Significance of chronic bifascicular block without apparent organic heart disease

All-Cause Mortality for Life Insurance Applicants with the Presence of Bundle Branch Block

Objective.-To determine the all-cause mortality of life insurance applicants who have a bundle branch block. Background.-Bundle branch block is an electrocardiographic pattern that has variable prognostic implications. Research studies have shown that both left and right bundle branch block are associated with increased mortality among cases that have heart disease. In the general population and life insurance applicant population, the prevalence of bundle branch block is relatively low, and its effects on long-term prognosis are not as well established. Methodology.-Life insurance applicants with reported bundle branch block were extracted from data covering United States residents between October 2009 and October 2016. Information about these applicants was matched to the Social Security Death Master (SSDMF) file for deaths occurring from 2009 to 2012 and to another commercially available death source file (Other Death Source, ODS) for deaths occurring from 2009 to 2016 to determine vital status. Actual to expected (A/E) mortality ratios were calculated using the Society of Actuaries 2015 Valuation Basic Table (2015VBT), select and ultimate table (age last birthday). All expected bases were not smoker distinct. Confidence bands around these mortality ratios were calculated. The variables of interest were applicant age, gender, location of the bundle branch block, and the presence of cardiac or cardiovascular conditions. Results.-There were 258,529.85 person-years exposure for applicants with bundle branch block. Of the applicants, 57.2% had right bundle branch block. Of person-years exposure, 11.5% had a cardiac condition along with the bundle branch block, and 4.4% had an underlying cardiovascular condition. Female mortality ratios were higher than those for males, but due to the low number of deaths, this difference was not significant. Left bundle branch block mortality ratios (1.01) were 1.4 times higher than those with right (0.74). Those applicants with a cardiac condition along with their bundle branch block had between 1.6 to 1.8 times the mortality ratio depending on the bundle branch block location, and those with a cardiovascular condition had between 1.5 to 1.7 times the mortality ratio over those applicants with just bundle branch block alone. Conclusion.-The presence of bundle branch block in an insurance applicant may be associated with increased all-cause mortality. In this study, life insurance applicants overall had a mortality slightly lower than the expected mortality based on the 2015 VBT. However, applicants with bundle branch block and a cardiac or cardiovascular comorbid condition had a significantly higher mortality ratio.

[Long-term follow up of asymptomatic chagasic individuals with intraventricular conduction disturbances, correlating with non-chagasic patients]

This prospective study was designed to evaluate intraventricular conduction disturbances in asymptomatic patients with Chagas' disease, and patients with primary sclerosis of the conducting system of the heart (Lev-Lenègre's disease). Eighty-four asymptomatic individuals with right- or left-bundle branch block were submitted to electrophysiological evaluation and long-term follow-up. Fifty-five had positive serologic blood tests for Chagas' disease and 29 had Lev-Lenègre's disease. Mean-age of 45 years in chagasic and 63 in non-chagasic patients (p< 0.001). There were 54 (98.2%) with right-bundle branch block in chagasic and 14 (48.3%) among non-chagasic patients (p <0.001). Sinus nodal and atrioventricular nodal functions presented no differences in either group. However, mean HV interval was greater in the NCH than in the CH group (p< 0.01). After a mean follow-up of 121 +/- 63.75 months among chagasic and 94.97 +/- 67.55 months among non-chagasic patients, total mortality was 20 (36.6%) patients in chagasic and 9 (31%) among non-chagasic patients (NS). Cardiac death was recorded in 17 (85%) individuals among chagasic and 3 (33.3%) among non-chagasic patients(p <0.05). Sudden death occurred in 10 (50%) among chagasic and was not observed in non-chagasic patients (p <0. 01).

IN CONCLUSION

1. Asymptomatic chagasic individuals with intraventricular conduction disturbances showed higher cardiac mortality, sudden or non-sudden death in relation to non-chagasic individuals. 2. The evaluated electrophysiological parameters were of no prognostic value in relation to mortality, although programmed ventricular stimulation was not performed.

Death due to paroxysmal atrioventricular block during ambulatory electrocardiographic monitoring

Witnessed sudden cardiac death due to paroxysmal atrioventricular (AV) block during ambulatory monitoring occurred in a 56-year-old female with primary conduction system disease. The control tracings showed right bundle branch block. Holter recordings obtained during the fatal event revealed paroxysmal complete AV block followed by ventricular asystole of approximately 13 seconds which, in turn, preceded the emergence of a slow idioventricular rhythm. The patient was definitely alive 5 minutes and 10 seconds following the onset of the AV block (since she activated the event marker in the recorder twice) and, possibly, 8 minutes later. Complete AV block persisted until the cessation of all cardiac activity, which took place 47 minutes following the occurrence of AV block. It is very likely that this patient could have been resuscitated in a city having a rapidly responding rescue squad.

