Risk stratification in patients with nonischemic cardiomyopathy and ventricular arrhythmias based on quantification of intramural delayed enhancement on cardiac magnetic resonance imaging

Long-term outcomes of patients with ventricular arrhythmias and negative programmed ventricular stimulation followed with implantable loop recorders: Impact of delayed-enhancement cardiac magnetic resonance imaging

BACKGROUND

Programed ventricular stimulation (PVS) is a risk stratification tool in patients at risk for adverse arrhythmia outcomes. Patients with negative PVS may yet be at risk for adverse arrhythmia-related events, particularly in the presence of symptomatic ventricular arrhythmias (VA).

OBJECTIVE

To investigate the long-term outcomes of real-world patients with symptomatic VA without indication for device therapy and negative PVS, and to examine the role of cardiac scaring on arrhythmia recurrence.

METHODS

Patients with symptomatic VA, and late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR), and negative PVS testing were included. All patients underwent placement of implantable cardiac monitors (ICM). Survival analysis was performed to investigate the impact of LGE-CMR findings on survival free from adverse arrhythmic events.

RESULTS

Seventy-eight patients were included (age 60 ± 14 years, women n = 36 (46%), ejection fraction 57 ± 9%, cardiomyopathy n = 26 (33%), mitral valve prolapse [MVP] n = 9 (12%), positive LGE-CMR scar n = 49 (62%), history of syncope n = 23 (29%)) including patients with primarily premature ventricular contractions (n = 21) or nonsustained VA (n = 57). Patients were followed for 1.6 ± 1.5 years during which 14 patients (18%) experienced VA requiring treatment (n = 14) or syncope due to bradycardia (n = 2). Four/9 patients (44%) with MVP experienced VA (n = 3) or syncope (n = 1). Baseline characteristics between those with and without adverse events were similar (p > 0.05); however, the presence of cardiac scar on LGE-CMR was independently associated with an increased risk of adverse events (hazard ratio: 5.6 95% confidence interval: [1.2-27], p = 0.03, log-rank p = 0.03).

CONCLUSIONS

In a real-world cohort with long-term follow-up, adverse arrhythmic outcomes occurred in 18% of patients with symptomatic VA despite negative PVS, and this risk was significantly greater in patients with positive DE-CMR scar. Long term-monitoring, including the use of ICM, may be appropriate in these patients.

Role of advanced imaging with cardiac computed tomography and MRI in atrial and ventricular ablation

PURPOSE OF REVIEW

Increasing evidence supports the use of advanced imaging with cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) in the work-up of patients with arrythmias being considered for ablation.

RECENT FINDINGS

Advances in imaging technology and postprocessing are facilitating the use of advanced imaging before, during and after ablation in patients with both atrial and ventricular arrhythmias.In atrial arrythmias, quantitative assessment of left atrial wall thickness on CCT and quantification of late gadolinium enhancement (LGE) on CMR identify patients more likely to develop recurrent atrial arrythmias following ablation. In addition, in patients with recurrent arrythmia post ablation, LGE CMR can potentially identify targets for repeat ablation.In ventricular arrythmias, qualitative assessment of LGE can aide in determining the optimal ablation approach and predicts likelihood of ventricular arrythmias inducibility. Quantitative assessment of LGE can identify conduction channels that can be targeted for ablation. On CCT, quantitative assessment of left ventricular wall thickness can demonstrate myocardial ridges associated with re-entrant circuits for ablation.

SUMMARY

This review focuses on the utility of CCT and CMR in identifying key anatomical components and arrhythmogenic substrate contributing to both atrial and ventricular arrhythmias in patients being considered for ablation. Advanced imaging has the potential to improve procedural outcomes, decrease complications and shorten procedural time.

Role of Cardiac Magnetic Resonance Imaging in the Evaluation of Athletes with Premature Ventricular Beats

Premature ventricular beats (PVBs) in athletes are not rare. The risk of PVBs depends on the presence of an underlying pathological myocardial substrate predisposing the subject to sudden cardiac death. The standard diagnostic work-up of athletes with PVBs includes an examination of family and personal history, resting electrocardiogram (ECG), 24 h ambulatory ECG (possibly with a 12-lead configuration and including a training session), maximal exercise testing and echocardiography. Despite its fundamental role in the diagnostic assessment of athletes with PVBs, echocardiography has very limited sensitivity in detecting the presence of non-ischemic left ventricular scars, which can be revealed only through more in-depth studies, particularly with the use of contrast-enhanced cardiac magnetic resonance (CMR) imaging. The morphology, complexity and exercise inducibility of PVBs can help estimate the probability of an underlying heart disease. Based on these features, CMR imaging may be indicated even when echocardiography is normal. This review focuses on interpreting PVBs, and on the indication and role of CMR imaging in the diagnostic evaluation of athletes, with a special focus on non-ischemic left ventricular scars that are an emerging substrate of cardiac arrest during sport.