Kiril Aleksov Ahtarovski

Final infarct size measured by cardiovascular magnetic resonance in patients with ST elevation myocardial infarction predicts long-term clinical outcome: an observational study

AIMS Tailored heart failure treatment and risk assessment in patients following ST-segment elevation myocardial infarction (STEMI) is mainly based on the assessment of the left ventricular (LV) ejection fraction (EF). Assessment of the final infarct size in addition to the LVEF may improve the prognostic evaluation. To evaluate the prognostic importance of the final infarct size measured by cardiovascular magnetic resonance (CMR) in patients with STEMI. METHODS AND RESULTS In an observational study the final infarct size was measured by late gadolinium enhancement CMR 3 months after initial admission in 309 patients with STEMI. The clinical endpoint was a composite of all-cause mortality and admission for heart failure. During the follow-up period of median 807 days (IQR: 669-1117) 35 events (5 non-cardiac deaths, 3 cardiac deaths, and 27 admissions for heart failure) were recorded. Patients with a final infarct size ≥ median had significantly higher event rates than patients with a final infarct size <median (17 vs. 6%; Log rank P = 0.002). In a multivariable Cox regression analysis, including age, peak troponin T, LVEF, LV volume index, and heart rate, the final infarct size remained significantly associated with the occurrence of subsequent events (adjusted hazard ratio 1.13 per 1% increase (95% CI: 1.05-1.21; P = 0.001). The overall Wald χ(2) value of a model including known risk factors was 47.3, which increased to 57.9 when the final infarct size was added (P = 0.001 for the difference). CONCLUSION Assessment of the final infarct size by CMR 3 months after a STEMI provides strong independent prognostic information incremental to known risk factors including the LVEF, and may help to improve the risk stratification of STEMI patients.

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.

Deferred stent implantation in patients with ST-segment elevation myocardial infarction: a pilot study

AIMS Disturbance in the flow of an infarct-related artery due to embolisation of thrombus and plaque material occurs frequently during primary percutaneous coronary intervention (PCI) and is associated with impaired prognosis. The aim of the present study was to minimise the risk of embolisation during PCI in patients with ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS Of 124 consecutive patients with STEMI, thrombectomy and/or balloon dilatation was performed in 110 (89%). Stent implantation was deferred in 113 (91%) patients who then comprised the study group. In 38% of the patients stent implantation was deemed unnecessary at the second examination because of <30% residual stenosis and no visible thrombus, and all lesions re-examined three months later were patent. Major adverse cardiac events occurred in two patients during eight months of follow-up (one cardiac death, one case of reinfarction with target lesion revascularisation). In five patients no PCI was performed at all. Myocardial salvage determined by cardiac magnetic resonance in a subset of patients was relatively high. CONCLUSIONS Deferred stent implantation is safe in the majority of patients with STEMI. Although the concept has to be evaluated in a randomised trial, the strategy may prove beneficial for many patients referred for primary PCI.

Efficacy and safety of the angiotensin II receptor blocker losartan for hypertrophic cardiomyopathy: the INHERIT randomised, double-blind, placebo-controlled trial.

