Paroxysmal Ventricular Tachycardia Research Articles

The usefulness and effectiveness of prophylactic use of defibrillation electrode pads in adult patients undergoing living donor liver transplantation

Introduction: Life-threatening cardiac arrhythmia requiring cardioversion or defibrillation may be encountered during liver transplantation. The aim of current study is to evaluate the usefulness and effectiveness of prophylactic use of defibrillation electrode pads in adult patients undergoing living donor liver transplantation. Methods and patients: Three hundred sixty three anesthesia records of adult patients undergoing living donor liver transplantation were reviewed retrospectively. All the patients received similar general anesthesia and monitoring as previously reported. After induction of the anesthesia, adhesive defibrillation pads (Multifunction Adult defib Electrodes Alternative to M1749A (Philips Medical Systems, 3000 Minuteman Rd. Andover, MA, USA)) were prophylactic placed in the chest of the patient. The anterior electrode is placed on the right, below the clavicle and the other electrode is placed on the back behind the heart. The function of the electrode pads were tested by connecting it to the defibrillator (Heartstart XL, Phillips medical Systems, 3000, minuteman Road, Anderson MA, USA) before operation. Life-threatening cardiac arrhythmia which affected the hemodynamic, such as paroxysmal tachycardia, ventricular tachycardia or ventricular fibrillation will be treated with cardio-version or defibrillation. Results: Four patients amongst the 363 patients developed lifethreatening cardiac arrhythmia intraoperatively, 2 had paroxysmal tachycardia requiring cardio-version and the other two had ventricular fibrillation requiring closed chest cardiac massage and defibrillation. All 4 patients regained sinus rhythm after electrical treatment and tolerated the further operation well. The postoperative courses were smooth and uneventful. Conclusion: The incidence of life threatening cardiac arrhythmia was 1.1% in our serial. Although the thorax of the patients is covered with electric isolated Steri-Drape TM Ioban TM 2 (3 M Health Care, Dt. Paul, MN USA), but the electrode pads was prophylactic place in the thorax of the patients, we were able to do the closed chest cardiac massage and to treat the arrhythmia with electric shock immediately and successfully without interfering the sterility of the operation field.

Comparison of the diagnostic value between ECG and dynamic ECG for coronary heart disease arrhythmias

Objective To investigate and compare the clinical values of routine electrocardiogram and dynamic electrocardiogram in arrhythmia in coronary heart disease diagnosis.Methods 73 patients with coronary heart disease were collected and monitored by routine electrocardiogram and dynamic electrocardiogram,and two groups were e stablished including control group using routine electrocardiogram and observation group using dynamic electrocardiogram.The positive diagnosis rate and the specific diagnosis diresults of arrhythmia in coronary heart disease of both groups were compared.Results The positive diagnosis rate of arrhythmia in coronary heart disease of observation group(75.3％ ) was significantly higher than that of control group(54.8％ ) ( x2 =6.78,P ＜0.05).And the positive diagnosis rate of the observation group was also significantly higher than that of the control group in ventricular premature beats two,triple law,pairs of premature ventricular contractions,atrial premature beats two,triple law,atrial premature beats in pairs,atrioventricular block and paroxysmal ventricular tachycardia( all P ＜ 0.05 ).Conclusion Compared with routine electrocardiogram,the dynamic electrocardiogram in anrnythmia in coronary heart disease diagnosis could obtain higher positive diagnosis rate,and it is worthy of clinical application. Key words: Routine electrocardiogram; Dynamic electrocardiogram; Coronary heart disease; Arrhythmia

Myokardschädigung und Paroxysmale Ventrikuläre Tachykardie bei einem Hund nach Albuterolintoxikation

Intoxication with the beta2-agonist Albuterol may lead to immediate signs of beta-adrenergic stimulation like excitation, tachypnea and tachycardia. Furthermore, it typically causes severe hypokalemia, which then leads to muscle weakness and which predisposes to ventricular arrhythmias. We describe a dog where albuterol intoxication caused runs of fast paroxysmal ventricular tachycardia that persisted after normalization of the hypokalemia. Based on a markedly elevated serum troponin I level acute myocardial damage was identified as cause of the tachyarrhythmia. Repeated Troponin I measurements and Holter-ECGs were the means to document complete cure.

