected or known CAD underwent a standardized high-dose DSMR protocol at 1.5 T. CMR images were acquired at rest and during stress in three short-axis views (SAX; apical, medial, basal). None of the patients had evidence for WMAs or impaired left ventricular function at rest or scar tissue based on late gadolinium enhancement (LGE). For strain analysis the SAX planes were divided into 16 segments (n = 400 segments). All patients underwent x-ray coronary angiography for clinical reasons. Patients without WMA during DSMR and exclusion of CAD by coronary angiography were defined as normal and served as control (10 patients, 160 segments). 15 patients developed WMA during DSMR (34 segments). Additionally, based on angiographic findings, segments that were supplied by a vessel with >75% were defined as stenotic (64 segments). The remaining segments, which did not develop a WMA or were supplied by a vessel <50% narrowing, were considered as remote segments (161 segments). Results At rest no differences in CS were observed between groups (normal: -28.1 ± 8.9; WMA: -24.8 ± 12.9; stenotic: 25.8 ± 10.6; remote: 27.7 ± 11.7%; p = 0.23). High dose dobutamine stress revealed highly significant differences between normal segments and segments with WMA (normal: -39.3 ± 11.3%; WMA: 19.2 ± 19.1%; p < 0.001) as well as between normal and stenotic and normal and remote segments (stenotic: -23.8 ± 15.9%, p < 0.001; remote: -34.2 ± 14.1%, p < 0.001). Additionally, analysis of the absolute change in CS between rest and stress showed significant differences for normal segments vs. segments with WMA (Δ normal: -11.2 ± 12.6%, Δ WMA: 5.6 ± 22.9%; p = 0.001), as well as between normal and stenotic segments (Δ stenotic: 1.9 ± 18.4%; p < 0.001) and between normal and remote segments (Δ remote: -6.6 ± 16.3%; p = 0.027). CS results are summarized in Figure 1. ROC analysis of CS during maximum DSMR differentiated normal from stenotic segments with a sensitivity of 75% and specificity of 67% using a cutoff -33.2% with an area under the curve of 0.78 (Figure 2). Conclusions FT based CS analysis demonstrated significant differences between normal segments and segments with WMA in DSMR. Additionally, FT detected significantly impaired CS in stenotic segments compared to normal segments. FT based CS may improve the diagnostic accuracy of DSMR for detection of ischemia.

High-dose dobutamine stress magnetic resonance perfusion imaging at 3.0 Tesla

Background Dobutamine stress magnetic resonance (DSMR-wall motion) has been established as a valuable tool for the detection of inducible wall motion abnormalities. Additional perfusion imaging during DSMR (DSMR-perfusion) was shown to improve sensitivity for the detection of myocardial ischemia. Current experience is based on 1.5T only, mainly due to insufficient image quality of steady state free precession (SSFP) cine imaging at higher field strengths. Recently, image quality and diagnostic accuracy of SSFP sequences was significantly improved by dual-source parallel radiofrequency (RF) transmission for 3.0T. We examined whether the addition of myocardial perfusion imaging during DSMR at 3.0T is feasible and whether it provides incremental benefit for the evaluation of CAD.

Update on Dobutamine Stress Magnetic Resonance

Over the past years dobutamine stress magnetic resonance imaging (DSMR) has matured into a highly valuable clinical tool for the assessment of myocardial ischemia and viability. Furthermore, the results of DSMR can be utilized to direct clinical management and to determine cardiac prognosis. This article gives an update on recently published data regarding the performance of DSMR including technical developments, diagnostic accuracy, prognosis, and the implications on clinical management in patients with coronary artery disease (CAD).

Feasibility of high dose dobutamine stress and scar imaging in high field open MRI in patients with suspected coronary artery disease

Background High-dose dobutamine-stress magnetic resonance (DSMR) and late gadolinium enhanced cardiac magnetic resonance (LGE-CMR) imaging are well established for the detection of significant cardiovascular disease (CAD) and infarction for cylindrical 1.5 T or 3T. Due to the narrow bore, patients (pts) with obesity or claustrophobia usually cannot be studied with conventional MRI scanners. 1.0T high field open (HFO) is a non-cylindrical MRI system offering significantly more space but has only rarely been utilized for diagnostic cardiac MRI so far. In this pilot study we sought to investigate the performance of 1.0T HFO DSMR and LGE-CMR in pts with suspected CAD and low to intermediate risk profile.

