Current and future role of cardiovascular magnetic resonance in cardiac resynchronization therapy

Quantitative left ventricular mechanical dyssynchrony by magnetic resonance imaging predicts the prognosis of dilated cardiomyopathy

PURPOSE

Left ventricular (LV) dyssynchrony is believed to be associated with the prognosis of dilated cardiomyopathy (DCM) mainly assessed by echocardiography. This study sought to explore whether quantitative LV mechanical dyssynchrony by cardiovascular magnetic resonance imaging (CMR) tissue feature tracking could predict the prognosis of DCM.

METHOD

Patients undergoing CMR between January 2016 and December 2017 were reviewed to identify DCM patients. Quantitative LV mechanical dyssynchrony was assessed by CMR strain analysis. The outcomes of these DCM patients were followed up. The association between LV mechanical dyssynchrony and outcomes was analyzed by Cox proportional regression analysis.

RESULTS

A total of 417 patients with DCM were enrolled. At a median follow-up of 57 months, 109 patients reached endpoints: 19, sudden cardiac death; 34, heart failure death; 41, heart transplantation; 9, malignant ventricular arrhythmias; 2, LV assist devices; and 4, appropriate shocks of defibrillators. After adjustment for confounding variables, the 16-segment standard deviation of the time-to-peak radial strain (16SDTTPRS) (HR, 1.932 [95% CI: 1.079, 3.461]; P = 0.027), LV end-diastolic diameter index (HR, 1.049 [95% CI: 1.020, 1.080]; P = 0.001), NYHA classes (HR, 2.131 [95% CI: 1.597-2.844]; P < 0.001) and late gadolinium enhancement (HR, 3.219 [95% CI: 2.164, 4.787]; P < 0.001) were independently associated with composite endpoints.

CONCLUSIONS

The quantitative LV mechanical dyssynchrony parameter 16SDTTPRS derived from CMR was independently associated with adverse outcomes in patients with DCM.

Septal myocardial scar burden predicts the response to cardiac contractility modulation in patients with heart failure

We hypothesized that myocardial septal scarring, assessed by cardiac magnetic resonance (CMR) using late gadolinium enhancement (LGE), at the site of cardiac contractility modulation (CCM) lead placement may predict treatment response. Eligible heart failure (HF) patients underwent LGE CMR imaging before CCM device implantation. The response to CCM therapy at follow-up was determined by a change in NYHA class and echocardiographic left ventricular ejection fraction (LVEF) assessment. Patients were classified as responders, if they showed an improvement in either NYHA class or improvement of LVEF by ≥ 5%. 58 patients were included. 67% of patients were classified as responders according to improved NYHA; 55% according to LVEF improvement. 74% of patients were responders if either NYHA class or LVEF improvement was observed. 90% of responders (according to NYHA class) showed septal LGE < 25% at septal position of the leads, while 44% of non-responders showed septal LGE > 25% (p < 0.01). In patients treated with CCM, an improvement of NYHA class was observed when leads were placed at myocardial segments with a CMR- LGE burden less than 25%.

Role of cardiovascular imaging in cardiac resynchronization therapy: a literature review

: Cardiac resynchronization therapy (CRT) is an established treatment in patients with symptomatic drug-refractory heart failure and broad QRS complex on the surface ECG. Despite the presence of either mechanical dyssynchrony or viable myocardium at the site where delivering left ventricular pacing being necessary conditions for a successful CRT, their direct assessment by techniques of cardiovascular imaging, though feasible, is not recommended in clinical practice by the current guidelines. Indeed, even though there is growing body of data providing evidence of the additional value of an image-based approach as compared with routine approach in improving response to CRT, these results should be confirmed in prospective and large multicentre trials before their impact on CRT guidelines is considered.

Assessment of left ventricular mechanical dyssynchrony in left bundle branch block canine model: Comparison between cine and tagged MRI

PURPOSE

To compare cine and tagged magnetic resonance imaging (MRI) for left ventricular dyssynchrony assessment in left bundle branch block (LBBB), using the time-to-peak contraction timing, and a novel approach based on cross-correlation.

MATERIALS AND METHODS

We evaluated a canine model dataset (n = 10) before (pre-LBBB) and after induction of isolated LBBB (post-LBBB). Multislice short-axis tagged and cine MRI images were acquired using a 1.5 T scanner. We computed contraction time maps by cross-correlation, based on the timing of radial wall motion and of circumferential strain. Finally, we estimated dyssynchrony as the standard deviation of the contraction time over the different regions of the myocardium.

RESULTS

Induction of LBBB resulted in a significant increase in dyssynchrony (cine: 13.0 ± 3.9 msec for pre-LBBB, and 26.4 ± 5.0 msec for post-LBBB, P = 0.005; tagged: 17.1 ± 5.0 msec at for pre-LBBB, and 27.9 ± 9.8 msec for post-LBBB, P = 0.007). Dyssynchrony assessed by cine and tagged MRI were in agreement (r = 0.73, P = 0.0003); differences were in the order of time difference between successive frames of 20 msec (bias: -2.9 msec; limit of agreement: 10.1 msec). Contraction time maps were derived; agreement was found in the contraction patterns derived from cine and tagged MRI (mean difference in contraction time per segment: 3.6 ± 13.7 msec).