Pregnancy outcomes in women with Ebstein’s anomaly

To evaluate whether women with Ebstein's anomaly can tolerate pregnancy and whether the perinatal outcomes are influenced by the severity of Ebstein's anomaly. Data of four women with Ebstein's anomaly delivered in our unit were collected and analyzed retrospectively. (1) Two women with Ebstein's anomaly had uneventful pregnancies, cesarean section and puerperium. (2) The patient with the most serious Ebstein's anomaly (with central cyanosis and clubbing) had an episode of paroxysmal ventricular tachycardia and spontaneous cardioversion to sinus rhythm on day 4 postpartum. She developed intracerebral hemorrhage on day 25 postpartum. (3) One of them suffered from atrial flutter on 38 + 3 weeks of gestation which was restored to sinus rhythm after being treated with verapamil and remained stable afterward. (4) All neonatal birth weights were more than 2,500 g, and all neonatal Apgar scores were 10 at 1 min. (5) The gestational age at delivery of our cases was from week 36 + 4 to week 38 + 4. The mean duration of follow-up was 56 days postpartum. (1) The clinical features of pregnant women with Ebstein's anomaly vary. They might have good perinatal outcomes when given appropriate treatment. (2) Those with cyanosis should be given more attention, as they can have more complications during pregnancy, delivery and puerperium. (3) All women with Ebstein's anomaly should be offered fetal echocardiography during pregnancy. (4) Vaginal delivery is advised for most cases with Ebstein's anomaly.

The application of cardiac computed tomography to visualize the coronary vein anatomy for implantation of cardiac resynchronization therapy in a patient with a cardiac right-lateral displacement and rotation

A 64-year-old female patient with a history of heart failure, New York Heart Association class III/IV, paroxysmal atrial fibrillation and non-sustained ventricular tachycardia, left ventricular ejection fraction of 12%, and a QRS width of 180 ms qualified for implantation of an implantable cardiac defibrillator with cardiac resynchronization therapy (CRTD). She also underwent surgery for mitral valve replacement a few years ago. In 1964, she had a pneumonectomy due …

The recent therapeutical effects of septal pacing on the cardiac arrhythmia

ObjectiveTo investigate the therapeutical effects of septal pacing on the cardiac arrhythmia.Methods62 patients with sick sinus syndrome and (or) high/third degree A-V block were implanted with pacemaker in right atrial...

Efficacy of pharmacological treatment and genetic characterization in early diagnosed patients affected by long QT syndrome with impaired AV conduction

