Sudden death after operative repair of tetralogy of Fallot

The clinical and necropsy findings in 3 patients with tetralogy of Fallot who died suddenly after corrective operation are presented. Early postoperative electrocardiograms of 2 patients showed coexistent right bundle-branch block and left anterior hemiblock; one of these developed complete atrioventricular block and required a pacemaker. In the third a pacemaker. In the third patient, postoperative electrocardiograms showed anterior myocardial infarction. At necropsy, there was gross and histological evidence of myocardial infarction in each patient. After operation, extensive myocardial fibrosis and the development of right bundle-branch block and left anterior hemiblock are possible factors causing cardiac arrhythmias and sudden death.     

Vectorcardiographic study of aberrant conduction anterior displacement of QRS: another form of intraventricular block.

Aberrant ventricular conduction was induced in 44 subjects by introduction of atrial premature beats through a transvenous catheter-electrode. Multiple patterns of aberrant ventricular conduction were obtained in 32 patients and, in the whole group, 116 different configurations were recorded. Of these, 104 showed a classical pattern of mono- or biventricular conduction disturbance. The pattern frequencies were as follows: right bundle-branch block, 28; left anterior hemiblock combined with right bundle-branch block, 21; left anterior hemiblock, 17; left posterior hemiblock combined with right bundle-branch block, 12; left posterior hemiblock, 10; complete left bundle-branch block, 10; and incomplete left bundle-branch block, 6. The remaining 12 configurations could not be classified into the usual categories of intraventricular blocks. In 7 of them, the alterations only consisted of trivial modifications of the QRS contour. In the other 5 instances, aberrant conduction manifested itself by a conspicuous anterior displacement of the QRS loop, with increased duration of anterior forces. The latter observation is worthy of notice, as it indicates that, in the differential diagnosis of the vectorcardiographic pattern characterized by prominent anterior forces, conduction disturbances should be considered a possible aetiological factor in addition to right ventricular hypertrophy, and true posterior wall myocardial infarction.     

Long-term prognosis after acute anterior infarction with atrioventricular block.

The purpose of this study was to evaluate the need for permanent pacing in patients who have survived the effects of anterior myocardial infarction with complete heart block and have returned to sinus rhythm but who are left with impairment of intraventricular conduction. We have reviewed 52 patients with complete heart block complicating recent anterior myocardial infarction. Temporary pacing was instituted in all patients. There were 25 hospital survivors who were followed for an average of 49 months. Long-term pacing was established in 4 patients. Of the 21 patients in sinus rhythm, 14 had partial bilateral bundle-branch block with either right bundle-branch block and left anterior hemiblock or right bundle-branch block and left posterior hemiblock; at the end of the follow-up period, 10 of these 14 were alive and well. Furthermore, permanent pacing failed to prevent sudden death in 2 patients. At the present time, therefore, we conclude that long-term pacing is not justified in patients, otherwise asymptomatic, with partial bilateral bundle-branch block persisting after transient complete heart block in anterior myocardial infarction.     

Histopathology of conducting system in left anterior hemiblock.

In 8 cases of left anterior hemiblock, combined with right bundle-branch block in 7, serial sections of the conducting system of the heart were examined histologically. In all cases there were pathological changes in the left bundle-branch but the anterior part of it was predominantly affected in only 2 cases. Acute changes were found in 6 cases of early myocardial infarction, and fibrosis in 2 cases of chronic heart disease. Reversible lesions may have a pathogenetic role in acute hemiblocks. The right bundle-branch was disrupted by fibrosis in 6 of the 7 cases with right bundle-branch block, and minor changes in the AV node were observed in 1. The widespread damage to the left bundle-branch in the majority of the present cases does not seem to be consistent with the limited clinicopathological correlation implied by the terms anterior fascicular block or hemiblock. Other cardiac lesions within the left bundle-branch and outside it may contribute to this electrocardiographic pattern.     

Acute inferior wall myocardial infarction associated with complete atrioventricular block and left posterior hemiblock.

