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Biomedical subjects

M V Orlov

Publications and source records attributed to M V Orlov.

At least 19 recordsLinked to original sources
PubMed1999

Transesophageal echocardiographic visualization of left ventricular malpositioned pacemaker electrodes: implications for lead extraction procedures.

Two cases of malpositioned LV electrodes are presented. Transesophageal echocardiography (TEE) allowed for a careful inspection of left-sided leads and for tracking their course. One LV and two right-sided leads were safely retrieved with TEE monitoring. One chronic LV lead was left in place as it was heavily fibrosed. TEE was helpful in the inspection and monitoring of the extraction and also in guided traction efforts. This is the first published report of echocardiographic visualization of the lead retrieval procedure.

Adult↗
PubMed1997

Near doubling of heart rate after intravenous verapamil for treatment of atrial fibrillation without preexcitation.

Initial treatment of atrial fibrillation often involves pharmacological therapy to control ventricular response. While verapamil is usually safe and effective when used for this purpose, we report a proarrhythmic response. In this report a 30-year-old female presented with palpitations associated with atrial fibrillation and a ventricular response of 145 beats/min. Soon after she was given 5 mg of intravenous verapamil her ECG documented a regular wide QRS tachycardia at 290 beats/min. After 7 seconds the rhythm returned to an irregularly irregular narrow QRS tachycardia at 125-150 beats/min. At a later electrophysiology study there was neither evidence of preexcitation nor inducible supraventricular or ventricular tachycardia. These data suggest that verapamil may have been associated with acceleration of the heart rate. The mechanism of proarrhythmia may be related to an alteration in the atrial rhythm from atrial fibrillation to atrial flutter, with additional factors as well.

Adult↗
PubMed1996

Clinical assessment of adrenergic tone and responsiveness to beta-blocker therapy in patients with symptomatic ventricular tachycardia and no apparent structural heart disease.

To further define the relation between changing adrenergic tone, beta-blocker therapy, and clinical ventricular tachycardia (VT), we evaluated these factors in 35 patients with VT unrelated to coronary artery disease or ventricular dysfunction. Testing included Holter monitoring (91% had VT), exercise test (69% had VT), Adrenergic responsiveness of VT was graded according to diurnal variation, response to exercise, isoproterenol infusion, and response to beta-blockers. beta-Blockers were effective and well tolerated in this population. There was also a predictable relation between changing adrenergic tone and the arrhythmia response to beta-blocker therapy.

Adolescent↗
PubMed1995

Is the time domain signal-averaged electrocardiogram helpful in patients with ventricular tachycardia without apparent structural heart disease?

The signal-average electrocardiogram (SAECG) has been a screening method for identifying patients at risk for ventricular tachycardia (VT) in the setting of coronary artery disease (CAD). Its significance in patients with VT unrelated to CAD or left ventricular dysfunction is undetermined. In order to define the value of SAECG in this patient population further, we compared the time domain SAECG at 25, 40, and 80 Hz filters in 35 patients with clinically symptomatic VT in the absence of structural heart disease was compared with 10 normal controls and 10 patients with CAD and inducible VT. SAECG data in patients without structural heart disease were intermediate between normal controls and patients with CAD. No single or combined SAECG criterion helped to differentiate between patients with inducible and noninducible VT. There was no concordance to other arrhythmia testing. It was concluded that signal-averaged electrocardiography may have little screening value in VT unrelated to CAD or left ventricular dysfunction.

Adult↗
PubMed1994

A review of magnesium, acute myocardial infarction and arrhythmia.

