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Biomedical subjects

K Isaaz

Publications and source records attributed to K Isaaz.

At least 19 recordsLinked to original sources
PubMed2002

Factors associated with early atrial fibrillation after ablation of common atrial flutter. A single centre prospective study.

BACKGROUND: The occurrence of early atrial fibrillation (< or = 6 months) after ablation of common atrial flutter is of clinical significance. Variables predicting this evolution in ablated patients without a previous atrial fibrillation history have not been fully investigated. OBJECTIVES: The aim of the present study was: (1) to identify predictive factors of early atrial fibrillation (< or = 6 months) in the overall population following atrial flutter catheter ablation; (2) to identify predictive variables of early atrial fibrillation following (< or = 6 months) atrial flutter catheter ablation within a subgroup of patients without documented prior atrial fibrillation. METHODS: This study prospectively included 96 consecutive patients (age 65 +/- 13 years; 18 women) over a 12-month period. Their counterclockwise flutter was ablated by radiofrequency, by the same operator, with an 8-mm-tip catheter. Clinical, electrophysiological and echocardiographic data were collected and 27 variables were retained for analysis: age; gender; type of atrial flutter (permanent vs paroxysmal); symptom duration (months +/- SD); pre-ablation history of atrial fibrillation; structural heart disease; left ventricular ejection fraction (%); left atrial size (mm); cava--tricuspid isthmus dimension; septal isthmus dimension; systolic pulmonary pressure > or < or = 30 mmHg; right atrial area; left atrial area; isthmus block; number of radiofrequency applications (+/- SD); antiarrhythmic drugs at discharge; left ventricular diastolic diameter; left ventricular systolic diameter; left ventricular telediastolic volume; left ventricular telesystolic volume; A-wave velocity (cm . s(-1)); E-wave velocity (cm . s(-1)); E/A; isovolumetric relaxation time; E-wave deceleration time; significant mitral regurgitation and flutter cycle length (ms). RESULTS: Of the 96 consecutive ablated patients, early atrial fibrillation was documented in 16 patients (17%). Atrial fibrillation occurred 30 +/- 46 days (range 1 to 171 days) after ablation. Univariate analysis associated an early occurrence of atrial fibrillation with: atrial fibrillation history, left ventricular ejection fraction, left atrial size, left ventricular telesystolic volume, A-wave velocity, significant mitral regurgitation and flutter cycle length. Multivariate analysis using a Cox model found that the only independent predictors of early atrial fibrillation were left ventricular ejection fraction and pre-ablation history of atrial fibrillation. In the subgroup without prior atrial fibrillation history (n=63; 66%), the only independent predictor of early atrial fibrillation was the presence of a significant mitral regurgitation. CONCLUSIONS: In a subgroup of patients without atrial fibrillation history, 8% of patients revealed an early atrial fibrillation. Mitral regurgitation is a strong predictive factor of early atrial fibrillation occurrence with 80% sensitivity, 78% specificity and 98% negative predictive value. These data should be considered in post-ablation management.

Adult↗
PubMed2001

Chronotropic incompetence response to exercise in congestive heart failure, relationship with the cardiac autonomic status.

In chronic congestive heart failure (CHF), attenuated heart rate response to exercise, a manifestation of chronotropic incompetence (CI), contributes to limiting exercise capacity. The present study was thus conducted to evaluate the respective role of chronic attenuation of cardiac vagal tone associated with depressed baroreflex sensitivity or affected cardiac sympathetic responsiveness in CHF patients with CI. Spontaneous cardiac baroreflex sensitivity (BRS) assessed by sequence method and spectral- and time-domain analysis of heart rate variability (HRV) were analysed in 21 chronic CHF patients. All patients performed a symptom-limited exercise test with measurement of gas exchange. Chronic incompetence which was defined as failure to achieve > or =80% of the heart rate reserve (%HRR) given by (HRpeak - HRrest)/(predictive maximal heart rate - HRrest) was observed in 14 (66%) patients. There was no significant difference in age, heart rate, peak oxygen uptake or left ventricular ejection fraction between the patients with and without CI. Although there was no significant difference in BRS, low frequency power of HRV in normalized units (LFnu) and SDNN were significantly lower in CI patients. Percentage of HRR correlated significantly with LFnu on 15 min (r=0.64, P<0.005) and, with LFnu on 24 h (r=0.52, P<0.01), SDNN (r=0.48, P=0.03) and SDANN (r=0.48, P=0.03), but not BRS (r=0.04, P=NS). Autonomic nervous system derangement is a complex process in CHF. The role of basal depressed cardiac sympathetic tone seems to contribute more closely than depressed baroreflex sensitivity to the impaired heart rate response to exercise frequently observed in CHF patients.