Usefulness of gas chromatographic profiles of plasma total lipids in diagnosis of phytosterolemia

A Cambodian male (aged 5 years and 9 months) presented with subcutaneous and tendon xanthomas in association with hypercholesterolemia. He was erroneously diagnosed as having familial hypercholesterolemia and treated with a low cholesterol diet (+/- cholestyramine) to which he did not respond. A determination of plasma total lipid profile by high-temperature gas chromatography revealed elevated plasma levels of free and esterified plant sterols along with the hypercholesterolemia. Introduction and maintenance of a diet low in cholesterol and plant sterols resulted in significant reduction in the blood concentration of these sterols, which returned to pretreatment level upon discontinuation of the low sterol regimen. The rapid identification and quantitation of the plant sterols by high-temperature gas chromatography provides a sensitive means of distinguishing phytosterolemia, which might be more common than previously suspected, from other forms of dyslipidemia, and for following the course of any treatment.

The value of intracardiac electrophysiologic techniques in recurrent syncope of "unknown cause"

We prospectively evaluated and followed-up 45 patients with syncope in whom conventional cardiovascular and neurological investigations did not reveal the cause. All patients underwent electrophysiologic studies to assess the function of the sinus node and the integrity of atrioventricular conduction. These included the ajmaline test and the inducibility of supraventricular or ventricular tachycardia. Seven patients (15.5%) had evidence of sinus node dysfunction, 8 patients (17.7%) had evidence of infra-His atrioventricular block after ajmaline administration and 5 patients (11.1%) had inducible ventricular tachycardia. The remaining 25 patients (55.5%) had non-diagnostic studies. All patients with sinus node dysfunction and inducible infra-His atrioventricular block were asymptomatic during a mean follow-up period of 14.3 +/- 9.5 months after implantation of a permanent pacemaker. Patients with inducible ventricular tachycardia (except 1 with poor left ventricular function who died) were likewise asymptomatic while receiving laboratory guided anti-arrhythmic drug therapy. Twenty-five patients with non-diagnostic studies who were treated empirically are alive but the symptoms persist in 14 (56%). Provocative electrophysiological studies are of diagnostic and therapeutic utility in a significant number of patients with recurrent syncope of "unknown cause".

The presence of 5 alpha-sitostanol in the serum of a patient with phytosterolemia, and its biosynthesis from plant steroids in rats with bile fistula

The presence of 5 alpha-sitostanol (24-ethyl-5 alpha-cholestan-3 beta-ol) in serum of a patient with the rare genetic disease phytosterolemia was confirmed. This study aimed at clarifying the pathway(s) for the formation of 5 alpha-sitostanol, by use of rats with bile fistula. 5 alpha-Sitostanol was formed only slowly from sitosterol, but readily from 24-ethyl-4-cholesten-3-one. Some conversion was also obtained with 7 alpha-hydroxysitosterol as precursor. In view of the low rate of 7 alpha-hydroxylation of sitosterol, however, a pathway from sitosterol to 5 alpha-sitostanol involving 7 alpha-hydroxysitosterol as intermediate is probably of small physiological importance. Intestinal microorganisms are not essential for the above conversions, since the 5 alpha-sitostanol was found in bile from bile fistula rats. 5 alpha-Sitostanol was converted to water soluble metabolites (bile acids) much more slowly than was cholestanol (5 alpha-cholestan-3 beta-ol), and was accumulated serum to a much larger extent.

Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block

Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block were evaluated in 108 patients with block (age 74 +/- 10 years, 69% male) and 108 age- and sex-matched control patients with normal conduction. Clinical characteristics were similar initially except for more congestive heart failure in patients with block. Life table analysis revealed a higher 12 year mortality with block, even after omitting patients with moderate or severe congestive heart failure (risk ratio 1.47, p less than 0.05). Compared with control subjects, the group of patients with block had more sudden death and deaths of unknown cause, but a similar number of noncardiac and diagnosed cardiac deaths. More patients with block developed new second and third degree atrioventricular block or new overt coronary artery disease, but this finding did not support prophylactic pacing in asymptomatic patients. The importance of internal controls in assessing the natural history of clinical and electrocardiographic abnormalities is emphasized.

