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Biomedical subjects

M Knippel

Publications and source records attributed to M Knippel.

At least 19 recordsLinked to original sources
PubMed1990

DDI pacing in the bradycardia-tachycardia syndrome.

The bradycardia-tachycardia syndrome is a subgroup within the larger category of sinus node dysfunction. Pacing is often required to treat either the protracted asystolic spells following the spontaneous termination of a paroxysmal supraventricular tachyarrhythmia or to protect the patient from pharmacologically exacerbated bradycardias. While the optimal pacing mode for this subset of patients remains debatable, recent reports have favored the use of atrial ventricular sequential pacing with intact atrial sensing (DDI). This paper reports our experience with a series of 30 consecutive patients in whom the DDI mode was utilized as part of the management of this syndrome. DDI pacing has been demonstrated to be safe, extremely effective, and easy to use in this group of patients.

Aged↗
PubMed1988

[Echography in aneurysm of the interatrial septum].

Atrial septal aneurysm can be detected by subcostal echocardiography as a bulge of the intermediate interatrial septum, ballooning toward the right atrium. We retrospectively revised 5412 echo examinations, consecutively performed in our laboratory, and we found 14 cases of atrial septal aneurysm (0.26%), mean age 36 +/- 15 years, 9 males and 5 females. In 7 patients atrial septal aneurysm was wide, including the whole atrial septum; in 5, only cranial two-thirds of the septum were involved and in 2, it regarded only the intermediate septum. No patients referred to arrhythmias, syncope, embolism, endocarditis or transient ischemic neurologic disorders. Cardiac abnormalities or defects were associated to atrial septal aneurysm in 12/14 patients: they consisted of atrial septal defect, mitral valve prolapse, false ventricular tendons or persistent Chiari network. Atrial left-to-right shunt was detected in all 6 cases with atrial communication. Considering each single associated cardiac abnormality, the prevalence of atrial septal aneurysm was 7% in patients with atrial septal defect, 1.7% in those with mitral valve prolapse, 6.6% in persistent Chiari network and 0.9% in false ventricular tendons. In conclusion, echocardiography is the first-choice technique to detect atrial septal aneurysm and other related cardiac defects.

Adolescent↗
PubMed1987

Echocardiographic evaluation of right heart responses to sublingual nifedipine in dilated cardiomyopathy.

Twelve patients with dilated cardiomyopathy were studied in order to evaluate whether the favourable effect of Nifedipine on the right heart is due to a direct action of the drug on pulmonary resistances or is related to an improvement of left ventricular function. Echocardiographic examination of left and right heart was performed at basic conditions, after Nifedipine treatment--20 mg sublingually--and after 20 minutes of oxygen breathing (FiO2 75%). This was done in order to verify if oxygen vasodilating action could potentiate the Nifedipine effect. Echocardiographic date were obtained in basic conditions, 10, 20 and 30 minutes after Nifedipine and immediately after oxygen breathing. Ten normal subjects were used for comparison for basic data. Peak Nifedipine activity was observed 10 minutes after administration. At this time inferior vena cava emptying index and systolic pulsation were significantly increased, whereas left and right ventricle isometric contraction time, left and right ventricle ejection time, left and right ventricle isovolumetric relaxation time, end-diastolic left ventricular diameter, inferior vena cava diameters and systolic blood pressure had decreased, thus showing the favourable effect of Nifedipine of both heart sides. Heart rate did not significantly change. Oxygen inhalation induced a significant decrease of right ventricular isovolumetric relaxation and an increase of the inferior vena cava indexes, suggesting an improvement in right heart function, without any change in other parameters. No significant difference was found between data after-oxygen and data obtained 10' after Nifedipine, showing that the Nifedipine effect was not potentiated by oxygen.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Sublingual↗
PubMed1986

Echocardiographic evaluation of inferior vena cava wall motion and pulmonary flow velocity responses to sublingual nifedipine.

