Protective or Inhibitory Effect of Pharmacological Therapy on Cardiac Ischemic Preconditioning: A Literature Review.

Ischemic preconditioning (IP) is an innate phenomenon, triggered by brief, non-lethal cycles of ischemia/reperfusion applied to a tissue or organ that confers tolerance to a subsequent more prolonged ischemic event. Once started, it can reduce the severity of myocardial ischemia associated with some clinical situations, such as percutaneous coronary intervention (PCI) and intermittent aortic clamping during coronary artery bypass graft surgery (CABG). Although the mechanisms underlying IP have not been completely elucidated, several studies have shown that this phenomenon involves the participation of cell triggers, intracellular signaling pathways, and end-effectors.

Effect of ischemic preconditioning on cardiovascular outcomes in patients with symptomatic coronary artery disease: a cohort study.

Background: Despite the powerful myocardial protection of ischemic preconditioning (IP) observed in experimental studies, it remains a challenge to observe such protection in humans. Thus, the aim of this study was to evaluate the possible effects of IP on clinical outcomes in patients with coronary artery disease (CAD).

Patients And Methods: In this cohort study, patients with multivessel CAD, preserved systolic ventricular function, and stable angina were prospectively selected.

Use of imaging and clinical data to screen for cardiovascular disease in asymptomatic diabetics.

Background: There is increasing evidence to suggest that not all individuals with type 2 diabetes mellitus (T2DM) have equal risk for developing cardiovascular disease. We sought to compare the yield of testing for pre-clinical atherosclerosis with various approaches.

Methods: 98 asymptomatic individuals with T2DM without known coronary artery disease (CAD) were enrolled in a prospective study and underwent carotid ultrasound, exercise treadmill testing (ETT), coronary artery calcium (CAC) scoring, and coronary computed tomography angiography (CTA).

Role of Trimetazidine in Ischemic Preconditioning in Patients With Symptomatic Coronary Artery Disease.

Ischemic preconditioning (IP) is a powerful cardioprotective cellular mechanism that has been related to the "warm-up phenomenon" or "walk-through" angina, and has been documented through the use of sequential exercise tests (ETs). It is known that several drugs, for example, cromokalim, pinacidil, adenosine, and nicorandil, can interfere with the cellular pathways of IP. The purpose of this article is to report the effect of the anti-ischemic agent trimetazidine (TMZ) on IP in symptomatic coronary artery disease (CAD) patients.

Type 2 diabetes mellitus and myocardial ischemic preconditioning in symptomatic coronary artery disease patients.

Background: The influence of diabetes mellitus on myocardial ischemic preconditioning is not clearly defined. Experimental studies are conflicting and human studies are scarce and inconclusive.

Objectives: Identify whether diabetes mellitus intervenes on ischemic preconditioning in symptomatic coronary artery disease patients.

Hypotheses, rationale, design, and methods for evaluation of ischemic preconditioning assessed by sequential exercise tests in diabetic and non-diabetic patients with stable coronary artery disease--a prospective study.

Background: Ischemic preconditioning is a powerful mechanism of myocardial protection and in humans it can be evaluated by sequential exercise tests. Coronary Artery Disease in the presence of diabetes mellitus may be associated with worse outcomes. In addition, some studies have shown that diabetes interferes negatively with the development of ischemic preconditioning.

Effect of hypoglycemic agents on ischemic preconditioning in patients with type 2 diabetes and symptomatic coronary artery disease.

Objective: To assess the effect of two hypoglycemic drugs on ischemic preconditioning (IPC) patients with type 2 diabetes and coronary artery disease (CAD).

Research Design And Methods: We performed a prospective study of 96 consecutive patients allocated into two groups: 42 to group repaglinide (R) and 54 to group vildagliptin (V). All patients underwent two consecutive exercise tests (ET1 and ET2) in phase 1 without drugs.

New prognostic score for stable coronary disease evaluation.

Background: The need to improve the exercise testing accuracy, pushed the development of scores, whose applicability was already broadly recognized.

