Emotional stressors trigger cardiovascular events.

AIMS: To describe the relation between emotional stress and cardiovascular events, and review the literature on the cardiovascular effects of emotional stress, in order to describe the relation, the underlying pathophysiology, and potential therapeutic implications. MATERIALS AND METHODS: Targeted PUBMED searches were conducted to supplement the authors' existing database on this topic. RESULTS: Cardiovascular events are a major cause of morbidity and mortality in the developed world. Cardiovascular events can be triggered by acute mental stress caused by events such as an earthquake, a televised high-drama soccer game, job strain or the death of a loved one. Acute mental stress increases sympathetic output, impairs endothelial function and creates a hypercoagulable state. These changes have the potential to rupture vulnerable plaque and precipitate intraluminal thrombosis, resulting in myocardial infarction or sudden death. CONCLUSION: Therapies targeting this pathway can potentially prevent acute mental stressors from initiating plaque rupture. Limited evidence suggests that appropriately timed administration of beta-blockers, statins and aspirin might reduce the incidence of triggered myocardial infarctions. Stress management and transcendental meditation warrant further study.

Proarrhythmic effects of antiarrhythmic drugs during programmed ventricular stimulation in patients without ventricular tachycardia.

The proarrhythmic effects of class IA antiarrhythmic drugs were prospectively evaluated during programmed ventricular stimulation in 24 consecutive patients with frequent ventricular premature beats whose baseline study, performed while no antiarrhythmic drugs were being taken, showed no inducible sustained ventricular arrhythmias. No patient had nonsustained (greater than 5 beats) or sustained ventricular tachycardia by history or baseline 24 hour ambulatory electrocardiographic monitoring. Sequential stimulation studies using up to three extra-stimuli were performed after administration of procainamide, quinidine and disopyramide on different days. Proarrhythmic response was defined as induction of one or more of the following: sustained monomorphic ventricular tachycardia; sustained polymorphic ventricular tachycardia; ventricular fibrillation; reproducibly inducible nonsustained monomorphic ventricular tachycardia. During 55 antiarrhythmic drug trials (24 of procainamide, 21 of quinidine, 10 of disopyramide) in the 24 patients, 6 patients had a proarrhythmic response: sustained monomorphic ventricular tachycardia in 3, ventricular fibrillation in 2, nonsustained monomorphic ventricular tachycardia in 1. Thus, 11% of drug trials resulted in a proarrhythmic response and 25% of patients had a proarrhythmic response to one of the drugs tested. A proarrhythmic response to one drug did not predict a similar response to another drug of the same class. The 6 patients with a proarrhythmic response did not differ significantly from the other 18 patients with regard to underlying heart disease, electrocardiographic or baseline 24 hour ambulatory electrocardiographic characteristics; however, they did have a higher incidence of digoxin usage (p less than 0.02), a shorter baseline right ventricular effective refractory period (p less than 0.01) and a smaller increment in effective refractory period during antiarrhythmic drug testing (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Day to day reproducibility of electrically inducible ventricular arrhythmias in survivors of acute myocardial infarction.

Day to day reproducibility of the response to programmed ventricular stimulation has not been evaluated in survivors of acute myocardial infarction. Programmed ventricular stimulation was performed prospectively on 2 consecutive days in 56 patients on an average of 12 +/- 5 days (range 7 to 29) after an acute myocardial infarction. No patient had a history of documented or suspected sustained ventricular tachycardia or fibrillation occurring greater than 48 h after infarction. During initial programmed ventricular stimulation, 21 patients had induction of sustained ventricular tachycardia or fibrillation (Group I), and 35 patients had induction of either nonsustained ventricular tachycardia or no ventricular tachycardia (Group II). Repeat programmed ventricular stimulation in Group I patients induced sustained ventricular tachycardia or fibrillation in 16 of 21 patients (reproducibility 76%); the maximal induced response in the other 5 patients was nonsustained ventricular tachycardia in 2 patients and fewer than six repetitive ventricular responses in 3 patients. The day to day reproducibility was significantly higher for inducible sustained ventricular tachycardia of cycle length greater than or equal to 240 ms compared with rapid sustained ventricular tachycardia of cycle length less than 240 ms (100% versus 44%, p less than 0.009) or ventricular fibrillation (100% versus 43%, p less than 0.009). Repeat programmed ventricular stimulation in Group II patients did not induce sustained ventricular arrhythmias in 31 of 35 patients (reproducibility 89%). Thus, in survivors of acute myocardial infarction, inducible slow sustained ventricular tachycardia was a highly reproducible finding, whereas inducibility of rapid sustained ventricular tachycardia and ventricular fibrillation showed a significant day to day variability.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary artery aneurysms: echocardiographic features in 5 patients.