Adult↗
PubMed2001

Clinical characteristics, aetiological factors and long-term prognosis of myocardial infarction with an absolutely normal coronary angiogram; a 3-year follow-up study of 91 patients.

OBJECTIVES: The purpose of this study was to evaluate the clinical outcome of a large cohort of patients who suffered an acute myocardial infarction with absolutely normal epicardial coronary arteries at the post-myocardial infarction coronary angiogram. The aetiological and prognostic factors in this population were also analysed. BACKGROUND: Few data exist concerning the outcome, and aetiological and prognostic factors, of patients with myocardial infarction and angiographically absolutely normal coronary arteries. METHODS: Ninety-one patients (34 females/57 males; mean age 50+/-13 years, range 24--78 years) admitted with an acute myocardial infarction had absolutely normal coronary arteries at the angiogram performed 6.2+/-4 days (range 1--15 days) after the myocardial infarction, defined by smooth contours and no focal reduction (NC). Of the 91 NC patients, 71 were evaluated prospectively, alongside a systematic search of all aetiological factors reported in the literature. The NC patients were matched for age, sex, and the same period of myocardial infarction onset with a group of 91 patients with coronary artery stenosis (>50% diameter stenosis) at the angiogram performed 7.3+/-4 days (range 1--15 days) after the myocardial infarction (SC). RESULTS: The percent of smokers was similar between the two groups; higher prevalence rates of coronary heart disease family history, obesity, hypertension, hypercholesterolaemia and diabetes mellitus were found in SC (P=0.043 to 0.0001). In NC, coronary spasm was found in 15.5%, congenital coagulation disorders in 12.8%, collagen tissue disorders in 2.2%, embolization in 2.2%, and oral contraceptive use in 1.1%. Left ventricular ejection fraction at hospital discharge was higher in NC (60%+/-13%) than in SC (55%+/-13%, P=0.04). The mean follow-up was 35 months (range 1--100 months). Kaplan-Meier event-free survival, with the combined end-point defined as death, reinfarction, heart failure and stroke was 75% in NC vs 50% in SC (P<0.0001). Survival rate was 94.5% in NC compared to 92% in SC (ns). Univariate predictors of events in NC were left ventricular ejection fraction (P=0.03), age (P=0.02), diabetes (P=0.01), and smoking (P=0.03). Using Cox multivariate analysis, independent predictors of long-term outcome in NC patients were left ventricular ejection fraction (P=0.003) and diabetes (P=0.004). CONCLUSION: Aetiological factors, predominantly coronary spasm and inherited coagulation disorder, can be detected in only one third of the patients with myocardial infarction and absolutely normal coronary angiograms despite a systematic search in a prospective population. Mortality rates are similar but morbidity is lower in myocardial infarction patients with absolutely normal coronary angiography compared with those with coronary artery stenosis. The only two independent factors predictive of poor outcome in myocardial infarction patients with normal coronary arteries are left ventricular function and diabetes.

Adult↗
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

Safe and effective placement of two bipolar silicone leads in the cephalic vein using a hydrophilic guidewire and a split introducer.

The cephalic vein (CV) is preferable to the subclavian vein for implanting permanent pacing leads because of fewer complications. Unfortunately, this access is unusable in a substantial number of patients. This prospective study evaluates a technique to increase CV access for the placement of two silicone bipolar leads used in DDD pulse generator implants. A standard cephalic cutdown was performed under local anesthesia and a hydrophilic guidewire (HGW) threaded in the CV. The first (ventricular) bipolar lead was then introduced and positioned. When possible, introduction of the second (atrial) lead followed the same direct access. A failed introduction led to a modified procedure (MP) relying on a "split" introducer (8-9 Fr Plastimed) advanced with a circular motion over the HGW, then removal of the dilator, removal of the HGW, insertion of the pacing lead into the sheath with placement in the right atrium, followed by sheath withdrawal. Over an 18-month period, 90 consecutive patients had DDD pacemakers implanted. The CV was accessible in 76 (84.5%) of 90 patients and the direct introduction of the ventricular lead was obtained in 74 (97.4%) of these. Atrialization proceeded as follows: direct access CV in 14 (18%) of 76 patients, MP access in 54 (71%) of 76 patients, and MP failure in 8 (11%) of 76 patients. Overall, this approach allowed cephalic dual insertion in 68 (89%) of 76 patients. In conclusion, the modified procedure presented in this study allows a dual catheterization with bipolar leads in 89% of patients when a CV is available. This significantly improves the success rate for dual bipolar lead implants in this configuration.

