Hussam Ali

J wave, QRS slurring, and ST elevation in athletes with cardiac arrest in the absence of heart disease marker of risk or innocent bystander?

Background—QRS-ST changes in the inferior and lateral ECG leads are frequently observed in athletes. Recent studies have suggested a potential arrhythmogenic significance of these findings in the general population. The aim of our study was to investigate whether QRS-ST changes are markers of cardiac arrest (CA) of unexplained cause or sudden death in athletes. Methods and Results—In 21 athletes (mean age, 27 years; 5 women) with cardiac arrest or sudden death, the ECG recorded before or immediately after the clinical event was compared with the ECG of 365 healthy athletes eligible for competitive sport activity. We measured the height of the J wave and ST elevation and searched for the presence of QRS slurring in the terminal portion of QRS. QRS slurring in any lead was present in 28.6% of cases and in 7.6% of control athletes (P=0.006). A J wave and/or QRS slurring without ST elevation in the inferior (II, III, and aVF) and lateral leads (V4 to V6) were more frequently recorded in cases than in control athletes (28.6% versus 7.9%, P=0.007). Among those with cardiac arrest, arrhythmia recurrences did not differ between the subgroups with and without J wave or QRS slurring during a median 36-month follow-up of sport discontinuation. Conclusions—J wave and/or QRS slurring was found more frequently among athletes with cardiac arrest/sudden death than in control athletes. Nevertheless, the presence of this ECG pattern appears not to confer a higher risk for recurrent malignant ventricular arrhythmias.

Development of an Entirely Subcutaneous Implantable Cardioverter-Defibrillator

The recent advent of an entirely subcutaneous implantable defibrillator (ICD) has provided a relevant contribution to the debate concerning the use of ICD therapy in patients at high risk for death. Although conventional transvenous ICDs have proven very effective during the past 23 years, they still appear to be limited by nontrivial acute and long-term complications. This study delineates some of the historical and current issues characterizing the advent of the subcutaneous ICD system in daily clinical practice. Subcutaneous ICDs have proven effective in more than 1100 patients worldwide and appear to be competitive with transvenous ICD in all clinical conditions not requiring antibradycardia, antitachycardia, or cardiac resynchronization pacing.

Nodo- and fasciculoventricular pathways: Electrophysiological features and a proposed diagnostic algorithm for preexcitation variants

Introduction Fasciculoventricular and nodoventricular pathways (FVP and NVP) are uncommon preexcitation variants that can be misleading during electrophysiology studies (EPSs), and differentiating them could be challenging. In this article, we describe 2 representative cases and then we present various electrophysiological features and phenomenon encountered in patients with these particular accessory pathways (APs).

Electrophysiological study and catheter ablation of a Mahaim fibre located at the mitral annulus-aorta junction

Accessory pathways with slow and anterograde decremental conduction (Mahaim fibres) are responsible for a minority of atrioventricular reentrant tachycardias. While usually located along the tricuspid annulus, left-sided Mahaim fibres have been occasionally reported. We here report on a unique case of radiofrequency catheter ablation of a Mahaim pathway located at the supero-septal aspect of the mitral annulus, in a region known as mitral annulus–aorta junction, between the right and left fibrous trigons. Electrophysiological properties and embryological implications of this unusual accessory pathway are discussed.

An unusual case of permanent junctional reciprocating tachycardia: Successful ablation at the mitral annulus-aorta junction

A 25-year-old woman with drug-refractory permanent junctional reciprocating tachycardia (PJRT) and a previous failed ablation, was referred to our institution. Electrophysiological study confirmed the diagnosis of orthodromic atrioventricular reentry tachycardia using a slowly conducting accessory pathway. This accessory pathway was successfully ablated by conventional radiofrequency at the left anteroseptal region using a transseptal approach. Catheter ablation of this accessory pathway (Coumel type) at the mitral annulus-aorta junction offers insights on a rare anatomical location of PJRT.

The Entirely Subcutaneous Defibrillator - A New Generation and Future Expectations.

Although conventional implantable cardioverter-defibrillators (ICDs) have proved effective in the prevention of sudden cardiac death (SCD), they still appear to be limited by non-trivial acute and long-term complications. The recent advent of an entirely subcutaneous ICD (S-ICD) represents a further step in the evolution of defibrillation technology towards a less-invasive approach. This review highlights some historical and current issues concerning the S-ICD that may offer a viable therapeutic option in selected patients at high risk of SCD and in whom pacing is not required. After the CE Mark and US Food and Drug Administration (FDA) approvals, the S-ICD is being implanted worldwide with growing clinical data regarding its safety and efficacy (the EFFORTLESS Registry). The recently developed new generation of S-ICD (EMBLEM, Boston Scientific) demonstrates favourable features including a smaller device, longer longevity and remote-monitoring compatibility. Further innovations in the S-ICD system and potential integration with leadless pacing may play an important role in defibrillation therapy and prevention of SCD in the near future.