Two-dimensional (2-D) echocardiographic studies were performed in 5 patients (2 adults, 3 pediatric cases) with proved aneurysm of the main pulmonary artery (PA). Two-dimensional echocardiography correctly localized the site of the aneurysm in all 5 patients and accurately categorized the type of aneurysm as saccular in 2 patients and fusiform in 3 patients. Fusiform aneurysms were characterized by their huge size, which made it impossible to image them completely in any single 2-D sector plane in 2 patients and by their tendency to cause displacement of the left atrium in 1 patient. Two-dimensional echocardiographic diagnosis of PA aneurysm was suggested prospectively without knowledge of angiographic findings in 3 of 5 patients. Two-dimensional echocardiography appears to be a useful noninvasive technique in the recognition of PA aneurysms.

Myocardial texture characterization by two-dimensional echocardiography.

Twenty-four normal subjects and 181 patients with various cardiac disorders (36 autopsies) were studied by 2-dimensional echocardiography. In vitro echocardiographic studies were performed on 26 of 36 autopsied hearts utilizing an ultrasonically visible metallic probe to correlate myocardial echo patterns with histopathologic features. All normal subjects and the majority of patients with ventricular hypertrophy due to valvular or hypertensive lesions showed a uniformly speckled or an echolucent appearance of the myocardium (type I texture). No autopsied heart with this texture had gross fibrosis (visible to the naked eye) or infiltrative disease. All patients with infiltrative disorders (amyloidosis, 7 of 7; Pompe's disease, 4 of 4) had multiple, discrete, and small (3 to 5 mm) highly refractile echoes (HREs) in the myocardium involving the ventricle or ventricles completely (type IIA texture) or partly (type IIB texture). However, this finding was non-specific and was observed in many other conditions such as left heart hypoplastic syndrome (10 of 10), hypertrophic cardiomyopathy (19 of 26), and chronic renal failure (4 of 9). In the noninfiltrative group, HREs in the autopsied cases were shown to result from gross fibrosis or endocardiofibroelastosis utilizing in vitro echocardiographic studies and metallic probe-guided biopsies, while HREs in the autopsied cases with cardiac amyloidosis could be correlated only with amyloid deposits since fibrosis was absent. Larger HREs (greater than 5 mm) presenting as broad patches or long linear echoes in the myocardium (type IIC texture) was seen in old myocardial infarctions (9 of 21) and congestive cardiomyopathy (4 of 26) and were correlated with large areas of myocardial fibrosis. Two-dimensional echocardiographic studies of myocardial texture help identify various infiltrative and degenerative processes in the heart.

Decline in inducibility of sustained ventricular tachycardia from two to twenty weeks after acute myocardial infarction.

To determine temporal evolution of sustained ventricular arrhythmias inducible after acute myocardial infarction (AMI), serial programmed ventricular stimulation (PVS) was performed in 27 patients 15 +/- 4 and 150 +/- 28 days after AMI. These patients did not have worsening of congestive heart failure or angina, coronary artery bypass surgery or spontaneous sustained ventricular tachycardia (VT) in the period between 2 PVS studies. During initial PVS, sustained VT or ventricular fibrillation (VF) was inducible in 17 patients (group I) and was not inducible in 10 (group II). Late PVS in group I induced sustained VT or VF in 8 patients (47%) and nonsustained VT or no VT in 9 (53%). A decrease in late inducibility of sustained VT/VF was greater for arrhythmias induced during initial PVS by triple extrastimuli and burst pacing than for those induced by double extrastimuli (88% vs 25%, p less than 0.04), but appeared to be unrelated to the morphologic characteristics or cycle length of the initially induced sustained VT or VF and to other clinical, hemodynamic or angiographic variables. During late PVS in 10 group II patients, sustained VT or VF remained noninducible in 9 (90% concordance); in 1 patient sustained VT was induced. During a mean follow-up of 14 +/- 5 months since late PVS, none of 27 patients had spontaneous sustained VT and 2 patients in group I died suddenly.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency and significance of induced sustained ventricular tachycardia or fibrillation two weeks after acute myocardial infarction.

