Impact of Atrial Fibrillation on the Symptoms and Echocardiographic Evaluation of Patients With Aortic Stenosis.

Atrial fibrillation (AF) is common in patients with aortic stenosis (AS) and complicates the assessment of AS severity. The overlapping of symptoms in these 2 conditions may postpone valve replacement. This study aimed to evaluate the effect of AF on the severity assessment of AS and its impact on symptoms and quality of life (QoL). Patients with severe AS were prospectively recruited. Echocardiography, symptom questionnaires, and RAND-36 QoL assessment were performed preoperatively and 3 months postoperatively. The aortic valve calcium score (AVC) was measured using computed tomography. Of the 279 patients, 74 (26.5%) had AF. Patients with AF had lower mean gradients and 45.9% had a low-gradient phenotype, with a mean gradient <40 mm Hg, compared with 22.4% of those without AF (p <0.001). The AVC measurements revealed severe valve calcification equally in patients with or without AF (85.7% vs 87.7%, p = 0.78). Patients with AF were more symptomatic at baseline, with 50.0% versus 27.3% in New York Heart Association class III or higher (p <0.001), and after intervention. Patients with AF had more residual dyspnea (27.3% vs 12.0%, p = 0.007) and exercise intolerance (36.4% vs 17.0%, p = 0.002). The QoL improved significantly in both groups but was worse at baseline in patients with AF and remained impaired after intervention. In conclusion, low-gradient AS phenotype is overrepresented in patients with AF, but they have equally severe stenosis determined using AVC, despite the lower gradients. Patients with AF have more symptoms and worse QoL, but they improve significantly after intervention. In patients with AF, multimodality imaging is important in the assessment of AS severity.

Peak flow measurements in patients with severe aortic stenosis: a prospective comparative study between cardiovascular magnetic resonance 2D and 4D flow and transthoracic echocardiography.

BACKGROUND: Aortic valve stenosis (AS) is the most prevalent valvular disease in the developed countries. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) is an emerging imaging technique, which has been suggested to improve the evaluation of AS severity compared to two-dimensional (2D) flow and transthoracic echocardiography (TTE). We investigated the reliability of CMR 2D flow and 4D flow techniques in measuring aortic transvalvular peak systolic flow in patients with severe AS. METHODS: We prospectively recruited 90 patients referred for aortic valve replacement due to severe AS (73.3 ± 11.3 years, aortic valve area 0.7 ± 0.1 cm2, and 54/36 tricuspid/bicuspid), and 10 non-valvular disease controls. All the patients underwent echocardiography and 2D flow and 4D flow CMR. Peak flow velocity measurements were compared using Wilcoxon signed rank sum test and Bland-Altman analysis. RESULTS: 4D flow underestimated peak flow velocity in the AS group when compared with TTE (bias - 1.1 m/s, limits of agreement ± 1.4 m/s) and 2D flow (bias - 1.2 m/s, limits of agreement ± 1.6 m/s). The differences between values obtained by TTE (median 4.3 m/s, range 2.7-6.1 m/s) and 2D flow (median 4.5 m/s, range 2.9-6.5 m/s) compared to 4D flow (median 3.1 m/s, range 1.7-5.1 m/s) were significant (p < 0.001). The difference between 2D flow and TTE were insignificant (bias 0.07 m/s, limits of agreement ± 1.5 m/s). In non-valvular disease controls, peak flow velocity was measured higher by 4D flow than 2D flow (1.4 m/s, 1.1-1.7 m/s and 1.3 m/s, 1.1-1.5 m/s, respectively; bias 0.2 m/s, limits of agreement ± 0.16 m/s). CONCLUSIONS: CMR 4D flow significantly underestimates systolic peak flow velocity in patients with severe AS. 2D flow, in turn, estimated the AS velocity accurately, with measured peak flow velocities comparable to TTE.

Peak CK-MB has a strong association with chronic scar size and wall motion abnormalities after revascularized non-transmural myocardial infarction - a prospective CMR study.

