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We report 3 cases (mean age 48.3 ± 11.6 years) of idiopathic ventricular fibrillation (IVF), in which a triggering premature ventricular complex leading to IVF could not be identified. All patients underwent posterior fascicle transection with empirical linear ablation of the mid-Purkinje potentials identified along the left ventricular interventricular inferior septum, and no ventricular fibrillation recurrence was documented in any of the patients. (Level of Difficulty: Advanced.), Graphical abstract

Magnetic resonance imaging (MRI) is a valuable imaging modality for the assessment of both cardiac and non-cardiac structures. With a growing population of patients with cardiovascular implantable electronic devices (CIEDs), 50%-75% of these patients will need an MRI. MRI-conditional CIEDs have demonstrated safety of MRI scanning with such devices, yet non-conditional devices such as hybrid CIEDs which have generator and lead brand mismatch may pose a safety risk. In this retrospective study, we examined the outcomes of patients with hybrid CIEDs undergoing MRI compared to those patients with non-hybrid CIEDs. A total of 349 patients were included, of which 24 patients (7%) had hybrid CIEDs. The primary endpoint was the safety of MRI for patients with hybrid CIEDs as compared to those with non-hybrid devices, measured by the rate of adverse events, including death, lead or generator failure needing immediate replacement, loss of capture, new onset arrhythmia, or power-on reset. Secondary endpoints consisted of pre- and post-MRI changes of decreased P-wave or R-wave sensing by ≥50%, changes in pacing lead impedance by ≥50 ohms, increase in pacing thresholds by ≥ 0.5 V at 0.4 ms, and decreasing battery voltage of ≥ 0.04 V. The primary endpoint of any adverse reaction was present in 1 (4.2%) patient with a hybrid device, and consistent of atrial tachyarrhythmia, and in 10 (3.1%) patients with a non-hybrid device, and consisted of self-limited atrial and non-sustained ventricular arrhythmias; this was not statistically significant. No significant differences were found in the secondary endpoints. This study demonstrates that MRI in patients with hybrid CIEDs does not result in increased patient risk or significant device changes when compared to those patients who underwent MRI with non-hybrid CIEDs.

Introduction: Atrial flutter (AFL) with figure-of-eight reentry (FOER) is effectively terminated by catheter ablation (CA) of the shared isthmus. Case: A 50-year-old man with prior mitral valve (MV) repair presented to our hospital with palpitations for 9 months refractory to metoprolol. ECG showed coarse atrial fibrillation at 61 bpm. Echocardiography showed left ventricular LVEF of 45%. Electrophysiology study revealed AFL (cycle length, TCL 290 msec) with a concentric activation pattern on the coronary sinus (CS) catheter, and a chevron pattern on the Halo catheter placed against the lateral tricuspid annulus (TA). Entrainment map revealed a near equal post-pacing interval and TCL in proximal CS, low lateral right atrium (RA), and CTI. Incomplete line of block was noted in the anterior wall of RA near the superior vena cava (SVC), likely from prior atriotomy scar. Double loop reentry (DLR) was demonstrated with one wavefront (WV) traveling counterclockwise around the TA using the CTI, and the other WV traveling posteriorly around the SVC (Figure). After CTI ablation, TCL changed from 290 msec to 330 msec suggesting blocked CTI. Now, the WV was a single loop around the SVC, confirmed by repeat activation mapping. Linear ablation from anterior TA to the anterior aspect of the SVC terminated the AFL. Differential pacing from either side of the anterior line and the CTI demonstrated a conduction time of > 200 msec and 150 msec in either direction, respectively. Decremental atrial pacing was unable to induce any arrhythmias. Discussion: FOER in this case is suggested by fusion of WVs in the lateral RA. The 2 circuits each had their own conduction gap, in the CTI and anterior RA wall near the SVC, respectively. DLR was proven by entrainment as well as activation mapping. The faster CTI-dependent AFL was entraining the upper loop reentry circuit. Conclusion: Atypical right AFL with DLR mimicking FOER was successfully terminated by CA of CTI and anterior line of ablation from TA to SVC.

The primary goal of myocardial viability assessment in ischemic cardiomyopathy is to predict the likelihood of contractile recovery of dysfunctional myocardium following medical therapy and revascularization. Myocardial viability is estimated by probing a variety of biologic properties of a ‘living myocyte’, typically by cardiac imaging modalities—echocardiography, nuclear (SPECT & PET), and cardiac magnetic resonance—each with its own merits and limitations. While there is still an ongoing debate on the degree of therapeutic value of viability assessment, current guidelines acknowledge its prognostic and therapeutic utility in clinical practice. Viability status may not always be an all or none binary phenomenon but can be a wide spectrum from early hibernating to terminal pre-scar stages of the myocardium. As a result, estimating myocardial viability and predicting the revascularization benefits in severe ischemic cardiomyopathy with adverse remodeling can be a challenging task, at times. The decision to pursue revascularization should be based on the several factors that may determine the success of therapy, including the degree of myocardial ischemia, extent of viable and non-viable myocardium in the territory of the culprit coronary artery, left ventricular volumes, left ventricular ejection fraction, patient’s comorbidities and procedural risk. This chapter provides an overview of assessment of myocardial viability, its therapeutic and prognostic implications as well as management of ischemic cardiomyopathy based on the myocardial viability status.

Primary cardiac tumors are a rare occurrence with myxomas accounting for about half of the benign tumors. Once diagnosed, surgical resection is the standard of care. Our case describes a female in her 50s who underwent a myxoma resection under cardiopulmonary bypass via biatrial approach. Intraoperatively, the thin septal crux between the wall of the aorta and mitral valve was damaged during resection, requiring stem cell tissue matrix for repair. The patient also developed severe mitral regurgitation suggesting infarct to the left coronary system during resection, subsequently receiving a mechanical mitral valve and a saphenous vein bypass graft. Postoperatively, she developed atrial fibrillation with a left atrial appendage thrombus, heart failure with an ejection fraction of 30%–35%, and a transient ischemic attack. In conclusion, it is important for the clinician to appreciate the possible complications of resection peri and postoperatively.