Biomedical subjects
Publications and source records attributed to J Clementy.
In a patient with severe congestive heart failure and ischemic disease, frequent episodes of ventricular tachycardia were completely suppressed by an implantable cardioverter defibrillator with biventricular pacing.
Biventricular (BV) pacing acutely improves the hemodynamic status of patients with chronic heart failure (CHF) and wide QRS complex. Long-term data are few. This study examined the relationship between hemodynamic and clinical status of BV-paced CHF patients over an intermediate duration of follow-up. Forty-seven patients (mean age 64 +/- 11 years, 19% women, LVEF 0.23 +/- 0.07) with QRS > or = 140 ms received a DDD-BVP device for management of CHF due to ischemic disease in 21 (45%) patients. Clinical, electrocardiographic, exercise testing, and hemodynamic measurements were followed over an 8-month period. Seven patients died during the study, four patients suddenly. A significant decrease in NYHA class, from 3.3 +/- 0.6 before implantation, to 2.5 +/- 0.57 months after device implantation (P < 0.01) was measured, although 23% of patients reported no symptomatic improvement. Paced QRS narrowing by BVP was unchanged throughout follow-up (166 +/- 28 vs 159 +/- 23 ms, P = NS). Maximal VO2 values did not change (15.7 +/- 5 vs 16 +/- 8 mL/kg per min, P = NS). Echocardiographic parameters showed that the degree of mitral regurgitation was significantly decreased during BV pacing compared with no pacing (1.8 +/- 1.0 before implantation vs 1.3 +/- 0.7, P < 0.01). The radionuclide LVEF was not statistically different during no pacing, versus BV pacing at 3 months or 8 months after pacemaker implantation (24 +/- 9 vs 26 +/- 11 vs 25 +/- 10%, respectively, P = NS). Of nine patients whose QRS duration was prolonged by BV pacing, two were not hemodynamically and clinically improved at the end of follow-up. Patients not improved by BV pacing had the same degree of QRS shortening (203 +/- 39 vs 167 +/- 26 ms, P < 0.01) as patients who were clinically improved during follow-up (193 +/- 40 to 171 +/- 24 ms, P < 0.01). In multivariate analysis, ischemic heart disease (P = 0.025), absence of mitral regurgitation regression (P = 0.01), and older age (P = 0.04) predicted the absence of improvement by BV pacing. By standard noninvasive measures, intermediate-term BV pacing was associated with no objective hemodynamic improvement, though more than three fourths of the patients reported being clinically improved. A global improvement in left ventricular function by BV pacing may become apparent only over longer periods of observations. Patients with CHF unimproved by BV pacing are more likely to suffer from ischemic heart disease and less likely to have BV pacing induced regression of mitral regurgitation, regardless of changes in QRS duration.
Multisite ventricular pacing acutely improves the hemodynamic status in heart failure, though longer-term observations require invasive procedures. The hemodynamics of multisite ventricular pacing were assessed by echocardiography and peak endocardial acceleration (PEA) measured by a pacemaker sensor. PEA variations are highly correlated with those of dP/dt. Thirteen end-stage heart failure patients (left ventricular ejection fraction < 0.30) with a QRS > or = 140 ms received a DDD PEA sensor-driven pacemaker allowing right (RV), left (LV) and biventricular (BV) pacing. Ten days after implantation, standard echocardiographic parameters and variations in PEA were measured after 20 minutes at each pacing mode. The aortic systolic preejection time interval was statistically comparable between RV and LV pacing (218 +/- 24 vs 219 +/- 34 ms; P = NS), and significantly shorter with BV pacing (198 +/- 27 ms; P = 0.013). Aortic ejection duration was nonsignificantly shorter during BV pacing than during LV pacing (-.061, P = 0.09). The aortic velocity time integer increased during LV pacing versus RV pacing (+21%, P < 0.05) and during BV pacing versus RV pacing (+37%, P = 0.05). As a result, the values of the PEA variations over a 15-minute period were significantly greater during LV pacing and BV pacing versus RV pacing (+43%, P < 0.05, and +38%, P = 0.05, respectively) and were statistically comparable between BV pacing and LV pacing (9% for LV pacing, P = NS). During various ventricular pacing configurations, PEA measurements were consistent with echocardiographic data, showing comparable hemodynamic effects of BV and LV pacing. The PEA sensor is a promising tool for long-term hemodynamic monitoring and serial evaluation of the effects of multisite ventricular pacing in heart failure patients.
