Cardiac implantable electrical devices in patients with hypertrophic cardiomyopathy: single center implant data extracted from the Swedish pacemaker and ICD registry

Figures & data

Figure 1. Pacemaker and ICD implant numbers per year in HCM patients at the Karolinska University Hospital from 2005 to 2016.

Table 1. Baseline clinical and echocardiographic variables of HCM study population.

Clinical data of HCM population	HCM patients implanted with a pacemaker (n = 70)	HCM patients implanted with an ICD (n = 99)
Age (years)	71 ± 10	53 ± 15*
Male gender [n (%)]	33 (47)	69 (70)*
Cause of death [n (%)]
Heart failure	15 (21)	12 (12)
Sudden cardiac death	5 (7)	6 (6)
Other	14 (20)	6 (6)
Permanent or paroxysmal AF [n (%)]	4 (6)	23 (23)*
Time of follow-up (years)	7.5 ± 3.9	6.0 ± 3.2*
Echocardiographic variables	HCM patients implanted with a pacemaker (n = 49)	HCM patients implanted with an ICD (n = 79)
LV dimensions and systolic function
LVEDV (mL)	73 ± 36	91 ± 35*
LVESV (mL)	26 ± 25	38 ± 30*
LVEF (%)	67 ± 10	61 ± 15*
Septum (mm)	19 ± 3	19 ± 5
Posterior wall (mm)	12 ± 3	12 ± 3
LV diastolic function
E wave velocity (m/s)	0.90 ± 0.34	0.85 ± 0.22
A wave velocity (m/s)	0.93 ± 0.32	0.63 ± 0.28*
E/A ratio	1.0 ± 0.5	1.7 ± 1.1*
Deceleration time (ms)	255 ± 78	207 ± 59*
E slope (m/s^2)	3.7 ± 1.9	5.6 ± 4.5*
E/E' ratio	21.1 ± 10.2	19.8 ± 10.3
LA volume indexed to BSA (mL/m^2)	34 ± 15	44 ± 21*
Mitral regurgitation degree (0–4)	0.9 ± 0.8	0.9 ± 0.7
LVOT maximal velocity (m/s) (at rest or Valsalva)	2.8 ± 1.4	2.1 ± 1.4*
LVOT obstruction [n (%)] (at rest or Valsalva)	23 (47)	20 (25)*

A: late diastolic velocity; AF: atrial fibrillation; BSA: body surface area; E: early diastolic velocity; E': pulsed-wave TDI velocity in early diastole at the septal border of the mitral annulus; HCM: hypertrophic cardiomyopathy; LA: left atrial; LV: left ventricular; LVED: left ventricular end-diastolic volume; LVEF: left ventricular ejection fraction; LVESV: left ventricular end-systolic volume; LVOT: left ventricular outflow tract.

*p<.05 versus HCM patients implanted with a pacemaker.

Figure 2. Distribution of pacemaker (left) and ICD (right) first implants according to patient age in HCM patients referred to the Karolinska University Hospital.

Figure 3. Pacemaker (PM) and ICD first implant distribution in HCM patients according to the device type. For abbreviations see the text.

Table 2. Clinical and echocardiographic variables of obstructive and non-obstructive HCM patients in the pacemaker population with available echo data (n = 49).

	PM patients with obstructive HCM (n = 23)	PM patients with non-obstructive HCM (n = 26)
Clinical data
Age (years)	69 ± 12	73 ± 9
Male gender [n (%)]	10 (43)	16 (59)
Cause of death [n (%)]
Heart failure	3 (13)	7 (26)
Sudden cardiac death	1 (4)	3 (11)
Other	4 (17)	5 (19)
Permanent or paroxysmal AF [n (%)]	1 (4)	2 (7)
Echocardiographic variables
LV dimensions and systolic function
LVEDV (mL)	68 ± 24	78 ± 44
LVEF (%)	70 ± 5	65 ± 12
Septum (mm)	19 ± 3	18 ± 4
LV diastolic function
E/A ratio	1.0 ± 0.7	1.0 ± 0.3
Deceleration time (ms)	263 ± 67	247 ± 90
E/E' ratio	20.0 ± 5.0	22.4 ± 14.0
LA volume indexed to BSA (mL/m^2)	33 ± 15	35 ± 15
LVOT maximal velocity (m/s)  (at rest or Valsalva)	4.0 ± 1.1	1.7 ± 0.5*
LVOT gradient (mmHg)  (at rest or Valsalva)	69 ± 41	12 ± 7*

For abbreviations, see Table 1.

