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Clinical presentation of supraventricular tachycardia in the elderly
Heart,
Lung
and Circulation
2000; 9
ABLATION OF THE CONNECTIONS BETWEEN THE LEFT AND RIGHT ATRIUM GUIDED BY ELECTROANATOMIC MAPPING: EFFECTS ON PERPETUATION OF ATRIAL FIBRILLATION. DP.0. s University of California, San Francisco, USA. Introduction 6 Methods: Bachmann’s bundle (BB) and the coronary sinus (CS) musculature are important electrical connections between the lefl (LA) and rigM atrium @?A) and may be involved in the maintenance of atrial fibrillation (AF). We hypothesized that right&ted ablation of 88 and the proximal CS cou!d modify transeptal conduction and affecl AF maintenance. In 8 closedchest dogs with chronic AF induced by atria1 pacing at 600 bpm for >3 months, multipolar catheters ware used to determine RA, saptal and LA organization, defibrillation thresholds (DFTs) and sustainability of AF before and after ablation. During sinus rhythm, eledroanatomic (CARTO) mapping of the RA was used 10 identify preferential points of left to right septal breakthrough. After identification of the CS os and high septum (BB) as earliest breakthrough points, CARTOdirectad RF energy was used to ablate the RA insertion of BB. A novel through-the-balloon ultrasound ablation catheter was used to ablate the proximal CS musculature. Resutts: Either ultmsound ablation of the CS or ablation of the RA insertion of BB shied septal breakthrough to the fossa ovalis. Interntrial conduction time increased from 72f13 to 131i12ms (p12Osac) inducad by rapid atrial pacing decreased fmm 94/108 pacing altempls to 39/104 pacing attempts (pcO.01). Ablation resulted in more pmlonged and organized AF cycle lengths at RA (183f27 vs 119flOms), septal(158f27 vs 103Q2ms) and LA sites (157Q8 vs lOOi17ms) (pcO.01). Ventricular cycle length during AF increased from 3-3 to 508i54ms after proximal CS musculature ablation (p
THE FREQUENCY 1000 CONSECUTIVE Charles Hospital,
OF THE BRUGADA ECG ABNORMALITY IN PATIENTS. -in*. S. Boucau Cardiac Sciences Unit. The Prince Brisbane, Qld.
To determine the frequency of the Brugada ECG abnormality we evaluated 1000 consecutive patients referred to our hospital. Standard 12 lead ECGs were performed using the Marquette MAC 8 on 1000 consecutive patients who presented to the Prince Charles Hospital Outpatients Department between the dates of the 1” of September and the 20th of December 1999. Standard ECG settings of lOOhz, 25mm/sec, and lOmm/mV were used and all ECGs were performed in a climate controlled environment. Children below the age of 2 years were excluded as were patients with a history of acute myocardial infarction. The criteria used to define the Brugada ECG abnormality were: 1. A right bundle branch like pattern. 2. Convex ST segment elevation in leads VI-V3. The age range was from 2-99 years. The average age was 54.25 years. The ratio of males to females was 1.64. Country of origin and indigenous status were also examined. ECG findings included: -
Paced Rhythm LBBB-.. ,_-RBBB Normal
2 patient’s ECGs satisfied the specified criteria for the Brugada ECG abnormality. Both of these had congenital heart abnormalities and had undergone surgical correction. Conclusions: The incidence of the Brugada ECG abnormality in cardiac patients referred for 12 lead ECGs is infrequent (0.2%).
48th Annual
Scientific
Meeting
of CSANZ
A147
LESIONS SUITABLE FOR ATRIAL AND VENTRICULAR ABLATION CAN BE PRODUCED WITH A SINGLE NOVEL + + MICROWAVE ANTENNA DJR Guv*. HM Chlu . AS Mphgn,sE Toomas. Department of Cardiology, Westmead Hospital and ‘Telecoms Group, Faculty of Engineering, University of Technology, Sydney. Antenna design is a cribcal factor for efficient coupling of microwave energy to the myocardium for ablation. Using finite difference time domain antenna modelling we designed a novel array antenna and tested Its performance in a tissue phantom gel. The radiated field appeared suitable for long linear atrial ablation and deep ventricula ablation.. The array was constructed t?om 2.2mm diameter high energy cable. The effect of power and duration of ablation on lesion size was investigated to determine if this army would be suitable for creating transmural lesions in atria1 or ventricular myocardium. Under anaesthesia hearts and blood were removed from 8 sheep. The hearts were mounted in a perspex chamber and superfUsed with the heparinised oxygenated blood with a flow rate of 3l/min, the temperature maintained at 37 degrees Celsius. 4 lesions were created on the left ventricular endocardial surface in each of 8 hearts. The lesions were stained with nitroblue tetrazolium, sectioned at the mid point of the lesion, digitally photographed and measured with Scion image software. Depth (mm) Width (mm) Width/depth SOW 15 set 2.9+1-2.2 3.6+/-2.6 l.l+/-0.9 50W 30 set 4.1+1-2.7 4.3+1-3.5 0.8+/-0.5 1OOW 15 set 3.9+/-2.6 6.4+/-3.4 1.6~.0.9 1OOW 30 set ) 7.7+/.1.85 1 10.9+/-2.6 1 l.S+/-0.3 There was no surface chanine or crater formation. Lesions were deener (p=O.O12) and wider @~O.OO&) with higher power settings. Longerhuration of ablation produced deeper @=O.OOS) and wider @=0.027) lesions. The width/depth ratio increased with power @0.016) but not duration (p=O.37). In relatively short time periods this novel array antenna produced lesions of sufficient depth for transmural ahial, and in some cases transmural ventricular ablation. Varying the power used and the duration of the ablation has a significant effect on lesion size.