Three cases of acute inferior wall myocardial infarction associated with complete atrioventricular block and junctional escape rhythm showing left posterior hemiblock are presented. The triad appears to consitiute a distinct syndrome. It is postuated that the subsidiary pacemaker is situated either in the bundle of His or the proximal part of the anterior division of the left bundle-branch.     

Acute inferior wall myocardial infarction associated with complete atrioventricular block and left posterior hemiblock.

Three cases of acute inferior wall myocardial infarction associated with complete atrioventricular block and junctional escape rhythm showing left posterior hemiblock are presented. The triad appears to consitiute a distinct syndrome. It is postuated that the subsidiary pacemaker is situated either in the bundle of His or the proximal part of the anterior division of the left bundle-branch.     

Incidence and prognostic significance of intraventricular block in acute myocardial infarction.

In 404 consecutively admitted patients with their first myocardial infarction (MI), intraventricular block (IV) was a complication in 124 (31%). The following types of block were encountered: 21 (5%) had left bundle-branch block (LBBB), 73 (18%) left anterior hemiblock (LAH), 13 (3%) left posterior hemiblock (LPH); 7 (2%) right bundle-branch block (RBBB); 9 (2%) RBBB + LAH, and 1 (0.3%) RBBB + LPH. Patients with IV block at the time of admission did not develop total atrioventricular block more frequently in the acute phase of MI (0-30 days) or in the follow-up period (3-5 years) than patients without IV block. During the acute phase, only patients with RBBB with or without hemiblock showed significantly higher mortality than patients without IV blocks. The other types of IV block did not influence the short-term prognosis. Among patients who survived the acute phase, significantly lower long-term survival rates were found in patients with LBBB compared to patients without IV block, whereas the presence of LAH did not affect the long-term prognosis.     

Right ventricular infarction: unusual electrocardiographic and electrophysiological manifestations

Right ventricular infarction occurs in 19-43% of patients with acute inferior wall infarction (Lorell et al., 1979). Its clinical, hemodynamic, and anatomic features are well known and include associated inferior wall infarction, distended neck veins, clear lung fields, hypotension, and heart block (Cintron et al., 1981; Coma-Canella et al., 1979; Lloyd et al., 1981; Lopez-Sendon et al., 1981; Raabe and Chester, 1978; Rotman et al., 1974). Isolated right ventricular infarction is less frequent and occurs in 2.5-4.6% of autopsy studies of myocardial infarction (Cohn et al., 1974; Erhardt et al., 1976; Wartman and Hellerstein, 1948). This report describes a patient with isolated right ventricular infarction with unusual electrophysiological findings. Her initial electrocardiogram showed atrial escape rhythm with incomplete right bundle-branch block and left posterior hemiblock. Later, she developed atrioventricular (AV) block with supra- and infra-Hisian, "phase 4," conduction defects. The sinus malfunction and high degree AV block persisted over 2 weeks and an atrioventricular sequential pacemaker was implanted. Hymodynamic study showed that her cardiac output was highly dependent on the heart rate and properly timed AV interval, and the pacemaker was programmed accordingly.     

Right bundle-branch block and left axis deviation in acute myocardial infarction

Of 114 patients with acute myocardial infarction admitted consecutively to a coronary care unit, 10 had recent antero-septal myocardial infarction associated with right bundle-branch block and obvious left axis deviation, and I had recent antero-septal myocardial infarction with right bundle-branch block and right axis deviation. Attention is drawn to the high mortality (7 out of 11 patients), due mainly to cardiogenic shock. Frequent complications were sudden complete heart block (5 patients) and ventricular asystole (4 patients) without previous lengthening of the atrioventricular conduction time. An external on-demand pacemaker was inserted in 10 patients, and no patient died of complete heart block or ventricular asystole.     

Right bundle-branch block and left axis deviation in acute myocardial infarction.

