Joerg O. Schwab

Acute Myocarditis: Multiparametric Cardiac MR Imaging

PURPOSE To evaluate the diagnostic value of cardiac magnetic resonance (MR) imaging at 3 T in patients suspected of having acute myocarditis by using a multiparametric cardiac MR imaging approach including T1 relaxation time as an additional tool for tissue characterization. MATERIALS AND METHODS Ethics commission approval was obtained for this prospective study, and written informed consent was obtained from all subjects. Twenty four patients with acute myocarditis (mean age ± standard deviation, 34.7 years ± 15.1; 75% men) and 42 control subjects (mean age, 38.7 years ± 10.2; 64% men) were included. Cardiac MR imaging approaches included relative T2 short tau inversion-recovery signal intensity ratio (T2 ratio), early gadolinium enhancement ratio, late gadolinium enhancement, native T1 relaxation times, and extracellular volume fraction. Receiver operating characteristic analysis was performed to compare diagnostic performance. The reference standard was the clinical evidence for acute myocarditis. RESULTS Native T1 relaxation times were significantly longer in patients with acute myocarditis than in control subjects (1185.3 msec ± 49.3 vs 1089.1 msec ± 44.9, respectively; P < .001). Areas under the curve of native T1 relaxation times (0.94) were higher compared with those of other cardiac MR parameters (late gadolinium enhancement, 0.90; T2 ratio, 0.79; extracellular volume fraction, 0.71; early gadolinium enhancement ratio, 0.63; P = .390, .018, .002, and < .001, respectively). Sensitivity (92%), specificity (91%), and diagnostic accuracy (91%) for native T1 relaxation times (cutoff, 1140 msec) were equivalent compared with those of the established combined Lake Louise criteria (sensitivity, 92%; specificity, 80%; diagnostic accuracy, 85%). CONCLUSION Diagnostic performance with native T1 mapping was superior to that with T2 ratio and early gadolinium enhancement ratio, and specificity was higher with native T1 mapping than that with Lake Louise criteria. This study underlines the potential of native T1 relaxation times to complement current cardiac MR approaches in patients suspected of having acute myocarditis.

Strategy for safe performance of magnetic resonance imaging on a patient with implantable cardioverter defibrillator.

Clinically indicated magnetic resonance imaging (MRI) of the brain was safely performed at 1.5 T on a patient with an implantable cardioverter defibrillator (ICD). The ICD was reprogrammed to detection only, and imaging hardware and protocols were modified to minimize radiofrequency power deposition to the ICD system. The integrity of the ICD system was verified immediately post‐MRI and after 6 weeks, including an ICD test with induction of ventricular fibrillation. This case demonstrates that in exceptional circumstances, in carefully selected patients, and using special precautions, an MRI exam of the brain may be possible in patients with ICDs.

“Torsade de Pointes” in Patients with Structural Heart Disease and Atrial Fibrillation Treated with Amiodarone, β-Blockers, and Digitalis

Amiodarone is one of the most efficient and safe antiarrhythmic drugs in the treatment of atrial fibrillation (AF). Yet, though rare, proarrhythmic effects remain a clinical problem. We present three cases of amiodarone‐associated “Torsade de pointes” tachycardia (Tdp) in patients treated concomitantly with heart rate controlling medication for AF. Amiodarone loading therapy was started for the treatment of tachyarrhythmic AF in all the three patients. All presented with a history of coronary heart disease, resulting in a severely reduced left ventricular ejection fraction in two patients. One received oral amiodarone loading, in the others, amiodarone was administered intravenously because of hemodynamically relevant AF episodes. Amiodarone therapy was combined with a heart rate controlling medication including a β‐blocking agent and digitalis in all the cases. All the subjects suffered from clinically relevant Tdp in the early run after initiation of amiodarone loading (max. 48 hours). The mean QTc in all patients before induction of Tdp was prolonged. The present case reports imply that amiodarone in combination with β‐blocker/digitalis therapy may be associated with an elevated proarrhythmic risk in selected patients with structural heart disease and AF.

Incidence, determinants, and prognostic implications of true pleomorphism of ventricular tachycardia in patients with implantable cardioverter-defribillators: a substudy of the DATAS trial

Background—The occurrence of monomorphic ventricular tachycardia (M-VT) with >1 QRS morphology during the same episode (pleomorphism [PL]) or in different episodes (multiple morphologies [MM]) has been described through ECG. Implantable cardioverter-defribillator (ICD) electrograms (EGs) provide the opportunity to analyze virtually all spontaneous M-VT episodes. We sought to study the incidence, determinants, and prognostic significance of PL and MM as assessed by ICD-EG in a prospective series of patients with ICDs. Methods and Results—Spontaneous episodes of M-VT were analyzed before ICD intervention. PL was defined as >1 ICD-EG morphology, each having ≥6 consecutive identical beats during the same VT episode, and MM as >1 ICD-EG morphology in different M-VT episodes in the same patient. We analyzed 1881 M-VT episodes from 315 patients followed for 17 months. PL and MM occurred in 6% and 19%, respectively, of the total population (16% and 62% of patients with M-VT). Recurrent M-VT as diagnosis for ICD indication predicted PL and MM. Patients with PL more frequently developed MM (85% versus 15%; P<0.001) compared to patients without PL. Total mortality (5%) was significantly higher in patients with PL (20%), in patients with MM (11.5%), and in women (12%). In multivariate analysis, only PL (odds ratio, 5.33; P=0.009) and female sex (odds ratio, 3.1; P=0.038) predicted mortality. Conclusions—In a prospective series of patients with ICDs, mostly indicated for secondary prevention, both PL and MM of VT, as judged by ICD-EG, were not uncommon and were strongly associated. Female sex and the development of PL VT were the only independent predictors of mortality.

