Biomedical subjects

F I Parthenakis

Publications and source records attributed to F I Parthenakis.

26 records · Page 2Linked to original sources

PubMed1998

Intravenous propafenone versus intravenous amiodarone in the management of atrial fibrillation of recent onset: a placebo-controlled study.

UNLABELLED: The efficacy and safety of intravenous propafenone, amiodarone, or placebo were compared in the treatment of atrial fibrillation (AF) of recent onset (duration < or = 48 hours). METHODS: 143 patients (77 men, mean age 63 +/- 12 years) were studied, of whom 46 received propafenone (2 mg/kg over 15 minutes followed by 10 mg/kg over the next 24 hours), 48 received amiodarone (300 mg intravenously over 1 hour, followed by 20 mg/kg over the next 24 hours, plus 1,800 mg/day orally, in 3 divided doses), and 49 received placebo (the equivalent amount of saline i.v. over 24 hours). Digoxin was administered to all patients who had not previously received it. RESULTS: Conversion to normal sinus rhythm occurred in 36 of 46 patients (78.2%) receiving propafenone, in 40 of 48 patients (83.3%) receiving amiodarone, and in 27 of the 49 (55.10%) controls (P < 0.02, drug vs placebo, between drugs NS). The mean time to conversion was 2 +/- 3 hours for propafenone, 7 +/- 5 hours for amiodarone, and 13 +/- 9 for placebo (P < 0.05). Patients who converted had smaller atria than those who did not (diameter: 42.7 +/- 5 vs 47.2 +/- 7 mm, P < 0.001 for all). Treatment was discontinued in one patient in the amiodarone group because of an allergic reaction and in two patients in the propafenone group because of excessive QRS widening. No side effects were observed in the placebo group. CONCLUSIONS: Both drugs tested intravenously were equally effective and safe for the rapid conversion of recent-onset atrial fibrillation to sinus rhythm. However, propafenone offered the advantage of more rapid conversion than amiodarone.

Amiodarone↗

PubMed1997

Left ventricular diastolic filling changes during dipyridamole-induced ischaemia. An echo-Doppler study.

OBJECTIVE: To evaluate the usefulness of the Doppler assessment of left ventricular diastolic functioning during dipyridamole-induced ischaemia in patients with coronary artery disease (CAD). METHODS: We studied 28 patients with angiographically proven CAD [18 men, aged 62 +/- 7 years (mean +/- SD)] and 18 normal subjects (12 men, aged 59 +/- 7.5 years). Two-dimensional and transmitral flow Doppler echocardiography studies were performed at baseline and after intravenous administration of a high dose of dipyridamole (0.84 mg/kg during 10 min). Left ventricular wall motion was evaluated by two-dimensional Doppler echocardiography, with the left ventricle divided into a 16-segment model, whereas peak velocities of early and late diastolic flow, the early:late diastolic flow ratio and the deceleration rate of early diastolic flow were determined from transmitral flow Doppler echocardiography. RESULTS: Sixteen patients developed new wall-motion abnormalities (WMA), whereas the remaining 12 patients and the controls did not. Multivariate logistic regression analysis was performed to identify which of the parameters had independent diagnostic value for revealing CAD. WMA was entered at the first step and yielded a 57% sensitivity and 100% specificity; the changes in deceleration rate were entered as the second step, which improved the sensitivity to 85.5%, and reduced the specificity to 83% and raised the overall accuracy to 85% from 70% for WMA alone. More specifically, the sensitivity improved from 37.5, 63.5 and 65.5% to 62.5, 91 and 100%, respectively, for patients with one-, two- and three-vessel disease. The cut-off value of the change in deceleration rate was 7%. CONCLUSIONS: Patients could be classified as having CAD either if they developed new WMA or if the deceleration rate of early diastolic flow during dipyridamole-stress echocardiography increased by more than 7% compared with the rest value.

Case-Control Studies↗

PubMed1997

AAIR versus DDDR pacing in patients with impaired sinus node chronotropy: an echocardiographic and cardiopulmonary study.

