Critical analysis of the vectorcardiogram's reliability in the quantitative diagnosis of old myocardial infarction.

The purpose of this work is to verify if the vectorcardiogram (VCG) can be used for the quantification of old myocardial infarction (OMI). 50 cases of acute myocardial infarction were studied by mean of seriate determination of MB-CK isoenzyme and Sobel Index (SI); 4 weeks later, Frank's VCG was recorded. The studied cases did not show any conduction disturbances or other electrical abnormalities besides the sign of OMI. The 50 cases were divided into two groups according to the site of the necrosis: Group A, including 27 cases of inferior and/or posterior infarction and Group B, including 23 cases of septal and/or anterior infarction. On the VCG records, the variables related to OMI and to the general shape of ventricular depolarization and repolarization were measured. The electrical variables and the SI were compared by means of the methods of linear regression and of principal components analysis. No significant correlations were detected. Therefore, we conclude that the VCG is useless in the quantitative assessment of OMI; that such terms as "extensive, localized" and so on, at present widely used in electro- and vector-cardiography, are misleading if based only on surface electrical records obtained at distance from the acute phase of infarction and should therefore be avoided; that the work is consistent with the hypothesis that the electrical pattern of OMI could depend mainly upon peripheral intraventricular conduction disturbances.

[Vectorcardiographic analysis of atrial activation in isolated mitral valve prolapse. Atrial vectorcardiography in prolapsed mitral valve]. / Analisi vettorcardiografica della attivazione atriale nel prolasso mitralico isolato. VCG atriale nel prolasso mitralico.

The purpose of our work is to study atrial depolarization in primary mitral prolapse (MVP), since, as far as we know, such a study has never been performed. Thirty patients with MVP were studied: 23 females, aged 37,3 +/- 15,5 years and 7 males, aged 45.1 +/- 18.1 years. MVP was diagnosed by M-mode echocardiography. Atrial depolarization was analysed on photographically recorded Frank's vectorcardiograms. On PsE loops, magnitude and direction of maximum planar vector (VMax) in the frontal (F) and left sagittal (LS) planes, magnitude and direction of anterior (HV1) and posterior (HV2) vectors in the horizontal (H) plane, HV1 to HV2 amplitude ratio and total atrial activation time (T) were measured. This last value (T), measured on vectorcardiographic records, was confirmed by high-speed (200 mm/sec) electrocardiograms. These data were compared, by mean of Student's test, with those measured on records obtained from a similar group of normals. The following statistically significant (P less than 0.05) differences were detected: decreased amplitude of VMax in F (0.11 +/- 0.03 vs. 0.080 +/- 0.03) and LS (0.11 +/- 0.03 vs. 0.085 +/- 0.03), backward shift of HV2 (+65 degrees +/- 39 degrees vs. + 11 degrees +/- 35 degrees) and decreased T (98 +/- 25 vs. 85 +/- 17). The decrease of total atrial activation time, about 13% less than in normals, is the most interesting finding of our research. Such an alteration of atrial depolarization can be explained by inter- and/or intra-atrial conduction disturbance, on anatomical or functional base. Therefore, our findings are consistent either with the hypothesis that MVP is secondary to widespread pathological changes or with the one that MVP is a consequence of neurovegetative imbalance.

[Motion of the interventricular septum in patients with right intraventricular electric stimulators. Echocardiographic and vectorcardiographic study]. / Il movimento del setto interventricolare nei portatori di elettrostimolatore endoventricolare destro. Studio eco- e vettocardiografico.

An echo- and vectorcardiographic study had been performed in order to analyze the motion of the interventricular septum (IVS) in thirty-six patients with chronic pacing at the apex of the right ventricle. As this pattern has been reported as just like that of LBBB, five patients with LBBB have been studied as well, with transient pacing. As far as the first group, in 25 P. IVS moves, both during spontaneous activity and pacing, like in normal subjects; in 8 P. the records were questionable; in 3 P. IVS moves liek in LBBB. The group of 5 P. with LBBB shows paradoxical motion of IVS both before and during pacing. In vectorcardiograms, the initial ventricular vectors (from 0 to 30 msec) are upward, backward and rightward oriented, in 33 of the first group's 36 P. The second group of 5 LBBB failed to show a costant pattern. The possible electrophysiologic hypotheses, about genesis of these patterns, are discussed.

[Statistical evaluation of vectorcardiographic criteria for the diagnosis of posterior myocardial necrosis (author's transl)]. / Valutazione statistica dei criteri vettorcardiografici per la diagnosi di necrosi miocardica posteriore.

85 vectorcardiograms, characterized by anteriorly oriented horizontal ventricular loop, were analized in order to evaluate if this pattern can be considered diagnostic at all for strictly posterior myocardial infarction. Records were divided into two groups according to positivity or negativity of clinical history for myocardial infarction. Records consistent with right ventricular hypertrophy were ruled out. Nine parameters related to ventricular depolarization and repolarization were measured and the values were submitted to statistical analysis. The study showed that:--selection of the two groups was correct, because of first group's homogeneity and control group's unhomogeneity;--mean values of the nine parameters did not differ significantly in the two groups;--single parameter into each group was unrelated to others. As a consequence, criteria at the time in use for diagnosis of strictly posterior myocardial infarction seem not to be useful, as other conditions beside myocardial infarction or right ventricular hypertrophy are able to determine the same vectorcardiographic pattern.

["Peripheral infarction blocks". Vectocardiographic analysis and electrogenetic hypothesis (author's transl)]. / I blocchi infartuali periferici. Analisi vettorcardiografica ed ipotesi elettrogenetiche

500 vectorcardiograms of variously located myocardial infarctions were analysed. Abnormalities of the afferent limb of QRS loop, consistent with intraventricular conduction disturbances, were detected in 42 cases. This pattern, according to Rosenbaum, was called "infarction block"; it was always associated with inferior and/or posterior infarction. This kind of block is shown by a large downward, righward and backward-directed vector, which always appears about 50 msec after the onset of ventricular activation. Total ventricular depolarization time was not significantly prolonged. The pattern was explained as a variant of "peri-infarction block" and its origin is hypothesized as the interruption of a peripheral ramification of LBB posterior fascicle.

[Peripheral disorders of intraventricular conduction in ischemic cardiopathy]. / I disturbi periferici della conduzione intraventricolare nella cardiopatia ischemica

The complex question of peri-infarction blocks is examined. Whereas this term was once used for conduction disturbances now interpreted as fascicular blocks, a distinction is drawn here between these and parietal, post-Hisian blocks and infarctual blocks. Their vectorcardiographic picture are described, along with the possible expression of segmentary blocks at the peripheral branches of the posterior fascicle of the left branch. These electrogenetic interpretations are discussed in the light of data obtained by phonomechanographic methods in cases of parietal block.

[Phono-mechanographic aspects in parietal blocks of left ventricle (author's transl)]. / Aspetti fono-meccanografici nei blocchi parietali del ventricolo sinistro

20 subjects with parietal ventricular block, detected by Frank vectoracardiogram, were submitted to phono-mechanographic examination. Prolongation of PEP was shown; the second period of electromechanical interval (A-C interval in apex-cardiogram) was given in detail. Isovolumetric contraction, systolic ejection time and diastolic period were normal. This pattern is quite typical for parietal block and completely differs from bundle blocks and cardiomyopathies. Therefore it may be useful in differntial diagnosis of these kinds of conduction disturbances as well.