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OBJECTIVE: To assess the effect of adding propafenone to atrial overdrive for the prevention of atrial arrhythmia episodes in patients with DDD pacemakers. DESIGN: 22 patients (8 female, 14 male, mean (SD) age 67 (9) years, range 48 to 77) with DDD pacemakers and frequent paroxysmal atrial arrhythmia episodes were evaluated in a randomised crossover study. SETTING: University hospital. METHODS: Atrial overdrive was defined as a paced rate of 10 paced beats/min above the mean ventricular rate stored for the last 24 hours in the pacemaker memory function. The protocol consisted of two phases of one month each. The first phase consisted of atrial overdrive alone, while in the second phase, propafenone (600 mg/day) was added to atrial overdrive (atrial overdrive + propafenone). All 22 patients underwent the two phases in random order. RESULTS: Mean ventricular rate was 72 (8) beats/min with atrial overdrive v 73 (6) with atrial overdrive + propafenone (NS). With atrial overdrive, 14 patients (64. 6%) had no recorded atrial arrhythmia v 15 (68.2%) with atrial overdrive + propafenone (NS). There was no statistical difference between the atrial overdrive and atrial overdrive + propafenone phases with regard to the number of atrial arrhythmia episodes (14 (27) v 13 (28)), their total duration (30 (78) v 29 (63) h), and their maximum duration (41 (72) v 31 (58) min). However, in the brady-tachy subgroup with persistent atrial arrhythmias, atrial overdrive + propafenone produced a shorter mean cumulative duration of atrial arrhythmia than atrial overdrive (104 (115) v 178 (149) h, p = 0.04), with a significant decrease in the number of atrial arrhythmia episodes (134 (98) v 102 (83), p = 0.05). The proportion of asymptomatic atrial arrhythmia episodes increased only in the AV block group during atrial overdrive + propafenone (p = 0.03). Three patients had atrial arrhythmias during atrial overdrive + propafenone but not with atrial overdrive alone. CONCLUSIONS: In DDD paced patients, the overall effect of propafenone during atrial overdrive is variable. Propafenone may increase the proportion of asymptomatic atrial arrhythmia episodes. A proarrhythmic effect of propafenone was documented (aggravation of atrial arrhythmias). These results need to be confirmed by further larger randomised studies.
BACKGROUND: Hypertension is accompanied by abnormalities in left ventricular filling; however, there is a lack of agreement on the extent of the influence of antihypertensive treatment on them. HYPOTHESIS: The present study was designed to evaluate the long-term course of these abnormalities in both treated and untreated hypertensive patients. METHODS: Left ventricular filling assessed by pulsed Doppler echocardiography of mitral flow was studied over a long follow-up period in both untreated and treated hypertensive patients. This retrospective study included 73 hypertensive patients who had not received any treatment. They had been followed up for at least 3 years and were divided a posteriori into two groups: Group 1 comprised the untreated patients, while Group 2 included the patients who had received antihypertensive treatment throughout the follow-up period. RESULTS: In the overall population, age and heart rate measured during the Doppler examination were the only parameters that correlated significantly with mitral flow. No significant changes in blood pressure or left ventricular mass were observed in Group 1 (14 patients) over the study period. There was a slight but nonsignificant decrease in E/A ratio of mitral flow. In the treated patients, there was a drop in heart rate-adjusted E/A ratio, despite a reduction in blood pressure and left ventricular mass, at mean follow-up of 5 years. CONCLUSION: Antihypertensive therapy did not arrest the long-term reduction in E/A ratio in hypertensive patients despite reduction in blood pressure and left ventricular mass.