Many years ago, experimental medicine accumulated substantial evidence that magnesium (Mg) balance was important for a stable cardiovascular system. Recent clinical interest was aroused by evidence of decreased mortality in patients with acute myocardial infarction (AMI), treated with Mg infusions. Pharmacologic actions of Mg include its antiarrhythmic, antivasospastic and other important cardiovascular effects, substantiating the rationale for its use in AMI. Direct pharmacologic effect of this ion, rather than compensation of hypomagnesemia frequently encountered during acute ischemic injury, has been suggested to account for the above benefits. Several trials studied the efficacy of early Mg therapy in decreasing mortality from AMI while most of the data point to improved survival, a few trials could not demonstrate any benefit of Mg. The reported rate of complications with this therapy is low though the potential for serious side effects exists. Larger studies of Mg in AMI are expected to resolve the existing controversy.

Arrhythmias, Cardiac↗
PubMed1993

Spectrum of right heart involvement in patients with ventricular tachycardia unrelated to coronary artery disease or left ventricular dysfunction.

We studied 41 patients with clinically symptomatic ventricular tachycardia in the absence of coronary artery disease or left ventricular dysfunction to define the extent of right and left heart derangement and their relation to electrophysiologic and clinical data. Individual echocardiographic measurements as well as global assessment scores of the right and left heart demonstrated a wide spectrum of right heart echocardiographic abnormalities. There was much less variation in the left heart, with the majority of patients being close to normal. There was an association between the right heart score, the clinical presentation of arrhythmia, the response to programmed electrical stimulation, and the recurrence of arrhythmia (p < 0.05). Thus echocardiographic findings demonstrate the whole spectrum of right heart involvement in patients with apparent idiopathic ventricular tachycardia and can give insight into clinical history, arrhythmia inducibility, and prognosis.

Adolescent↗
PubMed1993

Determinants of inducible ventricular tachycardia in patients with clinical ventricular tachyarrhythmia and no apparent structural heart disease.

Thirty-seven patients with symptomatic ventricular tachyarrhythmia and no apparent structural heart disease were evaluated with multiple cardiovascular tests to establish the relationship between the results of programmed electric stimulation and other clinical and arrhythmia variables. Of 37 patients, 12 (32%) had inducible sustained ventricular tachycardia. Factors associated with the results of programmed electric stimulation included a history of ventricular tachycardia > or = 30 seconds requiring intervention for termination and global right heart abnormality documented by echocardiography. During treatment for a mean follow-up of 50 months, 29 patients did well, 6 patients had recurrences of major arrhythmia symptoms, 1 was lost to follow-up and 1 had a noncardiac death. Those patients with an adverse outcome were more likely to have inducible ventricular tachycardia. Thus certain clinical and echocardiographic data are associated with the results of programmed electric stimulation, which in turn have important prognostic value in this group of patients. Sustained ventricular tachycardia is unlikely to be induced in patients with no evidence of structural heart disease and clinical nonsustained ventricular tachycardia.

Adolescent↗
PubMed1992

Adjuvant metoprolol improves efficacy of class I antiarrhythmic drugs in patients with inducible sustained monomorphic ventricular tachycardia.

Inducible ventricular tachycardia frequently persists despite solitary class I antiarrhythmic drug therapy. To determine the effect of metoprolol as adjuvant therapy, 19 patients with clinical ventricular tachycardia with baseline inducible sustained monomorphic ventricular tachycardia and persistently inducible ventricular tachycardia despite class I drugs were evaluated. Eight of 19 patients (42%) became noninducible when metoprolol was added to class I drug therapy. Sixteen of 19 patients (84%) were harder to induce or noninducible on a regimen of adjuvant metoprolol therapy. In evaluating the clinical characteristics of the 19 patients, no significant differences were found between patients who were persistently inducible and those rendered noninducible. In evaluating the electrophysiologic characteristics, the group eventually rendered noninducible had a significantly shorter baseline induced cycle length (259 +/- 27 vs 305 +/- 53 msec). Combination class I drug and metoprolol therapy significantly lengthened the ventricular effective refractory period in both groups compared with baseline. The long-term follow-up was excellent in all patients remaining on metoprolol in the noninducible group. Therefore adjuvant metoprolol therapy creates a significant improvement in a number of patients with persistently inducible ventricular tachycardia despite class I drug therapy.