Cardiac magnetic resonance myocardial feature tracking correlates with natural radial strain and corresponds to inotropic stimulation

Summary We have demonstrated that cardiac magnetic resonance (CMR) myocardial feature tracking (FT) and natural radial strain correlate and correspond to inotropic stimulation. CMR-FT has the potential for quantitative wall motion assessment at rest and during dobutamine stress magnetic resonance (DSMR) imaging. Background CMR-FT is a recently introduced technique for tissue voxel motion tracking on standard steady-state free precession (SSFP) images to derive radial myocardial mechanics. CMR-FT has the potential to facilitate DSMR analysis however has not yet been compared to external reference standards (with stress) such as SSFP derived natural radial strain. Methods 10 healthy subjects were studied at 1.5 Tesla. LV shortaxis radial strain ErrSAX was derived from SSFP cine images using dedicated CMR-FT software (Diogenes MRI prototype, Tomtec, Germany) at rest and during dobutamine stress (10 and 20 μg * kg-1* min-1). Natural radial strain values (loge [End-systolic wall thickness/ end-diastolic wall thickness]) were calculated in identical segments as analysed for ErrSAX using commercially available software (Philips View Forum, The Netherlands). 95% confidence intervals (CI) of the difference and p-values were calculated to compare the 2 techniques. Results In all volunteers strain parameters could be derived from the SSFP images at rest and stress. ErrSAX values showed significantly increased contraction with DSMR (rest: 19.6±14.6; 10 μg: 31.8±20.9; 20 μg: 42.4±25.5, p<0.05). Natural radial strain values increased with dobutamine (rest: 24±8.9; 10 μg: 36.5±8.9; 20 μg: 44.2 ±8.5, p<0.05). There was reasonable agreement between mean ErrSAX and natural radial strain at rest and with dobutamine stress (figure 1 and table 1) as determined by 95% CI of the difference. Conclusions

High-dose dobutamine stress SSFP cine MRI at 3 Tesla with patient adaptive local RF shimming using dual-source RF transmission

Background Image quality of cine imaging using steady state free precession (SSFP) sequences at 3T is insufficient due to increased RF-inhomogeneity (B1 field) and the high sensitivity of SSFP sequences to off-resonance artefacts. Recently, the introduction of a dual source RF transmission system with patient-adaptive local RF-shimming has led to a significant improvement of image quality of SSFP imaging at 3T. The objective of this study was to prospectively evaluate the feasibility, image quality and diagnostic accuracy of high-dose dobutamine stress magnetic resonance imaging (DSMR) at 3T comparing dual-source versus single-source transmit technology.

Assessment of warranty time for dobutamine stress magnetic resonance imaging in 3138 consecutive patients: a bi-center study

Summary We aimed to determine the prognostic value of wall motion assessment during high-dose dobutamine stress cardiac magnetic resonance imaging (DCMR) for the prediction of hard cardiac events in a large patient cohort and within a long follow-up duration. DCMR can accurately identify between patients with inducible ischemia who are at increased risk for future hard cardiac events and revascularization procedures. Within the ‘primary warranty time’ of 3 years after DCMR excellent outcomes (annual hard cardiac event rate 90 days after the MR-scans were prospectively collected at least 6 months after DCMR. Results

Cardiovascular magnetic resonance myocardial feature tracking for quantitative viability assessment in ischemic cardiomyopathy

