PubMed Health⌕ Search

Biomedical subjects

G Kirkorian

Publications and source records attributed to G Kirkorian.

At least 19 recordsLinked to original sources
PubMed2006

[Ictero-haemorrhagic leptospirosis with a cardiac presentation in a patient returning from an endemic zone].

On returning from a tropical area, the occurrence of rapidly evolving cardiogenic shock in an infectious context should quickly suggest the diagnosis, for which specific treatment can affect the outcome. The dramatic case of a young female presenting with ictero-haemorrhagic leptospirosis diagnosed post-mortem, demonstrated this pathology with the unusual association of complete atrio-ventricular block and myocarditis in a haemorrhagic context.

Adult↗
PubMed2001

Non-invasive testing of acquired long QT syndrome: evidence for multiple arrhythmogenic substrates.

BACKGROUND: Although well-defined clinically and electrocardiographically, Acquired Long QT Syndrome (LQTS) remains elusive from a pathophysiologic point of view. An increasingly accepted hypothesis is that it represents an attenuated form of Congenital Long QT Syndrome. To test this hypothesis further, we investigated patients with Acquired LQTS, using various investigations that are known to give information in patients with Congenital LQTS. METHODS: All the investigations were performed in patients with a history of Acquired Long QT Syndrome, defined by marked transient QT lengthening (QT>600 ms) and/or torsades de pointes. Measurement of the QT interval dispersion, the interlead difference for the QT interval on a 12-lead ECG, was performed in 18 patients and compared with 18 controls, matched for age and sex. To assess sympathetic myocardial innervation, I-123 Meta-iodobenzylguanidine (I-123-MIBG) scintigraphy was performed in 12 patients, together with Thallium scintigraphy, to rule out abnormal myocardial perfusion. Time-frequency analysis of a high-resolution ECG using a wavelet technique, was made for nine patients and compared with 38 healthy controls. Finally, genetic studies were performed prospectively in 16 consecutive patients, to look for HERG, KCNE1, KCNE2 and KCNQ1 mutations. The functional profile of a mutated HERG protein was performed using the patch-clamp technique. RESULTS: Compared with the control group, a significant increase in QT dispersion was observed in the patients with a history of Acquired LQTS (55+/-15 vs. 33+/-9 ms, P<0.001). In another group of patients with Acquired LQTS, 123 I-MIBG tomoscintigraphy demonstrated a decrease in the sympathetic myocardial innervation. Time--frequency analysis using wavelet transform, demonstrated an abnormal frequency content within the QRS complexes, in the patients with Acquired LQTS, similar to that found in Congenital LQTS patients. Molecular screening in 16 consecutive patients, identified one patient with a missense mutation on HERG, one of the LQTS genes. Expression of the mutated HERG protein led to altered K(+) channel function. CONCLUSION: Our results suggest that Acquired and Congenital Long QT Syndromes have some common features. They allow the mechanism of the clinical heterogeneity, found in both syndromes, to be understood. Further multi-facet approaches are needed to decipher the complex interplay between the main determinants of these arrhythmogenic diseases.

Aged↗
PubMed2001

Influence of atrial flutter ablation on right to left inter-atrial conduction.

AIMS: Ablation of the atrial isthmus between the tricuspid annulus and the inferior vena cava changes P-wave morphology during low lateral right atrial pacing. For better understanding of the mechanism of this alteration, the sequence of activation of the inter-atrial septum and the left atrium were compared before and after ablation of the isthmus between the inferior vena cava and the tricuspid annulus. METHODS AND RESULTS: In 13 patients, left atrial mapping was performed using a duodecapolar electrode catheter advanced to the far distal coronary sinus. The inter-atrial septum was mapped using a right atrial duodecapolar electrode catheter. Conduction times were measured during low lateral right atrial pacing from the pacing artefact and during sinus rhythm from the earliest right atrial electrogram to every intra-cardiac electrogram before and after the ablation. During low lateral right atrial pacing, isthmus ablation resulted in a significant delay in every left atrial lead. Changes were maximal at the posterior aspect of the left atrium and minimal at its anterior aspect. No significant change was discernible on the inter-atrial septum. During sinus rhythm, atrial activations remained unchanged. CONCLUSION: Electrocardiographic changes of P-wave morphology result from alteration in the sequence of left atrial activation rather than that of the inter-atrial septum.

Atrial Flutter↗
PubMed2000

[Acute dissection of the ascending thoracic aorta complicated by myocardial infarct: an unavoidable diagnostic pitfall?].

