Asymptomatic Apical Hypertrophic Cardiomyopathy in an Elite Competitive Athlete

A 17-year-old male elite athlete presented for evaluation after an abnormal pre-competitive college screening electrocardiogram. Subsequent evaluation revealed the presence of hypertrophic cardiomyopathy. He remained asymptomatic throughout four years of follow-up. Through shared decision making, he continued to play competitively and is now a professional athlete. (Level of Difficulty: Advanced.).

High defibrillation threshold with right-sided ICD implantation was resolved by a dual coil lead via persistent left superior vena cava

Persistent left superior vena cava (PLSVC) can be problematic when device implantation is scheduled from the left side because of the technical difficulty in delivering leads. Right-sided implantation is an alternative method, but there is a risk of a high defibrillation threshold (DFT). Transvenous implantation of an implantable cardioverter defibrillator (ICD) was scheduled for a 54-year-old man with idiopathic dilated cardiomyopathy and monomorphic non-sustained ventricular tachycardia, but computed tomography revealed the presence of a PLSVC. Right-sided ICD implantation was performed first; however, an ICD shock at 35 J failed to terminate the induced ventricular fibrillation (VF). Re-implantation via the PLSVC by a left subclavian approach with a dual coil lead was performed next. The dual coil right ventricular lead was successfully implanted via the PLSVC, and the induced VF was terminated by a single shock at 25 J. In the present case, the proximal coil was located in the coronary sinus (CS) and it enabled an antero-posterior defibrillation vector across the left ventricle. In addition to the re-location of the ICD generator from the right side to the left side, the new positioning of the proximal coil inside the CS is likely to have contributed to the great improvement of the DFT. .

3 Cases of Superior Vena Cava Syndrome Following Percutaneous Right Ventricular Assist Device Placement

We present 3 cases of superior vena cava (SVC) syndrome following percutaneous right ventricular assist device (RVAD) placement. Each case underscores the importance of early recognition of SVC syndrome in patients with percutaneous RVAD insertion via the internal jugular vein and calls for heightened awareness of device-associated complications. (Level of Difficulty: Advanced.)

Sudden Cardiac Arrest Secondary to Early Repolarization Syndrome

A healthy 41-year-old man sustained cardiac arrest secondary to ventricular fibrillation. An extensive ischemic, structural, and genetic evaluation did not identify an attributable pathologic condition. Electrocardiograms were notable for early repolarization pattern. Here we review the diagnosis, prevalence, and prognostic significance of the early repolarization syndrome on sudden cardiac death. (Level of Difficulty: Intermediate.).

A Tragic Case of Wearable Cardioverter-Defibrillator Failure

The American College of Cardiology/American Heart Association guidelines recommend a wearable cardioverter defibrillator (WCD) for certain conditions or scenarios. WCD is felt to provide adequate protection against ventricular arrhythmias. This case highlights failure of a WCD to detect and deliver life-saving therapy and the need for improved detection algorithms. (Level of Difficulty: Beginner.)

Electrocardiographic "Northwest QRS Axis" in the Brugada Syndrome: A Potential Marker to Predict Poor Outcome

Conduction delay in the right ventricular outflow tract as manifested in the electrocardiogram constitutes a high-risk predictor of ventricular arrhythmias in patients with Brugada syndrome. We present a case with a right QRS axis between –90° and ±180°. This feature has never been reported in the context of Brugada syndrome. (Level of Difficulty: Advanced.)

Cardiac Transplantation for Refractory Catecholaminergic Polymorphic Ventricular Tachycardia

We present a patient with catecholaminergic polymorphic ventricular tachycardia who failed maximal antiarrhythmic drug therapy and bilateral sympathetic denervation, who presented with syncope and recurrent ventricular tachycardia for 11 min refractory to 21 shocks. She underwent cardiac transplantation as curative treatment for refractory ventricular arrhythmias in catecholaminergic polymorphic ventricular tachycardia. (Level of Difficulty: Advanced.).