The aim of this study was to compare AAIR and DDDR pacing at rest and during exercise. We studied 15 patients (10 men, age 65 +/- 6 years) who had been paced for at least 3 months with activity sensor rate modulated dual chamber pacemakers. All had sick sinus syndrome (SSS) with impaired sinus node chronotropy. The patients underwent a resting echocardiographic evaluation of systolic and diastolic LV function at 60 beats/min during AAIR and DDDR pacing with an AV delay, which ensured complete ventricular activation capture. Cardiac output (CO) was also measured during pacing at 100 beats/min in both pacing modes. Subsequently, the oxygen consumption (VO2AT) and VO2AT pulse at the anaerobic threshold were measured during exercise in AAIR mode and in DDDR mode with an AV delay of 120 ms. The indices of diastolic function showed no significant differences between the two pacing modes, except for patients with a stimulus-R interval > 220 ms, for whom the time velocity integral of LV filling and LV inflow time were significantly lower under AAI than under DDD pacing. At 60 beats/min, CO was higher under AAI than under DDD mode only when the stimulus-R interval was below 220 ms. For stimulus-R intervals longer than 220 ms, and also during pacing at 100 beats/min, the CO was higher in DDD mode. The stimulus-R interval decreased in all patients during exercise. The time to anaerobic threshold, VO2AT, and VO2AT pulse showed no significant differences between the two pacing modes. Our results indicate that, at rest, although AAIR pacing does not improve diastolic function in patients with SSS, it maintains a higher CO than does DDDR pacing in cases where the stimulus-R interval is not excessively prolonged. On exertion, the two pacing modes appear to be equally effective, at least in cases where the stimulus-R interval decreases in AAIR mode.

Aged↗

PubMed1997

Left atrial appendage function during DDD and VVI pacing.

OBJECTIVE: To examine, using transoesophageal echocardiography, the possible disturbances of left atrial appendage function during VVI and DDD pacing in patients with a normal atrium paced with a dual chamber system. DESIGN: Randomised controlled trial. SETTING: Tertiary care centre. PATIENTS: 22 patients (mean age 68 (SD 6) years) who had been paced with dual chamber pacemakers for at least six months. Exclusion criteria were valvar disease, cardiomyopathy, hypertension, and diabetes mellitus. INTERVENTIONS: All patients underwent a transoesophageal echocardiographic evaluation of left atrial appendage function under DDD and VVI modes in random order. Measurements were made after at least two months' pacing in each mode. MAIN OUTCOME MEASURES: Echocardiographic indices of left atrial appendage flow under both pacing modes. RESULTS: All 22 patients had higher emptying and filling flow velocities under DDD than under VVI mode. The filling and emptying flow velocity integrals were also significantly higher under DDD mode (P < 0.001, P = 0.019). CONCLUSIONS: Left atrial appendage function, as reflected in indices of emptying and filling assessed by transoesophageal echocardiography, is significantly different with DDD than with VVI pacing. This may explain the higher incidence of thromboembolic episodes in patients paced under VVI mode.

Aged↗

PubMed1996

QT interval in cardiac amyloidosis.

The aim of the study was to investigate whether cardiac amyloidosis is associated with QT interval abnormalities and ventricular arrhythmias. A controlled study of 30 patients was undertaken at a university cardiology department in a large referral hospital. Thirty patients (18 men, 12 women, mean age 56 +/- 12 years) with systemic amyloidosis verified by biopsy and strong indications of cardiac amyloidosis comprised the study group, with 30 healthy age- and sex-matched individuals serving as controls. Complete M-mode and two-dimensional echocardiographic study was undertaken and QT interval and QTc were calculated. All patients and controls underwent 24-h Holter monitoring for arrhythmias. Left ventricular (LV) wall thickening was found in all patients with cardiac amyloidosis. The LV mass in the patients with cardiac amyloidosis was significantly greater than that of the control group, as was the ratio LV mass/body surface area (p < 0.001). There was no significant difference in the max QT interval or in QTc dispersion between the two groups, although the max QTc was greater in the patients with cardiac amyloidosis. Patients with cardiac amyloidosis did not have a higher incidence of arrhythmias than the controls. Although patients with thickened cardiac walls due to cardiac amyloidosis have a prolonged QTc in comparison with controls, they do not show an increase in interlead QTc dispersion which might suggest the possibility of regional disturbances of the uniformity of repolarization. Patients with cardiac amyloidosis do not have a higher incidence of arrhythmias than controls.

Adult↗

PubMed1996

Is there increased sympathetic activity in patients with mitral valve prolapse?

