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Biomedical subjects

George E Kochiadakis

Publications and source records attributed to George E Kochiadakis.

At least 19 recordsLinked to original sources
PubMed2006

Reduced systemic inflammatory response to implantation of sirolimus-eluting stents in patients with stable coronary artery disease.

Stent implantation causes significant injury to the vascular wall, resulting in inflammatory activation. Although sirolimus-eluting stents (SES) have anti-inflammatory properties, their effect on periprocedural systemic inflammatory response has not been sufficiently investigated. Eighty-one patients with stable coronary artery disease involving severe stenosis of one major epicardial coronary artery underwent coronary angioplasty with stent implantation and randomly received either SES or bare metal stents (BMS). Blood samples were taken 24h before, at 24h, 48 h and 1 month after the angioplasty and levels of high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), interleukin-1 beta (IL-1 beta), and monocyte chemoattractant protein-1 (MCP-1) were determined. HsCRP after BMS implantation increased over 24h (p<0.001) and then remained steady, as did IL-6 and IL-1 beta similarly. In contrast, their levels in SES patients decreased to below baseline by the end of the month. MCP-1 levels increased by the end of 1 month (p<0.001) in the BMS group, whereas in SES they steadily decreased, becoming significantly lower than baseline from 48 h (p=0.015). In conclusion, patients with SES exhibit an attenuation of the postprocedural systemic inflammatory activation during a 1-month follow-up after stent implantation. This might partially explain the reduced restenosis rate associated with SES.

Aged↗
PubMed2006

Effect of inhaled salbutamol on coronary circulation in humans.

In 12 patients we assessed the effect of inhaled salbutamol on the coronary circulation. According to our results, large doses of salbutamol increase coronary flow, but not in proportion to the needs of the myocardium (as documented by the increase in coronary oxygen extraction), and decrease coronary flow reserve. These effects may have deleterious consequences in patients with coronary artery disease, causing or worsening myocardial ischemia.

Administration, Inhalation↗
PubMed2005

Peripheral arterial embolism due to a left ventricular diverticulum in a young adult.

A 32-year-old man was admitted to the emergency department of our hospital after experiencing a peripheral arterial embolism. Investigation of the possible embolic sources in an otherwise asymptomatic patient revealed the existence of a left ventricular diverticulum. The left ventricular diverticulum is a rare congenital anomaly, either isolated or as a part of a syndrome including other congenital malformations. The treatment of choice, especially in symptomatic patients, is surgical resection, while in asymptomatic patients anticoagulation therapy is indicated.

Adult↗
PubMed2004

Left ventricular mechanics during right ventricular apical or left ventricular-based pacing in patients with chronic atrial fibrillation after atrioventricular junction ablation.

OBJECTIVES: The aim of the study was to evaluate whether left ventricular (LV) mechanics are better under LV-based pacing than under right ventricular (RV) apical pacing in patients with permanent atrial fibrillation (AF) after atrioventricular junction (AVJ) ablation. BACKGROUND: "Ablate and pace" is an acceptable therapy for drug-refractory AF. However, the RV apical stimulation commonly used seems to interfere with the beneficial hemodynamic effect of regularization of heart rhythm. METHODS: The study included 12 patients (5 men, mean age 62 +/- 8.3 years), 6 with impaired and 6 with normal LV systolic function. All of them had a biventricular pacemaker system implanted and underwent atrioventricular node ablation for drug-refractory chronic AF. Using a conductance catheter, we analyzed LV pressure-volume loops during routine coronary angiography in order to evaluate short-term changes in LV mechanics during RV apical and LV-based (LV free wall or biventricular) pacing. RESULTS: Compared with RV pacing, LV-based pacing significantly improved the indexes of LV systolic function (i.e., end-systolic pressure and volume, cardiac index, stroke work, preload recruitable stroke work, maximal rate of rise of LV pressure [dP/dt(max)], LV ejection fraction, and end-systolic elastance). The LV diastolic filling indexes, end-diastolic pressure and volume, were better during LV-based pacing, whereas LV diastolic function indexes, -dP/dt(max), passive diastolic chamber stiffness, and time constant of LV isovolumic relaxation showed no clear change. CONCLUSIONS: In the short term, LV-based pacing is superior to RV apical pacing in terms of contractile function and LV filling after AVJ ablation for drug-refractory AF.

Atrial Fibrillation↗
PubMed2004

Autonomic nervous system changes in vasovagal syncope: is there any difference between young and older patients?