An impaired renal function and advanced heart failure represent independent predictors of the incidence of malignant ventricular arrhythmias in patients with an implantable cardioverter/defibrillator for primary prevention

AIMS Malignant ventricular arrhythmias and inappropriate therapies represent unsolved problems in patients with implantable cardioverter/defibrillator (ICD) for primary prevention. This study focuses on the incidence of such therapies and thereby seeks to identify new predictors of adverse events to enhance risk stratification. METHODS AND RESULTS Ninety-four consecutive patients with mild-to-moderate heart failure (NYHA II-III) and depressed left ventricular function (≤35%) were followed for 34 ± 20 months. Two hundred and ninety-one malignant ventricular arrhythmias were documented in 51 patients (54%). Eighteen patients (19%) received inappropriate ICD therapies (e.g. atrial fibrillation, sinus tachycardia, etc.). Patients with malignant arrhythmia (1.34 ± 0.44 vs. 1.16 ± 0.4 mg/dL, P = 0.017) and patients suffering from inappropriate ICD therapies (1.54 ± 0.48 vs. 1.2 ± 0.38 mg/dL; P = 0.007) revealed a significantly worse renal function before ICD implantation than participants without any therapy. An increased serum creatinine at baseline (2 vs. 1 mg/dL; odds ratio (OR) 3.96; P = 0.02; 95% CI: 1.2-13.04) and NHYA class III compared with II (OR: 2.96; P = 0.02; 95% CI: 1.16-7.48) represent strong and independent predictors for the occurrence of ventricular arrhythmias. Moreover, an impaired renal function is identified as an independent risk factor for inappropriate therapies (OR: 5.6; P = 0.004; 95% CI: 1.72-18.22). CONCLUSION An impaired renal function and advanced heart failure before ICD implantation for primary prevention are identified as independent predictors for the incidence of appropriate ICD interventions. With regard to current guidelines and economical aspects, patients suffering from an impaired renal function or advanced heart failure seem to benefit most from ICD therapy.

Incidence, Determinants and Prognostic Implications of True Pleomorphism of Ventricular Tachycardia in ICD Patients: A Substudy of the DATAS Trial

Background—The occurrence of monomorphic ventricular tachycardia (M-VT) with >1 QRS morphology during the same episode (pleomorphism [PL]) or in different episodes (multiple morphologies [MM]) has been described through ECG. Implantable cardioverter-defribillator (ICD) electrograms (EGs) provide the opportunity to analyze virtually all spontaneous M-VT episodes. We sought to study the incidence, determinants, and prognostic significance of PL and MM as assessed by ICD-EG in a prospective series of patients with ICDs. Methods and Results—Spontaneous episodes of M-VT were analyzed before ICD intervention. PL was defined as >1 ICD-EG morphology, each having ≥6 consecutive identical beats during the same VT episode, and MM as >1 ICD-EG morphology in different M-VT episodes in the same patient. We analyzed 1881 M-VT episodes from 315 patients followed for 17 months. PL and MM occurred in 6% and 19%, respectively, of the total population (16% and 62% of patients with M-VT). Recurrent M-VT as diagnosis for ICD indication predicted PL and MM. Patients with PL more frequently developed MM (85% versus 15%; P<0.001) compared to patients without PL. Total mortality (5%) was significantly higher in patients with PL (20%), in patients with MM (11.5%), and in women (12%). In multivariate analysis, only PL (odds ratio, 5.33; P=0.009) and female sex (odds ratio, 3.1; P=0.038) predicted mortality. Conclusions—In a prospective series of patients with ICDs, mostly indicated for secondary prevention, both PL and MM of VT, as judged by ICD-EG, were not uncommon and were strongly associated. Female sex and the development of PL VT were the only independent predictors of mortality.

Can Contrast-Enhanced Multi-Detector Computed Tomography Replace Transesophageal Echocardiography for the Detection of Thrombogenic Milieu and Thrombi in the Left Atrial Appendage: A Prospective Study with 124 Patients.

