Why is the clinical response to cardiac resynchronization better in LBBB patients?

AIMS: The improved clinical response in patients with left bundle branch block (LBBB) over LBBB-free patients treated with cardiac resynchronization therapy with a defibrillator (CRT-D) is commonly attributed to an LBBB abnormality. We aimed to find an alternative explanation. METHODS AND RESULTS: We analysed an immediate effect of selecting the LBBB group of patients in a cohort of 63 non-ischaemic cardiomyopathy (non-ICM) and 83 ischaemic cardiomyopathy (ICM) patients treated with CRT-D; 75% of non-ICM and 51% of ICM patients had an LBBB abnormality on the electrocardiogram, with a significant difference (P = 0.0032 by χ2 ). As a result of this difference, the proportion of non-ICM patients increased from 43% in the primary cohort to 53% in LBBB selection and decreased to 28% in non-LBBB group. By nonparametric survival analysis, the hazard ratio in non-ICM patients in the LBBB selection decreased from 0.48 (P = 0.0488) to 0.36 (P = 0.0251) and increased in the non-LBBB group to 0.75 (P = 0.6496). Any comparison of LBBB and non-LBBB groups must compare sets with a significantly altered proportion of patients of different aetiologies. Most publications on LBBB patients are erroneous because they compare LBBB with non-LBBB groups, not taking into account that the groups have been substantially changed by the selection process. CONCLUSIONS: The declared outcome of the LBBB groups reflects inevitably the survival outcome of their non-ICM patients and not the intended outcome of patients with LBBB. CRT-D in patients with different aetiologies of cardiomyopathy calls for separate evaluation.

Prevention of contrast-induced acute kidney injury by theophylline in elderly patients with chronic kidney disease.

Although the optimal strategy for preventing contrast-induced acute kidney injury (CI-AKI) has not yet been established, the current strategy focuses on adequate periprocedural hydration, the use of a low amount of low or iso-osmolar contrast medium, and the application of adjunctive therapies, including hemofiltration, hemodialysis and drugs. Previous trials and meta-analyses concerning the use of the adenosine antagonist theophylline have revealed contradictory results. We sought to evaluate the effect of theophylline in CI-AKI prevention in well-hydrated elderly patients with chronic kidney disease. We therefore conducted a randomized, double-blind, placebo-controlled trial involving 56 patients who had been referred for cardiac coronary angiography and/or angioplasty. 31 of these patients were randomly assigned to 200 mg theophylline IV before the procedure, and 25 to a placebo. The iso-osmolar contrast medium iodixanol was used. The primary endpoint was an increase in serum creatinine at study termination 48 h after contrast medium administration. Baseline characteristics in the placebo and theophylline groups were similar in terms of median age (75 years), estimated glomerular filtration rate (33 ± 10 vs. 33 ± 10 ml/min/1.73 m²; p = 0.87), diabetes mellitus (80 vs. 71%; p = 0.54), and amount of contrast used (94 ± 35 vs. 95 ± 38 ml; p = 0.89). There was no difference in serum creatinine at baseline (2.06 ± 0.59 vs. 2.02 ± 0.45 mg/dl; p = 0.62) or study termination (2.06 ± 0.68 vs. 2.10 ± 0.53; p = 0.79). A prophylactic effect of theophylline was not observed. The incidence of renal impairment following exposure to the contrast medium was low. This fact can be attributed to adequate parenteral hydratation and the use of the minimum amount of contrast medium necessary.

The association of atrial tachyarrhythmias with isolated atrial amyloid disease: preliminary observations in autopsied heart specimens.

OBJECTIVE: Isolated atrial amyloidosis (IAA) is associated with atrial tachyarrhythmias. However, only a few studies have appraised atrial tachyarrhythmias and atrial depolarization abnormalities in connection with high-grade IAA. We conducted a collaborative retrospective study to assess this association. METHODS: One hundred consecutive autopsied hearts were studied histologically for IAA. To increase the specificity for atrial depolarization abnormalities in this preliminary study, we excluded those specimens with intermediate amyloid involvement, i.e. IAA grades 1 and 2 (grade 0 = absent or trivial deposits; grade 1 = small deposits; grade 2 = moderate deposits; grade 3 = dense, large deposits). We then screened for baseline, premortem electrocardiograms (ECGs) to assess rhythm. In those with sinus rhythm, the P wave axis, duration, dispersion and terminal force in V1 were determined under magnification. RESULTS: Of the 27 premortem ECGs corresponding to the autopsy specimens with grades 3 (sample) or 0 (controls) IAA, 9 showed sinus rhythm, 13 showed atrial fibrillation, 1 showed atrial flutter and 4 were uninterpretable. Fourteen autopsied hearts (52%) were positive for grade 3 IAA. Ten of those had atrial tachyarrhythmias (9 atrial fibrillation and 1 atrial flutter) compared to 4 of the 13 hearts with grade 0 IAA (72 vs. 31%, respectively; p = 0.03). Although there was excellent interobserver agreement using intraclass correlation coefficients, there were no significant differences in P wave measurements among the small number of patients with sinus rhythm for grade 3 versus grade 0 IAA. CONCLUSION: In a collaborative, preliminary, pilot assessment of autopsied hearts for which premortem ECGs were necessarily screened retrospectively, significantly more hearts with high-grade IAA were associated with atrial tachyarrhythmias compared to those with low-grade IAA. A larger study with an appropriately matched autopsy control group is needed to confirm these and previous observations.