BACKGROUND: Acute dissection of the aorta during myocardial infarction is exceptional. In such cases, fibrinolysis can be fatal. CASE REPORTS: A 63-year-old woman with a history of hypertension was referred to our intensive care unit with the diagnosis of early stage inferior myocardial infarction. Thrombolysis was instituted and the patient rapidly developed cardiovascular collapse with global heart failure. Coronarography was attempted to revascularize the occluded coronary artery but the coronary arteries could not be catheterized. An aortography was performed and gave the diagnosis of De Bakey type I dissection of the aorta. The patient died from cardiac arrest after a phase of low cardiac output. DISCUSSION: This case illustrates how myocardial infarction can complicate or mask acute dissection of the aorta. It also raises the question of transthoracic echocardiography prior to institution of fibrinolysis.

Aortic Dissection↗
PubMed2000

[Secondary infections after pacemaker implantation].

INTRODUCTION: Infectious complications following pacemaker implantation are not common but may be particularly severe. Localized wound infections at the site of implantation have been reported in 0.5% of the cases in the most recent series, with an average of about 2%. The incidence of septicemia and infectious endocarditis is lower, about 0.5% of the cases. The operator's experience, the duration of the procedure and repeat procedures are considered to be predisposing factors. CURRENT KNOWLEDGE AND KEY POINTS: The main cause of these infections has been recently demonstrated to be local contamination during implantation. The commonest causal organism is Staphylococcus (75 to 92% of the cases), Staphylococcus aureus being the cause of acute infections (less than 6 weeks), whereas Staphylococcus epidermidis is associated with cases of secondary infection (more than 2 months). The usual clinical presentation is infection at the site of the pacemaker but other forms such as abscess, endocarditis, rejection of the implanted material, septic emboli or phlebitis have been described. The diagnosis is confirmed by local and systemic biological investigations and by echocardiography (especially transesophageal echocardiography) in cases of right heart endocarditis. There are two axes of treatment: bactericidal double antibiotherapy and surgical ablation of the infected material either percutaneously or by cardiotomy. FUTURE PROSPECTS AND PROJECTS: A recent meta-analysis supported the role of systematic, preoperative, prophylactic antibiotic therapy in the prevention of these complications. These data should be confirmed by suitably powered clinical trials.

Aged↗
PubMed2000

Cardiac pacemakers. When clinical evaluation lags behind technological progress.

OBJECTIVE: The rise in the number of implantations of cardiac pacemakers is of some concern to decision makers in the health sector. We assessed the intrinsic and relative clinical efficacy of cardiac pacemakers in current clinical indications to find out whether scientific or clinical arguments might justify differences in market prices. METHODS: We retrieved papers on cardiac pacing (January 1993-April 1998) from five databases (MEDLINE, HealthSTAR, EMBASE, Cochrane Library, and PASCAL). The citations in these papers were used to seek further articles. We selected the articles that met the criteria of evidence-based medicine (EBM) (randomized and nonrandomized controlled trials) and classified them according to clinical indication and type of evaluation (either of the intrinsic efficacy of a pacemaker versus a control or of the relative efficacy of different pacing modes). RESULTS: A total of 542 references were retrieved, but under 10% met our EBM criteria. Very few were comparative studies versus controls; most were recent and tended to use endpoints other than survival. Clinical efficacy was not proven on the basis of EBM criteria, even in common indications (e.g., sick sinus syndrome). Studies comparing different pacing modes were rarely randomized and did not provide consistent evidence for the superiority of any pacing mode in a given indication. CONCLUSIONS: Knowledge of the natural history of the diseases for which cardiac pacing is indicated is scarce. There is an approximately 20-year gap between technological progress and clinical evaluation that cannot be easily bridged because of methodologic difficulties and ethical issues. Current guidelines on pacemaker use either rely on expert opinion or highlight present inadequacies and make recommendations for future work. Available clinical efficacy data do not justify the wide differences in the price of cardiac pacemakers.

Evidence-Based Medicine↗
PubMed2000

Serum cardiac troponin I and ST-segment elevation in patients with acute pericarditis.