cardiac autonomic control in patients with subclinical and overt hyperthyroidism. Eur J Endocrinol 2001;145:691–6. [15] Biondi B. Should we treat all subjects with subclinical thyroid disease the same way? Eur J Endocrinol Sep 2008;159(3):343–5 Electronic publication 2008 Jul 22. [16] Haentjens P, Van Meerhaeghe A, Poppe K, Velkeniers B. Subclinical thyroid dysfunction and mortality: an estimate of relative and absolute excess all-cause mortality based on time-to-event data from cohort studies. Eur J Endocrinol Sep 2008;159(3):329–41 Electronic publication 2008 May 29. [17] Patane S, Marte F, Di Bella G, Turiano G. Acute myocardial infarction and subclinical hyperthyroidism without significant coronary stenoses. Int J Cardiol 2009 May 29;134(3):e135–7 [Electronic Publication ahead of print 2008 Jun 24]. [18] Patane S, Marte F. Paroxysmal atrial fibrillation during acute myocardial infarction associated with subclinical hyperthyroidism, severe three vessels coronary artery disease and elevation of prostate-specific antigen after Turp. Int J Cardiol 2010;138:e28–30. [19] Patane S, Marte F. Paroxysmal ventricular tachycardia and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism, chronic renal failure and elevation of prostate-specific antigen during acute myocardial infarction. Int J Cardiol 2010 Feb 4;138(3):e44–6 [Electronic Publication ahead of print 2008 Aug 21]. [20] Patane S, Marte F. Atrial fibrillation associated with subclinical hyperthyroidism. Int J Cardiol 2009 May 29;134(3):e155–8 [Electronic Publication ahead of print 2009 Jan 29]. [21] Patane S, Marte F. Intermittent changing axis deviationwith intermittent left anterior hemiblock during atrial flutter with subclinical hyperthyroidism. Int J Cardiol 2009 Jun 26;135(2):e37–9 [Electronic Publication ahead of print 2008 Jan 24]. [22] Patane S, Marte F. Changing axis deviation and paroxysmal atrial flutter associated with subclinical hyperthyroidism. Int J Cardiol 2010 Oct 8;144(2):e31–3 [Electronic Publication ahead of print 2009 Jan 26]. [23] Erem C. Blood coagulation, fibrinolytic activity and lipid profile in subclinical thyroid disease: subclinical hyperthyroidism increases plasma factor X activity. Clin Endocrinol (Oxf) Mar 2006;64(3):323–9. [24] Coban E, Aydemir M, Yazicioglu G, Ozdogan M. Endothelial dysfunction in subjects with subclinical hyperthyroidism. J Endocrinol Invest Mar 2006;29(3):197–200. [25] Coban E, Aydemir M. Levels of plasma fibrinogen and D-dimer in subjects with subclinical hyperthyroidism. Med Sci Monit Jan 2008;14(1):CR42–46. [26] Patane S, Marte F. Atrial fibrillation and acute myocardial infarction without significant coronary stenoses associated with subclinical hyperthyroidism and erythrocytosis. Int J Cardiol 2010 Nov 5;145(1):e36–9 [Electronic Publication ahead of print 2009 Jan 30]. [27] Patane S, Marte F, Curro A, Cimino C. Recurrent acute pulmonary embolism and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism. Int J Cardiol 2010 Jul 9;142(2):e25–6 [Electronic Publication ahead of print 2009 Jan 9]. [28] Coats AJ. Ethical authorship and publishing. Int J Cardiol 2009;131:149–50.

Ventricular Tachycardia in Hypertrophic Cardiomyopathy With Apical Aneurysm

Midventricular hypertrophic cardiomyopathy is a rare form of cardiomyopathy that may be associated with an apical aneurysm. The mechanism of aneurysm formation is uncertain, but it may be related to subendocardial ischemia. In this report, we describe a 57-year-old man with recurrent ventricular arrhythmias that were refractory to medical treatment because of midventricular hypertrophic cardiomyopathy and apical aneurysm. He was treated successfully with apical aneurysmectomy, myectomy, and subendocardial resection. Six months postoperatively, the patient was free of symptoms and was taken off all anti-arrhythmic medications with one inappropriate discharge from the implantable cardioverter-defibrillator at 4 months.

Characterizing atypical patterns of Heart Rate before Paroxysmal Ventricular Tachycardia

Results of a comparative analysis between Heart Rate (HR) patterns occurring before the onset of Paroxysmal Ventricular Tachycardia (PVT) and from healthy subjects are shown. Two study groups were made after electrocardiographic dynamical monitoring (Holter) of volunteers. The first group includes 100 h from 27 healthy control subjects, and the second group consists of 88 h, ending with self-terminating episodes of PVT from 55 patients. Patterns are defined as sequences of consecutive RR intervals, while atypical patterns are defined as corresponding to unlikely behavior of Heart Rate in healthy subjects. We investigated spatial and temporal distributions of these patterns in order to find early signs of PVT. We found that they can be grouped on a reduced number of clusters, and the number of atypical patterns increases as we approach the onset of the episode.

Longterm remission of left posterior fascicular ventricular tachycardia due to mechanical trauma

We present a case of a 28 year old woman with paroxysmal left posterior fascicular ventricular tachycardia (LPFVT). Ventricular tachycardia was not inducible after completing of left ventricle 3D reconstruction. Even though catheter ablation was not performed, no LPFVT recurrence has been documented during 60 months follow-up. We surmise that we caused mechanical trauma during the mapping of the posterior fascicle that damaged arrhythmogenic structures and subsequently led to long term remission of the left posterior fascicular ventricular tachycardia.