CLINICAL PRESENTATION OF sUPRAvENTRIcuLAR TACHYCARDIA IN THE ELDERLY. mls*. P Hereford-Ashlev, N Bu~X&K&..YZ~II and J W L.&h. Department of Cardiovascular Medicine, John Hunter Hospital, Newcastle. Aim: To characterise the clinical presentation of elderly patients undergoing electrophysiology study (EPS) for supraventricular tachycardia (SVT). Method: 33 patients older than 70 years were studied. Clinical records and EPS results were compared to 35 consecutive patients younger than 70 years undergoing EPS for SVT. Results: Mean age in the groups was 75+/-4 and 47+/-12 years. Older patients were more likely to be male (43% v 26%) and have cardiovascular disease with coronary artery disease (17% v 3%), left ventricular systolic dysfunction (13% v 0) and cerebrovascular disease (13% v 0). Older patients were more likely to receive class I antiarrhythmlc agents (19% v 6%). The cycle length of the clinical tachycardia was similar in both groups (361+1-25 v 352+/-30 msec ). Older patients experienced more syncope (33% v 6%), less palpitations (70% v 83%) and less dyspnoea (0 v 20%). There was no difference between groups with regard to investigations performed prior to EPS. At EPS, older patients were more likely to have atria1 tachycardia (33% v 17%) and less accessory pathway mediated tachycardia (9% v 23%). The predominant tachycardia induced in both groups was atrioventricular nodal reentrant tachycardia (AVNRT) (64% v 63%). Mean tachycardia cycle length was similar (320+/-63 v 323+/-78 msec). Catheter ablation was performed in 84% patients. Older patients were more likely to proceed to AV nodal ablation with pacemaker implantation (15% v 0). Ablation was equally successful in both groups (98%) with no increase in complication rate in the elderly (3%). Conclusion: Elderly patients with SVT more commonly present with syncope and are less likely to experience palpitations than younger patients. While atria1 tachycardia is more common in older patients, AV node reentrant tachycardia remains the predominant tachycatdia and catheter ablation is generally safe and effective.
Lung
and Circulation
2000; 9
ABLATION OF THE CONNECTIONS BETWEEN THE LEFT AND RIGHT ATRIUM GUIDED BY ELECTROANATOMIC MAPPING: EFFECTS ON PERPETUATION OF ATRIAL FIBRILLATION. DP.0. s University of California, San Francisco, USA. Introduction 6 Methods: Bachmann’s bundle (BB) and the coronary sinus (CS) musculature are important electrical connections between the lefl (LA) and rigM atrium @?A) and may be involved in the maintenance of atrial fibrillation (AF). We hypothesized that right&ted ablation of 88 and the proximal CS cou!d modify transeptal conduction and affecl AF maintenance. In 8 closedchest dogs with chronic AF induced by atria1 pacing at 600 bpm for >3 months, multipolar catheters ware used to determine RA, saptal and LA organization, defibrillation thresholds (DFTs) and sustainability of AF before and after ablation. During sinus rhythm, eledroanatomic (CARTO) mapping of the RA was used 10 identify preferential points of left to right septal breakthrough. After identification of the CS os and high septum (BB) as earliest breakthrough points, CARTOdirectad RF energy was used to ablate the RA insertion of BB. A novel through-the-balloon ultrasound ablation catheter was used to ablate the proximal CS musculature. Resutts: Either ultmsound ablation of the CS or ablation of the RA insertion of BB shied septal breakthrough to the fossa ovalis. Interntrial conduction time increased from 72f13 to 131i12ms (p
THE FREQUENCY 1000 CONSECUTIVE Charles Hospital,
OF THE BRUGADA ECG ABNORMALITY IN PATIENTS. -in*. S. Boucau Cardiac Sciences Unit. The Prince Brisbane, Qld.