Adult↗
PubMed2000

Predictive factors of ventricular fibrillation triggered by pause-dependent torsades de pointes associated with acquired long QT interval: role of QT dispersion and left ventricular function.

INTRODUCTION: Death due to acquired torsades de pointes usually is caused by ventricular fibrillation (VF), but the contributing factors to VF triggered by pause-dependent torsades de pointes are not understood. METHODS AND RESULTS: We evaluated 91 patients who fulfilled four criteria: (1) pause-dependent torsades de pointes; (2) prolonged QT interval and/or corrected QT (QTc) (>0.44 sec); (3) long-short initiation sequence; and (4) conditions known to induce pause-dependent torsades de pointes. There were 38 patients with a documented VF (group I) and 53 without VF (group II). Absolute and relative dispersions of QT and QTc were calculated based on the 12-lead standard ECG. Group I differed from group II with regard to myocardial infarction history (32% vs 13%; P = 0.035), left ventricular ejection fraction (44% +/- 14% vs 65% +/- 9%; P < 0.0001), presence of structural heart disease (100% vs 20.8%; P < 0.0001), QT mean (591 +/- 73 msec vs 514 +/- 78 msec; P < 0.0001), QTc mean (563 +/- 76 msec vs 508 +/- 90 msec; P = 0.002), absolute QT dispersion (166 +/- 56 msec vs 84 +/- 49 msec; P < 0.0001), relative QT dispersion (9.9% +/- 3.5% vs 6.3% +/- 3.2%; P < 0.0001), absolute QTc dispersion (158 +/- 57 msec vs 81 +/- 44 msec; P < 0.0001), and relative QTc dispersion (9.9% +/- 3.6% vs 6.2% +/- 3%; P < 0.0001). Multiple regression analysis showed that ejection fraction (P = 0.0001), presence of structural heart disease (P < 0.0001), and relative QTc dispersion (P = 0.038) were the only independent predictors of VF. CONCLUSION: Left ventricular function, presence of structural heart disease, and QTc relative dispersion should be evaluated carefully in patients with conditions susceptible to inducing torsades de pointes.

Aged↗
PubMed2000

Prevalence of factor V Leiden in patients with myocardial infarction and normal coronary angiography.

Factor V Leiden is associated with an increased risk of venous thrombosis and myocardial infarction in young women, but not in men in this latter case. The aim of this study was to evaluate the prevalence of this mutation in patients with myocardial infarction but normal coronary angiography. We compared 3 groups of patients: one group consisted of 107 patients with premature myocardial infarction but no significant coronary artery stenosis; another group of 244 patients with myocardial infarction and significant coronary artery stenosis; a third group of 400 healthy controls. Factor V Leiden was found in 13 patients (12.1%) who had a myocardial infarction without significant coronary artery stenosis, 11 patients (4.5%) who had a myocardial infarction with significant coronary artery stenosis (p = 0.01) and in 20 controls (5%) (p = 0.01). Odds ratio associated with factor V Leiden were respectively 2.93 (CI95: 1.18-7.31 ) and 2.63 (CI95: 1.19-5.78) when we compared myocardial infarction patients without significant coronary artery stenosis to controls or to patients with significant coronary artery stenosis. In myocardial infarction patients without significant coronary artery stenosis, prevalence of factor V Leiden is significantly higher than in controls. This new finding supports the hypothesis that thrombosis plays a key role in this selected situation.

Adult↗
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

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

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↗
PubMed1998

Use of the continuity equation for transesophageal Doppler assessment of severity of proximal left coronary artery stenosis: a quantitative coronary angiography validation study.