BackgroundLow dose dobutamine stress magnetic resonance imaging is valuable to assess viability in patients with ischemic cardiomyopathy. Analysis is usually qualitative with considerable operator dependency. The aim of the current study was to investigate the feasibility of cine images derived quantitative cardiac magnetic resonance (CMR) myocardial feature tracking (FT) strain parameters to assess viability in patients with ischemic cardiomyopathy. Methods15 consecutive patients with ischemic cardiomyopathy referred for viability assessment were studied at 3T at rest and during low dose dobutamine stress (5 and 10μg/kg/min of dobutamine). Subendocardial and subepicardial circumferential (Eccendo and Eccepi) and radial (Err) strains were assessed using steady state free precession (SSFP) cine images orientated in 3 short axis slices covering 16 myocardial segments. ResultsDysfunctional segments without scar (n=75) improved in all three strain parameters: Eccendo (Rest: −10.5±6.9; 5μg: −12.1±6.9; 10μg: −14.1±9.2; p<0.05), Eccepi (Rest: −7±4.8; 5μg: −8.2±5.5; 10μg: −9.1±5.9; p<0.05) and Err (Rest: 11.7±8.3; 5μg: 16±10.9; 10μg: 16.5±12.8; p<0.05).There was no response to dobutamine in dysfunctional segments with scar transmurality above 75% (n=6): Eccendo (Rest: −4.7±3.0; 5μg: −2.9±2.5; 10μg: −6.6±3.3; p=ns), Eccepi (Rest: −2.9±2.9; 5μg: −5.4±3.9; 10μg: −4.5±4.2; p=ns) and Err (Rest:9.5±5; 5μg:5.4±6.2; 10μg:4.9±3.3; p=ns). Circumferential strain (Eccendo, Eccepi) improved in all segments up to a transmurality of 75% (n=60; p<0.05). Err improved in segments <50% transmurality (n=45; p<0.05) and remained unchanged above 50% transmurality (n=21; p=ns). ConclusionsCMR-FT is a novel technique, which detects quantitative wall motion derived from SSFP cine imaging at rest and with low dose dobutamine stress. CMR-FT holds promise of quantitative assessment of viability in patients with ischemic cardiomyopathy.

Exercise capacity and cardiac reserve in children and adolescents with corrected pulmonary atresia with intact ventricular septum after univentricular palliation and biventricular repair

Management of pulmonary atresia with intact ventricular septum is challenging and depends on the severity of right ventricular hypoplasia. Clinical outcomes of biventricular repair seem favorable to univentricular palliation, but data on superiority of biventricular repair regarding exercise capacity are conflicting. We investigated the response to physical and pharmacologic stress in patients with surgically corrected pulmonary atresia with intact ventricular septum. Sixteen patients (7 patients after univentricular palliation, age 11.8 ± 2.6 years; 7 patients after biventricular repair, age 12.9 ± 2.7 years; and 2 patients after 1.5 ventricular repair, age 12 and 19 years) underwent cardiopulmonary exercise test, dobutamine stress magnetic resonance imaging, and delayed contrast-enhanced magnetic resonance imaging. The univentricular group showed impaired exercise capacity in contrast with normal exercise capacity in the biventricular group. Left ventricular ejection fraction increased in both groups. With dobutamine, left ventricular stroke volume increased only in the biventricular group (+11.3 ± 5.0 mL, P<.001) and not in the univentricular group (-0.04 ± 3.6 mL, P=.9). Heart rate increase was inadequate in the univentricular group. Maximum oxygen consumption and oxygen pulse were strongly correlated with left ventricular stroke volume during stress but not at rest. The results of the 2 patients after 1.5 ventricular repair were comparable to those of the univentricular group. No myocardial fibrosis was detected. Impaired exercise capacity in children and adolescents with pulmonary atresia with intact ventricular septum after univentricular palliation is related to decreased cardiac reserve and inadequate chronotropic response. Young patients with pulmonary atresia with intact ventricular septum after biventricular repair show normal exercise capacity and cardiac reserve.

