Increased ventricular ectopy precedes Torsades de Pointes in patients with prolonged QT

OBJECTIVE

Torsades de Pointes (TdP) is a potentially lethal ventricular tachydysrhythmia. Prolonged heartrate corrected QT interval (QTc) predicts TdP; however, with poor specificity. We performed this study to identify other predictors of TdP among patients with prolonged QTc.

METHODS

We performed a retrospective case control study with 2:1 matching at an urban academic hospital. We searched our hospital electrocardiogram (ECG) database for tracings with heartrate ≤ 60, QTc ≥ 500, and QRS < 120, followed by a natural language search for electronic records with "Torsades," "polymorphic VT," or similar to identify TdP cases from 2005 to 19. We identified controls from a similar ECG database search matching for QTc, heartrate, age, and sex. We compared cardiologic and historical factors, medications, laboratory values, and ECG measurements including ectopy using univariate statistics. For those cases with saved telemetry strips that included preceding beats or TdP onset, we compared ectopy and TdP onset characteristics between the ECG and telemetry strips using mixed linear modeling.

RESULTS

Seventy-five cases including 50 with telemetry strips and 150 controls were included. Historical, pharmacologic, laboratory, and cardiologic testing results were similar between cases and controls. The proportion of telemetry tracings with premature ventricular contractions (PVC's) preceding TdP was 0.78 compared to 0.16 for case ECG's (difference 0.62(95%CI 0.44-0.75)) and 0.10 for control ECGs (difference 0.68(95%CI 0.56-0.80)). Average telemetry heartrate was 72 and QTc 549 immediately preceding TdP, similar to the ECG values.

CONCLUSIONS

Clinical factors don't differentiate patients with long QTc who develop TdP, however, an increase in PVC's in patients with prolonged QTc may usefully predict imminent TdP.

Non-invasive investigation of chronic stable angina--a practical overview for medical practitioners

How does one decide on the best non-invasive test to investigate stable coronary ischaemia? This is a very common question faced by many medical practitioners. Chronic stable angina is a common presentation encountered in general practitice. Upon clinical assessment and risk stratification the patient needs to be investigated further to confirm the diagnosis. The first investigational modality involves a non-invasive test. It is important that practitioners possess a practical knowledge of the array of different tests that are available so that the best suited one for each patient can be chosen. This article aims to compare the efficacy and accuracy and the practical utility of the different non-invasive tests for coronary ischaemia and aid the practitioner in making sound decisions in this regard.

Effects of modified sample collection technique on fungal culture yield: nail clipping/scraping versus microdrill

OBJECTIVE

Onychomycosis requires accurate diagnosis but fungal culture yield is frequently low by routine sampling techniques. The aim of this study was to investigate the utility of nail plate/subungual microdrilling as an alternative to conventional nail clipping/subungual scraping.

METHODS

Patients with clinical evidence of onychomycosis (n=46) were prospectively evaluated for fungal potassium hydroride (KOH) microscopy and culture comparing two sampling techniques: nail clipping versus microdrilling.

RESULTS

Fungal cultures were positive in 48% with 2 additional cases detected by combining both methods. KOH microscopy was positive in 17% cases. Specimen obtained via the microdrill technique gave consistent heavier fungal growth on culture media. Candida species were the most common isolates (82.7% of cases) and were negative on KOH microscopy in 95 % of culture proven cases. The microdrill technique yielded consistent heavier growth on culture media

CONCLUSION

Microdrill technique improves laboratory diagnosis and ultimately treatment of onychomycosis, particularly in patients with repeated KOH microscopy and culture failure despite strong clinical suspicion.

Endothelial dysfunction in cerebral microcirculation during hypothermic cardiopulmonary bypass in newborn lambs

OBJECTIVES

Inflammatory stimuli or mechanical stresses associated with hypothermic cardiopulmonary bypass could potentially impair cerebrovascular function, resulting in inadequate cerebral perfusion. We hypothesize that hypothermic cardiopulmonary bypass is associated with endothelial or vascular smooth muscle dysfunction and associated cerebral hypoperfusion. Therefore we studied the cerebrovascular response to endothelium-dependent vasodilator, acetylcholine, endothelium-independent nitric oxide donor, sodium nitroprusside, and vasoactive amine, serotonin, in newborn lambs undergoing hypothermic cardiopulmonary bypass (nasopharygeal temperature = 18 degrees C).

METHODS

Studies were performed on 13 newborn lambs equipped with a closed cranial window, allowing for direct visualization of surface pial arterioles. Six animals were studied while undergoing hypothermic cardiopulmonary bypass, whereas seven served as nonbypass, warm (37 degrees C) controls. Pial arteriolar caliber (range = 111 to 316 microm diameter) was monitored using video microscopy.

RESULTS

Topical application of acetylcholine caused a dose-dependent increase in arteriolar diameter in the control group that was absent in animals undergoing hypothermic cardiopulmonary bypass. Hypothermic cardiopulmonary bypass did not alter the vasodilation in response to sodium nitroprusside. Furthermore, the contractile response to serotonin was fully expressed during hypothermic cardiopulmonary bypass.

