The Effects of QRS Duration and Pacing Sites on the Acute Hemodynamic Changes during Right Ventricular Pacing

BACKGROUND: Has been reported that patients exhibiting prolonged paced QRS duration tend to have more serious heart disease, and the paced QRS duration can be an effective indicator of impaired left ventricular function. However, the acute and chronic hemodynamic effects of paced QRS duration and pacing sites during right ventricular (RV) pacing remain unknown. METHODS: A total of 14 patients who underwent electrophysiologic study for paroxysmal supraventricular tachycardia were examined. RV pacing was performed at 10 different sites with cycle lengths of 600 ms and 500 ms utilizing a 6-7F deflectable quadripolar electrode catheter. Systolic, diastolic, and mean blood pressures during pacing were measured once the blood pressure was stabilized. RESULTS: During RV pacing, blood pressures (systolic/diastolic/mean) decreased. The change of post-pacing QRS duration and pre-pacing the systolic blood pressure (SBP) were greater in the group with paced QRS duration. The differences overall were greater than 140 ms. The SBP decrease during pacing was larger in the group exhibiting paced QRS duration of greater than 140 ms. The SBP decrease during pacing showed relation to QRS duration during pacing (r=0.500, p=0.001), the change of QRS duration post-pacing (r=0.426, p=0.001), and SBP during sinus rhythm (r=0.342, p=0.001) on linear correlation analysis. The pacing site, on the other hand, did not affect acute hemodynamic changes during pacing. CONCLUSION: Ventricular pacing of less than 40 ms at the area of paced QRS duration is recommended.

The effects of QRS duration and pacing sites on the acute hemodynamic change during right ventricular pacing / 대한내과학회지

BACKGROUND: Intraventricular conduction disturbances, as manifested by increased QRS duration, are common in patients with advanced left ventricular (LV) dysfunction and adversely affect LV systolic and diastolic function. It has been reported that the patients with prolonged paced QRS duration have more serious heart disease, and the paced QRS duration can be a useful indicator of impaired LV function. Hemodynamic effects of paced QRS duration and pacing site during right ventricular (RV) pacing are unknown. METHODS: A total of 14 patients who underwent electrophysiologic study for paroxysmal supraventricular tachycardia at Chonnam National University Hospital were examined. All the patients had no structural heart disease. RV pacing was performed at 10 different sites with cycle length of 600 ms and 500 ms using a 6-7F deflectable quadripolar electrode catheter (Livewire, St. Jude Medical, Minneapolis, MN, USA). Systolic, diastolic, and mean blood pressures were measured after stabilization of blood pressure during pacing. RESULTS: Blood pressures (systolic/diastolic/mean) decreased from 146 +/- 31/95 +/- 28/125 +/- 23 mmHg to 128 +/- 33/80 +/- 25/107 +/- 20 mmHg, respectively. The change of QRS duration during pacing and the systolic blood pressure (SBP) before pacing were higher in the group with paced QRS duration greater than 140 msec (59.1 +/- 13.6 msec vs 84.9 +/- 18.7 msec, 141 +/- 30 mmHg vs 152 +/- 38 mmHg, p<0.001, p=0.011, respectively). The decrease of SBP during pacing was higher in the group with paced QRS duration greater than 140 msec (13 +/- 11 mmHg vs 24 +/- 14 mmHg, p=0.009). The decrease of SBP during pacing was related with QRS duration during pacing (r=0.500, p=0.001), the change of QRS duration during pacing (r=0.426, p=0.001), and SBP during sinus rhythm (r=0.342, p=0.001) on linear correlation analysis. Pacing site, however, did not affect acute hemodynamic change during pacing. The independent factors associated with the decrease of SBP during pacing were SBP before pacing and QRS duration during pacing. CONCLUSION: We concluded that acute deleterious hemodynamic effects of RV pacing are related with paced QRS duration but not with pacing site. Ventricuar pacing at the area of paced QRS duration less than 140 msec is recommended particularly in high risk patients.

Late Local Urticaria as a Long-term Sequela of Allergen-Specific Immunotherapy

Local reaction to allergen-specific immunotherapy (SIT) usually appears within 30 minutes, but cases with exercise-induced urticaria at the SIT site 2-3 weeks after the last allergen injection have been reported. A 28-year-old man was treated with house dust mite-SIT for 5 years, due to asthma when he was an 11-year-old boy. On a treadmill exercise test for 50 minutes, erythema, swelling, and pruritus occurred at the SIT site, which lasted for one hour. There was no evidence of complement activation, and the skin biopsy specimens showed no apparent difference between the lesion and normal sites in the distribution of inflammatory cells and in mast cell degranulation. However, the morphine, but not the histamine, skin test responses were increased after the exercise. There must be a remaining long-term sequela of the SIT, including an increased releasability of mast cells, even after more than 10 years.