Syncope in a Pregnant Woman: Infiltrative Cardiomyopathy and Presumed Cardiac Sarcoidosis

Cardiac involvement in sarcoidosis is an uncommon manifestation of the disease process. Diagnosis and treatment during pregnancy can be challenging due to life-threatening ventricular arrhythmias. We describe a case of a 43-year-old, 21-week pregnant woman who presented after 2 episodes of syncope and was diagnosed with presumed cardiac sarcoidosis. (Level of Difficulty: Beginner.).

Relation between left atrial measurements and thromboembolic risk markers assessed by echocardiography in patients with nonvalvular atrial fibrillation: A cross-sectional study

Background

Left atrium (LA) dilatation has been associated with adverse cardiovascular outcomes in patients with sinus rhythm and atrial fibrillation (AF).

Aim of the study

We aimed to evaluate the accuracy of left atrial (LA) size to predict transesophageal echocardiographic (TEE) markers of increased thromboembolic risk left atrial appendage (LAA) thrombus, low LAA velocities and dense spontaneous echocardiographic contrast (SEC), and also to assess the best method to evaluate LA size.

Patients and methods

Cross-sectional study included 64 patients with nonvalvular AF undergoing transthoracic and transesophageal echocardiographic (TTE and TEE) evaluation. LA size was measured on TTE by several methods including the following: anteroposterior diameter (AP), LA area in four and two apical chamber views and volumes by ellipsoid, single plane (1P) and biplane area-length (2P) formulas. All these measures were indexed to the body surface area (BSA). Thromboembolic markers including LAA thrombus, low LAA velocities, dense SEC and LA abnormality (LA ABN) which means the presence of one or more of the previous three parameters were evaluated by TEE.

Results

There was statistically significant increase in indexed and non-indexed LA parameters in patients with LA ABN compared to patients without LA ABN. According to ROC curve, the study found that all indexed LA parameters were predictive for LAA thrombus with the highest AUC was indexed LA 1P area length volume (AUC 0.91, CI 95% 0.81-1.01, p < 0.000), for LAA low flow velocity were indexed and non-indexed LA AP diameters with the highest AUC was indexed LA AP diameter (AUC 0.89, CI 95% 0.80-0.98, p < 0.000), for LA dense SEC were indexed LA ellipsoid volume (AUC 0.78, CI 95% 0.66-0.96, p = 0.002) and indexed LA 1P area length volume (AUC 0.78, CI 95% 0.66-0.90, p = 0.002) and for LA ABN were all LA parameters with the highest AUC was indexed LA 1P area length volume (AUC 0.87, CI 95% 0.79-0.96, p < 0.000). On multivariate logistic regression analysis of TEE parameters, the study found that the most predictive LA measurement for LAA thrombus was indexed LA AP diameter with cutoff 3 cm/m² (OR 7.5, 95% CI 1.24-45.2, p = 0.02), for LAA low flow velocity was LA AP diameter with cutoff 6 cm (OR 17.6, 95% CI 3.23-95.84, p = 0.001), for LA dense SEC was indexed LA ellipsoid volume with cutoff 42 cm³/m² (OR 6.5, 95% CI 1.32-32.07, p = 0.02), and for LA ABN was indexed LA ellipsoid volume with cutoff 42 cm³/m² (OR 10.45, 95% CI 2.18-51.9, p = 0.008).

Conclusion

LA enlargement is suitable to predict thromboembolic markers in patients with non-valvular AF. The indexed and non-indexed LA AP diameter and indexed LA ellipsoid volume were the most accurate parameters for predicting thromboembolic markers.

Automatic atrial capture device control in real-life practice: A multicenter experience

Background

Device-based fully automatic pacing capture detection is useful in clinical practice and important in the era of remote care management.

The main objective of this study was to verify the effectiveness of the new ACAP Confirm® algorithm in managing atrial capture in the medium term in comparison with early post-implantation testing.

Methods

Data were collected from 318 patients (66% male; mean age, 73±10 years); 237 of these patients underwent device implantation and 81 box changes in 31 Italian hospitals. Atrial threshold measurements were taken manually and automatically at different pulse widths before discharge and during follow-up (7±2 months) examination.

