Mechanisms, time course and predictability of premature ventricular contractions cardiomyopathy-an update on its development and resolution.

Frequent premature ventricular contractions (PVCs) associated left ventricular systolic dysfunction (LVSD) is a well-known clinical scenario and numerous predictors for cardiomyopathy (CMP) development have been already thoroughly described. It may present as a "pure" form of dissynchrony-induced cardiomyopathy or it may be an aggravating component of a multifactorial structural heart disease. However, the precise risk to develop PVC-induced CMP (which would allow for tailored-patient monitoring and/or early treatment) and the degree of CMP reversibility after PVC suppression/elimination (which may permit appropriate candidate selection for therapy) are unclear. Moreover, there is limited data regarding the time course of CMP development and resolution after arrhythmia suppression. Even less known are the other components of PVC-induced CMP, such as right ventricular (RV) and atrial myopathies. This review targets to synthetize the most recent information in this regard and bring a deeper understanding of this heart failure scenario. The mechanisms, time course (both in experimental models and clinical experiences) and predictors of reverse-remodelling after arrhythmia suppression are described. The novel experience hereby presented may aid everyday clinical practice, promoting a new paradigm involving more complex, multi-level and multi-modality evaluation and possible earlier intervention at least in some patient subsets.

Clinical implementation of cardiac resynchronization therapy-regional disparities across selected ESC member countries.

BACKGROUND: The present analysis aimed to estimate the penetration of cardiac resynchronization therapy (CRT) on the basis of the prevalence and incidence of eligible patients in selected European countries and in Israel. METHODS AND RESULTS: The following countries were considered: Italy, Slovakia, Greece, Israel, Slovenia, Serbia, the Czech Republic, Poland, Romania, Hungary, Ukraine, and the Russian Federation. CRT penetration was defined as the number of patients treated with CRT (CRT patients) divided by the prevalence of patients eligible for CRT. The number of CRT patients was estimated as the sum of CRT implantations in the last 5 years, the European Heart Rhythm Association (EHRA) White Book being used as the source. The prevalence of CRT indications was derived from the literature by applying three epidemiologic models, a synthesis of which indicates that 10% of heart failure (HF) patients are candidates for CRT. HF prevalence was considered to range from 1% to 2% of the general population, resulting in an estimated range of prevalence of CRT indication between 1000 and 2000 patients per million inhabitants. Similarly, the annual incidence of CRT indication, representing the potential target population once CRT has fully penetrated, was estimated as between 100 and 200 individuals per million. The results showed the best CRT penetration in Italy (47-93%), while in some countries it was less than 5% (Romania, Russian Federation, and Ukraine). CONCLUSION: CRT penetration differs markedly among the countries analyzed. The main barriers are the lack of reimbursement for the procedure and insufficient awareness of guidelines by the referring physicians.

A comparative study of EEG suppressions induced by global cerebral ischemia and anoxia.

Cerebral ischemia and anoxia induce sequential changes that include ionic redistribution, alteration of enzimatic reactions governing metabolism and intracellular signaling. Despite high technology instrumentation including positron emission, tomography and magnetic resonance imaging used to unravel the intricacies of cerebral blood flow and metabolism, the electroencephalography (EEG) retains a useful place in the evaluation of processes induced by cerebral ischemia, especially in experimental conditions. We have investigated in this study EEG suppression and recovery following global cerebral ischemia, obtained by "four vessel occlusion model", reperfusion and anoxia. Both cerebral ischemia and anoxia have produced a sudden diminution of electrical brain activity and flat line was recorded after 8-10 sec. in the ischemic rats, but after 35-40 sec. in the anoxic rats. After same period of time (2 min) of ischemia and anoxia EEG recovery has been faster in the ischemic rat.

Preliminary EEG study of protective effects of Tebonin in transient global cerebral ischemia in rats.

Free radicals and platelet activating factor (PAF) have been implicated as important mediators in neuronal injury after cerebral ischemia-reperfusion and, particularly, in postischemic hypoperfusion. The electroencephalography (EEG) is a real time reflection of changes in neuronal activity and metabolism. The objective of this study was to investigate the effects of preventive treatment with Ginkgo biloba extract (EGb 761--Tebonin) in cerebral global ischemia and reperfusion in rats using computerized EEG analysis. Ginkgo biloba extract, known to be, in vitro, a free radicals scavanger and a PAF--antagonist, was administrated in dose of 100 mg/kg over 24 hours, for 5 days before and 5 days after cerebral ischemia--reperfusion. The apparition of isoelectric EEG (flat-line) following 4-vessel occlusion was observed after a mean time of 25 sec. in Ginkgo biloba treated rats and after 18 sec. in control rats (p < 0.0015). Computerized spectral analysis of EEG has shown that the percentage of slow waves at 10 minutes after reperfusion was 117% higher in control group than in Ginkgo biloba group (p < 0.015) and the percentage of slow waves after 15 minutes of reperfusion was 100% higher in the control group than in the Ginkgo biloba group (p < 0.02). Five days after cerebral ischemia--reperfusion the percentage of slow waves was unsignificantly higher in the control group than in the Ginkgo biloba group (p > 0.05).