Mortality in myotonic dystrophy patients in the area of prophylactic pacing devices

Objectives Our study purports to determine whether implantation of a prophylactic pacemaker in MD patients with HV interval ≥ 70 ms lowers the risk of sudden death, which may be essentially due to complete atrioventricular block. Background Sudden death occurs more frequently in patients with myotonic dystrophy (MD) than in the control population. Methods From 1994 to 2008, 100 consecutive patients were enrolled, 49 of whom were implanted. Results During an average follow-up of 74 ± 39 months, 10 deaths occurred. Nine were due to respiratory failure. Only one sudden death occurred, whereas 46% of patients were considered at risk of sudden death according to the criteria of Groh et al. [5]. The incidence rate of sudden death was only 0.2 per 100 patient-years. One patient developed a paroxysmal syncopal sustained ventricular tachycardia. Conclusions The prophylactic implantation of PM in MD patients who are identified as being at risk of sudden death according to Groh's criteria reduced the incidence rate of sudden death. The one sudden death in an implanted MD patient suggests the likelihood that pacemaker implantation did not totally forestall this event. Ventricular arrhythmias may be involved in the sudden deaths in MD patients, in which case the implantation of an implantable cardiac defibrillator could be indicated.

207 Incidence and clinical significance of the asssociation of paroxysmal supraventricular and ventricular tachycardia

Fine-QRS complex tachycardia alternating with wide-QRS complex tachycardia can lead to an erroneous diagnosis of paroxysmal supraventricular tachycardia (SVT) with or without aberrancy. The purpose of the study was to evaluate the incidence and the significance of the association of SVT and ventricular tachycardia (VT) in the same patient. 898 patients aged from 11 to 88 years were consecutively admitted for a sustained VT; 818 patients had associated heart disease (history of myocardial infarction 374, idiopathic dilated cardiomyopathy 69, arrhythmogenic right ventricular dysplasia 86, miscellaneous 289) and 80 had no apparent heart disease. Electrophysiological study including programmed atrial and ventricular stimulation, 2D cardiac echocardiography, coronary angiography in patients older than 40 years, right ventricular angiography and cardiac RMI since 2002, were performed in these patients. Fifteen patients presented (2%) with either SVT or VT. All SVT's were related to an atrioventricular node reentrant tachycardia (AVNRT). The association of SVT and VT was significantly more frequent in patients without heart disease and with verapamil-sensitive VT (n=6/80, 7.5%)(<0.001), arrhythmogenic heart disease (n=4/86, 5%)(0.05) than in those with myocardial infarction (n=4/374, 0.1%) or dilated cardiomyopathy (n=0). Among 692 patients with AVNRT, 39 had associated heart disease and only 5 have both tachycardias. Radiofrequency ablation of AVNRT performed in all patients did not change the recurrence of VT which required ablation in 3 patients and the implantation of antitachycardia device with defibrillator in 2 patients. The association of SVT and VT is rare in patients with heart disease except in those with arrhythmogenic right ventricular dysplasia. The association is more frequent in patients without heart disease diagnosis and could be underestimated; fine QRS complex tachycardia alternating with wide QRS complex tachycardia leads generally to the erroneous diagnosis of SVT with or without aberrancy.

Pheochromocytoma-induced ventricular tachycardia and reversible cardiomyopathy

A case of a 48-year-old male is described with recurrent paroxysmal ventricular tachycardia originating near the region of the posterior fascicle, as an initial presentation of a primary norepinephrine producing pheochromocytoma, including reversible catecholamine-induced cardiomyopathy. The ventricular arrhythmia was terminated by procainamide and labetalol. After adrenalectomy no recurrent ventricular arrhythmia was observed.

Recurrence of Local Anesthetic Cardiac Toxicity or Hypokalemia?