Electrophysiologic study, 24-hour ambulatory electrocardiographic monitoring, treadmill exercise test and angiographic evaluations were performed in 45 patients 14 +/- 3 days (mean +/- standard deviation) after acute myocardial infarction. Electrophysiologic study protocol included burst ventricular pacing and 1 to 3 ventricular extrastimuli at 2 cycle lengths from right ventricular apex, right ventricular outflow and left ventricle. Sustained monomorphic ventricular tachycardia (VT) (13 patients) or ventricular fibrillation (VF) (7 patients) was induced in 20 patients (44%) (group I). In these 20 patients, VT/VF was inducible with 2 extrastimuli in 10 patients, 3 extrastimuli in 9 patients and burst pacing in 1 patient. In the remaining 25 patients (56%), induction of no fewer than 7 ventricular beats were noted (group II). Severe left ventricular (LV) wall motion abnormalities occurred in 70% of group I patients and 22% of group II patients (p less than 0.005). There was no difference in the site of infarction, frequency and grade of ventricular ectopic rhythm on ambulatory electrocardiographic monitoring, double product on submaximal exercise, LV ejection fraction, and number of obstructed coronary arteries (70% or greater) (p greater than 0.1) between group I and group II patients. During a mean follow-up of 10 +/- 3 months, 1 patient in each group died suddenly, and in 1 group I patient spontaneous sustained VT developed which was identical in morphologic configuration to that induced during electrophysiologic study. In conclusion, electrical induction of sustained VT or VF during electrophysiologic study is common in patients 2 weeks after acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Wide complex tachycardias. Differential diagnosis and management.

The majority of wide complex tachycardias are secondary to VT. The differential diagnosis of wide complex tachycardia also includes SVT with aberrancy or underlying bundle branch block and antegrade SVT conduction over an accessory pathway (antidromic SVT). VT is usually the result of reentry and most commonly arises in an area of diseased myocardium in the setting of previous myocardial infarction or cardiomyopathy. VT, however, can also occur in patients with structurally normal hearts. Criteria useful in diagnosis of wide complex tachycardia include clinical criteria (presence of structural heart disease or a history of previous myocardial infarction) and electrocardiographic criteria (the presence of capture or fusion beats, relation of atrial or ventricular activity, QRS duration and axis, and morphology). The acute management of wide complex tachycardia includes cardioversion and intravenous pharmacologic therapy. Almost all patients with VT require chronic therapy, although in rare patients treatment of acute precipitating factors may be sufficient. While pharmacologic therapy has been the mainstay of treatment for these patients, there have been many exciting advances using surgical, device, and ablative therapies.

Narrow complex tachycardias. Differential diagnosis and management.

Narrow complex tachycardias are a common clinical problem and can be divided into those in which the arrhythmic circuit is located exclusively in the atrium (pharmacologic treatment is oriented toward altering atrial electrophysiologic properties) and those that involve the AV node or an accessory pathway (pharmacologic therapy is directed toward slowing conduction or increasing refractoriness in these structures). The electrocardiographic diagnosis of the mechanism responsible for SVT includes the regularity of the RR interval; the AV conduction ratio; the presence of P waves, P wave morphology, and the relationship of the P waves to the QRS complexes; and the response of the arrhythmia and atrial activity to vagal maneuvers. Acute therapy includes cardioversion in hemodynamically unstable patients and vagal maneuvers and specific pharmacologic therapy for SVT based on the electrocardiographic diagnosis. There have been recent exciting advances in the nonpharmacologic treatments of SVT, most notably surgery and radiofrequency percutaneous catheter ablation for AV nodal reentry, AV reciprocating tachycardia, atrial flutter, and atrial tachycardias.

Two-dimensional echocardiography of intracardiac masses: echo pattern-histopathology correlation.

Two-dimensional echo patterns (EP) of 21 pathologically confirmed intra-cardiac masses (10 tumors, 6 thrombi and 5 vegetations) were correlated with histopathology. Three types of echo patterns were defined. Five tumors and 3 thrombi demonstrated a fine, speckled and uniform appearance (type AEP) and none had any hemorrhages or calcification on pathological examination. Three left atrial masses showed large and discrete echolucent areas (type B EP) and histopathological correlation revealed large hemorrhages in the tumors and a large area of clot lysis in the thrombus. Three tumors, 2 thrombi and 5 vegetations revealed either localized areas of bright echoes or appeared uniformly bright (type C EP) and on pathological examination, all had calcification and/or fibrosis. Two-dimensional echo patterns are useful in delineating some of the structural components of intracardiac masses.