M-mode echocardiography in left bundle branch block: significance of frontal plane QRS axis

M-mode echocardiograms were obtained in 48 patients with complete left bundle branch block (LBBB). Of these 48 patients, 28 had LBBB with normal frontal plane QRS axis (-20 degrees to +90 degrees, mean +/- SD 18 degrees +/- 34 degrees), and 20 had LBBB with a left axis deviation (LAD) (-30 degrees to -60 degrees, mean +/- SD -48 degrees +/- 11 degrees). In the group with LBBB and normal axis, 25 patients had typical early mean +/- SD -48 degrees +/- 11 degrees). In the group with LBBB and normal axis, 25 patients had typical early systolic posterior septal motion characteristic of LBBB. Septal motion following early posterior septal motion (through the ejection period) was posterior in 24 patients (86%), anterior (paradoxical) in 2 (7%), and flat in 2 (7%). In the group with LBBB and LAD, 16 patients had the typical early systolic posterior septal motion; subsequent septal motion was posterior in 3 (15%), anterior (paradoxical) in 13 (65%), and flat in 4 (20%). Patients with LBBB and normal axis had a higher frequency of posterior septal motion, and patients with LAD had a higher frequency of anterior septal motion (p less than 0.001). The correlation of abnormal axis and paradoxical septal motion may be explained by the activation pattern producing LAD or by a septal disease process producing both abnormalities of axis and abnormal septal motion.

Natural history of "high-risk" bundle-branch block: final report of a prospective study

We conducted a prospective study in which 554 patients with chronic bifascicular and trifascicular conduction abnormalities were followed for an average of 42.4 +/- 8.5 months. Heart block occurred in 19 patients, and 17 were successfully treated. The actuarial five-year mortality from an event that could conceivably have been a bradyarrhythmia was 6 per cent (35 per cent from all causes). Of the 160 deaths 67 (42 per cent) were sudden; most of these were not ascribable to bradyarrhythmia but to tachyarrhythmia and myocardial infarction. Mortality was higher in patients with coronary-artery disease (P less than 0.01) and congestive heart failure (P less than 0.05). Patients in whom syncope developed before or after entry into the study had a 17 per cent incidence of heart block (2 per cent in those without syncope)(P less than 0.05); however, no single variable was predictive of which patients were at high risk of death from a bradyarrhythmia. The predictors of death were increasing age, congestive heart failure, and coronary-artery disease; the predictors of sudden death were coronary-artery disease and increasing age. The risks of heart block and of death from a bradyarrhythmia are low; in most patients, heart block can be recognized and successfully treated with a pacemaker.

The natural history of right bundle branch block and frontal plane QRS axis in apparently healthy men

We examined the characteristics, long-term follow-up, and prognosis of right bundle branch block (RBBB) detected on a routine ECG in men with no apparent heart disease. During the 29-year period, 59 cases of RBBB were observed in men with a mean age of 44.4 +/- 1.9 years. Because marked right or left axis deviation may identify cases with concomitant involvement of the left bundle branch system, subsets of frontal plane QRS (A QRS) were examined. Comparisons were made with groups of similar ages who were free of RBBB. Cases with RBBB were observed for 936 person-years (mean 15.9 +/- 1.6 years per case), showing no excess ischemic heart disease incidence, no cases of progression to advanced AV block (second- or third-degree), or sudden death. Right bundle branch block was associated with a greater proportion of both right axis (greater than or equal to +90 degrees) and marked left axis (-45 degrees to -90 degrees) deviation compared with those of the same age without this conduction disturbance. In apparently healthy men, RBBB had no adverse long-term prognosis regardless of frontal plane QRS axis.

Should this patient be paced? An indication for His bundle study: syncope, a normal P-R interval and a narrow QRS

This report describes a patient who presented with transient central nervous system symptoms of unknown etiology with an electro-cardiogram exhibiting a narrow QRS complex and normal. P-R interval. The decision to implant a permanent VII pacemaker was made on the basis of a His bundle study that revealed significant prolongation of the HV interval. The successful clinical outcome re-emphasizes the clinical usefulness of electrophysiological investigation in patients with syncope of undetermined etiology.

Failure to predict development of atrioventricular block with electrophysiological testing supplemented by ajmaline

Electrophysiological tests supplemented by pharmacological stress of atrioventricular conduction with ajamaline failed to predict the development of atrioventricular block in a patient with bifascicular block and no organic heart disease.

Systemic sarcoidosis and electrocardiographic conduction abnormalities. Electrophysiologic evaluation of two patients

Two patients with long histories of sarcoidosis had progression of conduction abnormalities to heart block and severe bradycardia. Conduction system involvement was trifascicular in both patients, though evidence for left ventricular functional impairment was otherwise lacking. Sudden death is seen more commonly in patients with sarcoidosis who have diffuse myocardial involvement, while conduction abnormalities can occur with relatively localized disease.