Posts Tagged ‘cardiac MRI’

High Resolution Late Gadolinium Enhanced CMR in Patients with Ventricular Arrhythmias

Hennig et al report on the value of high resolution three dimensional late gadolinium enhanced cardiac magnetic resonance imaging in patients with ventricular arrhythmias.

<h1> Abstract</h1>

Cardiac magnetic resonance (CMR) is recommended as a second-line method to diagnose ventricular arrhythmia
(VA) substrate. We assessed the diagnostic yield of CMR including high-resolution late gadolinium-enhanced (LGE)

<h2>Methods and results</h2>
Consecutive patients with sustained ventricular tachycardia (VT), non-sustained VT (NSVT), or ventricular fibrillation/ aborted sudden death (VF/SCD) underwent a non-CMR diagnostic workup according to current guidelines, and CMR including LGE imaging with both a conventional breath-held and a free-breathing method enabling higher
spatial resolution (HR-LGE). The diagnostic yield of CMR was compared with the non-CMR workup, including the incremental value of HR-LGE. A total of 157 patients were enrolled [age 54 ± 17 years; 75% males; 88 (56%) sustained VT, 52 (33%) NSVT, 17 (11%) VF/SCD]. Of these, 112 (71%) patients had no history of structural heart disease (SHD). All patients underwent electrocardiography and echocardiography, 72% coronary angiography, and 51% exercise testing. Pre-CMR diagnoses were 84 (54%) no SHD, 39 (25%) ischaemic cardiomyopathy (ICM), 11
(7%) non-ischaemic cardiomyopathy (NICM), 3 (2%) arrhythmogenic right ventricular cardiomyopathy (ARVC), 2 (1%) hypertrophic cardiomyopathy (HCM), and 18 (11%) other. CMR modified these diagnoses in 48 patients (31% of all and 43% of those with no SHD history). New diagnoses were 9 ICM, 28 NICM, 8 ARVC, 1 HCM, and
2 other. CMR modified therapy in 19 (12%) patients. In patients with no SHD after non-CMR tests, SHD was found in 32 of 84 (38%) patients. Eighteen of these patients showed positive HR-LGE and negative conventional LGE. Thus, HR-LGE significantly increased the CMR detection of SHD (17–38%, P < 0.001).

CMR including HR-LGE imaging has high diagnostic value in patients with VAs. This has major prognostic and therapeutic implications, particularly in patients with negative pre-CMR workup.



MRI in Patients with Cardiac Devices

Nazarian et al report on the safety of MRI in patients with cardiac devices.



Patients who have pacemakers or defibrillators are often denied the opportunity toundergo magnetic resonance imaging (MRI) because of safety concerns, unless the devices meet certain criteria specified by the Food and Drug Administration (termed “MRI-conditional” devices).


We performed a prospective, nonrandomized study to assess the safety of MRI at a
magnetic field strength of 1.5 Tesla in 1509 patients who had a pacemaker (58%) or an implantable cardioverter–defibrillator (42%) that was not considered to be MRI-conditional (termed a “legacy” device). Overall, the patients underwent 2103 thoracic and nonthoracic MRI examinations that were deemed to be clinically necessary. The pacing mode was changed to asynchronous mode for pacing-dependent patients and to demand mode for other patients. Tachyarrhythmia functions were disabled. Outcome assessments included adverse events and changes in the variables that indicate lead and generator function and interaction with surrounding tissue (device parameters).


No long-term clinically significant adverse events were reported. In nine MRI examinations (0.4%; 95% confidence interval, 0.2 to 0.7), the patient’s device reset to a backup mode. The reset was transient in eight of the nine examinations. In one case, a pacemaker with less than 1 month left of battery life reset to ventricular inhibited pacing and could not be reprogrammed; the device was subsequently replaced. The most common notable change in device parameters (>50% change from baseline) immediately after MRI was a decrease in P-wave amplitude, which occurred in 1% of the patients. At long-term follow-up (results of which were available for 63% of the patients), the most common notable changes from baseline were decreases in P-wave amplitude (in
4% of the patients), increases in atrial capture threshold (4%), increases in right ventricular capture threshold (4%), and increases in left ventricular capture threshold (3%). The observed changes in lead parameters were not clinically significant and did not require device revision or reprogramming.


We evaluated the safety of MRI, performed with the use of a prespecified safety protocol, in 1509 patients who had a legacy pacemaker or a legacy implantable cardioverter–defibrillator system. No long-term clinically significant adverse events were reported.


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Late Gadolinium Enhancement in Dilated Cardiomyopathy

Halliday et al (Circulation. 2017;135:2106–2115. DOI: 10.1161/CIRCULATIONAHA.116.026910) report on the relationship between late gadolinium enhancement on cardiac MRI and sudden cardiac death in patients with dilated cardiomyopathy. They identify a subgroup with LVEF \ge 40% at increased risk of sudden cardiac death.