Sudden cardiac death: New approaches for implantable cardioverter-defibrillators (ICDs)

The implantable cardioverter-defibrillator (ICD) has shown its superiority to anti-arrhythmic drugs in the prevention of sudden cardiac death. However, the conventional transvenous ICDs are still associated with substantial risks and comorbidities mainly related to the transvenous leads. The recent advent of an entirely sub-cutaneous ICD (S-ICD) represents an important progress in the defibrillation technology towards a less invasive approach. Clinical data are growing regarding the safety and efficacy of S-ICD in prevention of sudden cardiac death in selected patients without pacing indications. This novel technology seems promising and particularly beneficial in young patients with channelopathies, conditions at high risk of infection, or in those who experienced previous complications related to the transvenous leads. The S-ICD technology is still developing regarding the device, diagnostic capabilities, and the surgical implantation technique. Further advancements and potential integration with the leadless pacing technology may realize an outstanding evolution in defibrillation therapy and prevention of sudden cardiac death in the near future.

Clinical and electrocardiographic features of complete heart block after blunt cardiac injury: A systematic review of the literature

The underlying mechanisms and temporal course of complete heart block (CHB) after blunt cardiac injuries (BCIs) are poorly understood, and a systematic analysis of available data is lacking. In this systematic review, PubMed was searched for publications of reported cases of CHB-BCI analyzing clinical findings, electrocardiographic features, temporal course, and outcomes. Case reports on CHB-BCI were available for 50 patients, mainly secondary to traffic or sport accidents. A fatal outcome occurred in 10 of 50 (20%) of patients, while a structural damage of the atrioventricular (AV) conductive system was evident in 4 of 8 (50%) of necropsy studies. Clinical manifestation of CHB-BCI occurred within 72 hours of injury in 38 of 47 (∼80%) of patients, and 1:1 AV conduction was restored within 7-10 days in about half of early survivors. Permanent pacemaker implantation was indicated in 22 of 42 (∼50%) of early survivors because of recurrent or permanent CHB. Cardiac troponins, when analyzed, were elevated in 12 of 13 (∼90%) of patients, and electrocardiographic features of aberrancy were present in 29 of 40 (>70%) of patients. In conclusion, CHB secondary to BCI is associated with 20% mortality mainly occurring in the early posttraumatic period and most of the deaths are due to or triggered by this malignant arrhythmia. Recurrent or permanent CHB requiring pacemaker implantation occurs in ∼50% of survivors. A structural damage of the AV conductive system can be found in 50% of necropsy studies.

Negative concordance pattern in bipolar and unipolar recordings: An additional mapping criterion to localize the site of origin of focal ventricular arrhythmias.

BACKGROUND The relevance of the temporal relationship between a unipolar electrogram (UEGM) and a bipolar electrogram (BEGM) in determining the site of origin (SOO) of focal arrhythmias has been largely demonstrated. OBJECTIVE We sought to demonstrate that a negative concordance in the initial forces of these EGMs is also helpful in predicting the SOO of premature ventricular contractions (PVCs). METHODS Mapping and radiofrequency (RF) ablation were performed in 41 patients with symptomatic PVCs in the absence of structural heart disease. Simultaneous recordings of the minimally filtered (0.5-500 Hz) UEGM and filtered BEGM (30-500 Hz) were analyzed at 247 mapping sites, where RF was attempted. EGMs of 63 mechanically induced PVCs were separately analyzed as a validation group. All ablation sites had a QS pattern in the UEGM. Acute PVC suppression was defined as a complete disappearance of ventricular ectopic beats after a 60-second pulse of RF. RESULTS RF ablation obtained PVC suppression (RF+) in 33 of 247 sites (13.3%). A negative concordance pattern (NCP) during the initial 20 ms of both UEGM and BEGM was observed in 31 of 33 (94%) RF+ sites compared with 10 of 214 (4%)RF- sites (P < .0001). The NCP criterion demonstrated to be an additional powerful predictor of acute RF success with sensitivity, specificity, positive predictive value, and negative predictive value of 94%, 95%, 76%, and 99%, respectively. Similarly to RF+ sites, the NCP was observed in 60 of 63 sites (95.2%) in the mechanical PVC group. CONCLUSION An NCP in both UEGM and BEGM may be an additional criterion that helps to localize the SOO of focal ventricular arrhythmias.

Asystole Detected by Implantable Loop Recorders: True or False?

We report a case of a false asystole detected by an implantable loop recorder a few days after its implantation. In the discussion section we try to give some hints to help cardiac electrophysiologists in distinguish true from false asystoles, in order to avoid unuseful and potentially dangerous implantations of pacemakers.