Swallow Syncope After Whiplash Neck Injury.

Swallow syncope is a rare dysautonomic syndrome characterized by temporary loss of consciousness upon swallowing solid foods or liquids, displaying primarily in individuals with an underlying structural or functional esophageal or cardiac pathology. However, the evidence also suggests that isolated vagal dysfunction or abnormal reactions of esophageal mechanoreceptors after mechanical irritation, demyelination, or trauma can potentially evoke  a cardioinhibitory response or vasodepression upon swallowing. We present a case of a 49-year-old otherwise healthy female patient who developed swallow syncope two weeks after whiplash neck injury acquired in a rear-end collision. After no evident anatomical and/or functional cardiac or esophageal pathology was diagnosed using several diagnostic procedures, the final diagnosis was confirmed by a provocative tilt-table test while ingesting solid food. Subsequently, a dual-chamber pacemaker was implanted, relieving the patient from troublesome symptoms. Abnormal reactions of esophageal mechanoreceptors to stimuli associated with food ingestion and/or dysfunction of afferent and efferent vagal fibers due to stretch injury and related neck trauma (acquired during the car accident) may be the leading pathophysiological mechanisms of swallow syncope in our patient.

Short-term outcome of cardiac resynchronization therapy - a comparison between newly implanted and chronically right ventricle-paced patients.

BACKGROUND: Cardiac resynchronization therapy (CRT) is considered as a standard adjunct therapy in symptomatic patients with congestive heart failure (CHF) who have a prolonged QRS. There is an increasing number of patients who do not receive de novo CRT devices but are upgraded from right ventricular (RV) pacing to biventricular stimulation. We wanted to evaluate the benefit of CRT in patients with chronic RV pacing in comparison to previously non-paced heart failure patients. METHODS: One hundred and sixty-five patients who had their device newly implanted (group I) and 116 who were upgraded from previously implanted RV pacing systems (group II) at Mayo Clinic Hospital were retrospectively analyzed. Clinical and echocardiographic response to CRT was evaluated. Mean follow-up time was 290±250days. RESULTS: Baseline characteristics did not differ between the two groups of patients. Clinical response rate was identical in Groups I and II (65 vs. 65%, respectively; P=0.98) and echocardiographic response rate was similar in both groups of patients (64 vs. 62%; P=0.80). Post-implant QRS increased in group I and was reduced in group II (5 (27.4) vs. -20.0 (33.9) ms; P<0.001). NYHA class improvement (-0.7 (0.6) vs. -0.7 (0.6), P=0.81), LV ejection fraction increase (9.2 (12.9) vs. 8.2 (9.9)%; P=0.55) and LV end-systolic volume reduction (-34.5 (50.7) vs. -25.7 (47.4)%; P=0.28) were comparable in both groups. CONCLUSIONS: Chronically RV-paced patients who receive CRT have similar short-term benefits when compared with patients with new CRT implantations.

Myocardial stretch in early systole is a key determinant of the synchrony of left ventricular mechanical activity in vivo.

BACKGROUND: Recent in-vitro observations suggest that left ventricular (LV) contraction is powered by 'stretch activation', an intrinsic mechanism by which the stretching of an activated cardiomyocyte causes delayed force redevelopment. We hypothesized that mechanical dyssynchrony is related to prolonged early systolic stretch that delays the timing of peak segmental shortening. METHODS AND RESULTS: The time intervals from R wave to segmental longitudinal stretch in early systole (Tstretch) and peak shortening (Tpeak) and the respective standard deviations (σTstretch and σTpeak) were measured by speckle-tracking echocardiography in 57 patients undergoing cardiac resynchronization therapy (CRT). The percentage of time spent in shortening, normalized to Tpeak duration [corrected ΔT=(Tpeak-Tstretch)/Tpeak] correlated with LV reverse remodeling (reduction in end-systolic volume ≥ 15%). Of the 57 patients, 40 (70.2%) demonstrated LV reverse remodeling at an average follow-up of 263 ± 125 days after CRT. At baseline, Tstretch and σTstretch correlated with Tpeak and σTpeak, respectively. Though there was no difference in Tstretch, Tpeak, σTstretch and σTpeak between responders and non-responders, corrected ΔT in the mid-lateral and mid-septal segments was shorter in the responders (P<0.05 for both) and the average of the 2 independently predicted LV reverse remodeling (area under the curve: 0.77, P=0.001). CONCLUSIONS: Mapping LV segmental shortening in relation to early systolic stretch may aid dyssynchrony assessment in patients undergoing CRT.

Treatment of symptomatic coronary artery disease with stent implantation.

BACKGROUND: Percutaneous coronary intervention (PCI) with stent implantation is the therapy of choice for treatment of decreased blood flow through the coronary arteries. AIM: We evaluated the efficacy of the bare metal stent (BMS) for treatment of symptomatic coronary artery disease and compared BMS with the drug eluting stent (DES) to find out which one is better in the prevention of major adverse cardiac events (MACE) six months after stent implantation. MATERIALS AND METHODS: Our retrospective analysis included 387 consecutive patients with BMS implantation and 74 consecutive patients with DES implantation. Efficacy of BMS was evaluated by residual in-stent stenosis after the procedure. According to the Taxus II-Trial definition, MACE include cardiac death, acute myocardial infarction (AMI) and target vessel revascularization; the latter includes PCI with stent implantation or coronary artery bypass graft on previously revascularized vessel. RESULTS: In BMS group mean pre-procedure stenosis diameter was 81.9 ± 12.8% and mean post-procedure stenosis was 4.8% ± 12.5%. The residual in-stent stenosis was significantly higher in patients with longer lesions (p<0.05). Hypertension was the most frequent risk factor in both groups and AMI the commonest indication for stent implantation in the group with BMS, while stable and unstable angina pectoris in the group with DES, respectively. During the first six months after the implantation of DES, the incidence of MACE was significantly lower (p<0.05) compared to BMS. The most frequent subgroup of MACE present in the group with BMS was cardiac death, and in the group with DES it was repeated PCI with stent implantation. CONCLUSIONS: BMS provides and efficacious choice of treatment for patients with symptomatic coronary artery disease. Patients with longer lesions have higher residual in-stent stenosis after BMS implantation. Implantation of DES is more successful in preventing MACE in comparison with the implantation of BMS.

Retrospective analysis of mode survival, reliability of atrial sensing and incidence of atrial tachyarrhythmias in 307 single-lead VDD pacemaker patients.

AIMS: The aim of this retrospective analysis was to investigate VDD mode survival, development of atrial tachyarrhythmias (AT), and long-term atrial sensing performance of VDD pacing systems. METHODS AND RESULTS: We implanted single-lead VDD pacemakers in patients with isolated atrioventricular block and performed a retrospective analysis of 307 patients who had their devices implanted between May 1994 and September 2001. In 39 patients (12.7%), the pacing mode had to be reprogrammed to a single-chamber ventricular pacing mode, mostly due to permanent AT. In 16 of these patients, the atrial sensing safety margin was less than 150%. The atrial sensing safety margin was insufficient, i.e. less than 100% in only seven patients. Although only 12 (3.9%) of the patients had a history of paroxysmal AT at the time of pacemaker implantation, 200 (65%) patients presented with AT during follow-up. The mean AT burden at the last follow-up was 2.5%. CONCLUSION: These data illustrate that single-lead VDD pacemakers can be applied without serious complications in a highly selected group of patients. Our main concern is the development of AT in a large part of our population. Over a 10-year period, two thirds of our patients presented with AT.