ventricular parasystole

AIMS: Discrete, fragmented, local voltage potentials (LVPs) have been observed in electrograms recorded at the ablation site in patients undergoing radiofrequency ablation for arrhythmias originating in both the right and left ventricular outflow tract; however, the incidence and the significance of the LVP with respect to arrhythmogenesis is uncertain. METHODS AND RESULTS: We studied 25 patients with outflow tract arrhythmias referred for radiofrequency catheter ablation and recorded high-amplified intracardiac electrograms close to the site of origin of the arrhythmia...

BACKGROUND: In 1974, Kinoshita reported a case of 'irregular parasystole' due to type I second-degree entrance block. Since then, many cases of such 'irregular' parasystole have been reported by us. To explain the mechanism of 'irregular' parasystole, two theories have been suggested, namely, 'electrotonic modulation' by Jalife and Moe, and 'type I second-degree entrance block' by us. On the contrary, in 1960, Kinoshita et al. reported a case of concealed bigeminy for the first time. The electrocardiographic findings in concealed bigeminy have suggested that there are dual re-entrant pathways with markedly long effective refractory periods in the re-entrant pathway...

Mad honey poisoning syndrome has been reported in the Eastern Black Sea region and Southeastern regions of Turkey. Herein we report a case of 70-y-old man presented with syncope and severe hemodynamic instability following ingestion of one teaspoon of honey and his unusual electrocardiographic manifestations: nodal rhythm alternating with sinus bradycardia and intermittant ventricular parasystole. In this report, we also tried to explain the possible mechanism responsible for these electrocardiographic findings...

This case describes a patient with two separate foci of idiopathic ventricular tachycardia in the right ventricle. Both of the tachycardias manifested cycle length and QRS alternans. Both were successfully ablated and information from the electrophysiologic study and ablation procedure indicated that both tachycardias were focal, secondary to triggered activity, and that the best model to explain the cycle length and QRS alternans during tachycardia was that of "self-entraining modulated parasystole."

Isolated left ventricular noncompaction is a recently recognized age-independent cardiac genetic disorder caused by heterogeneous defects in endo-myocardial morphogenesis. Transthoracic echocardiography and cardiac magnetic resonance are the most reliable techniques to make a diagnosis of the disease, noninvasively. Arrhythmic atrial and ventricular disorders have been reported in 20-50% of these patients. The morphological and functional findings are described in a young woman in whom the exclusive clinical sign of isolated ventricular noncompaction was an atrial parasystole...

Electrocardiograms were taken from a 44-year-old man with irregular ventricular parasystole in whom pure parasystolic cycles without any intervening nonectopic QRS complexes were found. When a sinus impulse fell late in the parasystolic cycle, it hastened occurrence of the next parasystolic discharge. This suggested that type I second degree entrance block occurred in the re-entrant pathway containing the parasystolic focus. When a sinus impulse fell early in the parasystolic cycle, it delayed occurrence of the next parasystolic discharge...

At the time of the first visit to our clinic, an electrocardiographic examination of a 73-year-old female patient revealed ventricular premature contractions (VPCs) with variable coupling intervals that were diagnosed as parasystole. Characteristically many of the parasystoles had no sinus contractions between two consecutive VPCs, which we referred to as pure parasystole. We first repeatedly examined variations in the length of the parasystolic cycles between January 6, 1997 and March 2, 2003 using electrocardiography...

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Cyclic bursts of ventricular premature contractions (VPC) coming at minute-order intervals have been discerned by analyzing ambulatory ECG recordings, and their mechanism has not been clarified. The present study simulates this phenomenon by constructing a bidirectional modulated parasystole model. With Ts and Te as the intrinsic periods of the sinus and ectopic pacemakers, there are distinct and initial condition-dependent solutions in the model with Ts / Te values close to 1, 1/2, 1/4, etc. Typically, two distinct stable solutions are found existing together around Ts / Te = 1/2...

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