Of 114 patients with acute myocardial infarction admitted consecutively to a coronary care unit, 10 had recent antero-septal myocardial infarction associated with right bundle-branch block and obvious left axis deviation, and I had recent antero-septal myocardial infarction with right bundle-branch block and right axis deviation. Attention is drawn to the high mortality (7 out of 11 patients), due mainly to cardiogenic shock. Frequent complications were sudden complete heart block (5 patients) and ventricular asystole (4 patients) without previous lengthening of the atrioventricular conduction time. An external on-demand pacemaker was inserted in 10 patients, and no patient died of complete heart block or ventricular asystole.     

Pictures of the fascicular block inacute myocardial infarct with special reference to left anterior hemiblock and the bifascicular block of the anterior type]

In the etiology of uni, bi- and trifascicular block pictures the acute myocardial infarction plays an important role. From the topographic relations of the supply of coronary vessels to the coduction system certain correlations between localisation of infarction and kind of blocking are to be explained. The electrocardiographic changes of the individual block pictures are explained. 765 (581 males, 184 females) patients with acute myocardial infarction were examined concerning frequency and prognosis of the left anterior hemiblock and the bifascular block of anterior type (left anterior hemiblock, right bundle branch block). A left anterior hemiblock could be proved in 90 cases (11.8%), a bifascicular block of anterior type in 38 cases (5%). With 30% the lethality of the first group was not essentially above the lethality of patients with infarction without block pictures (29.6%). In patients with bifascicular block of anterior type it was significantly incrased with 68.4%. The two block forms were nearly exclusively found in the anterior wall infarction and its combination with a posterior wall infarction, respectively. 11 patients, out of whom 9 died, showed a transition of the bifascicular block into a trifascicular one. In 6 cases a left anterior hemiblock had preceded. The results concerning frequency and prognosis much correspond with the reports of other authors. In the bifascicular block, apart from the danger of a sudden asystolia, also the most cases larger size of the extension of the infarction with the adequately higher risk of a muscular insuficiency might be responsible for the bad prognosis. The therapeutic possibilities and necessities deriving from this are explained.     

Electrocardiographic changes of ST-elevation myocardial infarction in patients with complete occlusion of the left main trunk without collateral circulation: Differential diagnosis and clinical considerations

Acute coronary syndromes due to involvement of the left main trunk usually present with subtotal occlusion and electrocardiographic pattern with predominant ST depression (non-ST-elevation myocardial infarction). The cases with complete occlusion frequently present an ST-elevation myocardial infarction pattern, but these patients usually die before reaching the hospital. We present a series of 7 patients with total left main trunk occlusion without collateral circulation showing ST-elevation myocardial infarction pattern. The electrocardiographic pattern is similar to left anterior descending coronary artery proximal occlusion to first septal and first diagonal but without ST elevation in V(1) and aVR because of left circumflex coronary artery compromise. In 4 (60%) of 7 of cases, there is also advanced right bundle-branch block plus superoanterior hemiblock. Despite severe clinical state at entrance (5/7 presented cardiac arrest/cardiogenic shock), 3 patients (43%) survived after percutaneous coronary intervention.     

Spontaneous closure of ventricular septal defect in a case of double outlet right ventricle

A 5 year old child, previously diagnosed as having tetralogy of Fallot, was admitted to hospital in severe congestive heart failure. The electrocardiogram showed left anterior hemiblock and incomplete right bundle-branch block, neither of which was previously present. The child died in intractable congestive heart failure and the necropsy showed a double outlet right ventricle with complete spontaneous closure of the subaortic ventricular septal defect by fibrous tissue. The possible mechanism involved in the production of this unusual complication of double outlet right ventricle is discussed, together with an explanation for the electrocardiographic changes.     

Spontaneous closure of ventricular septal defect in a case of double outlet right ventricle.

A 5 year old child, previously diagnosed as having tetralogy of Fallot, was admitted to hospital in severe congestive heart failure. The electrocardiogram showed left anterior hemiblock and incomplete right bundle-branch block, neither of which was previously present. The child died in intractable congestive heart failure and the necropsy showed a double outlet right ventricle with complete spontaneous closure of the subaortic ventricular septal defect by fibrous tissue. The possible mechanism involved in the production of this unusual complication of double outlet right ventricle is discussed, together with an explanation for the electrocardiographic changes.     