OBJECTIVES: The purpose of this study was to prospectively evaluate preexisting partial isthmus block in the context of an electrophysiologically directed linear ablation strategy for typical atrial flutter (AF). BACKGROUND: Double potentials (DPs) separated by an isoelectric interval have been recognized as markers of local block. However, the presence and significance of DPs in the cavotricuspid isthmus during AF before ablation have not been evaluated. METHODS: Thirty consecutive patients with AF (counterclockwise: 24, clockwise: 6) were studied during AF. Sequential withdrawal mapping was performed in the cavotricuspid isthmus from the tricuspid valve (TV) to the inferior vena cava (IVC) edge with electrograms coinciding with the center of the surface electrocardiographic plateau during counterclockwise AF or with the initial downslope of the positive flutter wave during clockwise AF. Atrial electrograms along this line were categorized as double, single or fractionated potentials (SPs or FPs). After demarcation of the zone of contiguous DPs, radiofrequency (RF) catheter ablation was performed during AF only at sites with SPs or FPs (other than DPs) on the mapped line. If isthmus conduction still persisted after AF termination, additional RF applications were delivered using the same electrophysiologic strategy of avoiding DPs with an isoelectric interval during low lateral right atrial pacing for filling in the gap of residual conduction. RESULTS: Before ablation, no DPs were recorded in the isthmus in 19 patients (63%); DPs were recorded only at the IVC edge in five patients, and only at the TV edge in one patient. A contiguous line of DPs extending through more than half the isthmus to the IVC edge was documented in five patients (17%: group DP). In group DP, AF was terminated with 1.4+/-0.5 applications (vs. 5.8+/-3.5 in the remaining patients: p < 0.01). Complete isthmus block was achieved with a total of 3.4+/-0.5 applications (vs. 12+/-6 in the remaining patients: p < 0.01). CONCLUSIONS: Seventeen percent of patients undergoing ablation of AF have preexisting partial isthmus block indicated by a large contiguous zone of DPs separated by an isoelectric interval. Electrophysiologically directed linear ablation avoiding confluent DPs can prevent unnecessary applications for effective cure of AF.
Ambulatory measurement of timing of Korotkoff sounds (QKD interval) gives an estimate of arterial distensibility derived from the velocity of the pulse wave over a vascular territory that includes the ascending aorta. The main advantages of the method are that it is entirely automatic, non-operator-dependent, and highly reproducible, and produces a measure independent of instantaneous blood pressure. This study of a group of 180 normal subjects aged between 10 and 78 years was designed to produce references values and to study the influence of height. The results confirmed the reduction with age of arterial distensibility in the whole population. However before the age of 30, QKD100-60 was positively correlated with height according to the relationship QKD100-60 = 0.73 height (cm) + 91, but not with age. This equation enables calculation of the theoretical value of QKD100-60 as a function of height for any patient to which the observed value can be expressed as a percentage. This effectively eliminates the influence of height, which reflects the length of the arterial segment under investigation.
Relationships between ambulatory arterial pressure and arterial distensibility as assessed by ambulatory measure of the QKD interval and echocardiographic measurement of left ventricular mass and relative wall thickness were evaluated in a population of 163 untreated hypertensive patients. The height-corrected QKD100-60 interval was significantly correlated with left ventricular mass (LVM; r = -0.29, P<.001) and with relative wall thickness (r = -0.31, P<0.001). In a multivariate analysis, LVM was significantly correlated with mean arterial pressure, pulse pressure, and age, whereas the relative wall thickness was correlated with the QKD interval and the mean arterial pressure. The concentric character of the LVH of the hypertensive patient was thus linked to the reduction in arterial distensibility.