In Response: There are a number of observations supporting our contention that the recurrent cardiotoxicity was due to bupivacaine1 rather than hypokalemia as suggested by Krishnan and Raw.2 First, the onset of the recurrent dysrhythmia was acute and did not progressively worsen as would be expected if hypokalemia were the root cause of the problem. Furthermore, we were infusing potassium and magnesium at 20 mmol and 1 g/h, respectively, from when the (serum) hypokalemia was detected. Second, the dysrhythmia was not the only sign of local anesthetic toxicity. The paroxysms of ventricular tachycardia were accompanied by a 50 mm Hg decrease in systolic arterial pressure and a significant increase in central venous pressure (approximately 5 mm Hg). These observations and the favorable hemodynamic response to an increase in the rate of the inotropic infusion suggested depression of myocardial function. Third, Weinberg’s accompanying editorial indicates that recurrence of bupivacaine cardiotoxicity has been observed during animal experiments investigating lipid emulsion therapy.3–5 Fourth, other than the fractured humerus, the patient was well. Although not impossible, it is highly improbable to have had pancreatitis or severe preexisting electrolyte abnormalities in an otherwise clinically normal patient without a history of alcohol abuse. Furthermore, the serum potassium and magnesium concentrations were normal within 2 h of admission to the intensive care unit. In conclusion, we find little evidence to revise our original contention that the recurrent dysrhythmia reflected a recurrence of bupivacaine cardiotoxicity. Careful review reveals no evidence of preexisting electrolyte abnormalities or organ pathology in this patient. The low dose of insulin administered was intended to control hyperglycemia and not to treat bupivacaine cardiotoxicity. Although hypokalemia may have aggravated the dysrhythmias, we view the second episode accompanied by hypotension as secondary to recurrence of bupivacaine cardiotoxicity. Andrew Ian Levin, MBChB, DA(SA), MMed (Anes), FCA, PhD Peter C. Marwick, MBChB, DA(SA) Andre R. Coetzee, MBChB, PhD, MMed (Anes), FFA (SA), FFARCS, MD, Ph Department of Anesthesiology and Critical Care, University of Stellenbosch and Tygerberg Academic Hospital, South Africa, [email protected]

Mean and variability of QT-interval: Relevance to psychiatric illness and psychotropic medication

Byline: Rahul. Kumar, Chaitra. Ramachandraiah, Pratap. Chokka, Vikram. Yeragani The QT interval conceptually represents the duration from the onset of depolarization to the completion of repolarization of the cardiac cycle. On a standard ECG, it is measured from the beginning of the QRS complex (or RS complex if there is no Q wave) to the end of the T wave. This interval has been considered as a surrogate of action potential duration. The QT interval is slightly longer in women than in men, is affected by autonomic tone as well as catecholamines, and it shows circadian variations. The most important aspect of this interval is its relation with heart rate (the reciprocal of inter-beat-interval).[sup] A large number of formulae have been proposed to establish a rule allowing conversion of a pair of QT and R-R durations into a standardized QTc value corresponding to a basal R-R interval of 1 second. Bazett's formula is the most commonly used. Normally the QTc is between 350 to 430 milliseconds. Now there is substantial amount of evidence as to the electrophysiology and how changes in autonomic function can affect the function of the heart. [sup] [1],[2],[3],[4],[5],[6] The main myocardial cell type that determines the QT interval is the 'M' cell type. The cardiac action potential is generated by the changing transmembrane permeability to ion currents such as Na[sup] + , Ca[sup] 2 + and K[sup] + . Like all living cells, the potential inside a myocyte is negative compared to the outside. However, cardiac cells are excitable and when appropriately stimulated, the ion channels within the cell membrane open and close sequentially. This changes the transmembrane ion permeability and leads to the sequential development of the transmembrane potential that is called the action potential. The initial depolarization (phase 0) is triggered by the rapid inward sodium (INa) and the L- and T-type calcium currents (ICa-L and ICa-T), which change the cell potential from - 90 to 30 mV. The transient outward Ito potassium current is responsible for the slight repolarization immediately after the overshoot (phase 1). During the following plateau phase (phase 2), the cell potential is maintained by a balance between the inward L-type calcium current (ICa-L) and the electrogenic sodium-calcium exchange current (INaCa), and the outward Ito current. The repolarization phase (phase 3) of the myocyte is driven predominantly by outward movement of potassium ions, carried as the rapid (IKr) and slow (IKs) components of the delayed rectifier potassium current. The diastolic depolarization (phase 4) results from a combination of the decay of the outward delayed rectifier IKr and IKs currents, which maintains the resting potential at approximately - 90 mV, and the activation of the inward pacemaker current (If) and the inward sodium background leak current (INa-B). A variety of other different potassium channel subtypes are also present in the heart. Cardiac arrhythmias reflect disturbances of impulse initiation or impulse propagation. These consist of conduction blocks, reentrant rhythms and dysfunction of sino-atrial (SA) node and disturbances that originate from various ectopic foci. Paroxysmal ventricular tachycardia is the result of an ectopic focus in the ventricles and can be associated with bizarre QRS complexes in the ECG. This is much more serious than a paroxysmal supraventricular tachycardia as paroxysmal ventricular tachycardia could lead to ventricular fibrillation. Fibrillation is an irregular contraction and is ineffectual in propelling blood. In the ventricles, the vulnerable period coincides with the down slope of the T wave, and when a premature impulse arrives during the vulnerable period, this may lead to fibrillation. This may become self-sustaining due to reentrant process of cardiac excitability. Tricyclic antidepressants (TCAs) have profound effects on cardiovascular system due to their strong autonomic effects and also a quinidine-like effect on cardiac conduction. …

