The electrical cardiac systole originates from the beginning of the P wave (atrial depolarisation) until the end of the downward branch of the T wave (ventricular repolarisation). It includes, therefore, succession P-QRS-T and its corresponding intervals and segments: PQ, ST, and QT. The mathematical possibilities of variability in the length of the electrical systole of the heart may be diverse. It is well documented and established that such changes in length may make the myocardial cells more vulnerable and unstable, and may also cause serious cardiac arrhythmias and even sudden death. The current presentation illustrates these electrocardiographic entities with significant variations in the length of its waves and intervals: short PQ and QT intervals, short PQ and long QT, long PQ and long QT. All parameters appeared in young adult males.
Wolff-Parkinson-White syndrome (WPWS) is a congenital heart disease (PRKAG2. Genetic map 7q36) characterised by a premature ventricular depolarisation caused by an abnormal atrioventricular accessory pathway known as Kent's bundle. Prolonged QT syndrome (PQTS) consists of an abnormal prolongation of the QT interval on the ECG, which can be both inherited and acquired. This anomaly is known to favour the occurrence of malign cardiac arrhythmias, above all polymorphic ventricular tachycardia, ventricular fibrillation and "torsade de pointes".
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The Tako-tsubo cardiomyopathy, also known as transient apical dysfunction, transient apical dyskinesia, stress-induced cardiomyopathy or broken heart syndrome, is a type of nonischemic cardiomyopathy in which there is a sudden temporary weakening of the myocardium. The PR interval reflects the time the electrical impulse takes to travel from the sinus node through the AV node and entering the ventricles. The PR interval is therefore a good estimate of AV node function. Its normal values are between 0.120-0.200 seconds. When its length is lesser than 0.120 seconds, we speak as a short PR-interval. This event has a great capacity for severe cardiac arrhythmia production. Both entities can be very dangerous, separately. When they are together in the same individual, the consequences could be deadly.
Alterations in the cardiac electrical system are the cause of morbidity and a wide variety of symptoms -from mild to those requiring urgent intervention -because of the risk of sudden cardiac death. The most prevalent of these types of electrical disturbances is atrial fibrillation, the incidence of which is growing as the average age of the human being increases. Among many other electrical heart alterations is one I describe in this document: "The presence of short PR and QTc intervals together in the same ECG tracing". Methods: A cardiac calibrator was used by four different cardiologists in blinded fashion to document a distinct ECG pattern, that of a short PR and QTc intervals together in the same ECG tracing from more than 2.500 cases assessed for this condition (more than two thousand five hundred cases evaluated since 2.007 to date). Results: Here we describe the clinical features of 330 patients with a documented short PR and QTc intervals together in the same ECG tracing along with descriptions of their symptoms and ancillary investigations. Conclusions: ECG tracing must be studied carefully in patients with suggestive symptoms before declaring normal an ECG tracing with certain defined characteristics.
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