Objective: Prognostic evaluation of stable coronary disease through a new simplified score.

Methods: A new score was applied in 372 multivessel coronary patients with preserved ventricular function, 71.

Electrovectorcardiographic diagnosis of left septal fascicular block: anatomic and clinical considerations.

Several publications considering anatomical, histological, pathological, electrocardiographic, vectorcardiographic, and electrophysiologic studies have shown that the left bundle branch splits into three fascicles or in a "fan-like interconnected network" in the vast majority of human hearts. The left His system is trifascicular with a left anterior, a left posterior, and a left septal fascicle (LSF). Consequently, the classic term "hemiblock," to describe the block of one of the fascicles, established several decades ago by the Rosembaum's school, should be updated.

[Electrocardiographic score: application in exercise test for the assessment of ischemic preconditioning].

Background: the time for 1.0 mm ST-segment depression (T-1.0mm) adopted to characterize ischemic preconditioning (IPC) in sequential exercise tests is consistent and reproducible; however, it has several limitations.

Propofol infusion syndrome and Brugada syndrome electrocardiographic phenocopy.

This anesthetic drug may cause a rare condition named propofol infusion syndrome, characterized by unexplained lactic acidosis, lipemia, rhabdomyolysis, cardiovascular collapse and Brugada-like electrocardiographic pattern or Brugada electrocardiographic phenocopy changes following high-dose propofol infusion over prolonged periods of time. Several articles have contributed to our understanding of the cause of the syndrome, and the growing number of case reports has made it possible to identify several risk factors. Uncertainty remains as to whether a genetic susceptibility exists.

Study of the extent of the information of cardiologists from São Paulo city, Brazil, regarding a low-prevalence entity: Brugada syndrome.

Objective: To determine the degree of knowledge that cardiologists from São Paulo, Brazil, have regarding a low-prevalent entity associated with a high rate of sudden death-Brugada syndrome.

Methods: Two hundred forty-four cardiologists were interviewed by an instrument divided in two parts: in the first, we recorded gender, age, and data related to academic profile. The second--answered only by the professionals that manifested having some degree of knowledge on the syndrome--had 28 questions that evaluated their knowledge.

The enigmatic sixth wave of the electrocardiogram: the U wave.

The U wave is the last, inconstant, smallest, rounded and upward deflection of the electrocardiogram. Controversial in origin, it is sometimes seen following the T wave with the TU junction along the baseline or fused with it and before P of the following cycle on the TP segment. In this review we will study its temporal location related to monophasic action potential, cardiac cycle and heart sounds, polarity, voltage or amplitude, frequency and shapecontour.

The management of Brugada syndrome patients.

Brugada syndrome is a congenital electrical disorder characterised by the appearance of distinctive QRST-T patterns in the right precordial leads and an increased risk of sudden death (SCD) in young healthy adults. Although chamber enlargement is not apparent in most cases, autopsy and histological investigations have revealed structural abnormalities. The typical Brugada ECG manifestation is often concealed and may be revealed by Class IC anti-arrhythmic agents with the effect of blocking the fast component of sodium channel currents.

Relationship among amiodarone, new class III antiarrhythmics, miscellaneous agents and acquired long QT syndrome.

Class III drugs prolong the QT interval by blocking mainly the delayed rectifier rapid potassium outward current (IKr), with little effect on depolarization. This K(+) channel in encoded by the human ether-a-go-go-related gene (hERG). Inhibition of hERG potassium currents by class III antiarrhythmic drugs causes lengthening of cardiac action potential, which produces a beneficial antiarrhythmic effect.

Early repolarization variant: epidemiological aspects, mechanism, and differential diagnosis.

Early repolarization variant (ERV or ERPV) is a enigmatic electrocardiographic phenomenon, characterized by prominent J wave and ST-segment elevation in multiple leads. Recently, there has been renewed interest in ERV because of similarities to the arrhythmogenic Brugada syndrome (BrS). Not much is known about the epidemiology of ERV and several studies have reported that this condition is associated with a good prognosis.