Arrhythmogenesis and diagnosis of cardiac sarcoidosis. An immunohistochemical study in a sudden cardiac death

We present an uncommon case of sudden cardiac death in a 34-year-old white woman. She was found lifeless at home by her parents. Three months before death she was recovered at the Emergency Room for chest pain, palpitation and loss of consciousness. Subsequent cardiological evaluation with ECG showed sinusal rhythm, QRS deviation to the left, QS aspect, asymmetric and rounded T waves and slight length of QT. During hospitalization she presented some episodes of supraventricular paroxysmal tachycardia and non-sustained ventricular tachycardia. No echocardiography alterations were found. An anti-arrhythmic treatment was prescribed. Autopsy revealed some fibrotic scarring in the myocardium of left ventricle. The histological examination of the heart revealed diffuse and extensive fibrosis with non-caseating sarcoid granulomas. The lungs, kidneys and lymph node also showed the same non-caseating granulomas. The diagnosis of sarcoidosis with massive and extensive cardiac involvement was established as cause of death.

Paroxysmal ventricular tachycardia and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism, chronic renal failure and elevation of prostate-specific antigen during acute myocardial infarction

Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. Paroxysmal atrial fibrillation is a frequent complication of acute myocardial infarction. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including an increase in atrial fibrillation rate. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. Moreover chronic renal failure presents an increased arrhythmic risk. Apparently spurious result has been reported in a work about mean serum prostate-specific antigen (PSA) concentration during acute myocardial infarction with mean serum PSA concentration significantly lower on day 2 than either day 1 or day 3 and it has been reported that these preliminary results could reflect several factors, such as antiinfarctual treatment, reduced physical activity or an acute-phase response. We present a case of paroxysmal ventricular tachycardia and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism, chronic renal failure and elevation of serum PSA concentration in a 90-year-old Italian man during acute myocardial infarction. Also this case focuses attention on the importance of a correct evaluation of subclinical hyperthyroidism and of chronic renal failure. Moreover, our report also confirms previous findings and extends the evaluation of PSA during acute myocardial infarction.

Episodic syncope in hypertrophic cardiomyopathy: evidence for inappropriate vasodilation

Symptoms of impaired consciousness (syncope and pre-syncope) occur in 15–25% of patients with hypertrophic cardiomyopathy (HCM).1 In young patients a history of recurrent syncope is associated with an increased risk...