Current guidelines only recommend the use of an implantable
cardioverter defibrillator in patients with dilated cardiomyopathy for the primary prevention of sudden cardiac death (SCD) in those with a left ventricular ejection fraction (LVEF) 35%. Patients with an LVEF >35% also have low competing risks of death from nonsudden causes. Therefore, those at high risk of SCD may gain longevity from successful implantable cardioverter defibrillator therapy. We investigated whether late gadolinium enhancement (LGE) cardiovascular magnetic resonance identified patients with dilated cardiomyopathy without severe LV systolic dysfunction at high risk of SCD.


We prospectively investigated the association between midwall LGE and the prespecified primary composite outcome of SCD or aborted SCD among consecutive referrals with dilated cardiomyopathy and an LVEF ≥40% to our center between January 2000 and December 2011 who did not have a preexisting indication for implantable cardioverter defibrillator implantation.


Of 399 patients (145 women, median age 50 years, median LVEF 50%, 25.3% with LGE) followed for a median of 4.6 years, 18 of 101 (17.8%) patients with LGE reached the prespecified end point, compared with 7 of 298 (2.3%) without (hazard ratio [HR], 9.2; 95% confidence interval [CI], 3.9–21.8; P<0.0001). Nine patients (8.9%) with LGE compared with 6 (2.0%) without (HR,4.9; 95% CI, 1.8–13.5; P=0.002) died suddenly, whereas 10 patients (9.9%) with LGE compared with 1 patient (0.3%) without (HR, 34.8; 95% CI, 4.6–266.6; P<0.001) had aborted SCD. After adjustment, LGE predicted the composite end point (HR, 9.3; 95% CI, 3.9–22.3; P<0.0001), SCD (HR, 4.8; 95% CI, 1.7–13.8; P=0.003), and aborted SCD (HR, 35.9; 95% CI, 4.8–271.4; P5% compared with those without LGE were 10.6 (95% CI, 3.9–29.4), 4.9 (95% CI, 1.3–18.9), and 11.8 (95% CI, 4.3–32.3), respectively.


Midwall LGE identifies a group of patients with dilated cardiomyopathy and an LVEF ≥40% at increased risk of SCD and low risk of nonsudden death who may benefit from implantable cardioverter defibrillator implantation.


Area: Height Ratio in Patients With Proximal Ascending Aortic Dilation and Trileaflet Aortic Valve

Masri et al report an observational longitudinal study of patients with proximal dilation of the ascending aorta and trileaflet aortic valves. The authors report the relationship between ascending aortic area to height ration (as assessed by CT or MRI) and clinical outcome.



In patients with a dilated proximal ascending aorta
and trileaflet aortic valve, we aimed to assess (1) factors independently
associated with increased long-term mortality and (2) the incremental
prognostic utility of indexing aortic root to patient height.


We studied consecutive patients with a dilated aortic root (≥4
cm) that underwent echocardiography and gated contrast-enhanced thoracic
aortic computed tomography or magnetic resonance angiography between
2003 and 2007. A ratio of aortic root area over height was calculated
(cm2/m) on tomography, and a cutoff of 10 cm2/m was chosen as abnormal,
on the basis of previous reports. All-cause death was recorded.


The cohort comprised 771 patients (63 years [interquartile range,
53–71], 87% men, 85% hypertension, 51% hyperlipidemia, 56% smokers).
Inherited aortopathies, moderate to severe aortic regurgitation, and severe
aortic stenosis were seen in 7%, 18%, and 2%, whereas 91% and 54% were
on β-blockers and angiotensin-converting enzyme inhibitors, respectively.
Aortic root area/height ratio was ≥10 cm2/m in 24%. The Society of
Thoracic Surgeons score and right ventricular systolic pressure were 3.3±3
and 31±7 mm Hg, respectively. At 7.8 years (interquartile range, 6.6–8.9),
280 (36%) patients underwent aortic surgery (76% within 1 year) and 130
(17%) died (1% in-hospital postoperative mortality). A lower proportion of
patients in the surgical (versus nonsurgical) group died (13% versus 19%,
P<0.01). On multivariable Cox proportional hazard analysis, aortic root area/
height ratio (hazard ratio, 4.04; 95% confidence interval [CI], 2.69–6.231)
was associated with death, whereas aortic surgery (hazard ratio, 0.47;
95% CI, 0.27–0.81) was associated with improved survival (both P<0.01).
For longer-term mortality, the addition of aortic root area/height ratio ≥10
cm2/m to a clinical model (Society of Thoracic Surgeons score, inherited
aortopathies, hypertension, hyperlipidemia, medications, aortic regurgitation,
and right ventricular systolic pressure), increased the c-statistic from 0.57
(95% CI, 0.35–0.77) to 0.65 (95% CI, 0.52–0.73) and net reclassification
index from 0.17 (95% CI, 0.02–0.31) to 0.23 (95% CI, 0.04–0.34), both
P<0.01. Of the 327 patients with aortic root diameter between 4.5 and 5.5
cm, 44% had an abnormal aortic root area/height ratio, of which 78% died.


In patients with dilated aortic root and trileaflet aortic
valve, a ratio of aortic root area to height provides independent and
improved stratification for prediction of death.