CONCLUSION

This study shows that the proposed method is able to quantify dyssynchrony after induced LBBB in an animal model. Cine-assessed dyssynchrony agreed with tagged-derived dyssynchrony, in terms of magnitude and spatial direction. J. MAGN. RESON. IMAGING 2016;44:956-963.

Appropriateness and diagnostic yield of cardiac magnetic resonance imaging from a tertiary referral center in the Middle East

PURPOSE

Cardiac magnetic resonance imaging (CMRI) is a novel non-invasive modality with many potential indications, and was recently introduced in Lebanon. We sought to assess the appropriateness and diagnostic yield of CMR studies performed at a tertiary referral center from the Middle East since the inception of the program.

METHODS

All patients who underwent CMR studies between January 1(st) 2013 and June 18(th) 2014 were enrolled in this study. CMR reports were retrospectively reviewed. The study indication, clinical history, and findings were extracted and analyzed. The appropriateness of the study was judged according to the 2010 updated Asian Society of Cardiac Imaging guidelines.

RESULTS

There were a total of 142 patients [mean age 42.1 (SD: 18) years, 24.6% females] that underwent CMR study. Two-thirds of studies were performed on an outpatient basis, and outside referrals constituted 16.2% of the entire cohort. The cardiologists referred 122 cases (86%) with main contribution from electrophysiology and imaging specialists. Of the 142 cases, 12 (8.4%) were not indicated and added little value. Of the remaining 130 appropriate studies (appropriateness level A8-A9), one-third had an incorrect diagnosis prior to CMR, and 8% had relevant findings that were missed on other studies but captured by CMR. Furthermore, CMR confirmed the diagnosis in 28% of the cases, provided relevant information on scar burden, shunt quantification, and ruled out infiltrative disease in the remaining patients. Also, CMR demonstrated the presence of scar in 45 of patients, among whom 20 (44%) had significant scar volume quantification (>5% of left ventricular myocardium). Finally, 9% of patients had a relevant extra-cardiac finding that needed further investigation.

CONCLUSIONS

Despite the recent launch of the CMR program at our institution, the majority of studies were appropriately indicated, provided relevant data and were clinically useful. Inappropriate or uncertain studies did not provide relevant data, and should be further minimized to avoid unnecessary costs and downstream testing. Large prospective CMR database with clinical follow-up is needed to provide more insight about cardiovascular disease and outcomes in our population.

Metabolomic does not predict response to cardiac resynchronization therapy in patients with heart failure

AIMS

Metabolomic, a systematic study of metabolites, may be a useful tool in understanding the pathological processes that underlie the occurrence and progression of a disease. We hypothesized that metabolomic would be helpful in assessing a specific pattern in heart failure patients, also according to the underlining causes and in defining, prior to device implantation, the responder and nonresponder patient to cardiac resynchronization therapy (CRT).

METHODS

In this prospective study, blood and urine samples were collected from 32 heart failure patients who underwent CRT. Clinical, electrocardiography and echocardiographic evaluation was performed in each patient before CRT and after 6 months of follow-up. Thirty-nine age and sex-matched healthy individuals were chosen as control group. For each sample, 1H-NMR spectra, Nuclear Overhauser Enhancement Spectroscopy, Carr-Purcell-Meiboom-Gill and diffusion edited spectra were measured.

RESULTS

A different metabolomic fingerprint was demonstrated in heart failure patients compared to healthy controls with high accuracy level. Metabolomics fingerprint was similar between patients with ischemic and nonischemic dilated cardiomyopathy. At 6-month follow-up, metabolomic fingerprint was different from baseline. At follow-up, heart failure patients’ metabolomic fingerprint remained significantly different from that of healthy controls, and accuracy of cause discrimination remained low. Responders and nonresponders had a similar metabolic fingerprint at baseline and after 6 months of CRT.

CONCLUSION

It is possible to identify a metabolomic fingerprint characterizing heart failure patients candidate to CRT, it is independent of the different causes of the disease and it is not predictive of the response to CRT.

2014 korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the korean society of cardiology and the korean society of radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

2014 Korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the Korean Society of Cardiology and the Korean Society of Radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

[Advances in cardiac pacing]

This article contains a review of the current status of remote monitoring and follow-up involving cardiac pacing devices and of the latest developments in cardiac resynchronization therapy. In addition, the most important articles published in the last year are discussed.

Echocardiographic prediction of outcome after cardiac resynchronization therapy: conventional methods and recent developments

Echocardiography plays an important role in patient assessment before cardiac resynchronization therapy (CRT) and can monitor many of its mechanical effects in heart failure patients. Encouraged by the highly variable individual response observed in the major CRT trials, echocardiography-based measurements of mechanical dyssynchrony have been extensively investigated with the aim of improving response prediction and CRT delivery. Despite recent setbacks, these techniques have continued to develop in order to overcome some of their initial flaws and limitations. This review discusses the concepts and rationale of the available echocardiographic techniques, highlighting newer quantification methods and discussing some of the unsolved issues that need to be addressed.