The Utility of Ketamine in Facilitating the Induction of Isoproterenol-Refractory Idiopathic Ventricular Tachyarrhythmias

CATHETER ABLATION, initially used to treat select supraventricular arrhythmias, such as atrioventricular (AV) nodal re-entry and the Wolff-Parkinson-White syndrome, is now being applied to treat virtually all documented symptomatic tachyarrhythmias that are refractory to medical management. Cost-effectiveness analysis strongly favors catheter ablation for persons with highly symptomatic arrhythmias because of the potential for “cure.” 1 Cheng C.H. Sanders G.D. Hlatky M.A. et al. Cost-effectiveness of radiofrequency ablation for supraventricular tachycardia. Ann Intern Med. 2000; 133: 864-876 Crossref PubMed Scopus (65) Google Scholar Anesthetic management of the arrhythmia patient undergoing catheter ablation is evolving as an important aspect of clinical care. In the electrophysiology (EP) laboratory, the induction and maintenance of arrhythmias are integral to arrhythmia diagnosis and treatment. Normal and abnormal myocardial tissue shows varied responses to volatile and intravenous anesthetic agents. 2 Huneke R. Fassl J. Rossaint R. et al. Effects of volatile anesthetics on cardiac ion channels. Acta Anaesthesiol Scand. 2004; 48: 547-561 Crossref PubMed Scopus (51) Google Scholar Therefore, the potential effects of anesthetic agents on cardiac excitability and the autonomic nervous system are important considerations for the cardiology-anesthesia team. A case of a patient who presented for electrophysiologic evaluation of a medically refractory paroxysmal idiopathic ventricular tachycardia (VT) under general anesthesia is presented. Neither premature ventricular beats nor VT could be induced despite titration of isoproterenol and an aggressive ventricular stimulation pacing protocol until the anesthetic technique was changed to a ketamine infusion, suggesting a possible role for ketamine use during invasive EP testing to potentially enhance the induction of difficult to induce arrhythmias in humans.

Clinical significance of chemosensitivity in chronic heart failure: influence on neurohormonal derangement, Cheyne–Stokes respiration and arrhythmias

Increased chemosensitivity has been observed in HF (heart failure) and, in order to clarify its pathophysiological and clinical relevance, the aim of the present study was to investigate its impact on neurohormonal balance, breathing pattern, response to exercise and arrhythmic profile. A total of 60 patients with chronic HF [age, 66+/-1 years; LVEF (left ventricular ejection fraction), 31+/-1%; values are means+/-S.E.M.] underwent assessment of HVR (hypoxic ventilatory response) and HCVR (hypercapnic ventilatory response), neurohormonal evaluation, cardiopulmonary test, 24-h ECG monitoring, and assessment of CSR (Cheyne-Stokes respiration) by diurnal and nocturnal polygraphy. A total of 60% of patients had enhanced chemosensitivity. Those with enhanced chemosensitivity to both hypoxia and hypercapnia (i.e. HVR and HCVR), compared with those with normal chemosensitivity, had significantly (all P<0.01) higher noradrenaline (norepinephrine) and BNP (B-type natriuretic peptide) levels, higher prevalence of daytime and night-time CSR, worse NYHA (New York Heart Association) class and ventilatory efficiency [higher VE (minute ventilation)/VCO(2) (carbon dioxide output) slope], and a higher incidence of chronic atrial fibrillation and paroxysmal non-sustained ventricular tachycardia, but no difference in left ventricular volumes or LVEF. A direct correlation was found between HVR or HCVR and noradrenaline (R=0.40 and R=0.37 respectively; P<0.01), BNP (R=0.40, P<0.01), N-terminal pro-BNP (R=0.37 and R=0.41 respectively, P<0.01), apnoea/hypopnoea index (R=0.57 and R=0.59 respectively, P<0.001) and VE/VCO(2) slope (R=0.42 and R=0.50 respectively, P<0.001). Finally, by multivariate analysis, HCVR was shown to be an independent predictor of both daytime and night-time CSR. In conclusion, increased chemosensitivity to hypoxia and hypercapnia, particularly when combined, is associated with neurohormonal impairment, worse ventilatory efficiency, CSR and a higher incidence of arrhythmias, and probably plays a central pathophysiological role in patients with HF.