Nichtinvasive Diagnostik der chronisch stabilen koronaren Herzkrankheit: evidenzbasierte und nicht evidenzbasierte diagnostische Algorithmen

In Germany, every second left heart catheterization has no immediate interventional or surgical consequence. One main reason for this limited quality of indication of many left heart catheterizations is presumably the inaccuracy of preinvasive testing that is mainly based on clinical evaluation and exercise ECG in Germany. However, exercise electrocardiography has several limitations. The central issues are the inability to exercise in many, especially elderly patients, and the missing interpretability of the stress ECG in cases with already pathological rest ECG. In 2006, the "Nationale Versorgungsleitlinie Chronische KHK (NVL KHK)" was published in Germany, adopting for the first time the evidence-based algorithms of the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for non-invasive stress testing and complementary stress imaging. Stress imaging methods considered comparable and interchangeable are the following: stress echocardiography combined with physical or pharmacological stress testing, myocardial perfusion imaging with physical or pharmacological stress testing, dobutamine stress magnetic resonance imaging (DSMR), or myocardial perfusion magnetic resonance imaging (MRI). Basically, no stress imaging method is definitely superior to the others, each method has its own advantages and disadvantages that should be considered and adjusted to the individual patient. Of pivotal importance of all stress imaging methods is the high negative predictive value of 99% of a normal study predicting a very low (< 1%) cumulative likelihood of cardiac death or myocardial infarction for at least the next 12 months. Hence, in most clinical circumstances, coronary angiography is not necessary during the 12 months subsequent to a normal stress imaging study. In contrast to these established and evidence-based recommendations of the "Nationale Versorgungsleitlinie Chronische KHK" mainly focusing on ischemia stress imaging, many diagnostic centers have developed their own non-evidence based algorithms. In these non-evidence based algorithms the morphology-oriented non-invasive CT coronary angiography has taken over the diagnostic part of evidence-based ischemia stress imaging. However, beyond the scientifically established prognostic value of calcium scoring, there is so far no scientific evidence showing that morphology-oriented CT coronary angiography protocols are superior to functional stress imaging. A new innovative approach of staged non-invasive diagnostics for patients with intermediate likelihood (10-90%) of coronary artery disease are the 2010 recommendations of the National Institute for Health and Clinical Excellence (NICE) guiding the National Health Service (NHS) in the United Kingdom. Following this guidance, in patients with an estimated likelihood of CAD of 10-29% CT calcium scoring should be offered as first-line method, in patients with an estimated likelihood of CAD of 30-60% non-invasive functional imaging should be offered primarily, and in patients with an estimated likelihood of CAD of 61-90%, as in patients with an estimated likelihood of CAD of more than 90%, invasive coronary angiography should be preferred.

Wall motion recovery in dobutamine stress magnetic resonance imaging

Methods DSMR was performed in twenty-eight consecutive patients with suspected or known CAD scheduled for clinically indicated invasive coronary angiography. Each patient underwent routine DSMR including cine imaging at rest and during dobutamine infusion. Additionally, three standard short axis and longitudinal axis views were obtained after five, ten and fifteen minutes during the recovery period in order to detect persisting wall motion abnormalities in ischemic myocardial territories, which were assigned to coronary arteries based on the 17 segment model. Intermediate and severe coronary stenosis were defined as 50-75% and >75% luminal narrowing using invasive coronary angiography, respectively (figure 1). All patients received esmolol after stopping the dobutamine infusion to achieve a heart rate under 100bpm.

The role of dobutamine stress magnetic resonance in the clinical management of patients with coronary artery disease

The role of dobutamine stress magnetic resonance in the clinical management of patients with coronary artery disease

Myocardial feature tracking for viability assessment in ischemic cardiomyopathy

Background Low dose dobutamine stress magnetic resonance imaging (LDDSMR) is a widely accepted technique for assessment of hibernating myocardium in patients with ischemic cardiomyopathy (ICMP). It is particularly helpful in patients with intermediate transmurality of scar where prediction of functional recovery by late gadolinium enhancement imaging (LGE) alone is difficult. Analysis of LDDSMR is usually based on visual assessment and is therefore considerably operator dependant. Recently myocardial feature tracking (FT) has been introduced. It tracks tissue voxel motion of cine-MR images to assess circumferential and radial myocardial strain independent of additional sequences.