OBJECTIVES: We tested the value of transesophageal Doppler echocardiography (TEDE) for quantitating proximal left coronary artery (LCA) stenosis by using the continuity equation. BACKGROUND: The continuity equation applied to a stenosis states that the ratio of the time-velocity integral (TVI) of prestenotic to stenotic flow velocities is equal to the ratio of stenotic to prestenotic cross-sectional areas. TEDE allows the measurement of coronary blood flow velocities within the proximal part of the LCA. METHODS; Forty-one patients with a stenosis of the proximal or mid left anterior descending coronary artery or with a nonostial stenosis of the left main coronary artery were studied. Coronary flow velocities were recorded by TEDE guided by color flow imaging. Prestenotic velocities were recorded by pulsed Doppler echocardiography and transstenotic velocities were recorded by pulsed or high pulse repetition frequency or continuous wave Doppler echocardiography. The prestenotic and transstenotic diastolic TVIs were calculated and the TEDE-derived percent area stenosis was calculated as (1 - TVI ratio) x 100. Quantitative angiography lesion analysis was performed using a computer-assisted automated edge-detection system. RESULTS: TEDE recordings were successful in 35 of the 41 patients. A good linear correlation was found between TEDE and quantitative angiographically derived percent area stenosis (r = 0.89, p = 0.0001, SEE 5.7). However, TEDE measurements underestimated the actual percent area stenosis (slope of regression 0.54). A better agreement (slope 1.08) was obtained after dividing prestenotic velocity by 2 in the continuity equation, based on the assumption of a parabolic cross-sectional velocity profile in the prestenotic segment. CONCLUSIONS: TEDE may be used for quantitating stenosis of the proximal part of the LCA with the use of a modified continuity equation that takes into account the parabolic velocity profile in the normal prestenotic segment.

Adult↗
PubMed1998

Prevalence of factor V Leiden (APCR) and other inherited thrombophilias in young patients with myocardial infarction and normal coronary arteries.

OBJECTIVE: To investigate the role of activated protein C resistance (APCR, factor V Leiden) in coronary artery thrombosis. METHODS: The prevalence of APCR and of congenital deficiencies of antithrombin III, protein C, protein S, plasminogen, and factor XII was investigated in adult patients under 45 years of age with acute myocardial infarction. The results were compared with those of a group of 53 age and sex matched control subjects. RESULTS: Among 75 patients under the age of 45 years who were admitted from November 1994 to April 1996 for acute myocardial infarction, 22 (29.3%) had normal coronary arteriography (group I) and 53 (70.7%) had significant coronary artery disease (group II). Inherited thrombophilia was more often found in group I (4/22, 18.2%) than in group II (4/53, 7.5%) but the difference was not significant (F test: p = 0.22). The prevalence of APCR was 9.1% (2/22) in group I, 3.8% (2/53) in group 2 (p = 0.57), and 3.8% (2/53) in the normal control group (p = 0.57). CONCLUSIONS: The prevalence of congenital thrombophilias, including APCR, does not seem to be increased in young patients with myocardial infarction and normal coronary angiograms, compared with young patients with coronary atherosclerosis and with normal control subjects. However, the statistical power of the study is too low to detect a significant difference and these results are published to allow a meta-analysis of this problem in the future.

Activated Protein C Resistance↗
PubMed1998

[Infections secondary to implantation of cardiac pacemakers].

Infectious complications of pacemaker implantation are not common but may be particularly severe. Localised wound infections at the site of implantation have been reported in 0.5% of cases in the most recent series with an average of about 2%. The incidence of septicaemia and infectious endocarditis is lower, about 0.5% of cases. The operator's experience, the duration of the procedure and repeat procedures are considered to be predisposing factors. The main cause of these infections is though to be local contamination during the implantation. The commonest causal organism is the staphylococcus (75 to 92%), the staphylococcus aureus being the cause of acute infections whereas the staphylococcus epidermis is associated with cases of secondary infection. 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 and septic phlebitis have been described. The diagnosis is confirmed by local and systemic biological investigations and by echocardiography (especially transoesophageal 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. Though controversial, and unsupported by scientific evidence, the role of systematic, preoperative, prophylactic antibiotic therapy in the prevention of these complications seems to be increasing.

Abscess↗