OBJECTIVES: It has been suggested that hypertensives at high risk of cardiovascular complications can be identified on the basis of their left ventricular mass as determined echographically. However, there is as yet a lack of consensus on the mode of indexation (body surface area, height, height 2.7) of left ventricular mass (LVM), and on the cut-off values for definition of left ventricular hypertrophy (LVH). The main objective of this study is to test the influence of the different modes of indexation for LVM on the prevalence of LVH in a population of never treated hypertensive patients on the basis of cut-offs for LVM based upon its relationship with ambulatory blood pressure (BP) measurement. METHODS: A population of 363 untreated hypertensives was investigated using a standardised procedure. The men and women were analysed separately. We studied the relationship between mean daytime ambulatory systolic BP and LVM and calculated the LVM cut-off for a BP of 135 mm Hg using three different methods of indexation. On the basis of these criteria, the population was divided into those with and those without LVH. RESULTS: The prevalence of LVH was found to be higher when LVM was indexed to height2.7 (50.4%) or height (50.1%). Prevalence was lowest when LVM was indexed to body surface area (48.2%), which tended to minimise the hypertrophy in obese individuals. Only indexation by height 2.7 fully compensates for relationships between height and ventricular mass in this population. CONCLUSIONS: Indexing LVM to height 2.7 thus appeared to give a more sensitive estimate of LVH by eliminating the influence of growth. Cut-offs of 47 g/m2.7 in women and 53 g/m2.7 in men corresponded to a cardiovascular risk indicated by a daytime systolic BP >/=135 mm Hg.
This report describes two patients with atrial fibrillation in whom an implanted CHORUS DDD pacemaker programmed to the DDI mode produced an irregular ventricular stimulation rate. The lower rate timing of these devices is atrial-based only when an atrial event opens an AV interval shorter than the programmed AV delay. In the DDI mode, if Api represents the time when an atrial paced event (Ap) would have occurred if it had not been inhibited by a previous atrial sensed event (As), then Api-Vp constitutes the implied AV interval where Vp is a paced ventricular event. Although the As-Vp interval (As-Api + Api-Vp) generates an atrial refractory period during its entire duration, the pacemaker can sense an atrial event (AR) during the implied AV interval. AR cannot start another AV delay, but it can initiate the atrial-based lower rate interval. This timing mechanism can cause irregular prolongation of Vp-Vp intervals to a value longer than the programmed lower interval with a maximal extension equal to the programmed AV delay. Such behavior of the CHORUS pacemaker should not be interpreted as malfunction.
OBJECTIVE: To study the relationship between serum cholesterol level and left ventricular mass for a population of untreated hypertensive patients. DESIGN: A cross-sectional study. PATIENTS: We studied 273 untreated hypertensive patients without associated diseases consecutively referred for evaluation of blood pressure. All patients underwent M-mode echocardiographic assessment of left ventricular mass, office blood pressure measurement and 24 h ambulatory blood pressure monitoring. Fasting plasma glucose and total cholesterol levels were measured on the same day. RESULTS: We found a weak but significant correlation (r = 0.20-0.26, P < 0.01) between serum cholesterol level and left ventricular wall thickness or left ventricular mass irrespective of the mode of indexation used (height, height2.7 and body surface area). In multivariate analysis this relation remained significant after introduction of sex, age, weight, height, blood pressure and blood glucose level. When data for men and women were analysed separately the relationship between left ventricular mass and cholesterol remained significant for men only. CONCLUSION: There is a significant and independent positive relationship between serum cholesterol level and left ventricular mass that could contribute to the prognostic value of left ventricular hypertrophy.