BACKGROUND No medical treatment has been reliably shown to halt or reverse disease progression in hypertrophic cardiomyopathy, but the results of several pilot studies have suggested beneficial effects of angiotensin II receptor blockers on left ventricular hypertrophy and fibrosis, which are predictive of an adverse outcome. We aimed to assess the effect of the angiotensin II receptor blocker losartan on left ventricular hypertrophy and fibrosis in patients with hypertrophic cardiomyopathy. METHODS In this single-centre, randomised, double-blind, placebo-controlled trial, adult patients (aged 18 years and older) with obstructive or non-obstructive hypertrophic cardiomyopathy were randomly assigned via computer-based system to losartan (100 mg per day) or placebo for 12 months. Patients and investigators were masked to assigned treatment. The primary endpoint was change in left ventricular mass as assessed by cardiac magnetic resonance imaging (CMR) or CT. Efficacy analyses were done in the modified intention-to-treat population (all patients with data available at the 12-month follow-up). The trial is registered with ClinicalTrials.gov, number NCT01447654. FINDINGS Between Dec 1, 2011, and May 1, 2013, 318 patients were screened. 133 patients (mean age 52 years [SD 13], 35% women) consented and were randomly assigned to placebo (n=69) or losartan (n=64). 124 (93%) patients completed the study and were included in the modified intention-to-treat analysis for the primary endpoint. After 12 months we noted no significant difference in the change in left ventricular mass between the placebo group and the losartan group (mean difference 1 g/m(2), 95% CI -3 to 6; p=0·60). A decrease in systolic blood pressure in the losartan group (from mean 127 mm Hg [SD 12] to 121 mm Hg [14]; p=0·0001) confirmed drug compliance; blood pressure did not decrease in the placebo group. Two (2%) patients, both in the placebo group, died from sudden cardiac death during follow-up. In the losartan group, one (1%) patient had angioedema, one (1%) had deterioration of renal function, and one (1%) had hyperkalaemia. Treatment was well tolerated by patients with left ventricular outflow obstruction at baseline. INTERPRETATION Our findings challenge the generally held view that angiotensin II receptor blockers reduce cardiac hypertrophy. Treatment with losartan was safe, suggesting that it can be used for other indications in patients with hypertrophic cardiomyopathy, irrespective of obstructive physiology. Additional studies are needed to assess the effect of angiotensin II receptor blockers in preclinical hypertrophic cardiomyopathy-eg, in genotype-positive but phenotype-negative individuals.

Takotsubo cardiomyopathy, a two-stage recovery of left ventricular systolic and diastolic function as determined by cardiac magnetic resonance imaging

AIMS Takotsubo cardiomyopathy (TTC) is an entity mimicking acute myocardial infarction, characterized by transient severe systolic heart failure. Echocardiographic studies suggest that diastolic dysfunction is present in TTC at presentation; however, no reports exist regarding the time course of left ventricular (LV) recovery. This study describes the recovery of LV systolic and diastolic function in TTC. We hypothesized that, in TTC, there is diastolic dysfunction at admission, and that recovery is delayed compared with systolic function. METHODS AND RESULTS We enrolled (consecutively 2010-12) 16 patients (mean age 66, range 39-84 years) diagnosed with TTC and 20 healthy matched controls. We performed cardiac magnetic resonance imaging (CMR) at admission, pre-discharge, and 3-month follow-up. Diastolic function was assessed by LV peak filling rate (LVPFR) and left atrial (LA) emptying volumes. At admission, LV ejection fraction was low, increased at pre-discharge (37 ± 6 vs. 58 ± 6%, P < 0.001), and normalized at follow-up (to 65 ± 5%, P = 0.01). LVPFR did not increase during hospitalization (80 ± 3 vs. 89 ± 4 mL/s/m(2), P = 0.21), but was normalized at follow-up (to 206 ± 19, P < 0.001; controls, 214 ± 13, P = 0.23). During hospitalization, LA passive emptying volume remained low (6 ± 2 vs. 8 ± 3 mL/m(2), P = 0.05) and LA active emptying volume remained high (17 ± 3 vs. 16 ± 3 mL/m(2), P = 0.71), whereas LA conduit volume increased (7 ± 3 vs. 23 ± 4 mL/m(2), P < 0.001). T2-weighted imaging demonstrated non-coronary distributed apical oedema without contrast enhancement. CONCLUSION Patients with TTC undergo fast systolic recovery. However, at discharge, profound diastolic dysfunction is demonstrated by CMR. At follow-up, both LV systolic and diastolic function is normalized in patients with recovered TTC.