To determine the frequency of the Brugada ECG abnormality we evaluated 1000 consecutive patients referred to our hospital. Standard 12 lead ECGs were performed using the Marquette MAC 8 on 1000 consecutive patients who presented to the Prince Charles Hospital Outpatients Department between the dates of the 1” of September and the 20th of December 1999. Standard ECG settings of lOOhz, 25mm/sec, and lOmm/mV were used and all ECGs were performed in a climate controlled environment. Children below the age of 2 years were excluded as were patients with a history of acute myocardial infarction. The criteria used to define the Brugada ECG abnormality were: 1. A right bundle branch like pattern. 2. Convex ST segment elevation in leads VI-V3. The age range was from 2-99 years. The average age was 54.25 years. The ratio of males to females was 1.64. Country of origin and indigenous status were also examined. ECG findings included: -
Paced Rhythm LBBB-.. ,_-RBBB Normal
2 patient’s ECGs satisfied the specified criteria for the Brugada ECG abnormality. Both of these had congenital heart abnormalities and had undergone surgical correction. Conclusions: The incidence of the Brugada ECG abnormality in cardiac patients referred for 12 lead ECGs is infrequent (0.2%).
48th Annual
Scientific
Meeting
of CSANZ
A147
LESIONS SUITABLE FOR ATRIAL AND VENTRICULAR ABLATION CAN BE PRODUCED WITH A SINGLE NOVEL + + MICROWAVE ANTENNA DJR Guv*. HM Chlu . AS Mphgn,sE Toomas. Department of Cardiology, Westmead Hospital and ‘Telecoms Group, Faculty of Engineering, University of Technology, Sydney. Antenna design is a cribcal factor for efficient coupling of microwave energy to the myocardium for ablation. Using finite difference time domain antenna modelling we designed a novel array antenna and tested Its performance in a tissue phantom gel. The radiated field appeared suitable for long linear atrial ablation and deep ventricula ablation.. The array was constructed t?om 2.2mm diameter high energy cable. The effect of power and duration of ablation on lesion size was investigated to determine if this army would be suitable for creating transmural lesions in atria1 or ventricular myocardium. Under anaesthesia hearts and blood were removed from 8 sheep. The hearts were mounted in a perspex chamber and superfUsed with the heparinised oxygenated blood with a flow rate of 3l/min, the temperature maintained at 37 degrees Celsius. 4 lesions were created on the left ventricular endocardial surface in each of 8 hearts. The lesions were stained with nitroblue tetrazolium, sectioned at the mid point of the lesion, digitally photographed and measured with Scion image software. Depth (mm) Width (mm) Width/depth SOW 15 set 2.9+1-2.2 3.6+/-2.6 l.l+/-0.9 50W 30 set 4.1+1-2.7 4.3+1-3.5 0.8+/-0.5 1OOW 15 set 3.9+/-2.6 6.4+/-3.4 1.6~.0.9 1OOW 30 set ) 7.7+/.1.85 1 10.9+/-2.6 1 l.S+/-0.3 There was no surface chanine or crater formation. Lesions were deener (p=O.O12) and wider @~O.OO&) with higher power settings. Longerhuration of ablation produced deeper @=O.OOS) and wider @=0.027) lesions. The width/depth ratio increased with power @0.016) but not duration (p=O.37). In relatively short time periods this novel array antenna produced lesions of sufficient depth for transmural ahial, and in some cases transmural ventricular ablation. Varying the power used and the duration of the ablation has a significant effect on lesion size.
CLINICAL PRESENTATION OF sUPRAvENTRIcuLAR TACHYCARDIA IN THE ELDERLY. mls*. P Hereford-Ashlev, N Bu~X&K&..YZ~II and J W L.&h. Department of Cardiovascular Medicine, John Hunter Hospital, Newcastle. Aim: To characterise the clinical presentation of elderly patients undergoing electrophysiology study (EPS) for supraventricular tachycardia (SVT). Method: 33 patients older than 70 years were studied. Clinical records and EPS results were compared to 35 consecutive patients younger than 70 years undergoing EPS for SVT. Results: Mean age in the groups was 75+/-4 and 47+/-12 years. Older patients were more likely to be male (43% v 26%) and have cardiovascular disease with coronary artery disease (17% v 3%), left ventricular systolic dysfunction (13% v 0) and cerebrovascular disease (13% v 0). Older patients were more likely to receive class I antiarrhythmlc agents (19% v 6%). The cycle length of the clinical tachycardia was similar in both groups (361+1-25 v 352+/-30 msec ). Older patients experienced more syncope (33% v 6%), less palpitations (70% v 83%) and less dyspnoea (0 v 20%). There was no difference between groups with regard to investigations performed prior to EPS. At EPS, older patients were more likely to have atria1 tachycardia (33% v 17%) and less accessory pathway mediated tachycardia (9% v 23%). The predominant tachycardia induced in both groups was atrioventricular nodal reentrant tachycardia (AVNRT) (64% v 63%). Mean tachycardia cycle length was similar (320+/-63 v 323+/-78 msec). Catheter ablation was performed in 84% patients. Older patients were more likely to proceed to AV nodal ablation with pacemaker implantation (15% v 0). Ablation was equally successful in both groups (98%) with no increase in complication rate in the elderly (3%). Conclusion: Elderly patients with SVT more commonly present with syncope and are less likely to experience palpitations than younger patients. While atria1 tachycardia is more common in older patients, AV node reentrant tachycardia remains the predominant tachycatdia and catheter ablation is generally safe and effective.