*p<.05 versus pacemaker patients with obstructive HCM.

Table 3. Clinical and echocardiographic variables of HCM patients with primary and secondary preventive ICD.

	HCM patients with primary preventive ICD	HCM patients with secondary preventive ICD
Clinical data	(n = 65)	(n = 34)
Age (years)	53 ± 16	54 ± 14
Male gender (n (%))	46 (71)	23 (68)
Cause of death (n (%))
Heart failure	10 (15)	2 (6)
Sudden cardiac death	3 (5)	3 (9)
Other	5 (8)	1 (3)
Permanent or paroxysmal AF (n (%))	14 (22)	9 (26)
Echocardiographic variables	(n = 53)	(n = 26)
LV dimensions and systolic function
LVEDV (mL)	88 ± 37	97 ± 31
LVEF (%)	61 ± 15	61 ± 16
Septum (mm)	20 ± 6	18 ± 5
LV diastolic function
E/A ratio	1.7 ± 1.1	1.7 ± 1.0
Deceleration time (ms)	199 ± 60	224 ± 56
E/E' ratio	20.8 ± 10.8	17.3 ± 8.7
LA volume indexed to BSA (mL/m^2)	44 ± 21	45 ± 22
LVOT maximal velocity (m/s)  (at rest or Valsalva)	2.0 ± 1.2	2.4 ± 1.7

For abbreviations, see Table 1.

Figure 4. Kaplan–Meier survival estimates (upper part) in pacemaker (left) and ICD (right) patients, respectively. In the lower part, probability of death at different years from pacemaker (left) and ICD (right) implant according to clinical etiology. HF: heart failure; SCD: sudden cardiac death.

Table 4. Long-term survival estimates for pacemaker and ICD patients with HCM.

Time (years)	n at risk	Estimated survival	Lower 95% CI	Upper 95% CI
PM
6	43	0.67	0.57	0.79
8	35	0.59	0.48	0.72
10	24	0.52	0.41	0.66
ICD
6	42	0.76	0.67	0.86
8	25	0.69	0.59	0.81
10	15	0.66	0.55	0.79

Table 5. Univariable models investigating how each individual variable affects survival for the PM group and the ICD group, separately.

	Coef	HR	SE (coef)	z value	p value	Lower 95% CI	Upper 95% CI
PM
Man (ref = woman)	0.07	1.07	0.34	0.21	0.832	0.55	2.08
Age group – [10,53]	–17.67	0.00	5646.31	0.00	0.998	0.00	Inf
Age group – [53,64]	0.03	1.03	0.69	0.05	0.963	0.27	4.02
Age group – [72,89]	0.82	2.27	0.43	1.90	0.057	0.98	5.28
Age at implant	0.07	1.07	0.02	3.25	0.001	1.03	1.12
Alcohol ablation – yes	–0.87	0.42	0.53	–1.64	0.100	0.15	1.18
Rythm–atrial fibrillation	–0.14	0.87	0.73	–0.19	0.848	0.21	3.63
ICD
Man (ref = woman)	0.28	1.33	0.44	0.63	0.526	0.56	3.16
Age group – [10,53]	–2.20	0.11	0.69	–3.19	0.001	0.03	0.43
Age group – [53,64]	–0.79	0.45	0.49	–1.59	0.112	0.17	1.20
Age group – [72,89]	0.97	2.63	0.55	1.76	0.078	0.90	7.69
Age at implant	0.10	1.11	0.02	4.46	0.000	1.06	1.16
Alcohol ablation – yes	–1.65	0.19	1.02	–1.62	0.105	0.03	1.41
Rythm–atrial fibrillation	0.55	1.73	0.44	1.24	0.216	0.73	4.12

The independent prognostic variables analysed in the model were gender, age, alcohol ablation, and atrial fibrillation (first column). For each variable, the results of the statistical model are summarised in the corresponding row in terms of significance (p-value), Hazard ratio (HR) and 95% confidence interval (CI) for HR; results are commented in the text.