Procainamide induced sustained monomorphic ventricular tachycardia in a patient with benign premature ventricular complexes.

A 59-year old female with history of benign ventricular ectopy who developed sustained monomorphic ventricular tachycardia (VT) during therapy with procainamide is reported. The tachycardia occurred 24 hours after institution of procainamide without any other evidence of drug toxicity or QT prolongation. When procainamide was withheld, VT resolved completely and no arrhythmia could be induced by programmed ventricular stimulation. When the patient was rechallenged with procainamide at therapeutic level, sustained monomorphic VT was initiated reproducibly by programmed ventricular stimulation. Without antiarrhythmic therapy, patient has been asymptomatic and free of recurrent VT after a follow-up of 9 months. This case: Demonstrates that procainamide may cause the first emergence of sustained monomorphic VT in a patient with no previous history of VT; and Emphasizes the utility of programmed ventricular stimulation in providing direct evidence for drug mediated exacerbation of the ventricular arrhythmia.

Out-of-hospital cardiac arrest in patients with no overt heart disease: electrophysiologic observations and clinical outcome.

Electrophysiologic studies were performed in nine survivors of out-of-hospital cardiac arrest who had no overt heart disease on clinical, hemodynamic and angiographic evaluation. Cardiac arrest occurred during sedentary activity in seven patients and during exercise in two; no patient was on antiarrhythmic drugs at the time of cardiac arrest. Twenty-four hour ambulatory electrocardiographic monitoring demonstrated premature ventricular beats in four patients (44%). Electrophysiologic stimulation induced sustained ventricular tachycardia (VT) or fibrillation (VF) in five patients, nonsustained VT in one patient and less than five ventricular beats in the remaining three patients. Of five patients with inducible sustained VT or VF, four had complete suppression of inducible VT with antiarrhythmic therapy, and none of these four patients died suddenly or had clinical VT after an average follow-up of 27 months (range 12 to 41 months). The remaining patient with inducible sustained VT refused serial electropharmacologic testing, was treated empirically with amiodarone (400 mg/day) and died suddenly eight months later. Of the four patients with noninducible sustained VT or VF, three received no antiarrhythmic therapy and one was given a beta-blocker. None had recurrent cardiac arrest or symptomatic VT after an average follow-up of 17 months (range 13 to 20 months). Thus, inducibility of sustained VT or VF provided a reliable end point for long term antiarrhythmic therapy and noninducibility identified a subset of patients that had an excellent prognosis without specific antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiofrequency ablation in children.

Radiofrequency (RF) catheter ablation has ushered in a new era in the management of patients with symptomatic tachyarrhythmias. By providing the ability to cure the underlying arrhythmic substrate, RF catheter ablation obviates the need for life-long antiarrhythmic drugs. In the reported series, the success has been high and the complications have been infrequent and relatively minor. Not unexpectedly, RF catheter ablation has become the treatment of choice for patients with symptomatic paroxysmal tachyarrhythmias. The role of radiofrequency catheter ablation in infants and small children remains controversial, and awaits a larger experience and longer follow-up data.

Cuckoo search algorithm based satellite image contrast and brightness enhancement using DWT-SVD.

This paper presents a new contrast enhancement approach which is based on Cuckoo Search (CS) algorithm and DWT-SVD for quality improvement of the low contrast satellite images. The input image is decomposed into the four frequency subbands through Discrete Wavelet Transform (DWT), and CS algorithm used to optimize each subband of DWT and then obtains the singular value matrix of the low-low thresholded subband image and finally, it reconstructs the enhanced image by applying IDWT. The singular value matrix employed intensity information of the particular image, and any modification in the singular values changes the intensity of the given image. The experimental results show superiority of the proposed method performance in terms of PSNR, MSE, Mean and Standard Deviation over conventional and state-of-the-art techniques.

Triggered activity as a mechanism of recurrent ventricular tachycardia.

Triggered activity was shown to be the likely mechanism of recurrent tachycardia in a 28 year old Vietnamese man. During baseline electrophysiological testing the tachycardia was induced consistently by prolonged atrial or ventricular pacing but not by premature extrastimuli. Moreover, the tachycardia coupling intervals varied directly with the cycle length of the initiating drive. Procainamide and propranolol did not suppress tachycardia, but verapamil terminated it and prevented its reinitiation. The origin of the tachycardia was localised to the left ventricular inferoapical segment and four direct current countershocks of 200 J each delivered via an electrode catheter abolished the tachycardia. During 12 months of follow up the patient was not treated with antiarrhythmic agents and the tachycardia did not recur.