Spectral analysis of heart rate variability was used to compare the changes in autonomic function during tilting in young and older patients with vasovagal syncope. Twenty-four young (age 28 +/- 8 years) and 31 older (56 +/- 5 years) patients with unexplained syncope and a positive tilt test and 25 controls (age 48 +/- 12 years) were included in the study. Frequency-domain measurements of the low (LF) (0.06-0.15 Hz) and high (HF) (0.15-0.40 Hz) frequency bands and the ratio of LF to HF were computed from Holter recordings for 4-minute intervals before and immediately after tilting and just before the end in all groups. Syncopal patients showed a different pattern of response to tilting from controls in all spectral indexes. Young and older patients showed the same pattern of changes in all measurements, even though certain differences were observed. The LF after tilting reduced more in the older (-20 +/- 7% vs -14 +/- 5%, P < 0.001), while HF reduced more in young patients (-17 +/- 8% vs -8 +/- 3%, P < 0.001). Young patients showed mainly a cardioinhibitory type (71%) of response whereas a vasodepressor type response predominated (68%) in the older patients. The autonomic nervous system appears to play an important role in the pathophysiological mechanism of vasovagal syncope. This role is similar in young and in older patients and this should be taken into account in the therapeutic approach to the condition. Specific differences between age groups may be related to the type of vasovagal syncope.

Adult↗
PubMed2004

Long-term maintenance of normal sinus rhythm in patients with current symptomatic atrial fibrillation: amiodarone vs propafenone, both in low doses.

STUDY OBJECTIVES: To compare the efficacy and safety of amiodarone and propafenone when used for the prevention of atrial fibrillation (AF) and maintenance of normal sinus rhythm in patients with refractory AF. DESIGN: Prospective, randomized, single-blind trial. SETTING: Tertiary cardiac referral center. PATIENTS: One hundred forty-six consecutive patients (72 men; mean age, 63 +/- 10 years [+/- SD]) with recurrent symptomatic AF. INTERVENTIONS: We studied 146 patients after restoration of sinus rhythm; patients were randomized to amiodarone, 200 mg/d, or propafenone, 450 mg/d. Follow-up clinical evaluations were conducted at the first, second, fourth, and sixth months, and at 3-month intervals thereafter. The proportion of patients relapsing to AF and/or experiencing side effects was calculated for each group using the Kaplan-Meier method. End point of the study was recurrence of AF or occurrence of side effects necessitating discontinuation of medication. MEASUREMENTS AND RESULTS: Of 146 patients, 72 received amiodarone and 74 received propafenone. The two groups were clinically similar. Of the 72 patients receiving amiodarone, AF developed in 25 patients, after an average of 9.8 months, compared to 33 of the 74 patients receiving propafenone after an average of 3.8 months. Twelve patients receiving amiodarone and 2 patients receiving propafenone had side effects necessitating withdrawal of medication while still in sinus rhythm. CONCLUSIONS: Amiodarone tends to be more effective than propafenone in maintaining sinus rhythm in patients with AF, but this advantage is offset by a higher incidence of side effects.

Aged↗
PubMed2003

Peripheral monocytes from diabetic patients with coronary artery disease display increased bFGF and VEGF mRNA expression.

BACKGROUND: Macrophages can produce vascular endothelial growth factor (VEGF) in response to hypoxia, transforming growth factor beta1 (TGF-beta1), angiotensin II, basic fibroblast growth factor (bFGF), and interleukin-1. These factors have been found in the serum of coronary artery disease (CAD) patients as well as in atherosclerotic lesions. The aim of the present study was to test the hypothesis that the expression of VEGF, TGF-beta1 and bFGF in peripheral monocytes and lymphocytes is related to CAD. METHODS: Human Mononuclear cells and lymphocytes from peripheral blood were isolated from 53 donors undergoing angiography. Seventeen were found to be healthy and 36 were diagnosed with CAD. The respective mRNAs were extracted and quantified. RESULTS: The statistical analysis revealed a significant increase of the basal level expression for macrophage VEGF and bFGF in the CAD SA (stable angina) patient group compared to the noCAD (control) (p = 0.041 and p = 0.022 respectively) and CAD UA (unstable angina) (p = 0.024 and p = 0.005 respectively) groups, which was highly dependent on the diabetic status of the population. Furthermore, we demonstrated with an in vitro cell culture model that the levels of VEGF and bFGF in monocytes of healthy donors are not affected by short term exposure to increased glucose levels (usually observed in the diabetic patients) and/or statin. CONCLUSION: Our findings display a statistically significant association of the increased VEGF and bFGF levels in peripheral monocytes, with stable angina and diabetes in coronary artery disease. The results give new insight to CAD and the impaired collateral vessel formation in diabetics.