OBJECTIVE: ST-segment elevation in acute pericarditis is believed to be caused by superficial myocardial inflammation or epicardial injury. We used cardiac troponin I, a sensitive and specific marker of myocardial injury, to assess myocardial lesions in idiopathic acute pericarditis and its relationship to ST-segment elevation. PATIENTS AND METHODS: Sixty-nine consecutive patients (53 men, 48+/-17 years) with idiopathic acute pericarditis were included. We used an enzymoimmunoflurometric method to measure serum cardiac troponin I on admission (myocardial infarction threshold was 1.5 ng. ml(-1)). RESULTS: Cardiac troponin I was detectable in 34 patients (49%) and was beyond the 1.5 ng. ml(-1)threshold in 15 (22%). Coronary angiography performed in seven of these 15 patients was normal in all of them. ST-segment elevation was observed in 93% of the patients with cardiac troponin I >1.5 ng. ml(-1)vs 57% of those without (P<0.01). Sensitivity of ST-segment elevation to detect myocardial injury was 93% and specificity 43%. Patients with a cardiac troponin I increase higher than 1.5 ng. ml(-1)were more likely to have had a recent infection (66% vs 31%;P=0.01) and were younger (37+/-14 vs 52+/-16 years;P=0.002). There was no significant relationship with other parameters such as pericardial friction rub, fever, PR segment abnormalities, echocardiographic findings or C-reactive protein. CONCLUSION: In patients with idiopathic acute pericarditis, an increase in cardiac troponin I is frequently observed, especially in younger patients and those with a recent infection. Although ST-segment elevation does not reliably indicate myocardial injury, a significant cardiac troponin I increase is only seen in these patients.

Acute Disease↗
PubMed1999

Gated blood-pool SPECT evaluation of changes after radiofrequency catheter ablation of accessory pathways: evidence for persistent ventricular preexcitation despite successful therapy.

OBJECTIVES: This study was designed to prospectively evaluate the effects of radiofrequency ablation in Wolff-Parkinson-White (WPW) syndrome by scintigraphic analysis. BACKGROUND: The functional changes triggered by radiofrequency current ablation of atrioventricular accessory pathways are not fully known. METHODS: Forty-four patients with WPW syndrome were consecutively investigated before and 48 h after radiofrequency therapy. Fourteen patients had right sided atrioventricular pathways and 30 patients had left sided bypass-tracts. Planar gated imaging and gated blood pool tomography were performed in all of these patients. RESULTS: A significant increase in the left ventricular ejection fraction (LVEF) was demonstrated in patients with left preexcitation (62.2+/-7.9% before ablation against 64.4+/-6.3% after ablation, p = 0.02) but not for those with right sided anomalous pathway. Phase analysis only gave significant differences following ablation of right sided pathways (left-to-right phase difference = 14.4+/-13.8 degrees before ablation versus 7.5+/-7.2 degrees after ablation, p<0.05). Early abnormal ventricular contraction persisted in 12 patients with right accessory pathways and in 8 patients with left accessory pathways despite the complete disappearance of any abnormal conduction as proven electrophysiologically. CONCLUSIONS: Following catheter ablation of atrioventricular accessory pathways: 1) an improvement of left ventricular function may be seen, particularly in patients with left sided accessory pathways, and 2) unexpected persistence of local ventricular preexcitation at the site of successful ablation may be detected.

Adult↗
PubMed1999

Thoracoscopic epicardial radiofrequency ablation for vagal atrial fibrillation in dogs.

Epicardial radiofrequency catheter ablation of the atria in the open-chest dog has been shown to reduce inducibility of atrial fibrillation. Video-assisted endoscopic techniques decrease the operative trauma in adult thoracic surgery. We report our results of video-assisted thoracoscopic radiofrequency catheter ablation of the atria for the prevention of atrial fibrillation induction in canines. In 12 consecutive anesthetized dogs, induction of sustained atrial fibrillation was reproducibly obtained by burst pacing and cervical vagal stimulation. In six dogs, biatrial ablation was performed through right and left minithoracotomies and guided by video-assisted endoscopic techniques. The remaining six dogs underwent a video-guided left atrial procedure. Long continuous and transmural lesions were produced using epicardial temperature controlled radiofrequency energy delivery according to a simplified maze approach. Transmural lesions were demonstrated at the end of the study by examination of the heart. Sustained atrial fibrillation was still inducible after the right atrial ablation but sustained atrial fibrillation could not be induced following left atrial ablation. In acute canine studies: (1) epicardial radiofrequency catheter ablation of the atria is feasible using video-assisted endoscopic techniques; (2) ablation extended or confined to the left atrium appears to be effective in preventing the inducibility of sustained vagal atrial fibrillation; and (3) ablation of the right atrium alone had no antiarrhythmic effect.

Animals↗
PubMed1999

Accuracy and limitations of published algorithms using the twelve-lead electrocardiogram to localize overt atrioventricular accessory pathways.