CONCLUSIONS

The specific loss of acetylcholine-induced vasodilation suggests endothelial cell dysfunction rather than impaired ability of vascular smooth muscle to respond to nitric oxide. It is speculated that loss of endothelium-dependent regulatory factors in the cerebral microcirculation during hypothermic cardiopulmonary bypass may enhance vasoconstriction, and impaired cerebrovascular function may be a basis for associated neurologic injury during or after hypothermic cardiopulmonary bypass.

Open label trial of the efficacy and tolerability of Lamisil (Terbinafine) 500 mg once daily in the treatment of onychomycosis due to candida

An open label trial of Lamisil (Terbinafine) 500 mg daily for 16 weeks was conducted on 20 patients with Onychomycosis due to candida. Of these, 15 patients could complete the trial. Total number of target nails infected was 21. The follow-up period was from 16 to 52 weeks. At 16 weeks, 71% cases showed clinical improvement and 67% had mycological cure. Thirty-three percent had complete cure at 52 weeks. The results show that Terbinafine is effective against candida but requires a longer duration of treatment. The drug was well tolerated.

Cutaneous manifestations of systemic lupus erythematosus: study from Lahore, Pakistan

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disorder in which cutaneous lesions occur in 85% of patients. This study from Lahore, Pakistan, was conducted to determine the pattern and incidence of such lesions in SLE.

METHODS

Forty patients with SLE fulfilling the clinical and laboratory criteria of the American Rheumatism Association (ARA) (1982) were examined between October 1992 and September 1993 for the presence of cutaneous manifestations.

RESULTS

Skin changes noted were: noncicatricial diffuse alopecia (82.5%), malar rash (60%), mucosal lesions (60%), discoid eruption (57.5%), photosensitivity (60%), nail involvement (55%), vascular lesions (50%), pruritus (45%), and pigmentary changes (37.5%). Peripheral gangrene, chronic ulcers, Raynaud's phenomenon, urticaria, chilblains, thrombophlebitis, palmar erythema, and erythema multiforme were rare. Antinuclear antibody reaction was positive in 80% and anti-dSDNA antibodies in 70%.

CONCLUSION

A different clinical pattern was noted in our patients than reported previously.

Aortopulmonary fistula: an uncommon complication in dystrophic aortic aneurysm

Wall dissection is a typical complication in the evolution of Marfan aortic aneurysm and usually is associated with valve regurgitation. Formation of a fistula with adjacent structures is very uncommon. We report the case of a 32-year-old man who presented with the typical features of Marfan's syndrome, with chronic aneurysm of the ascending aorta and acute aortopulmonary fistula. Diagnosis was made preoperatively by aortography; operation was performed successfully. A review of the literature only shows a few cases of aortopulmonary fistula in atherosclerotic, syphilitic, or postendocarditis disease.

Acute myocarditis presenting as acute myocardial infarction

Myocarditis, often caused by an infectious agent, may have a presentation mimicking that of acute myocardial infarction. The authors describe a young man who, when first seen in the emergency department, appeared to have an acute myocardial infarction with normal coronary arteries. At autopsy, the histologic findings were diagnostic of active myocarditis, mixed-cell type. Neutrophilic infiltration with microabscess suggested an infectious cause, although the etiology was uncertain. The patient's clinical course, pathologic findings, and several treatment modalities are discussed. The differentiation between acute myocardial infarction and acute myocarditis can be difficult. Electrocardiographic changes and enzyme elevations are common in both. Therefore, clinicians should consider myocarditis in all patients--particularly young patients--with normal coronary arteries and suspected myocardial infarction.

[Value of the posterior route in the surgical treatment of popliteal aneurysm]

The authors report about 4 cases of surgical treatment of popliteal aneurysms through a strictly posterior approach. In all cases, the aneurysm was asymptomatic and diagnosed during the assessment of a controlateral symptomatic popliteal aneurysm that was treated in a conventional manner (exclusion and interposition of a femoropopliteal prosthetic tube through a medial approach). The procedure is carried out with the patient in ventral decubitus, and it consists in a debridement and graft with direct anatomical interposition of a straight PTFE tube. The posterior approach has limitations as it does not allow craniad extension and applies only to sacciform or short fusiform aneurysms the upper pole of which does not extend beyond Hunter's canal. The graft was an 8-mm PTFE straight tube in all 4 cases. All patients had a dynamic bilateral control angiography made and none of them presented with symptoms. Three conventional restorations required later embolectomy for thrombosis of the prosthesis. In our opinion, the use of the posterior approach for the surgery of popliteal aneurysm is appealing-provided strict criteria (aneurysm size, scheduled surgery, prosthesis) are complied with--as it reduces morbidity, restores the anatomical course and allows reducing the rate of postoperative thrombosis, thus ensuring better long-term patency.