Journal Article↗
PubMed2003

Phasic coronary blood flow velocity pattern and flow reserve in the atrium: regulation of left atrial myocardial perfusion.

OBJECTIVES: The purpose of this study was to assess rest and stress atrial coronary blood flow (CBF) velocity and flow reserve. BACKGROUND: Because of the limitations of the methods used until now for assessing myocardial perfusion (MP) in the small mass of atrial tissue, data are lacking for human atrial MP. METHODS: Seventeen patients with suitable coronary anatomy underwent CBF velocity measurements with the use of a Doppler guide wire in the proximal left circumflex coronary artery (LCx) and left atrial circumflex branch (LACB), at baseline and after adenosine administration. All measurements were performed at resting heart rate and at 100 and 120 beats/min. RESULTS: Coronary blood flow velocity in the LACB showed a predominant systolic pattern in contrast to the diastolic pattern of the LCx. There was a disproportionate increase in baseline time-averaged peak coronary flow velocity (cm/s) between the LACB and LCx during the two levels of pacing-induced stress (16.8 +/- 5.5 vs. 16.2 +/- 5.1 at rest; 22.9 +/- 7.9 vs. 18.4 +/- 5.2 at 100 beats/min; and 27.1 +/- 8.0 vs. 20.4 +/- 5.1 at 120 beats/min; significant interaction, p < 0.001), but there were no significant differences in coronary flow reserve (CFR). CONCLUSIONS: Coronary blood flow in the left atrium is out of phase with that in the ventricular myocardium, showing a predominant systolic pattern. Although atrial and ventricular CFR show no significant differences at rest and with two levels of stress, the disproportionate increase in atrial blood flow velocity during stress indicates a peculiarity of atrial perfusion regulation.

Aged↗
PubMed2003

Pharmacological cardioversion of recent onset atrial fibrillation with intravenous amiodarone in patients receiving long-term amiodarone therapy: is it reasonable?

In clinical practice the use of intravenous amiodarone has been proposed for the conversion of recurrent atrial fibrillation in patients already under chronic treatment with the same drug. Given that intravenous amiodarone exhibits different electrophysiological properties than when the drug is taken orally over a long period, this approach seems reasonable, but its effectiveness and safety have not been investigated systematically before. Of 45 patients under chronic treatment with amiodarone for the maintenance of sinus rhythm who had atrial fibrillation of recent onset, 23 were given intravenous loading of the same drug for 24 hours and 22 received placebo. Nine patients underwent an electrophysiological study several months after the successful restoration of sinus rhythm, before and after another intravenous loading dose of amiodarone, in order to examine the possible electrophysiological changes. In the amiodarone group 20 patients were successfully converted to sinus rhythm, compared to 13 of the placebo group (p < 0.05). No serious side effects of the intravenous administration were observed. Prolongation of refractoriness was seen in all 9 patients who underwent electrophysiological study after intravenous loading, without any effect on repolarization, atrioventricular conduction or sinus node function. In conclusion an intravenous loading dose of amiodarone exerts an additional electrophysiological effect in patients already under chronic treatment with the same drug. Such a combined therapy could be used with a high efficacy and safety for the conversion of recent onset atrial fibrillation in patients who are receiving long-term amiodarone therapy.

Aged↗
PubMed2003

Amiodarone for the restoration of sinus rhythm in patients with atrial fibrillation.

Although the use of amiodarone for the treatment of atrial fibrillation has increased, reports of its use for the restoration of sinus rhythm have been conflicting. In a recent prospective, randomized, single-blind, placebo controlled study, we examined the efficacy and safety of amiodarone as initial treatment to restore sinus rhythm in patients with atrial fibrillation of varying duration. We studied 335 patients (169 men, 166 women), aged 27-78 years (mean age 65 +/- 10 years), with symptomatic atrial fibrillation, who presented to the emergency room or to our clinic. Patients randomized to amiodarone ( n = 173) received 300 mg intravenously over 1 hour followed by 20 mg/kg over 24 hours. Oral administration was initiated simultaneously at 600 mg/day in 3 divided doses for one week followed by 400 mg/day, in two doses, for three weeks. Amiodarone was almost twice as likely as placebo to restore sinus rhythm (85% vs. 43%, p < 0.0001). Larger left atrial size and longer duration of atrial fibrillation decreased amiodarone's effectiveness. These factors were also associated with longer duration of treatment before conversion to sinus rhythm. We observed relatively few and only minor complications despite relatively high doses of amiodarone administered to achieve high serum concentrations. In conclusion, our findings indicate that amiodarone is an effective and safe antiarrhythmic drug even when administered in large doses. It may be used for the restoration of sinus rhythm when rapid cardioversion is not needed.