BACKGROUND: Large myocardial infarction (MI) is associated with adverse left ventricular (LV) remodeling (LVR). We studied the nature of LVR, with specific attention to non-transmural MIs, and the association of peak CK-MB with recovery and chronic phase scar size and LVR. METHODS: Altogether 41 patients underwent prospectively repeated cardiovascular magnetic resonance at a median of 22 (interquartile range 9-29) days and 10 (8-16) months after the first revascularized MI. Transmural MI was defined as ≥75% enhancement in at least one myocardial segment. RESULTS: Peak CK-MB was 86 (40-216) µg/L in median, while recovery and chronic phase scar size were 13 (3-23) % and 8 (2-19) %. Altogether 33 patients (81%) had a non-transmural MI. Peak CK-MB had a strong correlation with recovery and chronic scar size (r ≥ 0.80 for all, r ≥ 0.74 for non-transmural MIs; p < 0.001). Peak CK-MB, recovery scar size, and chronic scar size, were all strongly correlated with chronic wall motion abnormality index (WMAi) (r ≥ 0.75 for all, r ≥ 0.73 for non-transmural MIs; p < 0.001). There was proportional scar size and LV mass resorption of 26% (0-50%) and 6% (- 2-14%) in median. Young age (< 60 years, median) was associated with greater LV mass resorption (median 9%vs.1%, p = 0.007). CONCLUSIONS: Peak CK-MB has a strong association with chronic scar size and wall motion abnormalities after revascularized non-transmural MI. Considerable infarct resorption happens after the first-month recovery phase. LV mass resorption is related to age, being more common in younger patients.

Cardiac deformation imaging.

Deformation imaging (strain imaging) is an echocardiographic method for evaluating myocardial function that is also suitable for clinical use. There are two deformation imaging techniques: Tissue Doppler and 2D strain (speckle tracking). Deformation imaging allows the measurement of regional myocardial deformation in three dimensions. Longitudinal deformation (strain) measures longitudinal myocardial fiber contraction, and reflects subendocardial myocardial function, which is usually the first to deteriorate in patients with heart disease. Reduced longitudinal strain can reveal heart disease even when ejection fraction and cardiac contractility appear normal. Deformation imaging can be used for diagnosing ischemia, distinguishing between pathological and physiological hypertrophy, and early detection of heart disease in hypertension or diabetes. Global longitudinal strain (GLS) is an indicator of overall left ventricular systolic function, and correlates with the prognosis better than ejection fraction.

Assessment of myocardial infarct size with body surface potential mapping: validation against contrast-enhanced cardiac magnetic resonance imaging.

BACKGROUND: Assessment of myocardial infarct (MI) size is important for therapeutic and prognostic reasons. We used body surface potential mapping (BSPM) to evaluate whether single-lead electrocardiographic variables can assess MI size. METHODS: We performed BSPM with 120 leads covering the front and back chest (plus limb leads) on 57 patients at different phases of MI: acutely, during healing, and in the chronic phase. Final MI size was determined by contrast-enhanced cardiac magnetic resonance imaging (DE-CMR) and correlated with various computed depolarization- and repolarization-phase BSPM variables. We also calculated correlations between BSPM variables and enzymatic MI size (peak CK-MBm). RESULTS: BSPM variables reflecting the Q- and R wave showed strong correlations with MI size at all stages of MI. R width performed the best, showing its strongest correlation with MI size on the upper right back, there representing the width of the "reciprocal Q wave" (r = 0.64-0.71 for DE-CMR, r = 0.57-0.64 for CK-MBm, P < 0.0001). Repolarization-phase variables showed only weak correlations with MI size in the acute phase, but these correlations improved during MI healing. T-wave variables and the QRSSTT integral showed their best correlations with DE-CMR defined MI size on the precordial area, at best r = -0.57, P < 0.0001 in the chronic phase. The best performing BSPM variables could differentiate between large and small infarcts at all stages of MI. CONCLUSIONS: Computed, single-lead electrocardiographic variables can estimate the final infarct size at all stages of MI, and differentiate large infarcts from small.

Predicting recovery of myocardial function by electrocardiography after acute infarction.