INTRODUCTION: Some posteroseptal accessory pathways (APs) can be successfully ablated by radiofrequency current only from inside the coronary sinus (CS) or its branches, because of an absolute or relatively epicardial location. The aim of this study was to identify ECG features of manifest posteroseptal APs requiring ablation in the CS or the middle cardiac veins (MCVs). METHODS AND RESULTS: One hundred seventeen consecutive patients with manifest posteroseptal APs successfully ablated: (1) > or = 1 cm deep inside the MCV (group MCV: n = 13); (2) inside the CS, including the area adjacent to the MCV ostium (group CS: n = 10); (3) at the right (group R: n = 60); or (4) the left posteroseptal endocardial region (group L: n = 34) were included. We reviewed delta wave polarity (initial 40 msec) and QRS morphology during sinus rhythm and atrial pacing as well as electrogram characteristics in these patients. The local target site electrogram in groups MCV and CS was characterized by a longer atrial to ventricular electrogram interval, suggesting a longer course of the pathway and more frequent recording of a presumptive AP potential compared to the group ablated at the right or left endocardium. The most sensitive ECG feature for group CS or group MCV was a negative delta wave in lead II in sinus rhythm (87%), but specificity (79%) and positive predictive value (50%) were relatively low. A steep positive delta wave in aVR during maximal preexcitation possessed the highest specificity and positive predictive value (98% and 88%, sensitivity 61%) which increased to 99% and 91%, respectively, when combined with a deep S wave in V6 (R wave < or = S wave). CONCLUSION: These data suggest that posteroseptal APs ablated inside the coronary venous system have highly specific features, including the combination of a steep positive delta wave in lead aVR and a deep S wave in lead V6 (R wave < or = S wave) during maximal preexcitation. The highest sensitivity is provided by a negative delta wave in lead II. These findings may be helpful for anticipating and planning an epicardial ablation strategy.
BACKGROUND: Ambulatory measurement for the QKD interval is a new method for evaluation of the rigidity of large arterial trunks. Reliable indices of arterial rigidity can be distilled from the large number of measurements (usually around 100) obtained during 24 h monitoring. OBJECTIVE: To describe a shorter standardized protocol (4 h) including a 15 min effort test on an ergometric bicycle designed to reduce examination time and generate a wider range of heart rates and blood pressures, to test the equivalence of this short protocol with 24 h monitoring and to test its reproducibility. DESIGN: The results of the short protocol were compared with 24 h monitoring results for 15 subjects. The reproducibility of the short protocol for 15 subjects examined twice within 7 days was studied. RESULTS: We found a good correlation between the values obtained with this method and those from 24 h recordings, with comparable reproducibilities in the determination of QKD for systolic blood pressure 100 mmHg and heart rate 60 beats/min. CONCLUSION: A short (4 h) standardized protocol including an exercise test could replace 24 h ambulatory monitoring to assess arterial distensibility through QKD measurement.
BACKGROUND: Despite verification of bidirectional conduction block after radiofrequency (RF) catheter ablation in the inferior vena cava (IVC)-tricuspid annulus (TA) isthmus, recurrence of common atrial flutter is relatively common. Although complete linear reablation is usually performed, we evaluated a simplified electrophysiological strategy selectively targeting recovered conducting isthmus tissue. METHODS AND RESULTS: Twenty-one patients (18 men and 3 women, age, 54+/-10 years) with a recurrence of typical atrial flutter 6+/-7 months after an apparently successful catheter ablation in the IVC-TA isthmus prospectively underwent electrophysiologically targeted reablation during flutter. Sites with narrow electrograms or fractionated electrograms interposed between adjacent sites with double potentials considered to represent gaps were ablated without movement of the catheter. Mapping showed that 18 of 21 patients had a single gap. Successful ablation required a single application in 14 patients and, in the group as a whole, a median of one application (mean, 2+/-2; range, 1 to 11) with resultant bidirectional block in 13 of 16. A single narrow electrogram (duration, 48+/-6 ms; amplitude, 0.1+/-0.05 mV) was noted at the successful site in 11, whereas a fractionated electrogram (97+/-32 ms, 0.05+/-0.04 mV, P<.05) was noted in 9. There were four additional recurrences during a follow-up at 7+/-5 months; three were similarly ablated with a median of one pulse. CONCLUSIONS: Transmural ablation lesions in the isthmus can be recognized during flutter by double potentials separated by an isoelectric interval. Postablation recurrent flutter is usually due to a single discrete recovered gap; this is represented by a single or a fractionated potential spanning the isoelectric interval of adjacent double potentials, which can be selectively targeted to minimize repeat ablation.