Comparison of Selvester QRS score with magnetic resonance imaging measured infarct size in patients with ST elevation myocardial infarction

BACKGROUND AND PURPOSE Recent studies have shown that the Selvester QRS score is significantly correlated with delayed enhancement-magnetic resonance imaging (DE-MRI) measured myocardial infarct (MI) size in reperfused ST elevation MI (STEMI). This study further tests the hypothesis that Selvester QRS score correlates well with MI size determined by DE-MRI in reperfused STEMI. METHODS AND RESULTS The relationship was evaluated retrospectively in 55 first-time STEMI patients 3 months after receiving primary percutaneous coronary intervention. Selvester QRS score and DE-MRI MI size were significantly correlated, r = 0.41 (P < .01). The difference between the Selvester QRS score and DE-MRI was 5.8% MI of the left ventricle (95% confidence interval, 2.9%-8.6%). Furthermore, increasing difference between Selvester QRS score and DE-MRI was observed with increasing MI size. CONCLUSION Selvester QRS score correlated only moderately with DE-MRI MI size. Selvester QRS score overestimated MI size.

Effect of Ischemic Postconditioning During Primary Percutaneous Coronary Intervention for Patients With ST-Segment Elevation Myocardial Infarction: A Randomized Clinical Trial

Importance Ischemic postconditioning of the heart during primary percutaneous coronary intervention (PCI) induced by repetitive interruptions of blood flow to the ischemic myocardial region immediately after reopening of the infarct-related artery may limit myocardial damage. Objective To determine whether ischemic postconditioning can improve the clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Design, Setting, And Participants In this multicenter, randomized clinical trial, patients with onset of symptoms within 12 hours, STEMI, and thrombolysis in myocardial infarction (TIMI) grade 0-1 flow in the infarct-related artery at arrival were randomized to conventional PCI or postconditioning. Inclusion began on March 21, 2011, through February 2, 2014, and follow-up was completed on February 2, 2016. Analysis was based on intention to treat. Interventions Patients were randomly allocated 1:1 to conventional primary PCI, including stent implantation, or postconditioning performed as 4 repeated 30-second balloon occlusions followed by 30 seconds of reperfusion immediately after opening of the infarct-related artery and before stent implantation. Main Outcome and Measures A combination of all-cause death and hospitalization for heart failure. Results During the inclusion period, 1234 patients (975 men [79.0%] and 259 women [21.0%]; mean [SD] age, 62 [11] years) underwent randomization in the trial. Median follow-up was 38 months (interquartile range, 24-58 months). The primary outcome occurred in 69 patients (11.2%) who underwent conventional primary PCI and in 65 (10.5%) who underwent postconditioning (hazard ratio, 0.93; 95% CI, 0.66-1.30; P = .66). The hazard ratios were 0.75 (95% CI, 0.49-1.14; P = .18) for all-cause death and 0.99 (95% CI, 0.60-1.64; P = .96) for heart failure. Conclusions and Relevance Routine ischemic postconditioning during primary PCI failed to reduce the composite outcome of death from any cause and hospitalization for heart failure in patients with STEMI and TIMI grade 0-1 flow at arrival. Trial Registration clinicaltrials.gov Identifier: NCT01435408

The decrease of cardiac chamber volumes and output during positive-pressure ventilation

Positive-pressure ventilation (PPV) is widely used for treatment of acute cardiorespiratory failure, occasionally at the expense of compromised cardiac function and arterial blood pressure. The explanation why has largely rested on interpretation of intracardiac pressure changes. We evaluated the effect of PPV on the central circulation by studying cardiac chamber volumes with cardiac magnetic resonance imaging (CMR). We hypothesized that PPV lowers cardiac output (CO) mainly via the Frank-Starling relationship. In 18 healthy volunteers, cardiac chamber volumes and flow in aorta and the pulmonary artery were measured by CMR during PPV levels of 0, 10, and 20 cmH2O applied via a respirator and a face mask. All cardiac chamber volumes decreased in proportion to the level of PPV. Following 20-cmH2O PPV, the total diastolic and systolic cardiac volumes (±SE) decreased from 605 (±29) ml to 446 (±29) ml (P < 0.001) and from 265 (±17) ml to 212 (±16) ml (P < 0.001). Left ventricular stroke volume decreased by 27 (±4) ml/beat; heart rate increased by 7 (±2) beats/min; and CO decreased by 1.0 (±0.4) l/min (P < 0.001). From 0 to 20 cmH2O, right and left ventricular peak filling rates decreased by -146 (±32) and -187 (±64) ml/s (P < 0.05) but maximal emptying rates were unchanged. Cardiac filling and output decrease with increasing PPV in healthy volunteers. The decrease is seen even at low levels of PPV and should be taken into account when submitting patients to mechanical ventilation with positive pressures. The decrease in CO is fully explained by the Frank-Starling mechanism.