Amiodarone↗
PubMed2003

Left ventricular mechanics and myocardial blood flow following restoration of normal activation sequence in paced patients with long-term right ventricular apical stimulation.

STUDY OBJECTIVES: Asynchronous ventricular activation, as induced by ventricular pacing, is known to affect left ventricular (LV) systolic and diastolic function and myocardial blood flow. However, it is not clear whether the long-term disturbances it causes are reversible after the restoration of the normal ventricular activation sequence. DESIGN: In this study, we used the conductance catheter method and a Doppler guidewire to assess the changes in LV mechanics, and correspondingly in myocardial blood flow, after the restoration of the normal ventricular activation sequence in patients with long-term right ventricular apical pacing. PATIENTS: Sixteen patients (mean [+/- SD] age, 61 +/- 11 years; 9 men) with right ventricular apical stimulation and complete ventricular pacing capture for a very long period were studied. In eight patients, we analyzed pressure-volume loops before and immediately after the restoration of the normal ventricular activation sequence, and in the remaining eight patients the myocardial blood flow and flow reserve were analyzed. MEASUREMENTS AND RESULTS: End-systolic elastance (Ees) [5.503 +/- 0.6 vs 4.287 +/- 0.28 mm Hg/mL, respectively; p = 0.003] and its ratio to effective arterial elastance (1.63 +/- 0.51 vs 2.00 +/- 0.64, respectively; p = 0.009), which are indexes of systolic function and ventriculoarterial coupling, respectively, improved significantly after restoration of the normal ventricular activation sequence. Indexes of diastolic function and the predicted myocardial oxygen consumption (MO(2)) showed no clear change. Coronary flow in the dominant coronary artery increased significantly (46.55 +/- 14.12 vs 71.55 +/- 27.53 mL/min, respectively; p = 0.002), while the coronary flow reserve in the same artery decreased (3.5 +/- 1.0 vs 2.6 +/- 0.5, respectively; p = 0.008). CONCLUSIONS: The restoration of a normal activation sequence after long-term ventricular asynchrony enhances acutely contractile function without affecting MO(2). These changes in LV function do not appear to have causal relationships with myocardial blood flow changes.

Cardiac Pacing, Artificial↗
PubMed2002

Transcatheter thrombolysis with high-dose bolus tissue plasminogen activator in iatrogenic arterial occlusion after femoral arterial catheterization.

PURPOSE: To assess the efficacy of percutaneous local thrombolysis with high-dose bolus recombinant tissue plasminogen activator (rt-PA) in patients with acute limb ischemia due to arterial thrombosis after cardiac catheterization. METHODS: We treated eight patients (7 men; mean age 56 years) with thrombotic occlusion of both the common femoral artery (CFA) and external iliac artery (EIA) in six patients and of the CFA only in two patients. Two 5 mg boluses of rt-PA were injected into the proximal clot through a 5 Fr end-hole catheter and subsequently two additional boluses of 5 mg rt-PA were given through a catheter with multiple side-holes. In case of a significant amount of residual thrombus, a continuous infusion of 2.5 mg/hr of rt-PA was started. RESULTS: Successful lysis was achieved in all patients. The mean duration of lysis was 2 hr 41 min. The mean total amount of rt-PA delivered was 23.16 mg. In four patients unmasked flow-limited dissections confined to the CFA were managed by prolonged balloon dilatation, while in the remaining four patients with extension of the dissection to the external iliac artery one or two Easy Wallstents were implanted. There was prompt relief of lower limb ischemic symptoms and signs in all patients. Two groin hematomas were conservatively treated. Clinical and color Doppler flow imaging follow-up with a mean duration of 15 months, showed no reappearance of ischemic symptoms or development of restenosis in any of the patients. One patient died 6 months after thrombolysis. CONCLUSIONS: Transcatheter thrombolysis with high-dose bolus rt-PA is a safe and effective treatment in patients with iatrogenic arterial occlusion after femoral catheterization. Underlying dissections should be treated by prolonged balloon dilatation but stent implantation is often required.

Angiography↗
PubMed2002

Electrocardiographic appearance of old myocardial infarction in paced patients.

