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Query: UMLS:C0728731 (prematurity)
 7,134 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

13 male patients suffering from arteriosclerotic heart disease and/or arterial hypertension were monitored continuously before and after vascular surgical procedures using an arrhythmia computer. Heart rate, paroxysmal supraventricular tachycardias, ventricular extrasystoles, ventricular tachycardias, ventricular fibrillation and prematurity index (QnQe/QTn) were recorded numerically. Ventricular arrhythmias were detected as follows preoperatively in 12 patients, after operation in all patients, paired ventricular extrasystoles or episodes of ventricular tachycardia were found in 5 cases before and in 7 after operation, ventricular fibrillation in one case. The incidence of ventricular dysrhythmias increased significantly (p less than 0.05) early after operation, as did the heart rate during the observed postoperative period (p less than 0.001). The prematurity index dropped below 1.0 during the two days following operation. This differed significantly from the preoperative value (p less than 0.05). The incidence of ventricular extrasystoles was related to postoperative myocardial infarction and heart failure (p less than 0.01), which occurred in 6 cases, with a lethal outcome in three. Only occasionally controlled by trained staff in a normal surgical ward the "Servomed Dysrhythmiemonitor" yielded reliable numerical results during the main part of the monitored period. In two cases it led to immediate detection and rapid institution of treatment of severe tachyar rhythmias.
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PMID:[Postoperative cardiac arrhythmias (author's transl)]. 8 Sep 61

This study analyzes 94 episodes of the ventricular tachycardia recorded in the ambulatory electrocardiograms of 23 patients with stable cardiac disease. The episodes were asymptomatic in 19 patients, and only one episode resulted in ventricular fibrillation. Eighty-five percent of the episodes occurred when the underlying heart rate was less than 100 beats/min, and 17 percent occurred during sleep. The rate of the ventricular tachycardia was between 120 and 180 beats/min in 78 percent of the episodes and showed a modest correlation with the underlying heart rate (r = 0.59, P less than 0.001). Only 14 of the 94 episodes were initiated by R on T premature ventricular contractions, and the mean prematurity index (+/- standard deviation) (R-R'/Q-T) for all episodes was 1.31 +/- 0.28. Episodes of ventricular tachycardia recorded during ambulatory electrocardiographic monitoring are usually self-limited and asymptomatic. They occur during ordinary nonexertional activity and are frequently initiated by late couples premature ventricular contractions.
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PMID:Characteristics of ventricular tachycardia in ambulatory patients. 55 93

A study was designed to examine ventricular arrhythmias in the acute phase of experimental myocardial infarction in the pig and to evaluate possible antiarrhythmogenic influence of the beta-adrenergic blocking drug pindolol (Visken) and the calcium antagonist Ro 11-1781. Ventricular fibrillation (VF) occurred in 17 of 18 animals, in 4 almost immediately after coronary occlusion and in 12 with a delay of about 17 min. VF was almost always induced by episodes of ventricular tachycardia (VT) which were started by single ventricular premature beats (VPBs). VPBs occurred in 3 phases, whereas VT and VF coincided only with phase 1 and phase 3. The prematurity index QR/QT of single VPBs decreased significantly with time after coronary occlusion. The beta-adrenergic blocking drug pindolol and the calcium antagonist Ro 11-1781 did not prevent VT or VF.
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PMID:[Ventricular arrhythmias in the acute stage of experimental swine myocardial infarct; effect of the beta blocker pindolol and the calcium antagonist Ro 11-1781]. 71 14

We examined the harbingers of 68 episodes of paroxysmal ventricular tachycardia in 42 patients with documented acute myocardial infarction. Late ventricular premature contractions initiated 46 bouts of paroxysmal ventricular tachycardia, while 17 were engendered by early ventricular premature contractions and five by atrial premature contractions. Paroxysmal ventricular tachycardia related to early ventricular premature contractions tended to last longer and failed to respond to therapy with lidocaine more often than paroxysmal ventricular tachycardia begun by late ventricular or atrial premature contractions. Ventricular fibrillation occurred in six cases of paroxysmal ventricular tachycardia due to early ventricular premature contractions but was absent in paroxysmal ventricular tachycardia related to late ventricular or atrial premature contractions. The "malignant" potential of a given ventricular premature contraction cannot be assessed from its degree of prematurity alone.
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PMID:Harbingers of paroxysmal ventricular tachycardia in acute myocardial infarction. 83 82