The aim of this study was to investigate autonomic nervous system tone in patients with mitral valve prolapse (MVP). Heart rate variability (HRV) was assessed from 24-hour ambulatory Holter recordings in 28 patients with primary MVP and in 28 age and sex matched normal control subjects in a drug-free state. Sixteen of the MVP patients were symptomatic and 12 asymptomatic. Spectral HRV was calculated in terms of low (LF: 0.06-0.15 Hz) and high (HF: 0.15-0.40 Hz) frequency components using fast Fourier transform analysis, and the ratio LF/HF was calculated. Spectral analysis of HRV showed that the MVP patients, taken as a single group, had lower HF and LF and a higher LF/HF ratio than the controls. No significant difference in HRV was found between the 16 symptomatic and the 12 asymptomatic patients, but the symptomatic patients had a significantly higher LF/HF ratio than the controls. Our observations suggest that, during normal daily activities, patients with MVP experience a significant deviation in autonomic nervous system tone with predominance of the sympathetic branch. This predominance is more marked in symptomatic patients.

Activities of Daily Living↗

PubMed1994

Study of late potentials and ventricular arrhythmias in hypertensive patients with normal electrocardiograms.

INTRODUCTION: Although an increase in the occurrence of ventricular arrhythmias has been observed in hypertensive patients, some basic questions remain unresolved regarding the prevalence and the pathophysiology of these arrhythmias. The basic aims of this study were as follows: (1) to examine the incidence and severity of ventricular arrhythmias in a substantial number of hypertensive patients without electrocardiographic indications of hypertrophy; and (2) to examine the correlation between late potentials, hypertrophy, and ventricular arrhythmias in these patients. MATERIALS AND METHODS: We studied 78 consecutive patients (31 men, 47 women), aged 60.5 +/- 7.8 years, with a history of hypertension but a normal electrocardiogram. All patients had an echocardiographic study, 24-hour ambulatory monitoring, exercise test, and signal-averaged electrocardiogram. The latter was analyzed using a 40- to 250-Hz filter and with a noise level < or = 0.3 microV. RESULTS: Of the 78 patients studied, 21 (26.9%) had severe ventricular arrhythmias, while 57 (73.1%) had either no ventricular ectopics or sporadic isolated ventricular extrasystoles. Left ventricular hypertrophy, defined by echocardiography, was found in 58 patients (74.3%), of which 16 (27.58%) had severe ventricular arrhythmias. Five (25%) of the 20 patients without hypertrophy also had severe ventricular arrhythmias (P = NS). Ventricular late potentials were recorded in 19 (24.5%) of the 78 patients. Of these, 11 (57.89%) had severe arrhythmias, while of the 59 patients without late potentials 10 (16.94%) had severe ventricular ectopic activity. CONCLUSIONS: In hypertensive patients without electrocardiographic signs of hypertrophy, the higher prevalence of ventricular arrhythmias does not appear to be related to left ventricular hypertrophy but is correlated with the existence of ventricular late potentials.

Action Potentials↗

PubMedDate not supplied

Segmental pattern of myocardial sympathetic denervation in idiopathic dilated cardiomyopathy: relationship to regional wall motion and myocardial perfusion abnormalities.

BACKGROUND: Iodine 123-labeled metaiodobenzylguanidine (MIBG) has been used to study cardiac adrenergic nerve activity. Cardiac MIBG uptake is diminished in patients with heart failure. However, it is not known how this reduction is related to regional abnormalities of myocardial wall motion or perfusion. METHODS AND RESULTS: We studied 24 patients with idiopathic dilated cardiomyopathy (ejection fraction <45%) and 15 healthy control subjects using I-123 MIBG cardiac imaging, echocardiographic assessment of wall motion abnormalities, technetium 99m sestamibi perfusion scintigraphy, and hemodynamic assessment. Cardiac MIBG was significantly correlated with ejection fraction (r = 0.67), cardiac index (r = 0.57), left ventricular wall motion score index (r = -0.68), and systolic wall stress (r = -0.61). MIBG was lower in patients than in control subjects (1.43 +/- 0.19 vs 2.05 +/- 0.02; P <.01), whereas the washout rate was higher (P <.01). Moreover, a significant correlation was found between the reduction in MIBG uptake and the severity of echocardiographic wall motion abnormalities in the anterior wall (r = 0.543), apex (r = 0.530), and septum (r = 0.675), as well as with the severity of decrease in resting myocardial perfusion in the anterior wall (r = 0.480) and septum (r = 0.580). CONCLUSIONS: Patients with idiopathic dilated cardiomyopathy show not only global but also regional abnormalities of cardiac sympathetic innervation. The severity of these changes is partially correlated with abnormalities of regional wall motion and myocardial perfusion.

3-Iodobenzylguanidine↗