PURPOSE To assess the diagnostic value of contrast-enhanced multi-detector computed tomography (MD-CT) for identifying patients with left atrial appendage (LAA) thrombus or circulatory stasis. MATERIALS AND METHODS 124 patients with a history of atrial fibrillation and/or cerebral ischemia (83 men, mean age 58.6 ± 12.4 years) and with a clinical indication for MD-CT of the heart and for transesophageal echocardiography (TEE) were included in the study. LAA thrombus or thrombogenic milieu was visually identified in TEE and MD-CT. In addition, MD-CT was analyzed quantitatively measuring the Hounsfield units (HU) of the left atrium (LA), the LAA and the ascending aorta (AA), and calculating the HU ratios LAA/AA (HU [LAA/AA]) und LAA/LA (HU [LAA/LA]). Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were calculated. RESULTS The prevalence of a thrombus or thrombogenic milieu as assessed by TEE was 21.8 %. The HU ratio was lower in patients with thrombus or thrombogenic milieu (HU [LAA/AA]: 0.590 ± 0.248 vs. 0.909 ± 0.141; p < 0.001 und HU [LAA/LA] 0.689 ± 0.366 vs. 1.082 ± 0.228; p < 0.001). For the diagnosis of thrombus or a thrombogenic milieu, visual analysis yielded a sensitivity of 81.5 %, a specificity of 96.9 %, a PPV of 87.5 % and a NPV of 95.2 %. By combining visual and quantitative analysis with one criterion being positive, the specificity decreased to 91.8 %, the sensitivity to 77.8 %, the PPV to 72.4 %, and the NPV to 94.9 %. CONCLUSION Visual analysis of the LAA in the evaluation of thrombus or thrombogenic milieu yields a high NPV of 95.1 % and may especially be useful to rule out LAA thrombi in patients with contraindications for TEE. Additional calculation of HU ratios did not improve the diagnostic performance of MD-CT. KEY POINTS • MD-CT can reliably exclude atrial appendage thrombi/thrombogenic milieu. • MD-CT is an alternative method in patients with contraindications to TEE. • Calculation of relative HU ratios does not improve the diagnostic value of MD-CT.

Prolonged atrial fibrillation following generalized tonic–clonic seizures

We describe two male patients with focal epilepsy in whom transitory episodes of atrial fibrillation (AF) lasting for up to 25h were detected in the context of generalized tonic-clonic seizures (GTCSs). In five of seven previously published cases of transitory AF associated with epileptic seizures, AF was also associated with GTCS, suggesting a pathophysiological link via GTCS-related increase in sympathetic tone and release of catecholamines. Importantly, AF increases the risk of thromboembolic cerebral ischemia, prompting the question of whether antithrombotic preventive treatment should be initiated in people with pharmacoresistant epilepsy and prolonged peri-ictal AF. Furthermore, AF can considerably impair cardiac output and may, via this mechanism, contribute to the risk of sudden unexpected death in epilepsy following GTCS.

Usefulness of the wearable cardioverter defibrillator in patients in the early post-myocardial infarction phase with high risk of sudden cardiac death: A single-center European experience.

The effectiveness of the wearable cardioverter defibrillator (WCD) therapy in early post‐myocardial infarction (MI) patients remains uncertain.

Significance of Wedensky Modulation testing in the evaluation of non-invasive risk stratification for ventricular tachyarrhythmia in patients with coronary artery disease and implantable cardioverter-defibrillator

Objective: Evaluation of the significance of the Wedensky Modulation (WM) examination for ventricular tachyarrhythmias (VT) in patients with coronary artery disease and implantable cardioverter-defibrillator therapy (ICD). Design: Prospective, single-centre study conducted from 2004 to 2006. Setting: University of Bonn, Department of Medicine – Cardiology, Bonn, Germany. Patients: 37 consecutive patients with coronary artery disease receiving an ICD for primary or secondary prevention. Main outcome measures: Correlation of a positive WM-Index (WMI) with established non-invasive Holter parameter, the occurrence of VT after ICD implantation with regard to primary or secondary prevention, and inducibility of VT during electrophysiological (EP) studies. Results: The WMI was positive in 15 patients (67 (SD 8) years, 31% (SD 12%) EF) and showed significant correlation with heart rate variability (standard deviation of normal to normal intervals (SDNN): 143 (SD 80) ms vs 102 (SD 29) ms, p = 0.04, r = 0.45; total power (TP). 11 885 (SD 19 674) ms2 vs 2229 (SD 1779) ms2, p = 0.03, r = 0.384; very low frequency component (VLF): 2777 (SD 3039) ms2 vs 1184 (SD 565) ms2, p = 0.03; low frequency component (LF): 2955 (SD 5734) ms2 vs 468 (SD 725) ms2, p = 0.05, r = 0.375; high frequency component (HF): 4885 (SD 9939) ms2 vs 382 (SD 609) ms2, p = 0.05, r = 0.315) and turbulence (turbulence onset (TO): −0.002 (SD 0.008) vs +0.005 (SD 0.01), p = 0.05, r = 0.301; turbulence slope (TS): 3.4 (SD 3.1) vs 1.7 (SD 1.5), p = 0.04, r = 0.419). The positive predictive value of the WMI considering the inducibility of VT during EP testing was 100%. Those patients who received an ICD for primary prevention showed a higher WMI (p = 0.049) than the secondary prevention group. With respect to the occurrence of adequate VT episodes, a negative WM test result demonstrated a negative predictive value of 95%. Conclusion: The data presented show that the WM-Index predicts VT inducibility during EP testing and indicates a high negative predictive value regarding the occurrence of VT.