The sensitivity and specificity of a new protocol of programmed ventricular stimulation were evaluated in 71 consecutive patients who were divided into 2 groups: group 1 included 41 patients, of whom 25 had sustained ventricular tachycardia (VT) not associated with cardiac arrest and 16 had ventricular fibrillation (VF) not precipitated by any obvious factor; group 2 included 30 patients without demonstrable heart disease and no suspected or documented sustained ventricular tachyarrhythmias. The study consisted of a standard protocol (up to 2 extrastimuli given only once for each extrastimulus prematurity, 2 right ventricular sites and 3 basic pacing cycle lengths, as well as rapid ventricular pacing) in which double extrastimulation at the shortest coupling intervals that allowed ventricular capture was repeated 10 times. A stimulus current of 3 mA was used. Sustained ventricular tachyarrhythmias were induced in 23 of 25 (92%) patients who presented with sustained VT, 14 of 16 (88%) patients who presented with VF and 2 of 30 (7%) group 2 patients. Eighteen of 25 (72%) patients with sustained VT but only 4 of 16 (25%) with VF had arrhythmias inducible at "immediate" trials of single or double extrastimulation (p less than 0.01). Repetition of double extrastimulation increased the yield of inducible sustained ventricular tachyarrhythmia to 92% in patients with sustained VT (+20%, p = 0.14) and 75% (+50%, p = 0.013) in patients with VF. Rapid right ventricular pacing added a 13% increase in the overall yield in patients with VF. This new protocol of programmed ventricular stimulation has both high sensitivity (90%) and specificity (93%) for induction of sustained VT.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Programmed ventricular stimulation using up to two extrastimuli and repetition of double extrastimulation for induction of ventricular tachycardia: a new highly sensitive and specific protocol. 230 31

The role of supraventricular extrasystoles in the initiation of ventricular arrhythmia was studied in 72 consecutive patients who developed primary ventricular fibrillation during the acute phase of myocardial infarction. In six patients (8%), a total of 12 episodes of ventricular fibrillation and 16 episodes of ventricular tachycardia were initiated by supraventricular extrasystoles. Ventricular fibrillation and tachycardia were initiated by single supraventricular extrasystoles in 16 and by salvos greater than or equal to two beats in 12 episodes. The RR coupling interval of the supraventricular impulse immediately preceding ventricular tachycardia ranged from 240 to 420 ms (mean 356 (62)) and was characteristic of R-on-T (prematurity index less than 1) in 63% of episodes. Average peak serum creatine kinase activity in the six patients in whom ventricular tachycardia was initiated by a supraventricular extrasystole was 1275 units compared with 720 units in the remaining 66 patients. Five of these six patients later showed evidence of pump failure. Lignocaine or procainamide or both suppressed the ventricular arrhythmia in five of the six patients. The initiation of ventricular fibrillation or tachycardia by supraventricular extrasystoles in acute myocardial infarction is not uncommon and may reflect the increased vulnerability of the heart after a large infarct. These arrhythmias may respond to drugs that suppress ventricular irritability.
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PMID:Initiation of ventricular fibrillation by supraventricular beats in patients with acute myocardial infarction. 244 33

Sixty-two Holter recordings of sudden death due to ventricular fibrillation (VF) were analysed by full disclosure and computerized processing. Thirteen sudden deaths were due to torsades de pointes in noncoronary subjects (11/13), related to quinidine-like drugs and/or hypokalaemia: they were always initiated by a long RR cycle due to a post-extrasystolic pause, and announced by a progressive decrease of mean heart rate (from 77.5 +/- 2.5 to 60.6 +/- 2.7 beats min-1, P less than 0.001), in the three preceding hours. The other cases occurred in coronary patients (45/49), with acceleration of ventricular tachycardia (VT), monomorphic in 24 cases, polymorphic in 13, the ventricular rate increasing from 220.6 +/- 55 to 241.5 +/- 69 beats min-1, rather than with primary VF (12 cases). A cardiac pause (RR cycle exceeding 125% of the mean five preceding cycles) was present in 22/49 cases immediately before the onset of VT/VF. The coupling interval of the extrasystole initiating VT/VF was shorter than the shortest value encountered before: 377.6 +/- 94.5 ms vs 421.4 +/- 92.3. The prematurity index (coupling interval/preceding RR cycle ratio) was lower in primary VF than in VT leading to VF. In the last hour preceding VF, ST changes were unusual (five cases), whereas heart rate increased from 82.8 +/- 20 to 92.0 +/- 26.7 beats min-1, (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Respective role of sympathetic tone and of cardiac pauses in the genesis of 62 cases of ventricular fibrillation recorded during Holter monitoring. 322 22