Adult↗
PubMed1989

[Complex ultrasonic examination in the diagnosis and evaluation of cardiac function in right-ventricular infarction].

Combined ultrasound investigation (two-dimensional, contrast, Doppler, Mechocardiography) was performed in 32 patients with acute myocardial infarction (AMI). Echo- and electrocardiographic evidence and clinical symptoms suggested AMI of both ventricles in 22 patients. Ten patients with AMI in the left ventricle only made up the control sample. Right cardiac compartments were probed to verify right-ventricular insufficiency. Right-ventricular involvement was confirmed by autopsy in 6 patients. Clinical signs of right-ventricular AMI were detected in 63.6% of second-group patients, and electrocardiographic signs of the same, in 54.6%. Asynergic areas were detected in right-ventricular wall of 90.5% of patients. In cases of right-ventricular AMI, right compartment section area was increased significantly, while right-ventricular evacuation fraction was as significantly reduced. Doppler echocardiography demonstrated a low right-ventricular rapid filling peak rate, as compared to the respective slow filling rate, an indirect indication of right-ventricular AMI. Combined ultrasound investigation is therefore an effective tool for the diagnosis of right-ventricular AMI and assessment of heart performance.

Adult↗
PubMed1988

[Changes in the indices of central hemodynamics and myocardial metabolism as affected by plasmapheresis in patients with myocardial infarct].

Gravitation plasmapheresis (PP) on PF-0.5 fractionator was used in 32 patients with acute myocardial infarction to control blood rheologic disorders. Central hemodynamics and myocardial metabolism were monitored by means of right heart probing and echocardiography. A control group of 7 patients were subjected to "mock PP" with a rheopolyglucin infusion. PP limited manifestations of heart failure, normalized the levels of compounds with high molecular weights which conditioned plasma viscosity, reduced significantly total peripheral and total pulmonary resistance, increased the cardiac index, stroke volume and ejection fraction, and improved regional left-ventricular contractility. Myocardial metabolic studies demonstrated a decline in left-ventricular myocardial ischemia, as evidenced by the arteriovenous difference in lactate levels. It is therefore suggested that PP can be effectively used as part of combined treatment for complicated acute myocardial infarction.

Aged↗
PubMed1986

[Contrast echocardiography using hydrogen peroxide].

The practicability of using hydrogen peroxide solutions for contrast echocardiography was examined. The administration of 1-3 ml of 0.2% solution mixed with a drop of the patient's blood, into the cubital or catheterized subclavian vein produced intensive and lasting (up to 2 min) contrast of the right cavities of the heart. Cubital injection of the solution was associated with a more lasting effect, as compared to the subclavian administration. The causes of this difference are yet to be investigated. The contrasting effect was fairly persistent and marked even when concentrations of the hydrogen peroxide solutions were reduced to 0.15 or 0.1%. The rate of administration was not more than 1 ml/s and had no negative effect on the quality of the contrast. No side effects associated with repeated administration of 1-3 ml hydrogen peroxide solution in the above-mentioned concentrations were noted in either of the 20 patients thus examined.

Contrast Media↗
PubMed1985

[Echocardiographic study of patients with alcoholic heart lesions].

The authors provide data obtained during echocardiographic examination of 16 patients with different patterns of alcoholic heart injury primarily at the early stages of alcoholism. The group of patients without heart rhythm abnormality showed a decrease in myocardial contractile function, moderate dilatation of the left ventricle and its hypertrophy. In patients with heart rhythm abnormalities, the progress of myocardial lesions, dilatation of the left ventricle, left atrium and right ventricle prevailed over hypertrophy of the left ventricle. Hypertrophy and dilatation of the left ventricle were most pronounced in patients with permanent atrial fibrillation. The disease was discovered to run its course in stages with gradual superimposition on left ventricle hypertrophy and dilatation followed by a decrease in myocardial contractile function.

Adult↗