INTRODUCTION: The purpose of this study was to evaluate the accuracy and limitations of published algorithms using the 12-lead ECG to localize AV accessory pathways (APs). METHODS AND RESULTS: The 11 relevant algorithms found in the literature (MEDLINE database and major scientific sessions) were tested on a series of 266 consecutive patients who successfully underwent radiofrequency catheter ablation of a single overt AV AP. The positive predictive values (PPV) of the algorithms in applicable patients were significantly lower for algorithms with > 6 accessory location sites (40.6% +/- 10.9% vs 61.2% +/- 8.0%; P < 0.03) and show a tendency for algorithms not relying on delta wave polarity but on QRS polarity only (36.6% +/- 11.2% vs 52.3% +/- 13.1%; P = 0.09). The PPV in applicable patients is related to the AP location (P < 0.001) and ranked from the highest to the lowest as follows: left lateral (mean PPV = 86.3%), posteroseptal (mean PPV = 65.2%), right anteroseptal (mean PPV = 45.2%), and right posterolateral (mean PPV = 23.4%). CONCLUSION: Our study suggests that the accuracy of algorithms relying on the 12-lead ECG depends on AP locations as defined in the algorithms and on the number of AP sites. The accuracy tends to be lower when delta wave polarity is not included in the algorithm's architecture. This should be considered when using these algorithms or when building new ones.

Adolescent↗
PubMed1998

Selective effects of methylphenidate in attention deficit hyperactivity disorder: a functional magnetic resonance study.

Functional MRI revealed differences between children with Attention Deficit Hyperactivity Disorder (ADHD) and healthy controls in their frontal-striatal function and its modulation by methylphenidate during response inhibition. Children performed two go/no-go tasks with and without drug. ADHD children had impaired inhibitory control on both tasks. Off-drug frontal-striatal activation during response inhibition differed between ADHD and healthy children: ADHD children had greater frontal activation on one task and reduced striatal activation on the other task. Drug effects differed between ADHD and healthy children: The drug improved response inhibition in both groups on one task and only in ADHD children on the other task. The drug modulated brain activation during response inhibition on only one task: It increased frontal activation to an equal extent in both groups. In contrast, it increased striatal activation in ADHD children but reduced it in healthy children. These results suggest that ADHD is characterized by atypical frontal-striatal function and that methylphenidate affects striatal activation differently in ADHD than in healthy children.

Adolescent↗
PubMed1998

Safety and tolerability of intravenous cibenzoline for acute termination of spontaneous sustained ventricular tachycardia. Cibenzoline and spontaneous VT.

STUDY OBJECTIVES: To evaluate prospectively, the tolerability and safety of intravenous cibenzoline therapy, for the cardioversion of spontaneous monomorphic ventricular tachycardia (VT). SETTING AND PATIENTS: Between February 1990 and December 1996, fifty-eight patients aged 59+/-10 years old (fifty-three males, five females), with spontaneous VT not causing cardiac arrest, received intravenous cibenzoline. Their underlying heart conditions were: ischemic heart disease [35], dilated cardiomyopathy [14], right ventricular dysplasia [3], hypertrophic cardiomyopathy [1], valvulopathy [2], Fallot's Tetralogy [1] and primary arrhythmogenic disease [2]. The left ventricular ejection fraction was 42+/-13% (range 20%-76%). RESULTS: The mean dose of cibenzoline was 70+/-12 mg. The tachycardia stopped within 6+/-3 min in 47 (81%) patients. Side effects from cibenzoline occurred in two patients. The hemodynamic complications were limited to hypotension, that required vasopressor therapy in one patient. The only apparent proarrhythmic effect consisted of an isolated change in the morphology of the VT, that resolved spontaneously on withdrawal of the drug. No mortality occurred at the hospital. CONCLUSION: With appropriate rules for its administration, intravenous cibenzoline has the potential to become one of the first-line antiarrhythmic drugs, to be used for cardioversion of patients with spontaneous VT.

Analysis of Variance↗
PubMed1998

Role of the preaxillary flora in pacemaker infections: a prospective study.

BACKGROUND: Infection remains a severe complication after pacemaker implantation. The purpose of our prospective study was to evaluate the role of the local bacteriologic flora in its occurrence. METHODS AND RESULTS: Specimens were collected at the site of implantation for culture from the skin and the pocket before and after insertion in a consecutive series of patients who underwent elective permanent pacemaker implantation. Microorganisms isolated both at the time of insertion and of any potentially infective complication were compared by using conventional speciation and ribotyping. There were 103 patients (67 men and 36 women) whose age ranged from 16 to 93 years (mean+/-SD, 67+/-15). At the time of pacemaker implantation, a total of 267 isolates were identified. The majority (85%) were staphylococci. During a mean follow-up of 16.5 months (range, 1 to 24), infection occurred in four patients (3.9%). In two of them, an isolate of Staphylococcus schleiferi was recognized by molecular method as identical to the one previously found in the pacemaker pocket. In one patient, Staphylococcus aureus, an organism that was absent at the time of pacemaker insertion, was isolated. In another patient, a Staphylococcus epidermidis was identified both at the time of pacemaker insertion and when erosion occurred; however, their antibiotic resistance profiles were different. CONCLUSIONS: This study strongly supports the hypothesis that pacemaker-related infections are mainly due to local contamination during implantation. S schleiferi appears to play an underestimated role in infectious colonization of implanted biomaterials and should be regarded as an important opportunistic pathogen.