The fate of patients with intraventricular conduction disturbances complicating acute myocardial infarction.

The partial incidence and the early and late mortality were studied in 104 patients with acute myocardial infarction complicated by intraventricular conduction defects. Right bundle branch block and left anterior hemiblock had a greater incidence than the other conduction anomalies, while the hospital mortality was greater for the complete right bundle branch block combined with left anterior or posterior hemiblock, followed in order by complete left bundle branch block. Late morality was higher in cases with complete right bundle branch block combined with left posterior hemiblock and also in cases with focal block or left bundle branch block indicating a poor prognosis for these patients. For the rest sub-groups of patients late mortality was relatively low indicating the possibility of long survival after passing the acute phase. However, longer periods of observation are desirable for further estimation of their ultimate prognosis.     

Permanent pacing in patients with transient trifascicular block during acute myocardial infarction

Patients with acute myocardial infarction and transient complete atrioventricular (A-V) block in association with right bundle branch block and left anterior hemiblock have a high incidence rate of late sudden death presumably due to recurrent A-V block. Over a 5 year period, 18 patients demonstrated right bundle branch block and left anterior hemiblock and had transient complete block during an acute myocardial infarction and survived to hospital discharge. Of six patients who did not have permanent pacing, five died suddenly (one was lost to follow-up) with a mean survival time of 2.4 months after hospital discharge. Twelve subsequent patients received permanent demand pacemakers and had a significantly improved prognosis with a mean survival time of 18 months (P < 0.001). Six patients were still alive at an average follow-up time of 20 months. Prophylactic permanent pacing significantly improves the prognosis after acute myocardial infarction in this select subgroup of patients.     

The electrocardiogram in aortic valvular atresia.

In a review of the electrocardiograms of 27 patients with aortic valvular atresia, several showed an unusual pattern. In two, the Wolff-Parkinson-White syndrome was present, and in the third, complete right bundle-branch block was seen. The study also confirms that left axis deviation and left ventricular hypertrophy can occur rarely. No patient showed a Q wave in lead V6.     

Should ECG criteria be modified for geriatric patients?

When an elderly patient has an abnormal electrocardiogram but no other objective evidence of heart disease, the physician may question whether the ECG is really a reliable index of heart disease in old people or whether aging has some influence on which findings are normal and which are abnormal. The study reported here plus data gathered from an extensive review of the literature indicate the ECG criteria do not have to be changed for geriatric patients. Regardless of age, the prognosis of a specific abnormality remains that of the underlying disease. With age, both heart disease and abnormal electrocardiograms increase in incidence--in a parallel fashion. Specific abnormalities that increase in frequency are first-degree atrioventricular block, bundle-branch block, ST-T wave changes, premature systoles, left anterior hemiblock, left ventricular hypertrophy, and atrial fibrillation. Those that correlate strongly with heart disease are atrial fibrillation, left bundle-branch block, and nonspecific intraventicular condution defect.     

Left posterior hemiblock in acute myocardial infarction.

Fifteen cases of left posterior hemiblock associated with acute myocardial infaction were studied. In 5 cases the left posterior hemiblock was the only intraventricular conduction defect, while in the other 10 cases it was associated with complete right bundle-branch block. Left posterior hemiblock proved to be an early complication, appearing within a few hours from the onset of the acute episode, and an ominous sign, since hospital mortality rate was 87 per cent. Cause of death was mainly pump failure. In most of these cases ther was electrocardiographic evidence of infarction involving both anterior and inferior ventricular walls. Infarction of most or all of the ventricular septum was a common finding in the cases examined anatomically. Histologically, acute changes involving mainly the posterior septal and midseptal fibres were observed in 6 of the 8 cases studied. On the basis of these findings and of other published findings an alternative physiopathological mechanism for so-called left posterior hemiblock is proposed.