Wellens syndrome associated with prominent anterior QRS forces: an expression of left septal fascicular block?

Wellens syndrome is a clinical-electrocardiographic entity also referred to as left anterior descending (LAD) coronary T-wave syndrome or acute coronary T-wave syndrome. It is a complex of symptoms and signals indicating the existence of an undesirable condition secondary to critical high-grade proximal stenosis of the LAD coronary artery characterized by the association of prior history of acute coronary syndrome with little or no elevation of markers of myocardial damage (unstable angina) and characteristic electrocardiographic changes consistent with subepicardial anterior ischemic pattern (persistently symmetrical, deep negative and broad-based T waves) or plus-minus T waves with inversion of the terminal portion in the LAD coronary artery territory (V1 through V5 or V6). We present a case of a variant of Wellens syndrome that reveals association and, transitorily, the criteria described in literature for left septal fascicular block.

The history of left septal fascicular block: chronological considerations of a reality yet to be universally accepted.

There are several papers in literature that prove in a conclusive and incontestable way, that the left branch of the His bundle, in most instances (85% of the cases) splits into three fascicles of variable morphological pattern, and not into two: left anterior fascicle (LAF), left posterior fascicle (LPF), and left septal fascicle (LSF). The abovementioned papers have anatomical, histological, anatomo-pathological, electrocardiographic, and vectocardiographic, body surface potential mapping or ECG potential mapping and electrophysiological foundation.Additionally, the mentioned papers have been performed both in animal models (dogs) and in the human heart.

Significance of vectorcardiogram in the cardiological diagnosis of the 21st century.

Until the mid-1980s, it was believed that the vectorcardiogram presented a greater specificity, sensitivity and accuracy in comparison to the conventional electrocardiogram, in the diagnosis of the different heart diseases. Recent studies revealed that the vectorcardiogram still is superior to the electrocardiogram in very specific situations, such as in the evaluation of electrically inactive areas, in intraventricular conduction disorders combined and/or in association to inactive areas, in the identification and location of ventricular preexcitation, in the differential diagnosis of patterns varying from normal of electrical axis deviation, in the evaluation of particular aspects of Brugada syndrome, and in the estimation of the severity of some enlargements, among others. With the advent of computerized vectorcardiography, a technology that improves the processing and recording method; a future still promising is expected for this methodology.

Head-to-head comparison of dobutamine and adenosine stress real-time myocardial perfusion echocardiography for the detection of coronary artery disease.

We sought to determine the value of dobutamine versus adenosine real-time myocardial perfusion (MP) echocardiography for detecting coronary artery disease and the value of quantitative analysis of MP over electrocardiography, wall motion, and qualitative MP. We studied 54 patients by real-time MP echocardiography and coronary angiography. Replenishment velocity (beta) and an index of myocardial blood flow (A(n)xbeta) were derived from quantitative MP.

The signal-averaged electrocardiogram of atrial activation in patients with or without paroxysmal atrial fibrillation.

Objective: To analyze the parameters of the time domain P-wave signal-averaged electrocardiogram (P-SAECG) and compare them with the P-wave duration on the conventional electrocardiogram (P on ECG) as well as the left atrium diameter (LAD) and left ventricular ejection fraction (EF) obtained on the echocardiogram in order to evaluate patients with paroxysmal atrial fibrillation (PAF).

Methods: One hundred and eighty-one patients were included in the study: 117 with confirmed PAF and 64 without PAF. The P-SAECG parameters used were: the filtered P-wave duration (FPD), the root mean square (RMS) voltages in the last 40, 30 and 20 ms of the filtered P-wave (RMS 40, RMS 30 and RMS 20), the root mean square voltage of the filtered P-wave potentials (RMS P), the integral of the potentials during the filtered P-wave (Integral P) and the filtered P-wave late potential durations below 3 microV (PL<3).