Myocardial sleeves of pulmonary veins and atrial fibrillation: a postmortem histopathological study of 100 subjects.

Atrial fibrillation (AF) is triggered by ectopic beats originating from extensions of the left atrial myocardium over the pulmonary veins (PVs), so-called myocardial sleeves. A total of 100 hearts (393 PVs) obtained at autopsy were studied. Of these, 50 were from patients with chronic AF and 50 from controls in sinus rhythm. Out of a total of 393 PVs studied, a sleeve was present in 349 PVs (88.8%). The myocardial sleeves frequently harboured senile atrial amyloid and scarring. These two changes were evaluated semi-quantitatively (grade 0-3). Amyloidosis was found in 68% of all hearts and in 55% of all sleeves. It was more frequent in patients with AF (58.5%) than in those without (51.7%), however, without statistical significance (p values 0.948, 0.306, 0.166 and 1). Scarring was present in all 349 sleeves studied. It was significantly more severe in patients with AF (average grade 2.44) than in those without (average grade 2.00) (p values <0.001, <0.1, <0.05 and <0.01). In conclusion, amyloidosis and particularly scarring of the myocardial sleeves of the pulmonary veins, appear to be common in the elderly population as an arrhythmogenic substrate for AF.

The influence of fluid and diuretic administration on the index of atrial contribution in sequentially paced patients.

AIMS: To examine whether acute changes in patient hydration can change atrial contribution (AC) to circulatory function. METHODS AND RESULTS: Atrial contribution was quantified by beat-to-beat changes in the amplitude of pulse oximetry signal in 24 paced outpatients. Changes in body weight were used for assessment of changes in total body water. The first measurement was performed at steady state. The second measurement was made after infusion of saline (5 mL/kg) and the third measurement was obtained 2 h after a bolus of furosemide (1 mg/kg). Changes found after furosemide administration (compared with steady state): a substantial decrease in body weight from median 78.6 (interquartile range 65.7-86.5) to 77.1 (64.4-85.6) kg (P < 0.001), accompanied by an increase in AC from 30.4 (20.2-47.1) up to 43.3 (30.6-80.9)% (P < 0.001). An increase in heart rate and shortening of the atrioventricular conduction time occurred during acute hypohydration in some of the subjects. CONCLUSION: Administration of furosemide was followed by a decrease in body weight and an increase in AC to stroke volume. This suggests that in conditions where pre-load is reduced cardiac output is preserved by an increase in AC enforced by sympathetic activation.

Characteristics and short-term survival of individuals with out-of-hospital cardiac arrests in the East Bohemian region.

AIM: We describe survival after admission to hospital from out-of-hospital cardiac arrest (OHCA) in the East Bohemian region, according to the Utstein Style guidelines and have identified the main diagnosis including in those who died and had an autopsy. PATIENT GROUP: Over a period of 29 months we used a questionnaire supplied to 24 rescue stations, to identify 718 individuals (511 men and 207 women, aged 16-97 years) with confirmed cardiac arrest who were considered for resuscitation. RESULTS: Out of 560 patients in whom cardiopulmonary resuscitation for OHCA of confirmed cardiac aetiology was attempted, 350 patients (62.5%) died in the field and 61 (10.9%) died during transport. Hospital admission was achieved in 149 cases (26.6%) and, of these, 96 patients died. Fifty-three patients (9.5%) were discharged home alive, 36 (6.4%) with an intact CNS. The first monitored rhythm showed asystole in 264 cases (47.1%) followed by ventricular fibrillation in 227 cases (40.5%). The main diagnosis of coronary heart disease (CHD) was established clinically in 467 cases (83.4%). In 175 autopsy reports this diagnosis was noted in 152 cases (86.9%). CONCLUSION: Of patients resuscitated for OHCA of cardiac aetiology, 9.5% survived to leave the acute hospital. CHD was the principle diagnosis in the entire group and this correlated with the same finding in the group of patients who received an autopsy.