This study evaluated the possibility of diagnosing chronic myocardial infarction in the presence of the pacing electrocardiogram. Forty-five patients with known myocardial infarction (anterior 23, inferior 22) and 26 healthy controls were studied. After coronary angiography, pacing was applied from the right ventricular apex, and the sensitivity, specificity, and average diagnostic accuracy of five criteria on the paced electrocardiogram were assessed: (1) Notching 0.04 second in duration in the ascending limb of the S wave of leads V3, V4, or V5 (Cabrera's sign); (2) Notching of the upstroke of the R wave in leads I, aVL, or V6 (Chapman's sign); (3) Q waves > 0.03 second in duration in leads I, aVL, or V6; (4) Notching of the first 0.04 second of the QRS complex in leads II, III, and aVF; (5) Q wave > 0.03 second in duration in leads II, III, and aVF. The most sensitive criteria, for anterior and inferior myocardial infarctions were Cabrera's and Chapman's (91.1 and 86.6%, respectively). All criteria had low specificity (range 42.3-69.2%). The combination of Cabrera's and Chapman's sign decreased the sensitivity to 77.7%, but increased specificity to 82.2%. The sensitivity and specificity of all the criteria were independent of the myocardial infarction site. In paced patients, the application of electrocardiographic criteria, and especially the combination of Cabrera and Chapman, provides useful clinical information in recognizing prior myocardial infarction but not in assigning the specific infarct site.

Cardiac Pacing, Artificial↗
PubMed2002

Anomalous collateral from the coronary artery to the affected lung in a case of congenital absence of the left pulmonary artery: effect on coronary circulation.

A case of congenital absence of the left pulmonary artery, in which perfusion of the affected lung was accomplished via an arterial shunt from the circumflex coronary artery, is discussed. Data from myocardial perfusion scintigraphy showed that myocardial perfusion was unaffected by the existence of the shunt, largely because the flow through the shunt occurred mainly during systole.

Abnormalities, Multiple↗
PubMedDate not supplied

Acute myocardial infarction in a patient with normal coronary arteries after an allergic reaction.

The case is described of a man aged 51 years who, one hour after a coronary angiographic examination that showed coronary arteries without lesions, suffered an acute inferior myocardial infarction as the result of an acute allergic reaction, probably to the iodinated contrast agent that was used. Acute myocardial infarction following an allergy is an extremely rare clinical entity that, according to existing data, is due to the local release of vasoconstrictive substances as a result of the allergic reaction.

Angina Pectoris↗
PubMedDate not supplied

Successful thrombus removal during angioplasty in a patient with acute myocardial infarction using a new aspiration catheter.

We describe the case of a male patient, aged 62 years, with acute myocardial infarction, who underwent primary angioplasty using a new thrombus aspiration catheter in conjunction with the conventional technique. This catheter is easier to use than similar devices available to date and is extremely effective in the removal of large intracoronary thrombi, thus providing protection against distal embolism during angioplasty procedures.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Efficacy and safety of oral amiodarone in controlling heart rate in patients with persistent atrial fibrillation who have undergone digitalisation.

INTRODUCTION: Oral amiodarone has been suggested by some authors for rate control in patients with persistent atrial fibrillation. In this study we evaluated the efficacy and safety of oral amiodarone versus placebo for rate control during exercise and daily activities in patients with chronic atrial fibrillation who had undergone digitalisation. METHODS: The study group consisted of 53 patients (35 men, mean age 65 +/- 9 years) with persistent atrial fibrillation (mean duration 17 +/- 7 months). All patients had therapeutic levels of digitalis and were under anticoagulation treatment with acenocoumarol. Twenty-eight of them were treated with amiodarone (200 mg per day orally) and 25 received placebo. All patients were assessed with 24-hour ECG monitoring, a maximal symptom-limited cardiopulmonary exercise test and evaluation of adverse events. RESULTS: The mean exercise duration was similar in both groups. Amiodarone produced a lower heart rate than placebo at all exercise levels (p<0.0001 for all). VO2 was similar in both groups whereas O2 pulse was higher in the amiodarone group at all exercise levels. During daily life, heart rate showed a significant circadian pattern in both groups, with higher values during the day than at night (time effect for both p<0.001). The mean value of heart rate under amiodarone was lower than for placebo (75 +/- 10 vs. 86 +/- 12/min, p<0.001) but this difference was due to a significant difference during the day (p<0.001) that was not present during the night (p =0.48). CONCLUSIONS: Oral amiodarone is very effective when combined with digoxin for control of heart rate in patients with chronic atrial fibrillation and it should be considered as an alternative treatment when more traditional drugs, such as Ca(+2) inhibitors or b-blockers have proven ineffective or are contraindicated.

Aged↗