Left atrial and ventricular function during dobutamine and glycopyrrolate stress in healthy young and elderly as evaluated by cardiac magnetic resonance

The aim of this study is to describe phasic volume changes of the left atrium (LA) in healthy young and elderly subjects at rest and during pharmacological stress (PS). LA maximum size is related to cardiovascular mortality. LA has passive, active, and conduit function for left ventricular (LV) filling. We hypothesized that changes in LV compliance from normal aging are reflected in LA volume changes and that PS will augment these differences. We enrolled twenty young (20-30 yr) and twenty elderly (60-70 yr) healthy subjects and measured their LV and LA volumes by cardiac magnetic resonance imaging at rest and during dobutamine and glycopyrrolate stress. We identified LA minimum, maximum, and middiastolic volumes and the volume before atrial contraction. LA emptying volumes were calculated as LA passive and active emptying volumes and LA conduit volume. We also calculated LV peak filling rates (LVPFRs). Both at rest and during PS, LA maximum and minimum volumes were similar in the groups, whereas middiastolic volume was higher in the elderly. During PS, a marked decrease in LA passive emptying function and a corresponding increase in LA active emptying function were seen in the elderly but not in the young. At rest, LVPFR was lower in the elderly, and during PS this difference was augmented. The aging heart has reduced LVPFR, which is reflected in reduced LA passive and compensatory increased LA active volumetric contribution to LV stroke volume. These age-related differences are evident at rest and highly augmented during both dobutamine and glycopyrrolate stress.

Myocardial fibrosis in patients with myotonic dystrophy type 1: a cardiovascular magnetic resonance study

BackgroundMyotonic dystrophy type 1 (DM1) is associated with increased cardiac morbidity and mortality. Therefore, assessment of cardiac involvement and risk stratification for sudden cardiac death is crucial. Nevertheless, optimal screening-procedures are not clearly defined. ECG, echocardiography and Holter-monitoring are useful but insufficient. Cardiovascular magnetic resonance (CMR) can provide additional information of which myocardial fibrosis may be relevant.The purpose of this study was to describe the prevalence of myocardial fibrosis in patients with DM1 assessed by CMR, and the association between myocardial fibrosis and abnormal findings on ECG, Holter-monitoring and echocardiography.MethodsWe selected 30 unrelated patients with DM1: 18 patients (10 men, mean age 51 years) with, and 12 patients (7 men, mean age 41 years) without abnormal findings on ECG and Holter-monitoring.Patients were evaluated with medical history, physical examination, ECG, Holter-monitoring, echocardiography and CMR.ResultsMyocardial fibrosis was found in 12/30 (40%, 9 men). The presence of myocardial fibrosis was associated with the following CMR-parameters: increased left ventricular mass (median (range) 55 g/m2 (43–83) vs. 46 g/m2 (36–64), p = 0.02), increased left atrial volume (median (range) 52 ml/m2 (36–87) vs. 46 ml/m2 (35–69), p = 0.04) and a trend toward lower LVEF (median (range) 63% (38–71) vs. 66% (60–80), p = 0.06). Overall, we found no association between the presence of myocardial fibrosis and abnormal findings on: ECG (p = 0.71), Holter-monitoring (p = 0.27) or echocardiographic measurements of left ventricular volumes, ejection fraction or global longitudinal strain (p = 0.18).ConclusionPatients with DM1 had a high prevalence of myocardial fibrosis which was not predicted by ECG, Holter-monitoring or echocardiography. CMR add additional information to current standard cardiac assessment and may prove to be a clinically valuable tool for risk stratification in DM1.