Echocardiographic and cardiac catheterization were used to test the effect of Nifedipine, sublingually administered, on the right heart function and pulmonary flow velocity and pressure in 25 cases. Systolic and mean pulmonary pressure, wedge pressure, mean right atrial and ventricular end-diastolic pressure, aortic pressure, and total pulmonary resistance decreased after Nifedipine in 10 patients who underwent diagnostic cardiac catheterization. While pulmonary flow velocity, expressed as the slope of the contrast echo lines on the pulmonary valve, increased as a mean value after Nifedipine, it showed different behaviour in single cases and thus failed to provide any reliable conclusion as to the effect of Nifedipine. Nifedipine slightly reduced the internal diameters of the inferior vena cava and significantly increased the values of collapsibility and emptying indexes and pulsation. The results confirm the beneficial effect of Nifedipine on right heart function and pulmonary bed. In addition, echocardiography is seen to be a valuable and reliable non-invasive means of testing the acute and chronic effects of either Nifedipine or other drugs on the right heart sections.

Adult↗
PubMed1982

Detection of atrial septal defect with left-to-right shunt by inferior vena cava contrast echocardiography.

Contrast echocardiography was used before cardiac catheterisation in 37 patients with atrial septal defect and a left-to-right shunt and in 18 patients with a raised right atrial and ventricular pressure to assess the contrast echo effect in the inferior vena cava. Using two dimensional contrast apical echocardiography we found a negative contrast echo effect within the right atrium in many but not all patients with atrial defect. Contrast echoes entering the inferior vena cava during presystole or early to mid-diastole were detected in patients with heart disease causing raised right atrial and ventricular pressures and also in all patients with atrial septal defect. No contrast echo effect in the inferior vena cava was detected in 10 normal subjects. The sensitivity of this contrast pattern in the inferior vena cava in diagnosing atrial septal defect was 100%. When other conditions causing raised right atrial pressure were excluded, the specificity and predictive accuracy were 100% for both. The presystolic contrast echo effect in the inferior vena cava, semiquantitatively graded, correlated with the size of the shunt determined by oximetry. In 20 patients re-examined after the surgical correction of the atrial septal defect, no presystolic contrast echo effect was detected in the inferior vena cava. Contrast echocardiography of the inferior vena cava is a valuable and reliable method for diagnosing atrial septal defect with left-to-right shunt.

Adolescent↗
PubMed1982

An unusual case of congenital double coronary arteriovenous fistula.

A double coronary arteriovenous fistula (CAVF) was observed in a ten-year-old girl. A large, tortuous, and elongated right coronary artery, communicating with the right ventricle, was detected by two-dimensional echocardiography and confirmed at angiography. To our knowledge, no echocardiographic recognition of the origin and termination of a CAVF has been reported previously. Moreover, another fistula, connecting the left anterior descending coronary artery with the main pulmonary artery was also detected by selective left coronary arteriography. The anatomy of double CAVF was confirmed on surgery. A right CAVF draining into the right ventricle and a left CAVF draining into the main pulmonary artery seemed to be a very unusual combination.

Arteriovenous Malformations↗
PubMed1982

Echocardiographic assessment of left ventricular wall motion in hypertrophic cardiomyopathy.