The electrocardiographic responses to programmed ventricular stimulation and acute posterolateral myocardial ischemia were studied in conscious dogs treated with the resolved optical isomers of sotalol. Studies were conducted 3-7 days after anterior myocardial infarction to determine the relative contributions of beta-adrenergic receptor blockade and direct Class III electrophysiologic actions in the antiarrhythmic and antifibrillatory actions of the isomers. With cumulative i.v. administration of up to 8 mg/kg, both the beta-blocking levorotatory isomer and the dextrorotatory isomer suppressed the induction of ventricular tachyarrhythmias by programmed stimulation in at least 50% of dogs tested. Both isomers produced equivalent 15-20% increases in normal zone ventricular refractoriness, thereby preventing propagation of programmed ventricular extrastimuli of sufficient prematurity to elicit tachyarrhythmias. The levorotatory isomer of sotalol prolonged the PR interval; the administration of the dextrorotatory isomer increased QTc and, in several dogs, was associated with the development of ventricular ectopy. The prior administration of 8 mg/kg of either optical isomer of sotalol prevented the immediate spontaneous development of ventricular fibrillation in response to ischemia at a distance from the previous site of infarction. These results suggest that alterations in ventricular refractoriness may underlie the antiarrhythmic and antifibrillatory actions of the optical isomers of sotalol and of racemic sotalol.
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PMID:Antiarrhythmic and antifibrillatory actions of the levo- and dextrorotatory isomers of sotalol. 608 71

Forty-four patients with acute myocardial infarction were studied using 24-hour electrocardiographic monitoring. A linear correlation has been shown to exist between heart rate preceding accelerated idioventricular rhythm and ventricular tachycardia and the rates of these. The prematurity index was found to be inversely related to the preceding heart rate and also to the rate of accelerated idioventricular rhythm or ventricular tachycardia. Faster heart rates preceded extrasystoles with shorter prematurity indices and a significant inverse correlation was observed between preceding heart rate and prematurity index. Patients developing ventricular tachycardia had more frequent isolated ventricular extrasystoles and faster heart rates preceding the episode as compared with patients not showing ventricular tachycardia. No association was observed between ventricular tachycardia and accelerated idioventricular rhythm. All four patients developing ventricular fibrillation showed preceding ventricular tachycardia, with three of these patients demonstrating faster rates of ventricular tachycardia (greater than 170/min) and shorter prematurity indices (less than 0.80) than patients without ventricular fibrillation. Heart rate may influence the severity of ventricular arrbythmia; the prematurity of an extrasystole is of importance in patients developing accelered idioventricular rhythm or ventricular tachycardia.
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PMID:Heart rate and ectopic prematurity in relation to sustained ventricular arrhythmias. 615 59

Fifteen patients sustained ventricular fibrillation during ambulatory electrocardiographic recording in a period of 3.5 years over which time 16,500 ambulatory electrocardiograms were analyzed (prevalence = 0.09% or 1/1,100). Eight patients died, and seven survived cardiopulmonary resuscitation. Quantitative analysis of hourly ventricular arrhythmias prior to ventricular fibrillation revealed an increased frequency of premature ventricular beats and ventricular tachycardia, especially in the 2 hours immediately before ventricular fibrillation. Ventricular fibrillation was initiated by ventricular tachycardia in all 15 cases. These runs of ventricular tachycardia were characterized by their unusual length (mean = 560 +/- 536 beats) and their rapid rate (241 +/- 45 beats/min). Although an R on T premature ventricular beat initiated ventricular tachycardia and ventricular fibrillation occasionally, the mean prematurity index of the initiating premature ventricular beat was not early (mean = 1.27 +/- 0.28). QT prolongation was present in only 3 of the 15 patients (mean QTc interval = 0.42 +/- 0.06). Left ventricular dysfunction (mean left ventricular ejection fraction = 34.9 +/- 9.9%) and coronary artery disease were nearly always present. The cardiac medications most frequently associated with these patients at the time of ventricular fibrillation were digitalis and quinidine.
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PMID:Analysis of ambulatory electrocardiograms in 15 patients during spontaneous ventricular fibrillation with special reference to preceding arrhythmic events. 663 Jul 59


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