Abscess↗
PubMed1998

Antibiotic prophylaxis for permanent pacemaker implantation: a meta-analysis.

BACKGROUND: Infection remains a serious complication after permanent pacemaker implantation. Antibiotic prophylaxis is frequently prescribed at the time of insertion to reduce its incidence, although results of well-designed, controlled studies are lacking. METHODS AND RESULTS: We performed a meta-analysis of all available randomized trials to evaluate the effectiveness of antibiotic prophylaxis to reduce infection rates after permanent pacemaker implantation. Reports of trials were identified through a Medline, Embase, Current Contents, and an extensive bibliography search. Trials that met the following criteria were included: (1) prospective, randomized, controlled, open or blind trials; (2) patients assigned to a systemic antibiotic group or a control group; (3) end point events related to any infection after pacemaker implantation: wound infection, septicemia, pocket abscess, purulent secretion, right infective endocarditis, inflammatory signs, a positive culture, septic pulmonary embolism, or repeat operation for an infective complication. Seven trials met the inclusion criteria. They included 2023 patients with established permanent pacemaker implantation (new implants or replacements). The incidence of end point events in control groups ranged from 0% to 12%. The meta-analysis suggested a consistent protective effect of antibiotic pretreatment (P=.0046; common odds ratio: 0.256, 95% confidence interval: 0.10 to 0.656). CONCLUSIONS: Results of the present meta-analysis suggest that systemic antibiotic prophylaxis significantly reduces the incidence of potentially serious infective complications after permanent pacemaker implantation. They support the use of prophylactic antibiotics at the time of pacemaker insertion to prevent short-term pocket infection, skin erosion or septicemia.

Adult↗
PubMed1998

Hypertrophic cardiomyopathy and pregnancy.

The case of a young primiparous woman with defibrillator-assisted familial hypertrophic cardiomyopathy (HCM) has led us to review the literature on this pathology, which is exceptional because of its scarcity and the originality of the problems encountered. To our knowledge, this is the first observation ever reported of defibrillator-assisted activation during pregnancy in a woman with HCM. Several questions raised from this particular case, e.g. what are the risks caused by pregnancy in these patients, what is the impact of therapeutics, does the activation of an internal defibrillator involve particular risks, what is the best disposition for delivery and what are the risks for fetuses? We have tried to ask all of these questions, using as exhaustive a literature review as possible.

Adult↗
PubMed1998

Arrhythmic cardiac arrest due to isolated coronary artery spasm: long-term outcome of seven resuscitated patients.

OBJECTIVES: Our aim was to look at the clinical features and long-term follow-up of seven patients without coronary artery disease, who had a history of life-threatening ventricular arrhythmias due to coronary spasm. BACKGROUND: Arrhythmic cardiac arrest due to isolated coronary spasm is rare, and there is limited information on the patients affected by this entity alone. METHODS: The seven patients were recruited retrospectively from a cohort of survivors of cardiac arrest. None had a history of angina pectoris, structural heart disease or significantly narrowed coronary segments. All had a positive ergonovine provocation test result. RESULTS: The patients' mean age was 44 years; three were male and four female. All were habitual cigarette smokers. No arrhythmias were induced on programmed ventricular stimulation; corrected QT interval (QTc) and corrected JT interval (JTc) dispersion were within normal ranges. After the ergonovine provocation test, treatment with calcium channel blocking agents (diltiazem, verapamil, nifedipine or amlodipine) was initiated at a dose determined by titration until a negative test result was obtained. At a mean follow-up interval of 58 months for the total group, six patients remained free of symptoms, whereas the one patient who did not stop smoking had a new cardiac arrest despite treatment for coronary spasm. CONCLUSIONS: A favorable long-term outcome may be expected in survivors of cardiac arrest due to coronary spasm, in the absence of significant coronary artery disease. Calcium channel blockers are the most appropriate therapy in these patients. These observations provide further evidence for the role of silent ischemia in cardiovascular death.

Adult↗