Polymorphous ventricular tachycardia associated with a marked prolongation of the Q-T interval induced by amiodarone.

We report the case of a patient who developed a life-threatening polymorphous ventricular tachycardia ( PVT ) after six weeks of treatment with amiodarone. The Q-T interval was markedly prolonged at 0.86 second. The drug induction of PVT was strongly suggested by the fact that PVT resolved four days after withdrawal of amiodarone when the Q-T interval had shortened to 0.60 second; the arrhythmia has not recurred in the nine months of follow-up since then. Amiodarone, though a very effective antiarrhythmic agent, may induce serious PVT .

Efficacy of left cardiac sympathectomy in the treatment of patients with the long QT syndrome.

Ten patients with the long QT syndrome and recurrent syncope and/or cardiac arrest caused by ventricular arrhythmias underwent left stellate (one patient) or left cervicothoracic sympathectomy (nine patients) after failing to respond to high-dose beta-blocker therapy. The syndrome was familial in four and idiopathic in six. All patients had a prolonged resting QT interval (548 +/- 51 msec, mean +/- SD) and corrected QT interval (QTc) (556 +/- 43 msec). After sympathectomy the mean QTc shortened significantly from 556 +/- 43 to 508 +/- 65 msec (p less than .05) but the QTc remained abnormal in all but one patient. Over a mean follow-up period of 38.6 +/- 19 months, eight patients developed recurrent symptoms that included cardiac arrest in three (one fatal, two nonfatal), syncope in four, and presyncope in six. The addition of beta-blockers was ineffective in suppressing the recurrent symptoms. The control of symptoms required more extensive sympathectomy (three patients), chronic atrial pacing (three patients), and implantation of an automatic internal defibrillator (one patient). Only one patient has remained asymptomatic without drug or pacemaker therapy. In conclusion, left cervicothoracic sympathectomy proved inadequate for long-term control of symptoms in most patients with the long QT syndrome. These patients usually required concomitant drugs, more extensive surgery, or long-term cardiac pacing for symptomatic relief.

The long-term prognosis of patients with out-of-hospital cardiac arrest but no inducible ventricular tachycardia.

The long-term prognosis of patients successfully resuscitated from cardiac arrest who do not have acute precipitating factors and in whom ventricular arrhythmias cannot be induced during baseline electrophysiologic testing is controversial. The purpose of this investigation was to evaluate the long-term risk of recurrent sudden death and determine the clinical, angiographic, hemodynamic, and electrophysiologic predictors of recurrent cardiac arrest in such patients. Twenty-six (37%) of 71 consecutive patients with a single episode of aborted sudden death did not have inducible ventricular arrhythmias (less than 7 intraventricular responses) during baseline drug-free electrophysiologic study and they form the basis of this report. Their mean age was 54 +/- 13 (mean +/- SD) years and the left ventricular ejection fraction (LVEF) was 0.47 +/- 0.17. After a mean follow-up period of 16 months, 11 patients (42%) had a recurrent cardiac arrest (fatal in 10 patients). The actuarial incidence of recurrent cardiac arrest was 30 +/- 10% at 1 year and 55 +/- 13% at 3 years. Patients with LVEF less than or equal to 0.40 had a significantly higher occurrence of recurrent cardiac arrest than those with LVEF greater than 0.40 (p = 0.02; 1-year actuarial incidence of 57 +/- 17% versus 13 +/- 19%). Patients with recurrent sudden death had a significantly greater incidence of dilated cardiomyopathy (55% versus 7%; p = 0.02) and baseline frequent premature ventricular contractions (PVCs greater than 10/hr; 64% versus 17%, p = 0.036) or nonsustained ventricular tachycardia (36% versus 0%; p = 0.37) than patients without these characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the performance of microprocessor-based colorimeter.

Colorimetric estimations have an important role in quantitative studies. An inexpensive and portable microprocessor-based colorimeter developed by the authors is described in this paper. The colorimeter uses a light emitting diode as the light source; a pinphotodiode as the detector and an 8085A microprocessor. Blood urea, glucose, total protein, albumin and bilirubin from patient blood samples were analysed with the instrument and results obtained were compared with assays of the same blood using a Spectronic 21. A good correlation was found between the results from the two instruments.