Diagnostic value of implantable loop recorders in patients with unexplained syncope or palpitations.

BACKGROUND: The implantable loop recorder (ILR) is a small cardiac rhythm-monitoring device. Our aim was to determine ILR diagnostic value in patients with unexplained syncope, presyncope, or palpitations suggesting cardiac arrhythmias. METHODS: This has been a retrospective, observational, single-center study. We included 181 patients in whom ILR was implanted at the Clinical Center of Serbia between January 2006 and July 2019. An event was marked as diagnostic if it led to a diagnosis and ILR was considered diagnostic if it verified or excluded an arrhythmia as the cause of syncope or palpitations. RESULTS: The mean age was 51.8 ± 17.8 years and 94 (51.9%) were male. The mean follow-up period was 20.2 ± 15.8 months. ILR was diagnostic in 98 patients (54.1%). There was no significant difference in diagnostic value of ILR in regard to the baseline patients' characteristics. The mean time to occurrence of the diagnostic event was 11.1 ± 9.6 months. The time to occurrence of a diagnostic event did not differ significantly between patients who underwent basic as compared to extended diagnostics before ILR implantation. CONCLUSIONS: ILR was able to achieve an etiological diagnosis in 54.1% of patients with unexplained syncope, presyncope, or palpitations suggesting cardiac arrhythmias. In a subgroup of patients with recurrent palpitations, ILR was significantly less diagnostic than in patients with syncope or presyncope. ILR should be implanted beforehand in syncope evaluation process.

Autonomic dysfunction in alcoholic cirrhosis and its relation to sudden cardiac death risk predictors.

Patients with liver cirrhosis have autonomic dysfunction and complex cardiovascular changes. Increases risk for sudden cardiac death (SCD) was recently recognized in liver cirrhosis. This study analyzed risk predictors for SCD related to autonomic dysfunction in patients with alcoholic liver cirrhosis (ALC). Twenty five patients with ALC were examined and compared with healthy control group. Cardiovascular autonomic reflex tests, comprehensive ECG with QTc interval, late potentials, short-term heart rate variability (HRV) analysis (time domain, spectral and nonlinear-Poincare plot analysis) and 24-h Holter ECG with long-term HRV analysis were done. According to autonomic reflex tests patients with ALC had high incidence (56%) of severe autonomic dysfunction, manifested as pronounced damage of vagal function. Patients had significantly depressed HRV (SDNN, SDANN, triangular index, LF and HF) and more frequently had serious arrhythmias, prolonged QTc and Poincare plot in a shape of dot (p < 0.001). In patient group QTc significantly inversely correlated with spectral components from short-term HRV analysis (ln(LF): r = -0.53, ln(HF): r = -0.47; p < 0.05), and Lown class significantly correlated with total autonomic function score (r = 0.64, p = 0.04). This study indicates that in ALC autonomic neuropathy with vagal impairment and sympathetic predominance is related to SCD risk predictors and onset of serious ventricular arrhythmias.

[Brugada syndrome: case report].

INTRODUCTION: Brugada syndrome is an arrhythmogenic disease characterized by coved ST segment elevation and J point elevation of at least 2 mm in at least two of the right precordial ECG leads (V1-3) and ventricular arrhythmias, syncope, and sudden death. Risk stratifications of patients with Brugada electrocardiogram are being strongly debated. CASE OUTLINE: A 23-year-old man was admitted to the Coronary Care Unit of the Clinical Centre "Bezanijska kosa" due to weakness, fatigue and chest discomfort. The patient suffered from fainting and palpitations. There was a family history of paternal sudden death at 36 years. Electrocardiogram showed a coved ST segment elevation of 4 mm in leads V1 and V2, recognised as spontaneous type 1 Brugada pattern. Laboratory investigations revealed normal serum cardiac troponin T and serum potassium, and absence of inflammation signs. Echocardiographic finding was normal, except for a mild enlargement of the right atrium and ventricle. The diagnosis of Brugada syndrome was made by Brugada-type 1 electrocardiogram and the family history of sudden death <45 years. The patient was considered as a high risk, because of pre-syncope and palpitations. He underwent ICD implantation (Medtronic MaximoVR7232Cx) using the standard procedure. After implantation, noninvasive electrophysiology study was done and demonstrated inducible VF that was interrupted with the second 35 JDC shock. The patient was discharged in stable condition with beta-blocker therapy. After a year of pacemaker check-ups, there were no either VT/ VF events or ICD therapy. CONCLUSION: Clinical presentation is the most important parameter in risk stratification of patients with Brugada electrocardiogram and Brugada syndrome.

[Prognostic value of Poincare plot as nonlinear parameter of chaos theory in patients with myocardial infarction].

INTRODUCTION: There are different proofs about association of autonomic nervous system dysfunction, especially nonlinear parameters, with higher mortality after myocardial infarction. OBJECTIVE: The objective of the study was to determine predictive value of Poincaré plot as nonlinear parameter and other significant standard risk predictors: ejection fraction of the left ventricle, late potentials, ventricular arrhythmias, and QT interval. METHOD: The study included 1081 patients with mean follow-up of 28 months (ranging from 0-80 months). End-point of the study was cardiovascular mortality. The following diagnostic methods were used during the second week: ECG with commercial software Schiller AT-10: short time spectral analysis of RR variability with analysis of Poincaré plot as nonlinear parameter and late potentials; 24-hour ambulatory ECG monitoring: QT interval, RR interval, QT/RR slope, ventricular arrhythmias (Lown > II); echocardiography examinations: systolic disorder (defined as EF < 40%). RESULTS: There were 103 (9.52%) cardiovascular deaths during the follow-up. In univariate analysis, the following parameters were significantly correlated with mortality: mean RR interval < 800 ms, QT and RR interval space relationship as mean RR interval < 800 ms and QT interval > 350 ms, positive late potentials, systolic dysfunction, Poincaré plot as a point, ventricular arrhythmias (Lown > II). In multivariate analysis, the significant risk predictors were: Poincaré plot as a point and mean RR interval lower than 800 ms. CONCLUSION: Mean RR interval lower than 800 ms and nonlinear and space presentation of RR interval as a point Poincaré plot were multivariate risk predictors.

[Early risk predictors of sudden cardiac death after myocardial infarction: results of follow up of 881 patients].

INTRODUCTION: It has been shown that depolarization disorders, autonomic dysfunction, and systolic dysfunction of the left ventricle are associated with sudden cardiac death after myocardial infarction. OBJECTIVE: The objective of study was to examine the prognostic value of the most important predictors in the first week after myocardial infarction. METHOD: Study included 881 patients who were followed up from 1 to 60 months. During the first week after myocardial infarction, following examination were performed: ECG with standard leads and X, Y, Z orthogonal leads, vectorcardiogram, QT interval, late potentials, short-time spectral analysis of RR variability, nonlinear (Poincaré plot) analysis and echocardiogram. RESULTS: In univariate analysis, the following parameters measured on the first day were important predictors of sudden cardiac death: lower LF/HF ratio (<1.5) (p = 0.000), T wave inversion in X lead (p = 0.000), high P wave in D2 lead (p=0.030), and diminished systolic function (p = 0.000). In multivariate analysis, the following parameters were significant risk predictors: T wave inversion in X lead, lower LF/HF ratio, positive late potentials and the left ventricle systolic dysfunction. CONCLUSION: The parameters of the left ventricle systolic disfunction with sympathicovagal imbalance and electric instability are the key risk predictors in the first few days after myocardial infarction.