The peak incidence of cardiovascular complications in the morning points to a possible role of the abrupt increase in blood pressure on arising. However, there is as yet no firm evidence linking the extent of the elevation in blood pressure on arising and the risk of cardiovascular complications. We sought a correlation between blood pressure on arising and left ventricular mass in a population of 181 previously untreated hypertensive patients. Ambulatory blood pressure was measured over a 24-h period, and each patient was requested to trigger a blood pressure determination immediately after standing on arising in the morning. Left ventricular mass was measured with M-mode echocardiography and indexed for height, height(2.7), and body surface area. The systolic blood pressure on arising was significantly (P <.01) better correlated than office blood pressure with left ventricular mass index and wall thickness. On multivariate analysis, the values of systolic blood pressure on arising and mean 24-h systolic blood pressure contributed significantly and independently to the correlation with left ventricular mass and wall thickness. These observations point to the significance of the arising blood pressure. A marked abrupt daily elevation in blood pressure on arising, then maintained for a certain time, could contribute to the development of left ventricular hypertrophy and may constitute a trigger for cardiovascular complications.
Alteration in the physical properties of the large arteries is probably an important contributory factor in morbidity and mortality in the elderly as well as in patients with hypertension or diabetes. We have developed a simple method based on the ambulatory measurement of the timing of Korotkoff sounds (QKD interval), together with blood pressure, to assess these properties. We report its prognostic value in a retrospective survey of elderly hypertensives. We included in this study 134 hypertensive patients over 45 years of age with no cardiovascular complications, either receiving placebo or prior to treatment with antihypertensive medication and seen between January 1992 and July 1993. In June 1995, a survey was carried out to determine outcome by contacting the patients themselves and their family physicians. Data on outcome were obtained for 111 patients with a mean follow-up period of 30 +/- 8 months. At least one cardiovascular complication was recorded during the follow-up period in 14 patients. From the Cox model, data obtained from QKD monitoring, namely the QKD(100-60), was the best predictor of complications and remained significant (P < .01) even after introduction of age, mean 24 h SBP, gender, and smoking into the model. A QKD(100-60) below 187 msec was accompanied by a relative hazard of cardiovascular complications adjusted for age and mean 24 h BP of 7.3 (95% confidence interval: 2.9 to 11.7). The indices provided by the ambulatory measurement of QKD interval are significant predictors of cardiovascular complications independently of age and BP. This new method seems to add useful information to classic ambulatory blood pressure monitoring. However this will require confirmation in a large prospective study.
The relation between ambulatory blood pressure and left ventricular mass has been studied with three main aims. The first aim was to validate this new technique for measuring blood pressure. Most studies have shown that the left ventricular mass is correlated more closely to the ambulatory blood pressure than it is to the office blood pressure. The second aim was to define the parameters of most interest in ambulatory recordings. Although the mean 24 h blood pressure has emerged as the parameter of most clinical interest, other parameters, such as the blood pressure measured during activity, the difference between daytime and night-time values and the blood pressure measured when the subject arises in the morning, may also be of value. The interest of these parameters awaits confirmation in prospective studies. Random peak pressures and the variability as determined by discontinuous measurements using non-invasive methods appear to be of little value. The third aim was to assess the value of ambulatory monitoring in identifying the role played by mechanical as opposed to genetic, humoural and hormonal factors in the development of left ventricular hypertrophy in the hypertensive patient. Ambulatory blood pressure monitoring might prove of particular value in assessing the true impact of blood pressure reduction by antihypertensive therapy on left ventricular hypertrophy.