Association of early repolarization with long-term mortality and major adverse cardiac events in patients with ST-segment elevation myocardial infarction

Prevalence of early repolarization syndrome and long-term clinical outcome in patients with the diagnosis of idiopathic ventricular fibrillation

Idiopathic ventricular fibrillation (IVF) is diagnosed in up to 14% of sudden cardiac death (SCD) survivors. Early repolarization syndrome (ERS) in patients with ventricular tachyarrhythmia is characterized by an elevated J-point in inferior and/or antero-lateral leads. Our objectives were to determine the prevalence of ERS in IVF patients, and to evaluate potential differences in clinical outcome. Out of 3,552 implantable cardioverter defibrillator (ICD) carriers, 758 SCD survivors were retrospectively identified from the databases of the Medical Universities of Vienna and Innsbruck within the last three decades. Early repolarization pattern (ERP) was classified either as "notching" or "slurring". Endpoints were defined as appropriate ICD therapies for ventricular tachyarrhythmia, either anti-tachycardia pacing or shock, and all-cause mortality. After exclusion of recognized reasons for SCD, 50 patients were assigned to the diagnosis of IVF (6.6%). An ERP was identified in 10 patients, most of them with notching (n = 8). After a mean follow-up of 11.2 ± 6.7 years (539.3 patient years), appropriate ICD therapies were found in 50% of ERS and 43% of IVF patients without ERP (p = 0.732). In ERS patients, all ICD therapies were found in patients with notching pattern. Similarly, incidence of inappropriate ICD therapies, and all-cause mortality was comparable (30% vs. 23%, p = 0.707; 10% vs. 5%, p = 0.496, respectively). In 758 SCD survivors, we found a low prevalence of IVF and ERS. Similar event rates were reported concerning all-cause mortality and ICD therapies for ventricular tachyarrhythmia after long-term follow-up in this cohort.

A female patient with hypokalaemia-induced J wave syndrome: An unusual case report

RATIONALE

Prominent J waves can be seen in life-threatening cardiac arrhythmias such as Brugada syndrome, early repolarization syndrome, and ventricular fibrillation. We herein present an unusual case report of hypokalemia-induced J wave syndrome and ST (a part of ECG) segment elevation.

PATIENTS CONCERNS

A 52-year-old woman with chief complaints of chest pain for 2 hours and diarrhea showed a marked hypokalemia (2.8 mmol/L) and slightly elevated creatine kinase-MB (CK-MB) (57.5 U/L). The electrocardiographic (ECG) recording was normal upon admission and computed tomography (CT) aorta angiography excluded an aorta dissection. ECG done 17 hours after admission showed ST segment elevation and elevated J wave in leads II, III and aVF, and fusion of T and U wave in all leads.

DIAGNOSIS

We first thought that the diagnosis of this patient was acute myocardial syndrome.

INTERVENTION

Potassium chloride and oflocaxin treatment was given to the patient.

OUTCOMES

Laboratory test showed the level of serum potassium ion increased to 3.4 mmol/L and CK-MB did not have any significant change. The infusion of potassium chloride-induced disappearance of the elevated J wave, although QT (a part of ECG) intervals were still longer than that upon admission.

LESSONS

This case tells us that hypokalaemia might induce J wave and elevated ST segments which should be distinguished from acute myocardial syndrome.