BACKGROUND: In acute ischemic left ventricular (LV) dysfunction, distinguishing viable myocardium is clinically important. METHODS: Body surface potential mapping (Electrocardiography [ECG] with 123 leads), was recorded in 62 patients with acute coronary syndrome (ACS). ECG variables were computed from de- and repolarization phases. LV segmental wall motion was assessed by echocardiography acutely and after 1 year. RESULTS: The number of dysfunctional segments (DFS) diminished during follow-up in 37 patients (recovery group) and remained the same or increased in 25 patients (nonrecovery group). Acutely, DFS was 5.7 ± 2.1 versus 4.4 ± 2.4 (P = 0.02), and peak CK-MBm 141 ± 157 versus 156 ± 167 µg/L (P = 0.78) in the recovery versus nonrecovery group. At follow-up, DFS was 1.9 ± 1.7 versus 6.5 ± 2.6 (P < 0.001). The best ECG variable to predict decrease in DFS depended on the region of acute LV dysfunction: The best variable in the left anterior descending region was the integral of the first QRS integral (area under the curve [AUC] 0.82, P = 0.002); in the right coronary artery region, this was the integral of the ST segment (AUC 0.98, P = 0.003); and in the left circumflex region, the area including the ST segment and the T wave (AUC 0.97, P = 0.006). CONCLUSIONS: In ACS patients, computed ECG variables predict recovery of LV function from ischemic myocardial injury, even in the presence of comparable CK-MBm release and LV dysfunction.

Can strain rate imaging predict recovery of contraction after acute myocardial infarction?

AIMS: To assess whether strain rate imaging (SRI) can serve to evaluate myocardial viability in patients with acute coronary syndrome (ACS). METHODS AND RESULTS: In 23 patients with ACS, we measured longitudinal tissue Doppler strain and strain rate values from left ventricular basal, mid, and apical segments (n = 414). These segments were grouped according to their acute end-systolic strain values (S(ES)) into those with normocontraction (S(ES)≤-13%), hypocontraction (S(ES) between -13 and -7%), and severe contraction abnormality (S(ES)>-7%). At 8 months, we evaluated the recovery of contraction: Segments with acutely severe contraction abnormality that improved their strain values to ≤-7% were defined as viable, and those that failed to do so as non-viable. In the acute phase, S(ES), post-systolic strain, as well as systolic, early, and late diastolic strain rate values were significantly better in the viable than in the non-viable segments. Post-systolic strain had the best AUC 0.78, and a cut-off value of -3.8% predicted recovery from severe contraction abnormality with a sensitivity of 85% and specificity of 62%. The transmurality of the infarction, assessed by magnetic resonance imaging with delayed enhancement, was significantly larger in the non-viable than in the viable segments (P = 0.006). Acute global S(ES) and systolic strain rate showed the best correlations with final global S(ES) and global infarction percentage after recovery. CONCLUSION: SRI can serve to evaluate myocardial viability in patients with ACS, and to assess the recovery of segmental as well as global left ventricular function.

Tissue Doppler strain-mapping in the assessment of the extent of chronic myocardial infarction: validation using magnetic resonance imaging.

AIMS: The distribution of myocardial strain values can be visualized by colour-coded strain images. We examined for the first time if this strain-mapping function can be used to study the extent of prior myocardial infarction. METHODS AND RESULTS: Echocardiography and cardiac magnetic resonance imaging with delayed contrast enhancement were performed in 26 patients with chronic myocardial infarction. Two-dimensional strain images of the left ventricle were obtained in all standard apical views. Myocardial segments (n = 416) were assigned a score ranging from one to four based on the strain-coded colour of the segment, with higher scores representing worse myocardial function. Strain-mapping scores and quantitative strain values averaged, respectively, 1.3 +/- 0.6 and -16.4 +/- 7.6% in segments without infarction, 1.7 +/- 1.0 and -15.0 +/- 8.6% in non-transmural infarctions, and 2.8 +/- 1.2 and -6.5 +/- 8.6% in transmural infarctions. Strain-mapping had a sensitivity of 60% and a specificity of 95% in detecting segments with transmural myocardial infarction. Corresponding values for echocardiographic wall motion analysis were 50 and 96%. Strain-mapping was possible in 80% of the segments and inter-observer agreement was substantial (kappa = 0.63). CONCLUSION: Strain-mapping is a clinically applicable method for the assessment of regional myocardial function in post-myocardial infarction patients. Strain-mapping has reasonable feasibility and is more sensitive in detecting infarction damage than routine wall motion analysis.