Results

The algorithm worked as expected in 73% of cases, considering all performed tests. The success rate was 65% and 88% pre-discharge and during follow-up examination (p<0.001), respectively, in patients who had undergone implantation. We did not detect any difference in the performance of the algorithm as a result of the type of atrial lead used. The success rate was 70% during pre-discharge testing in patients undergoing device replacement.

Considering all examination types, manual and automatic measurements yielded threshold values of 1.07±0.47 V and 1.03±0.47 V at 0.2-ms pulse duration (p=0.37); 0.66±0.37 V and 0.67±0.36 V at 0.4 ms (p=0.42); and 0.5±0.28 V and 0.5±0.29 V at 1 ms (p=0.32).

Conclusions

The results show that the algorithm works before discharge, and its reliability increases over the medium term. The algorithm also proved accurate in detecting the atrial threshold automatically. The possibility of activating it does not seem to be influenced by the lead type used, but by the time from implantation.

Relationship between right and left ventricular function in candidates for implantable cardioverter defibrillator with low left ventricular ejection fraction

Background

Indications for the primary prevention of sudden death using an implantable cardioverter defibrillator (ICD) are based predominantly on left ventricular ejection fraction (LVEF). However, right ventricular ejection fraction (RVEF) is also a known prognostic factor in a variety of structural heart diseases that predispose to sudden cardiac death. We sought to investigate the relationship between right and left ventricular parameters (function and volume) measured by cardiovascular magnetic resonance (CMR) among a broad spectrum of patients considered for an ICD.

Methods

In this retrospective, single tertiary-care center study, consecutive patients considered for ICD implantation who were referred for LVEF assessment by CMR were included. Right and left ventricular function and volumes were measured.

Results

In total, 102 patients (age 62±14 years; 23% women) had a mean LVEF of 28±11% and RVEF of 44±12%. The left ventricular and right ventricular end diastolic volume index was 140±42 mL/m² and 81±27 mL/m², respectively. Eighty-six (84%) patients had a LVEF <35%, and 63 (62%) patients had right ventricular systolic dysfunction. Although there was a significant and moderate correlation between LVEF and RVEF (r=0.40, p<0.001), 32 of 86 patients (37%) with LVEF <35% had preserved RVEF, while 9 of 16 patients (56%) with LVEF ≥35% had right ventricular systolic dysfunction (Kappa=0.041).

Conclusions

Among patients being considered for an ICD, there is a positive but moderate correlation between LVEF and RVEF. A considerable proportion of patients who qualify for an ICD based on low LVEF have preserved RVEF, and vice versa.

Comparison of circadian, weekly, and seasonal variations of electrical storms and single events of ventricular fibrillation in patients with Brugada syndrome

In patients with Brugada syndrome (BS), VF occurred predominantly during the nocturnal period. Some patients also developed ESs. In addition to the circadian rhythm, patients showed weekly and seasonal patterns. The patients with ESs had peak episodes of VF on Saturday and in the winter and spring, while episodes of VF in patients with single VF events occurred most often on Monday with smaller seasonal variation. Except for age, there was no difference in the clinical or ECG characteristics between the patients with ESs and those with single VF episodes.

Recent advances in genetic testing and counseling for inherited arrhythmias

Inherited arrhythmias, such as cardiomyopathies and cardiac ion channelopathies, along with coronary heart disease (CHD) are three most common disorders that predispose adults to sudden cardiac death. In the last three decades, causal genes in inherited arrhythmias have been successfully identified. At the same time, it has become evident that the genetic architectures are more complex than previously known. Recent advancements in DNA sequencing technology (next generation sequencing) have enabled us to study such complex genetic traits.

This article discusses indications for genetic testing of patients with inherited arrhythmias. Further, it describes the benefits and challenges that we face in the era of next generation sequencing. Finally, it briefly discusses genetic counseling, in which a multidisciplinary approach is required due to the increased complexity of the genetic information related to inherited arrhythmias.