M-mode and two-dimensional parasternal long axis view echocardiography, and left anterior oblique cineangiography were employed to assess the left ventricular wall motion in 10 normal subjects (N) and in 25 patients with hypertrophic cardiomyopathy: 7 patients with symmetric hypertrophy (SH) and 6 patients with apical cardiomyopathy (AHCM) and no intraventricular gradient; 12 patients with hypertrophic obstructive cardiomyopathy and asymmetric septal hypertrophy with resting intraventricular gradient (6 pts) (HOCM-R) or gradient occurring only after isoproterenol infusion (6 pts) (HOCM-I). The left ventricle was divided into five portions: upper and lower septum, upper and lower posterior wall and apex. The excursion and thickness of the upper and lower portions of the septum and posterior wall were measured in all patients and compared to 10 normal subjects (N). From the superimposed end-diastolic and end-systolic echo frames and angio silhouettes a chordal and a radial-chordal method were used, respectively, to measure the motion of the left ventricular wall segments. In SH the left ventricular wall motion was qualitatively similar to N but a little reduced; the thickness was increased and no pressure gradient was present. In AHCM the lower septum, posterior wall, and apex showed significantly increased thickness and motion compared to N and compared to the upper portions of the septum and posterior wall. No gradient was present. In HOCM-R the upper septum moved towards the apex, the lower septum, upper posterior wall and lower posterior wall moved towards the left ventricular cavity. The upper posterior wall was hyperkinetic compared to N and compared to the lower posterior wall, resting gradient and SAM was present in all. In HOCM-I the upper septum moved towards the apex; the posterior wall was hyperkinetic (the excursion was a little wider in the lower posterior wall than in the upper posterior wall). No gradient was recorded at rest, but it could be provoked by isoproterenol. Echocardiography provides precise information on left ventricular wall motion in hypertrophic cardiomyopathy. Hyperkinesis of the lower left ventricular wall is related to AHCM; hyperkinesis of the upper posterior wall and the motion of the upper septum towards the apex are related to HOCM-R. Hyperkinesis of the lower posterior wall is related to HOCM-I. SAM and pressure gradients may be related to the hyperkinesis of the upper posterior wall. Finally, the septum is not an immobile structure in HOCM, since it moves mainly from the base to the apex and a less (or not at all) towards the posterior wall.

Cardiac Catheterization↗
PubMed1982

Reliability of subcostal TD echocardiography to detect atrial septal defect.

Echocardiography was used in 40 patients with atrial septal defect (ASD), diagnosed by cardiac catheterization. A dilated right ventricle and abnormal interventricular septal motion were observed at M-mode echocardiography in patients with large L-R shunt. The two-dimensional apical four chamber view was reliable to detect the ostium primum type but not the secundum type of ASD. Moreover the presence of false positives reduced the specificity and predictivity of this approach. The two-dimensional subcostal view provided a direct visualization of the interatrial communication (sensitivity, specificity and predictivity = 100%) and whether the defect was in the uppermost, lowermost or midportion of the septum. Subcostal two-dimensional echocardiography is considered valuable and reliable technique to detect atrial septal defect and the type of the defect itself.

Adolescent↗
PubMed1981

Subxiphoid echocardiographic assessment of left ventricular wall in old myocardial infarction.

We studied by cineangiography and standard and subxiphoid echocardiography the left ventricular wall motion in 50 patients with old myocardial infarction and 10 normal subjects. Coronary artery angiography showed a good correlation with the electrocardiographic site of infarction and with the asynergic areas detected by cineventriculographic examination and bidimensional echocardiography. From the correlation of data related to the asynergic areas detected by angiographic and echocardiographic methods it was possible to establish that subxiphoid approach allows to visualize the posterior-lateral wall whereas the parasternal approach the posterior-inferior wall of the left ventricle. Two-dimensional echocardiography from the subxiphoid approach resulted to be a useful and reliable technique for detecting the apical asynergies. The left ventricular wall motion parameters detected by M-mode echocardiography showed significant modifications in all the groups either in the comparison SUBX versus ST or in that with the control group. The subxiphoid approach either M-mode or bidimensional was, therefore, useful in the evaluation of the asynergic areas of the left ventricular lateral wall. The association of SUBX with ST provides further information on the left ventricular wall motion and then, since different areas are visualized with the two techniques, on the extent of myocardial damage.

Cineangiography↗
PubMed1979

Effects of creatinol O-phosphate on serum enzymes in acute myocardial infarction.

Two groups of 23 patients, each with acute myocardial infarction, were treated. The first group (control) received glucose-insuline-K+ (GIK) over a 3-day period, and the second GIK and N-methyl-N-(beta-hydroxyethyl) guanidine O-phosphate (creatinol O-phosphate, COP) (3.06 g i.v./24 h), again for a 3-day period. The six enzymes investigated, i. e. GOT, GPT, LDH, HBDH, CK and MBCK, all decreased between 33 and 49% in the COP group as compared with the control group, reaching a degree of statistical significance of less than 0.01. The decrease in these enzymes was attributed to the protective action of COP on the cell membrane permeability, in agreement with a series of previous papers.

Acute Disease↗
PubMed1978

A case of surgically corrected Wolff-Parkinson-White syndrome. Clinical and histological data.

A case of type B Wolff-Parkinson-White syndrome, with intractable atrial fibrillation, underwent surgical division of a right-sided accessory atrioventricular bundle of Kent. Pre-excitation and complicating tachyarrhythmias were henceforth abolished for 6 weeks, when the patient died of infective endocarditis. Histological examination showed a divided Kent's accessory atrioventricular pathway and apparently functionless James and Mahaim fibres.

Atrial Fibrillation↗
PubMed1978

[The endocardial ventricular activation map in a case of intermittent BBS in phase III (author's transl)].

To obtain information on endocardial activation-sequence, unipolar recordings at seven left ventricular and six right ventricular points were performed in a 37-year-old man suffering from cardiomyopathy and tachycardia-dependent left bundle branch block (LBBB). Results were as follows: 1) the recovery time was longer in anterior than in posterior portion of left bundle branch fibers; 2) an high posterior left ventricular point was directly activated via posterior left bundle branch fibers; 3) the directly activated left ventricular zone was too small and relatively too late excited in respect of the right interventricular septum, from which the stimulus reached the left septum, to mask the LBBB electrocardiographic pattern; 4) in the presence of tachycardia-dependent LBBB the duration of left ventricular endocardial activation was about twice (62 msec) that found in the absence of tachycardia-dependent LBBB (28 msec).

Adult↗
PubMed1978

[Observations on the sequence of endocardial activation in the left ventricle of the normal subject].

To obtain information on normal left ventricular activation, endocardial recordings with an electrode catheter were made a seven left ventricular sites in ten patients undergoing diagnostic heart catheterization. All the patients had: 1) sinus rhythm; 2) normal duration and shape of the QRS complex of left chest leads; 3) normal left ventriculography, i.e. normal volume and contractility of the left ventricle. The earliest left ventricular endocardial activation was recorded at septal and/or posterior level, i.e. at the septum (6 to 16 msec, average 9.7 msec, after the onset of intracardiac QRS complex) in seven patients; at the posterior wall (0 to 4 msec, average 2.6 msec, after the onset of intracardiac QRS complex) in three patients (in one of these, the earliest activation occurred at the posterior wall and apex simulaneously). If the earliest activation occurred at the left interventricular septum, the next excited point was found on the posterior wall or at the apex, and vice versa. The latest part to be activated was on the lateral free wall in seven patients; on the posterior wall in two patients; at the apex in the last one.

Adult↗
PubMed1978

[Electrophysiological evaluation of ventricular tachycardia by right and left ventricle endocardial mapping (author's transl)].

Eight patients with ventricular tachycardia (VT) have been studied by unipolar recordings of 7 endocardial points of the left ventricle (LV) and 6 endocardial points of the right ventricle (RV) in order to record if possible: 1) where the VT arose; 2) a continuous electrical activity during the sistodiastolic phase of the intracardiac ECG [late potentials (LP)], suggesting the reciprocating mechanism of VT. All the patients underwent cardiac catheterization with left and/or right ventriculography. A coronary arteriography was performed in four cases. Four patients had no evidence of heart disease; one patient had aortic stenosis; one patient had two vessels coronary disease and extensive ipo-akinesis of the LV; two patients had dyskinetic areas of the RV. In all the cases it was possible to identify where the VT arose by means of recordings during spontaneous VT episodes (the sites of origin of the VTs were stated in the points where the intracardiac QRS began with an intrinsic deflection), or by means of asyncronous ventricular stimulation (the sites of origin of the VTs were stated in the points where the ventricular stimulation reproduced a surface ECG similar to the one recorded during spontaneous VT). The fact that the site of origin of the VT is never in the same point of the earliest endocardial activation during sinus rhythm and the fact that this site is located in a zone with rich terminations of the conduction system, suggest the reciprocating VT may develop in a circuit, with both conduction and myocardial tissue.

Adolescent↗